1 | /* ---------- To make a malloc.h, start cutting here ------------ */ |
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2 | |
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3 | /* |
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4 | A version of malloc/free/realloc written by Doug Lea and released to the |
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5 | public domain. Send questions/comments/complaints/performance data |
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6 | to dl@cs.oswego.edu |
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7 | |
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8 | * VERSION 2.6.6 Sun Mar 5 19:10:03 2000 Doug Lea (dl at gee) |
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9 | |
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10 | Note: There may be an updated version of this malloc obtainable at |
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11 | ftp://g.oswego.edu/pub/misc/malloc.c |
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12 | Check before installing! |
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13 | |
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14 | * Why use this malloc? |
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15 | |
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16 | This is not the fastest, most space-conserving, most portable, or |
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17 | most tunable malloc ever written. However it is among the fastest |
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18 | while also being among the most space-conserving, portable and tunable. |
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19 | Consistent balance across these factors results in a good general-purpose |
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20 | allocator. For a high-level description, see |
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21 | http://g.oswego.edu/dl/html/malloc.html |
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22 | |
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23 | * Synopsis of public routines |
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24 | |
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25 | (Much fuller descriptions are contained in the program documentation below.) |
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26 | |
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27 | malloc(size_t n); |
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28 | Return a pointer to a newly allocated chunk of at least n bytes, or null |
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29 | if no space is available. |
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30 | free(Void_t* p); |
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31 | Release the chunk of memory pointed to by p, or no effect if p is null. |
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32 | realloc(Void_t* p, size_t n); |
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33 | Return a pointer to a chunk of size n that contains the same data |
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34 | as does chunk p up to the minimum of (n, p's size) bytes, or null |
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35 | if no space is available. The returned pointer may or may not be |
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36 | the same as p. If p is null, equivalent to malloc. Unless the |
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37 | #define REALLOC_ZERO_BYTES_FREES below is set, realloc with a |
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38 | size argument of zero (re)allocates a minimum-sized chunk. |
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39 | memalign(size_t alignment, size_t n); |
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40 | Return a pointer to a newly allocated chunk of n bytes, aligned |
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41 | in accord with the alignment argument, which must be a power of |
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42 | two. |
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43 | valloc(size_t n); |
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44 | Equivalent to memalign(pagesize, n), where pagesize is the page |
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45 | size of the system (or as near to this as can be figured out from |
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46 | all the includes/defines below.) |
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47 | pvalloc(size_t n); |
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48 | Equivalent to valloc(minimum-page-that-holds(n)), that is, |
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49 | round up n to nearest pagesize. |
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50 | calloc(size_t unit, size_t quantity); |
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51 | Returns a pointer to quantity * unit bytes, with all locations |
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52 | set to zero. |
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53 | cfree(Void_t* p); |
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54 | Equivalent to free(p). |
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55 | malloc_trim(size_t pad); |
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56 | Release all but pad bytes of freed top-most memory back |
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57 | to the system. Return 1 if successful, else 0. |
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58 | malloc_usable_size(Void_t* p); |
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59 | Report the number usable allocated bytes associated with allocated |
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60 | chunk p. This may or may not report more bytes than were requested, |
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61 | due to alignment and minimum size constraints. |
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62 | malloc_stats(); |
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63 | Prints brief summary statistics on stderr. |
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64 | mallinfo() |
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65 | Returns (by copy) a struct containing various summary statistics. |
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66 | mallopt(int parameter_number, int parameter_value) |
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67 | Changes one of the tunable parameters described below. Returns |
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68 | 1 if successful in changing the parameter, else 0. |
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69 | |
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70 | * Vital statistics: |
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71 | |
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72 | Alignment: 8-byte |
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73 | 8 byte alignment is currently hardwired into the design. This |
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74 | seems to suffice for all current machines and C compilers. |
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75 | |
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76 | Assumed pointer representation: 4 or 8 bytes |
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77 | Code for 8-byte pointers is untested by me but has worked |
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78 | reliably by Wolfram Gloger, who contributed most of the |
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79 | changes supporting this. |
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80 | |
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81 | Assumed size_t representation: 4 or 8 bytes |
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82 | Note that size_t is allowed to be 4 bytes even if pointers are 8. |
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83 | |
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84 | Minimum overhead per allocated chunk: 4 or 8 bytes |
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85 | Each malloced chunk has a hidden overhead of 4 bytes holding size |
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86 | and status information. |
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87 | |
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88 | Minimum allocated size: 4-byte ptrs: 16 bytes (including 4 overhead) |
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89 | 8-byte ptrs: 24/32 bytes (including, 4/8 overhead) |
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90 | |
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91 | When a chunk is freed, 12 (for 4byte ptrs) or 20 (for 8 byte |
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92 | ptrs but 4 byte size) or 24 (for 8/8) additional bytes are |
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93 | needed; 4 (8) for a trailing size field |
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94 | and 8 (16) bytes for free list pointers. Thus, the minimum |
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95 | allocatable size is 16/24/32 bytes. |
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96 | |
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97 | Even a request for zero bytes (i.e., malloc(0)) returns a |
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98 | pointer to something of the minimum allocatable size. |
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99 | |
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100 | Maximum allocated size: 4-byte size_t: 2^31 - 8 bytes |
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101 | 8-byte size_t: 2^63 - 16 bytes |
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102 | |
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103 | It is assumed that (possibly signed) size_t bit values suffice to |
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104 | represent chunk sizes. `Possibly signed' is due to the fact |
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105 | that `size_t' may be defined on a system as either a signed or |
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106 | an unsigned type. To be conservative, values that would appear |
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107 | as negative numbers are avoided. |
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108 | Requests for sizes with a negative sign bit when the request |
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109 | size is treaded as a long will return null. |
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110 | |
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111 | Maximum overhead wastage per allocated chunk: normally 15 bytes |
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112 | |
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113 | Alignnment demands, plus the minimum allocatable size restriction |
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114 | make the normal worst-case wastage 15 bytes (i.e., up to 15 |
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115 | more bytes will be allocated than were requested in malloc), with |
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116 | two exceptions: |
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117 | 1. Because requests for zero bytes allocate non-zero space, |
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118 | the worst case wastage for a request of zero bytes is 24 bytes. |
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119 | 2. For requests >= mmap_threshold that are serviced via |
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120 | mmap(), the worst case wastage is 8 bytes plus the remainder |
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121 | from a system page (the minimal mmap unit); typically 4096 bytes. |
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122 | |
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123 | * Limitations |
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124 | |
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125 | Here are some features that are NOT currently supported |
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126 | |
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127 | * No user-definable hooks for callbacks and the like. |
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128 | * No automated mechanism for fully checking that all accesses |
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129 | to malloced memory stay within their bounds. |
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130 | * No support for compaction. |
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131 | |
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132 | * Synopsis of compile-time options: |
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133 | |
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134 | People have reported using previous versions of this malloc on all |
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135 | versions of Unix, sometimes by tweaking some of the defines |
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136 | below. It has been tested most extensively on Solaris and |
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137 | Linux. It is also reported to work on WIN32 platforms. |
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138 | People have also reported adapting this malloc for use in |
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139 | stand-alone embedded systems. |
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140 | |
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141 | The implementation is in straight, hand-tuned ANSI C. Among other |
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142 | consequences, it uses a lot of macros. Because of this, to be at |
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143 | all usable, this code should be compiled using an optimizing compiler |
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144 | (for example gcc -O2) that can simplify expressions and control |
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145 | paths. |
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146 | |
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147 | __STD_C (default: derived from C compiler defines) |
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148 | Nonzero if using ANSI-standard C compiler, a C++ compiler, or |
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149 | a C compiler sufficiently close to ANSI to get away with it. |
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150 | DEBUG (default: NOT defined) |
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151 | Define to enable debugging. Adds fairly extensive assertion-based |
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152 | checking to help track down memory errors, but noticeably slows down |
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153 | execution. |
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154 | REALLOC_ZERO_BYTES_FREES (default: NOT defined) |
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155 | Define this if you think that realloc(p, 0) should be equivalent |
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156 | to free(p). Otherwise, since malloc returns a unique pointer for |
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157 | malloc(0), so does realloc(p, 0). |
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158 | HAVE_MEMCPY (default: defined) |
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159 | Define if you are not otherwise using ANSI STD C, but still |
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160 | have memcpy and memset in your C library and want to use them. |
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161 | Otherwise, simple internal versions are supplied. |
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162 | USE_MEMCPY (default: 1 if HAVE_MEMCPY is defined, 0 otherwise) |
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163 | Define as 1 if you want the C library versions of memset and |
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164 | memcpy called in realloc and calloc (otherwise macro versions are used). |
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165 | At least on some platforms, the simple macro versions usually |
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166 | outperform libc versions. |
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167 | HAVE_MMAP (default: defined as 1) |
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168 | Define to non-zero to optionally make malloc() use mmap() to |
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169 | allocate very large blocks. |
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170 | HAVE_MREMAP (default: defined as 0 unless Linux libc set) |
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171 | Define to non-zero to optionally make realloc() use mremap() to |
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172 | reallocate very large blocks. |
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173 | malloc_getpagesize (default: derived from system #includes) |
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174 | Either a constant or routine call returning the system page size. |
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175 | HAVE_USR_INCLUDE_MALLOC_H (default: NOT defined) |
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176 | Optionally define if you are on a system with a /usr/include/malloc.h |
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177 | that declares struct mallinfo. It is not at all necessary to |
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178 | define this even if you do, but will ensure consistency. |
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179 | INTERNAL_SIZE_T (default: size_t) |
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180 | Define to a 32-bit type (probably `unsigned int') if you are on a |
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181 | 64-bit machine, yet do not want or need to allow malloc requests of |
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182 | greater than 2^31 to be handled. This saves space, especially for |
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183 | very small chunks. |
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184 | INTERNAL_LINUX_C_LIB (default: NOT defined) |
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185 | Defined only when compiled as part of Linux libc. |
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186 | Also note that there is some odd internal name-mangling via defines |
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187 | (for example, internally, `malloc' is named `mALLOc') needed |
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188 | when compiling in this case. These look funny but don't otherwise |
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189 | affect anything. |
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190 | WIN32 (default: undefined) |
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191 | Define this on MS win (95, nt) platforms to compile in sbrk emulation. |
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192 | LACKS_UNISTD_H (default: undefined if not WIN32) |
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193 | Define this if your system does not have a <unistd.h>. |
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194 | LACKS_SYS_PARAM_H (default: undefined if not WIN32) |
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195 | Define this if your system does not have a <sys/param.h>. |
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196 | MORECORE (default: sbrk) |
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197 | The name of the routine to call to obtain more memory from the system. |
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198 | MORECORE_FAILURE (default: -1) |
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199 | The value returned upon failure of MORECORE. |
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200 | MORECORE_CLEARS (default 1) |
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201 | True (1) if the routine mapped to MORECORE zeroes out memory (which |
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202 | holds for sbrk). |
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203 | DEFAULT_TRIM_THRESHOLD |
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204 | DEFAULT_TOP_PAD |
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205 | DEFAULT_MMAP_THRESHOLD |
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206 | DEFAULT_MMAP_MAX |
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207 | Default values of tunable parameters (described in detail below) |
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208 | controlling interaction with host system routines (sbrk, mmap, etc). |
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209 | These values may also be changed dynamically via mallopt(). The |
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210 | preset defaults are those that give best performance for typical |
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211 | programs/systems. |
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212 | USE_DL_PREFIX (default: undefined) |
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213 | Prefix all public routines with the string 'dl'. Useful to |
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214 | quickly avoid procedure declaration conflicts and linker symbol |
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215 | conflicts with existing memory allocation routines. |
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216 | |
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217 | |
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218 | */ |
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219 | |
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220 | |
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221 | |
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222 | |
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223 | /* Preliminaries */ |
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224 | |
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225 | #ifndef __STD_C |
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226 | #ifdef __STDC__ |
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227 | #define __STD_C 1 |
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228 | #else |
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229 | #if __cplusplus |
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230 | #define __STD_C 1 |
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231 | #else |
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232 | #define __STD_C 0 |
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233 | #endif /*__cplusplus*/ |
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234 | #endif /*__STDC__*/ |
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235 | #endif /*__STD_C*/ |
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236 | |
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237 | #ifndef Void_t |
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238 | #if (__STD_C || defined(WIN32)) |
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239 | #define Void_t void |
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240 | #else |
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241 | #define Void_t char |
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242 | #endif |
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243 | #endif /*Void_t*/ |
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244 | |
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245 | #if __STD_C |
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246 | #include <stddef.h> /* for size_t */ |
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247 | #else |
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248 | #include <sys/types.h> |
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249 | #endif |
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250 | |
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251 | #ifdef __cplusplus |
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252 | extern "C" { |
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253 | #endif |
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254 | |
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255 | #include <stdio.h> /* needed for malloc_stats */ |
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256 | |
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257 | |
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258 | /* |
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259 | Compile-time options |
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260 | */ |
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261 | |
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262 | |
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263 | /* |
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264 | Debugging: |
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265 | |
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266 | Because freed chunks may be overwritten with link fields, this |
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267 | malloc will often die when freed memory is overwritten by user |
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268 | programs. This can be very effective (albeit in an annoying way) |
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269 | in helping track down dangling pointers. |
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270 | |
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271 | If you compile with -DDEBUG, a number of assertion checks are |
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272 | enabled that will catch more memory errors. You probably won't be |
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273 | able to make much sense of the actual assertion errors, but they |
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274 | should help you locate incorrectly overwritten memory. The |
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275 | checking is fairly extensive, and will slow down execution |
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276 | noticeably. Calling malloc_stats or mallinfo with DEBUG set will |
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277 | attempt to check every non-mmapped allocated and free chunk in the |
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278 | course of computing the summmaries. (By nature, mmapped regions |
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279 | cannot be checked very much automatically.) |
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280 | |
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281 | Setting DEBUG may also be helpful if you are trying to modify |
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282 | this code. The assertions in the check routines spell out in more |
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283 | detail the assumptions and invariants underlying the algorithms. |
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284 | |
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285 | */ |
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286 | |
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287 | #if DEBUG |
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288 | #include <assert.h> |
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289 | #else |
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290 | #define assert(x) ((void)0) |
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291 | #endif |
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292 | |
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293 | |
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294 | /* |
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295 | INTERNAL_SIZE_T is the word-size used for internal bookkeeping |
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296 | of chunk sizes. On a 64-bit machine, you can reduce malloc |
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297 | overhead by defining INTERNAL_SIZE_T to be a 32 bit `unsigned int' |
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298 | at the expense of not being able to handle requests greater than |
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299 | 2^31. This limitation is hardly ever a concern; you are encouraged |
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300 | to set this. However, the default version is the same as size_t. |
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301 | */ |
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302 | |
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303 | #ifndef INTERNAL_SIZE_T |
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304 | #define INTERNAL_SIZE_T size_t |
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305 | #endif |
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306 | |
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307 | /* |
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308 | REALLOC_ZERO_BYTES_FREES should be set if a call to |
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309 | realloc with zero bytes should be the same as a call to free. |
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310 | Some people think it should. Otherwise, since this malloc |
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311 | returns a unique pointer for malloc(0), so does realloc(p, 0). |
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312 | */ |
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313 | |
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314 | |
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315 | /* #define REALLOC_ZERO_BYTES_FREES */ |
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316 | |
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317 | |
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318 | /* |
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319 | WIN32 causes an emulation of sbrk to be compiled in |
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320 | mmap-based options are not currently supported in WIN32. |
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321 | */ |
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322 | |
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323 | /* #define WIN32 */ |
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324 | #ifdef WIN32 |
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325 | #define MORECORE wsbrk |
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326 | #define HAVE_MMAP 0 |
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327 | |
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328 | #define LACKS_UNISTD_H |
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329 | #define LACKS_SYS_PARAM_H |
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330 | |
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331 | /* |
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332 | Include 'windows.h' to get the necessary declarations for the |
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333 | Microsoft Visual C++ data structures and routines used in the 'sbrk' |
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334 | emulation. |
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335 | |
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336 | Define WIN32_LEAN_AND_MEAN so that only the essential Microsoft |
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337 | Visual C++ header files are included. |
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338 | */ |
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339 | #define WIN32_LEAN_AND_MEAN |
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340 | #include <windows.h> |
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341 | #endif |
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342 | |
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343 | |
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344 | /* |
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345 | HAVE_MEMCPY should be defined if you are not otherwise using |
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346 | ANSI STD C, but still have memcpy and memset in your C library |
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347 | and want to use them in calloc and realloc. Otherwise simple |
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348 | macro versions are defined here. |
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349 | |
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350 | USE_MEMCPY should be defined as 1 if you actually want to |
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351 | have memset and memcpy called. People report that the macro |
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352 | versions are often enough faster than libc versions on many |
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353 | systems that it is better to use them. |
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354 | |
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355 | */ |
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356 | |
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357 | #define HAVE_MEMCPY |
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358 | |
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359 | #ifndef USE_MEMCPY |
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360 | #ifdef HAVE_MEMCPY |
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361 | #define USE_MEMCPY 1 |
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362 | #else |
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363 | #define USE_MEMCPY 0 |
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364 | #endif |
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365 | #endif |
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366 | |
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367 | #if (__STD_C || defined(HAVE_MEMCPY)) |
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368 | |
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369 | #if __STD_C |
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370 | void* memset(void*, int, size_t); |
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371 | void* memcpy(void*, const void*, size_t); |
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372 | #else |
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373 | #ifdef WIN32 |
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374 | // On Win32 platforms, 'memset()' and 'memcpy()' are already declared in |
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375 | // 'windows.h' |
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376 | #else |
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377 | Void_t* memset(); |
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378 | Void_t* memcpy(); |
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379 | #endif |
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380 | #endif |
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381 | #endif |
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382 | |
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383 | #if USE_MEMCPY |
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384 | |
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385 | /* The following macros are only invoked with (2n+1)-multiples of |
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386 | INTERNAL_SIZE_T units, with a positive integer n. This is exploited |
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387 | for fast inline execution when n is small. */ |
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388 | |
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389 | #define MALLOC_ZERO(charp, nbytes) \ |
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390 | do { \ |
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391 | INTERNAL_SIZE_T mzsz = (nbytes); \ |
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392 | if(mzsz <= 9*sizeof(mzsz)) { \ |
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393 | INTERNAL_SIZE_T* mz = (INTERNAL_SIZE_T*) (charp); \ |
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394 | if(mzsz >= 5*sizeof(mzsz)) { *mz++ = 0; \ |
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395 | *mz++ = 0; \ |
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396 | if(mzsz >= 7*sizeof(mzsz)) { *mz++ = 0; \ |
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397 | *mz++ = 0; \ |
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398 | if(mzsz >= 9*sizeof(mzsz)) { *mz++ = 0; \ |
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399 | *mz++ = 0; }}} \ |
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400 | *mz++ = 0; \ |
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401 | *mz++ = 0; \ |
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402 | *mz = 0; \ |
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403 | } else memset((charp), 0, mzsz); \ |
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404 | } while(0) |
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405 | |
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406 | #define MALLOC_COPY(dest,src,nbytes) \ |
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407 | do { \ |
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408 | INTERNAL_SIZE_T mcsz = (nbytes); \ |
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409 | if(mcsz <= 9*sizeof(mcsz)) { \ |
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410 | INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) (src); \ |
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411 | INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) (dest); \ |
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412 | if(mcsz >= 5*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ |
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413 | *mcdst++ = *mcsrc++; \ |
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414 | if(mcsz >= 7*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ |
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415 | *mcdst++ = *mcsrc++; \ |
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416 | if(mcsz >= 9*sizeof(mcsz)) { *mcdst++ = *mcsrc++; \ |
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417 | *mcdst++ = *mcsrc++; }}} \ |
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418 | *mcdst++ = *mcsrc++; \ |
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419 | *mcdst++ = *mcsrc++; \ |
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420 | *mcdst = *mcsrc ; \ |
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421 | } else memcpy(dest, src, mcsz); \ |
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422 | } while(0) |
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423 | |
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424 | #else /* !USE_MEMCPY */ |
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425 | |
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426 | /* Use Duff's device for good zeroing/copying performance. */ |
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427 | |
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428 | #define MALLOC_ZERO(charp, nbytes) \ |
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429 | do { \ |
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430 | INTERNAL_SIZE_T* mzp = (INTERNAL_SIZE_T*)(charp); \ |
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431 | long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ |
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432 | if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ |
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433 | switch (mctmp) { \ |
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434 | case 0: for(;;) { *mzp++ = 0; \ |
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435 | case 7: *mzp++ = 0; \ |
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436 | case 6: *mzp++ = 0; \ |
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437 | case 5: *mzp++ = 0; \ |
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438 | case 4: *mzp++ = 0; \ |
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439 | case 3: *mzp++ = 0; \ |
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440 | case 2: *mzp++ = 0; \ |
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441 | case 1: *mzp++ = 0; if(mcn <= 0) break; mcn--; } \ |
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442 | } \ |
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443 | } while(0) |
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444 | |
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445 | #define MALLOC_COPY(dest,src,nbytes) \ |
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446 | do { \ |
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447 | INTERNAL_SIZE_T* mcsrc = (INTERNAL_SIZE_T*) src; \ |
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448 | INTERNAL_SIZE_T* mcdst = (INTERNAL_SIZE_T*) dest; \ |
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449 | long mctmp = (nbytes)/sizeof(INTERNAL_SIZE_T), mcn; \ |
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450 | if (mctmp < 8) mcn = 0; else { mcn = (mctmp-1)/8; mctmp %= 8; } \ |
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451 | switch (mctmp) { \ |
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452 | case 0: for(;;) { *mcdst++ = *mcsrc++; \ |
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453 | case 7: *mcdst++ = *mcsrc++; \ |
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454 | case 6: *mcdst++ = *mcsrc++; \ |
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455 | case 5: *mcdst++ = *mcsrc++; \ |
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456 | case 4: *mcdst++ = *mcsrc++; \ |
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457 | case 3: *mcdst++ = *mcsrc++; \ |
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458 | case 2: *mcdst++ = *mcsrc++; \ |
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459 | case 1: *mcdst++ = *mcsrc++; if(mcn <= 0) break; mcn--; } \ |
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460 | } \ |
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461 | } while(0) |
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462 | |
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463 | #endif |
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464 | |
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465 | |
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466 | /* |
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467 | Define HAVE_MMAP to optionally make malloc() use mmap() to |
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468 | allocate very large blocks. These will be returned to the |
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469 | operating system immediately after a free(). |
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470 | */ |
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471 | |
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472 | #ifndef HAVE_MMAP |
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473 | #define HAVE_MMAP 1 |
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474 | #endif |
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475 | |
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476 | /* |
---|
477 | Define HAVE_MREMAP to make realloc() use mremap() to re-allocate |
---|
478 | large blocks. This is currently only possible on Linux with |
---|
479 | kernel versions newer than 1.3.77. |
---|
480 | */ |
---|
481 | |
---|
482 | #ifndef HAVE_MREMAP |
---|
483 | #ifdef INTERNAL_LINUX_C_LIB |
---|
484 | #define HAVE_MREMAP 1 |
---|
485 | #else |
---|
486 | #define HAVE_MREMAP 0 |
---|
487 | #endif |
---|
488 | #endif |
---|
489 | |
---|
490 | #if HAVE_MMAP |
---|
491 | |
---|
492 | #include <unistd.h> |
---|
493 | #include <fcntl.h> |
---|
494 | #include <sys/mman.h> |
---|
495 | |
---|
496 | #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) |
---|
497 | #define MAP_ANONYMOUS MAP_ANON |
---|
498 | #endif |
---|
499 | |
---|
500 | #endif /* HAVE_MMAP */ |
---|
501 | |
---|
502 | /* |
---|
503 | Access to system page size. To the extent possible, this malloc |
---|
504 | manages memory from the system in page-size units. |
---|
505 | |
---|
506 | The following mechanics for getpagesize were adapted from |
---|
507 | bsd/gnu getpagesize.h |
---|
508 | */ |
---|
509 | |
---|
510 | #ifndef LACKS_UNISTD_H |
---|
511 | # include <unistd.h> |
---|
512 | #endif |
---|
513 | |
---|
514 | #ifndef malloc_getpagesize |
---|
515 | # ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */ |
---|
516 | # ifndef _SC_PAGE_SIZE |
---|
517 | # define _SC_PAGE_SIZE _SC_PAGESIZE |
---|
518 | # endif |
---|
519 | # endif |
---|
520 | # ifdef _SC_PAGE_SIZE |
---|
521 | # define malloc_getpagesize sysconf(_SC_PAGE_SIZE) |
---|
522 | # else |
---|
523 | # if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE) |
---|
524 | extern size_t getpagesize(); |
---|
525 | # define malloc_getpagesize getpagesize() |
---|
526 | # else |
---|
527 | # ifdef WIN32 |
---|
528 | # define malloc_getpagesize (4096) /* TBD: Use 'GetSystemInfo' instead */ |
---|
529 | # else |
---|
530 | # ifndef LACKS_SYS_PARAM_H |
---|
531 | # include <sys/param.h> |
---|
532 | # endif |
---|
533 | # ifdef EXEC_PAGESIZE |
---|
534 | # define malloc_getpagesize EXEC_PAGESIZE |
---|
535 | # else |
---|
536 | # ifdef NBPG |
---|
537 | # ifndef CLSIZE |
---|
538 | # define malloc_getpagesize NBPG |
---|
539 | # else |
---|
540 | # define malloc_getpagesize (NBPG * CLSIZE) |
---|
541 | # endif |
---|
542 | # else |
---|
543 | # ifdef NBPC |
---|
544 | # define malloc_getpagesize NBPC |
---|
545 | # else |
---|
546 | # ifdef PAGESIZE |
---|
547 | # define malloc_getpagesize PAGESIZE |
---|
548 | # else |
---|
549 | # define malloc_getpagesize (4096) /* just guess */ |
---|
550 | # endif |
---|
551 | # endif |
---|
552 | # endif |
---|
553 | # endif |
---|
554 | # endif |
---|
555 | # endif |
---|
556 | # endif |
---|
557 | #endif |
---|
558 | |
---|
559 | |
---|
560 | |
---|
561 | /* |
---|
562 | |
---|
563 | This version of malloc supports the standard SVID/XPG mallinfo |
---|
564 | routine that returns a struct containing the same kind of |
---|
565 | information you can get from malloc_stats. It should work on |
---|
566 | any SVID/XPG compliant system that has a /usr/include/malloc.h |
---|
567 | defining struct mallinfo. (If you'd like to install such a thing |
---|
568 | yourself, cut out the preliminary declarations as described above |
---|
569 | and below and save them in a malloc.h file. But there's no |
---|
570 | compelling reason to bother to do this.) |
---|
571 | |
---|
572 | The main declaration needed is the mallinfo struct that is returned |
---|
573 | (by-copy) by mallinfo(). The SVID/XPG malloinfo struct contains a |
---|
574 | bunch of fields, most of which are not even meaningful in this |
---|
575 | version of malloc. Some of these fields are are instead filled by |
---|
576 | mallinfo() with other numbers that might possibly be of interest. |
---|
577 | |
---|
578 | HAVE_USR_INCLUDE_MALLOC_H should be set if you have a |
---|
579 | /usr/include/malloc.h file that includes a declaration of struct |
---|
580 | mallinfo. If so, it is included; else an SVID2/XPG2 compliant |
---|
581 | version is declared below. These must be precisely the same for |
---|
582 | mallinfo() to work. |
---|
583 | |
---|
584 | */ |
---|
585 | |
---|
586 | /* #define HAVE_USR_INCLUDE_MALLOC_H */ |
---|
587 | |
---|
588 | #if HAVE_USR_INCLUDE_MALLOC_H |
---|
589 | #include "/usr/include/malloc.h" |
---|
590 | #else |
---|
591 | |
---|
592 | /* SVID2/XPG mallinfo structure */ |
---|
593 | |
---|
594 | struct mallinfo { |
---|
595 | int arena; /* total space allocated from system */ |
---|
596 | int ordblks; /* number of non-inuse chunks */ |
---|
597 | int smblks; /* unused -- always zero */ |
---|
598 | int hblks; /* number of mmapped regions */ |
---|
599 | int hblkhd; /* total space in mmapped regions */ |
---|
600 | int usmblks; /* unused -- always zero */ |
---|
601 | int fsmblks; /* unused -- always zero */ |
---|
602 | int uordblks; /* total allocated space */ |
---|
603 | int fordblks; /* total non-inuse space */ |
---|
604 | int keepcost; /* top-most, releasable (via malloc_trim) space */ |
---|
605 | }; |
---|
606 | |
---|
607 | /* SVID2/XPG mallopt options */ |
---|
608 | |
---|
609 | #define M_MXFAST 1 /* UNUSED in this malloc */ |
---|
610 | #define M_NLBLKS 2 /* UNUSED in this malloc */ |
---|
611 | #define M_GRAIN 3 /* UNUSED in this malloc */ |
---|
612 | #define M_KEEP 4 /* UNUSED in this malloc */ |
---|
613 | |
---|
614 | #endif |
---|
615 | |
---|
616 | /* mallopt options that actually do something */ |
---|
617 | |
---|
618 | #define M_TRIM_THRESHOLD -1 |
---|
619 | #define M_TOP_PAD -2 |
---|
620 | #define M_MMAP_THRESHOLD -3 |
---|
621 | #define M_MMAP_MAX -4 |
---|
622 | |
---|
623 | |
---|
624 | |
---|
625 | #ifndef DEFAULT_TRIM_THRESHOLD |
---|
626 | #define DEFAULT_TRIM_THRESHOLD (128 * 1024) |
---|
627 | #endif |
---|
628 | |
---|
629 | /* |
---|
630 | M_TRIM_THRESHOLD is the maximum amount of unused top-most memory |
---|
631 | to keep before releasing via malloc_trim in free(). |
---|
632 | |
---|
633 | Automatic trimming is mainly useful in long-lived programs. |
---|
634 | Because trimming via sbrk can be slow on some systems, and can |
---|
635 | sometimes be wasteful (in cases where programs immediately |
---|
636 | afterward allocate more large chunks) the value should be high |
---|
637 | enough so that your overall system performance would improve by |
---|
638 | releasing. |
---|
639 | |
---|
640 | The trim threshold and the mmap control parameters (see below) |
---|
641 | can be traded off with one another. Trimming and mmapping are |
---|
642 | two different ways of releasing unused memory back to the |
---|
643 | system. Between these two, it is often possible to keep |
---|
644 | system-level demands of a long-lived program down to a bare |
---|
645 | minimum. For example, in one test suite of sessions measuring |
---|
646 | the XF86 X server on Linux, using a trim threshold of 128K and a |
---|
647 | mmap threshold of 192K led to near-minimal long term resource |
---|
648 | consumption. |
---|
649 | |
---|
650 | If you are using this malloc in a long-lived program, it should |
---|
651 | pay to experiment with these values. As a rough guide, you |
---|
652 | might set to a value close to the average size of a process |
---|
653 | (program) running on your system. Releasing this much memory |
---|
654 | would allow such a process to run in memory. Generally, it's |
---|
655 | worth it to tune for trimming rather tham memory mapping when a |
---|
656 | program undergoes phases where several large chunks are |
---|
657 | allocated and released in ways that can reuse each other's |
---|
658 | storage, perhaps mixed with phases where there are no such |
---|
659 | chunks at all. And in well-behaved long-lived programs, |
---|
660 | controlling release of large blocks via trimming versus mapping |
---|
661 | is usually faster. |
---|
662 | |
---|
663 | However, in most programs, these parameters serve mainly as |
---|
664 | protection against the system-level effects of carrying around |
---|
665 | massive amounts of unneeded memory. Since frequent calls to |
---|
666 | sbrk, mmap, and munmap otherwise degrade performance, the default |
---|
667 | parameters are set to relatively high values that serve only as |
---|
668 | safeguards. |
---|
669 | |
---|
670 | The default trim value is high enough to cause trimming only in |
---|
671 | fairly extreme (by current memory consumption standards) cases. |
---|
672 | It must be greater than page size to have any useful effect. To |
---|
673 | disable trimming completely, you can set to (unsigned long)(-1); |
---|
674 | |
---|
675 | |
---|
676 | */ |
---|
677 | |
---|
678 | |
---|
679 | #ifndef DEFAULT_TOP_PAD |
---|
680 | #define DEFAULT_TOP_PAD (0) |
---|
681 | #endif |
---|
682 | |
---|
683 | /* |
---|
684 | M_TOP_PAD is the amount of extra `padding' space to allocate or |
---|
685 | retain whenever sbrk is called. It is used in two ways internally: |
---|
686 | |
---|
687 | * When sbrk is called to extend the top of the arena to satisfy |
---|
688 | a new malloc request, this much padding is added to the sbrk |
---|
689 | request. |
---|
690 | |
---|
691 | * When malloc_trim is called automatically from free(), |
---|
692 | it is used as the `pad' argument. |
---|
693 | |
---|
694 | In both cases, the actual amount of padding is rounded |
---|
695 | so that the end of the arena is always a system page boundary. |
---|
696 | |
---|
697 | The main reason for using padding is to avoid calling sbrk so |
---|
698 | often. Having even a small pad greatly reduces the likelihood |
---|
699 | that nearly every malloc request during program start-up (or |
---|
700 | after trimming) will invoke sbrk, which needlessly wastes |
---|
701 | time. |
---|
702 | |
---|
703 | Automatic rounding-up to page-size units is normally sufficient |
---|
704 | to avoid measurable overhead, so the default is 0. However, in |
---|
705 | systems where sbrk is relatively slow, it can pay to increase |
---|
706 | this value, at the expense of carrying around more memory than |
---|
707 | the program needs. |
---|
708 | |
---|
709 | */ |
---|
710 | |
---|
711 | |
---|
712 | #ifndef DEFAULT_MMAP_THRESHOLD |
---|
713 | #define DEFAULT_MMAP_THRESHOLD (128 * 1024) |
---|
714 | #endif |
---|
715 | |
---|
716 | /* |
---|
717 | |
---|
718 | M_MMAP_THRESHOLD is the request size threshold for using mmap() |
---|
719 | to service a request. Requests of at least this size that cannot |
---|
720 | be allocated using already-existing space will be serviced via mmap. |
---|
721 | (If enough normal freed space already exists it is used instead.) |
---|
722 | |
---|
723 | Using mmap segregates relatively large chunks of memory so that |
---|
724 | they can be individually obtained and released from the host |
---|
725 | system. A request serviced through mmap is never reused by any |
---|
726 | other request (at least not directly; the system may just so |
---|
727 | happen to remap successive requests to the same locations). |
---|
728 | |
---|
729 | Segregating space in this way has the benefit that mmapped space |
---|
730 | can ALWAYS be individually released back to the system, which |
---|
731 | helps keep the system level memory demands of a long-lived |
---|
732 | program low. Mapped memory can never become `locked' between |
---|
733 | other chunks, as can happen with normally allocated chunks, which |
---|
734 | menas that even trimming via malloc_trim would not release them. |
---|
735 | |
---|
736 | However, it has the disadvantages that: |
---|
737 | |
---|
738 | 1. The space cannot be reclaimed, consolidated, and then |
---|
739 | used to service later requests, as happens with normal chunks. |
---|
740 | 2. It can lead to more wastage because of mmap page alignment |
---|
741 | requirements |
---|
742 | 3. It causes malloc performance to be more dependent on host |
---|
743 | system memory management support routines which may vary in |
---|
744 | implementation quality and may impose arbitrary |
---|
745 | limitations. Generally, servicing a request via normal |
---|
746 | malloc steps is faster than going through a system's mmap. |
---|
747 | |
---|
748 | All together, these considerations should lead you to use mmap |
---|
749 | only for relatively large requests. |
---|
750 | |
---|
751 | |
---|
752 | */ |
---|
753 | |
---|
754 | |
---|
755 | |
---|
756 | #ifndef DEFAULT_MMAP_MAX |
---|
757 | #if HAVE_MMAP |
---|
758 | #define DEFAULT_MMAP_MAX (64) |
---|
759 | #else |
---|
760 | #define DEFAULT_MMAP_MAX (0) |
---|
761 | #endif |
---|
762 | #endif |
---|
763 | |
---|
764 | /* |
---|
765 | M_MMAP_MAX is the maximum number of requests to simultaneously |
---|
766 | service using mmap. This parameter exists because: |
---|
767 | |
---|
768 | 1. Some systems have a limited number of internal tables for |
---|
769 | use by mmap. |
---|
770 | 2. In most systems, overreliance on mmap can degrade overall |
---|
771 | performance. |
---|
772 | 3. If a program allocates many large regions, it is probably |
---|
773 | better off using normal sbrk-based allocation routines that |
---|
774 | can reclaim and reallocate normal heap memory. Using a |
---|
775 | small value allows transition into this mode after the |
---|
776 | first few allocations. |
---|
777 | |
---|
778 | Setting to 0 disables all use of mmap. If HAVE_MMAP is not set, |
---|
779 | the default value is 0, and attempts to set it to non-zero values |
---|
780 | in mallopt will fail. |
---|
781 | */ |
---|
782 | |
---|
783 | |
---|
784 | |
---|
785 | |
---|
786 | /* |
---|
787 | USE_DL_PREFIX will prefix all public routines with the string 'dl'. |
---|
788 | Useful to quickly avoid procedure declaration conflicts and linker |
---|
789 | symbol conflicts with existing memory allocation routines. |
---|
790 | |
---|
791 | */ |
---|
792 | |
---|
793 | /* #define USE_DL_PREFIX */ |
---|
794 | |
---|
795 | |
---|
796 | |
---|
797 | |
---|
798 | /* |
---|
799 | |
---|
800 | Special defines for linux libc |
---|
801 | |
---|
802 | Except when compiled using these special defines for Linux libc |
---|
803 | using weak aliases, this malloc is NOT designed to work in |
---|
804 | multithreaded applications. No semaphores or other concurrency |
---|
805 | control are provided to ensure that multiple malloc or free calls |
---|
806 | don't run at the same time, which could be disasterous. A single |
---|
807 | semaphore could be used across malloc, realloc, and free (which is |
---|
808 | essentially the effect of the linux weak alias approach). It would |
---|
809 | be hard to obtain finer granularity. |
---|
810 | |
---|
811 | */ |
---|
812 | |
---|
813 | |
---|
814 | #ifdef INTERNAL_LINUX_C_LIB |
---|
815 | |
---|
816 | #if __STD_C |
---|
817 | |
---|
818 | Void_t * __default_morecore_init (ptrdiff_t); |
---|
819 | Void_t *(*__morecore)(ptrdiff_t) = __default_morecore_init; |
---|
820 | |
---|
821 | #else |
---|
822 | |
---|
823 | Void_t * __default_morecore_init (); |
---|
824 | Void_t *(*__morecore)() = __default_morecore_init; |
---|
825 | |
---|
826 | #endif |
---|
827 | |
---|
828 | #define MORECORE (*__morecore) |
---|
829 | #define MORECORE_FAILURE 0 |
---|
830 | #define MORECORE_CLEARS 1 |
---|
831 | |
---|
832 | #else /* INTERNAL_LINUX_C_LIB */ |
---|
833 | |
---|
834 | #if __STD_C |
---|
835 | extern Void_t* sbrk(ptrdiff_t); |
---|
836 | #else |
---|
837 | extern Void_t* sbrk(); |
---|
838 | #endif |
---|
839 | |
---|
840 | #ifndef MORECORE |
---|
841 | #define MORECORE sbrk |
---|
842 | #endif |
---|
843 | |
---|
844 | #ifndef MORECORE_FAILURE |
---|
845 | #define MORECORE_FAILURE -1 |
---|
846 | #endif |
---|
847 | |
---|
848 | #ifndef MORECORE_CLEARS |
---|
849 | #define MORECORE_CLEARS 1 |
---|
850 | #endif |
---|
851 | |
---|
852 | #endif /* INTERNAL_LINUX_C_LIB */ |
---|
853 | |
---|
854 | #if defined(INTERNAL_LINUX_C_LIB) && defined(__ELF__) |
---|
855 | |
---|
856 | #define cALLOc __libc_calloc |
---|
857 | #define fREe __libc_free |
---|
858 | #define mALLOc __libc_malloc |
---|
859 | #define mEMALIGn __libc_memalign |
---|
860 | #define rEALLOc __libc_realloc |
---|
861 | #define vALLOc __libc_valloc |
---|
862 | #define pvALLOc __libc_pvalloc |
---|
863 | #define mALLINFo __libc_mallinfo |
---|
864 | #define mALLOPt __libc_mallopt |
---|
865 | |
---|
866 | #pragma weak calloc = __libc_calloc |
---|
867 | #pragma weak free = __libc_free |
---|
868 | #pragma weak cfree = __libc_free |
---|
869 | #pragma weak malloc = __libc_malloc |
---|
870 | #pragma weak memalign = __libc_memalign |
---|
871 | #pragma weak realloc = __libc_realloc |
---|
872 | #pragma weak valloc = __libc_valloc |
---|
873 | #pragma weak pvalloc = __libc_pvalloc |
---|
874 | #pragma weak mallinfo = __libc_mallinfo |
---|
875 | #pragma weak mallopt = __libc_mallopt |
---|
876 | |
---|
877 | #else |
---|
878 | |
---|
879 | #ifdef USE_DL_PREFIX |
---|
880 | #define cALLOc dlcalloc |
---|
881 | #define fREe dlfree |
---|
882 | #define mALLOc dlmalloc |
---|
883 | #define mEMALIGn dlmemalign |
---|
884 | #define rEALLOc dlrealloc |
---|
885 | #define vALLOc dlvalloc |
---|
886 | #define pvALLOc dlpvalloc |
---|
887 | #define mALLINFo dlmallinfo |
---|
888 | #define mALLOPt dlmallopt |
---|
889 | #else /* USE_DL_PREFIX */ |
---|
890 | #define cALLOc calloc |
---|
891 | #define fREe free |
---|
892 | #define mALLOc malloc |
---|
893 | #define mEMALIGn memalign |
---|
894 | #define rEALLOc realloc |
---|
895 | #define vALLOc valloc |
---|
896 | #define pvALLOc pvalloc |
---|
897 | #define mALLINFo mallinfo |
---|
898 | #define mALLOPt mallopt |
---|
899 | #endif /* USE_DL_PREFIX */ |
---|
900 | |
---|
901 | #endif |
---|
902 | |
---|
903 | /* Public routines */ |
---|
904 | |
---|
905 | #if __STD_C |
---|
906 | |
---|
907 | Void_t* mALLOc(size_t); |
---|
908 | void fREe(Void_t*); |
---|
909 | Void_t* rEALLOc(Void_t*, size_t); |
---|
910 | Void_t* mEMALIGn(size_t, size_t); |
---|
911 | Void_t* vALLOc(size_t); |
---|
912 | Void_t* pvALLOc(size_t); |
---|
913 | Void_t* cALLOc(size_t, size_t); |
---|
914 | void cfree(Void_t*); |
---|
915 | int malloc_trim(size_t); |
---|
916 | size_t malloc_usable_size(Void_t*); |
---|
917 | void malloc_stats(); |
---|
918 | int mALLOPt(int, int); |
---|
919 | struct mallinfo mALLINFo(void); |
---|
920 | #else |
---|
921 | Void_t* mALLOc(); |
---|
922 | void fREe(); |
---|
923 | Void_t* rEALLOc(); |
---|
924 | Void_t* mEMALIGn(); |
---|
925 | Void_t* vALLOc(); |
---|
926 | Void_t* pvALLOc(); |
---|
927 | Void_t* cALLOc(); |
---|
928 | void cfree(); |
---|
929 | int malloc_trim(); |
---|
930 | size_t malloc_usable_size(); |
---|
931 | void malloc_stats(); |
---|
932 | int mALLOPt(); |
---|
933 | struct mallinfo mALLINFo(); |
---|
934 | #endif |
---|
935 | |
---|
936 | |
---|
937 | #ifdef __cplusplus |
---|
938 | }; /* end of extern "C" */ |
---|
939 | #endif |
---|
940 | |
---|
941 | /* ---------- To make a malloc.h, end cutting here ------------ */ |
---|
942 | |
---|
943 | |
---|
944 | /* |
---|
945 | Emulation of sbrk for WIN32 |
---|
946 | All code within the ifdef WIN32 is untested by me. |
---|
947 | |
---|
948 | Thanks to Martin Fong and others for supplying this. |
---|
949 | */ |
---|
950 | |
---|
951 | |
---|
952 | #ifdef WIN32 |
---|
953 | |
---|
954 | #define AlignPage(add) (((add) + (malloc_getpagesize-1)) & \ |
---|
955 | ~(malloc_getpagesize-1)) |
---|
956 | #define AlignPage64K(add) (((add) + (0x10000 - 1)) & ~(0x10000 - 1)) |
---|
957 | |
---|
958 | /* resrve 64MB to insure large contiguous space */ |
---|
959 | #define RESERVED_SIZE (1024*1024*64) |
---|
960 | #define NEXT_SIZE (2048*1024) |
---|
961 | #define TOP_MEMORY ((unsigned long)2*1024*1024*1024) |
---|
962 | |
---|
963 | struct GmListElement; |
---|
964 | typedef struct GmListElement GmListElement; |
---|
965 | |
---|
966 | struct GmListElement |
---|
967 | { |
---|
968 | GmListElement* next; |
---|
969 | void* base; |
---|
970 | }; |
---|
971 | |
---|
972 | static GmListElement* head = 0; |
---|
973 | static unsigned int gNextAddress = 0; |
---|
974 | static unsigned int gAddressBase = 0; |
---|
975 | static unsigned int gAllocatedSize = 0; |
---|
976 | |
---|
977 | static |
---|
978 | GmListElement* makeGmListElement (void* bas) |
---|
979 | { |
---|
980 | GmListElement* this; |
---|
981 | this = (GmListElement*)(void*)LocalAlloc (0, sizeof (GmListElement)); |
---|
982 | assert (this); |
---|
983 | if (this) |
---|
984 | { |
---|
985 | this->base = bas; |
---|
986 | this->next = head; |
---|
987 | head = this; |
---|
988 | } |
---|
989 | return this; |
---|
990 | } |
---|
991 | |
---|
992 | void gcleanup () |
---|
993 | { |
---|
994 | BOOL rval; |
---|
995 | assert ( (head == NULL) || (head->base == (void*)gAddressBase)); |
---|
996 | if (gAddressBase && (gNextAddress - gAddressBase)) |
---|
997 | { |
---|
998 | rval = VirtualFree ((void*)gAddressBase, |
---|
999 | gNextAddress - gAddressBase, |
---|
1000 | MEM_DECOMMIT); |
---|
1001 | assert (rval); |
---|
1002 | } |
---|
1003 | while (head) |
---|
1004 | { |
---|
1005 | GmListElement* next = head->next; |
---|
1006 | rval = VirtualFree (head->base, 0, MEM_RELEASE); |
---|
1007 | assert (rval); |
---|
1008 | LocalFree (head); |
---|
1009 | head = next; |
---|
1010 | } |
---|
1011 | } |
---|
1012 | |
---|
1013 | static |
---|
1014 | void* findRegion (void* start_address, unsigned long size) |
---|
1015 | { |
---|
1016 | MEMORY_BASIC_INFORMATION info; |
---|
1017 | if (size >= TOP_MEMORY) return NULL; |
---|
1018 | |
---|
1019 | while ((unsigned long)start_address + size < TOP_MEMORY) |
---|
1020 | { |
---|
1021 | VirtualQuery (start_address, &info, sizeof (info)); |
---|
1022 | if ((info.State == MEM_FREE) && (info.RegionSize >= size)) |
---|
1023 | return start_address; |
---|
1024 | else |
---|
1025 | { |
---|
1026 | // Requested region is not available so see if the |
---|
1027 | // next region is available. Set 'start_address' |
---|
1028 | // to the next region and call 'VirtualQuery()' |
---|
1029 | // again. |
---|
1030 | |
---|
1031 | start_address = (char*)info.BaseAddress + info.RegionSize; |
---|
1032 | |
---|
1033 | // Make sure we start looking for the next region |
---|
1034 | // on the *next* 64K boundary. Otherwise, even if |
---|
1035 | // the new region is free according to |
---|
1036 | // 'VirtualQuery()', the subsequent call to |
---|
1037 | // 'VirtualAlloc()' (which follows the call to |
---|
1038 | // this routine in 'wsbrk()') will round *down* |
---|
1039 | // the requested address to a 64K boundary which |
---|
1040 | // we already know is an address in the |
---|
1041 | // unavailable region. Thus, the subsequent call |
---|
1042 | // to 'VirtualAlloc()' will fail and bring us back |
---|
1043 | // here, causing us to go into an infinite loop. |
---|
1044 | |
---|
1045 | start_address = |
---|
1046 | (void *) AlignPage64K((unsigned long) start_address); |
---|
1047 | } |
---|
1048 | } |
---|
1049 | return NULL; |
---|
1050 | |
---|
1051 | } |
---|
1052 | |
---|
1053 | |
---|
1054 | void* wsbrk (long size) |
---|
1055 | { |
---|
1056 | void* tmp; |
---|
1057 | if (size > 0) |
---|
1058 | { |
---|
1059 | if (gAddressBase == 0) |
---|
1060 | { |
---|
1061 | gAllocatedSize = max (RESERVED_SIZE, AlignPage (size)); |
---|
1062 | gNextAddress = gAddressBase = |
---|
1063 | (unsigned int)VirtualAlloc (NULL, gAllocatedSize, |
---|
1064 | MEM_RESERVE, PAGE_NOACCESS); |
---|
1065 | } else if (AlignPage (gNextAddress + size) > (gAddressBase + |
---|
1066 | gAllocatedSize)) |
---|
1067 | { |
---|
1068 | long new_size = max (NEXT_SIZE, AlignPage (size)); |
---|
1069 | void* new_address = (void*)(gAddressBase+gAllocatedSize); |
---|
1070 | do |
---|
1071 | { |
---|
1072 | new_address = findRegion (new_address, new_size); |
---|
1073 | |
---|
1074 | if (new_address == 0) |
---|
1075 | return (void*)-1; |
---|
1076 | |
---|
1077 | gAddressBase = gNextAddress = |
---|
1078 | (unsigned int)VirtualAlloc (new_address, new_size, |
---|
1079 | MEM_RESERVE, PAGE_NOACCESS); |
---|
1080 | // repeat in case of race condition |
---|
1081 | // The region that we found has been snagged |
---|
1082 | // by another thread |
---|
1083 | } |
---|
1084 | while (gAddressBase == 0); |
---|
1085 | |
---|
1086 | assert (new_address == (void*)gAddressBase); |
---|
1087 | |
---|
1088 | gAllocatedSize = new_size; |
---|
1089 | |
---|
1090 | if (!makeGmListElement ((void*)gAddressBase)) |
---|
1091 | return (void*)-1; |
---|
1092 | } |
---|
1093 | if ((size + gNextAddress) > AlignPage (gNextAddress)) |
---|
1094 | { |
---|
1095 | void* res; |
---|
1096 | res = VirtualAlloc ((void*)AlignPage (gNextAddress), |
---|
1097 | (size + gNextAddress - |
---|
1098 | AlignPage (gNextAddress)), |
---|
1099 | MEM_COMMIT, PAGE_READWRITE); |
---|
1100 | if (res == 0) |
---|
1101 | return (void*)-1; |
---|
1102 | } |
---|
1103 | tmp = (void*)gNextAddress; |
---|
1104 | gNextAddress = (unsigned int)tmp + size; |
---|
1105 | return tmp; |
---|
1106 | } |
---|
1107 | else if (size < 0) |
---|
1108 | { |
---|
1109 | unsigned int alignedGoal = AlignPage (gNextAddress + size); |
---|
1110 | /* Trim by releasing the virtual memory */ |
---|
1111 | if (alignedGoal >= gAddressBase) |
---|
1112 | { |
---|
1113 | VirtualFree ((void*)alignedGoal, gNextAddress - alignedGoal, |
---|
1114 | MEM_DECOMMIT); |
---|
1115 | gNextAddress = gNextAddress + size; |
---|
1116 | return (void*)gNextAddress; |
---|
1117 | } |
---|
1118 | else |
---|
1119 | { |
---|
1120 | VirtualFree ((void*)gAddressBase, gNextAddress - gAddressBase, |
---|
1121 | MEM_DECOMMIT); |
---|
1122 | gNextAddress = gAddressBase; |
---|
1123 | return (void*)-1; |
---|
1124 | } |
---|
1125 | } |
---|
1126 | else |
---|
1127 | { |
---|
1128 | return (void*)gNextAddress; |
---|
1129 | } |
---|
1130 | } |
---|
1131 | |
---|
1132 | #endif |
---|
1133 | |
---|
1134 | |
---|
1135 | |
---|
1136 | /* |
---|
1137 | Type declarations |
---|
1138 | */ |
---|
1139 | |
---|
1140 | |
---|
1141 | struct malloc_chunk |
---|
1142 | { |
---|
1143 | INTERNAL_SIZE_T prev_size; /* Size of previous chunk (if free). */ |
---|
1144 | INTERNAL_SIZE_T size; /* Size in bytes, including overhead. */ |
---|
1145 | struct malloc_chunk* fd; /* double links -- used only if free. */ |
---|
1146 | struct malloc_chunk* bk; |
---|
1147 | }; |
---|
1148 | |
---|
1149 | typedef struct malloc_chunk* mchunkptr; |
---|
1150 | |
---|
1151 | /* |
---|
1152 | |
---|
1153 | malloc_chunk details: |
---|
1154 | |
---|
1155 | (The following includes lightly edited explanations by Colin Plumb.) |
---|
1156 | |
---|
1157 | Chunks of memory are maintained using a `boundary tag' method as |
---|
1158 | described in e.g., Knuth or Standish. (See the paper by Paul |
---|
1159 | Wilson ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a |
---|
1160 | survey of such techniques.) Sizes of free chunks are stored both |
---|
1161 | in the front of each chunk and at the end. This makes |
---|
1162 | consolidating fragmented chunks into bigger chunks very fast. The |
---|
1163 | size fields also hold bits representing whether chunks are free or |
---|
1164 | in use. |
---|
1165 | |
---|
1166 | An allocated chunk looks like this: |
---|
1167 | |
---|
1168 | |
---|
1169 | chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1170 | | Size of previous chunk, if allocated | | |
---|
1171 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1172 | | Size of chunk, in bytes |P| |
---|
1173 | mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1174 | | User data starts here... . |
---|
1175 | . . |
---|
1176 | . (malloc_usable_space() bytes) . |
---|
1177 | . | |
---|
1178 | nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1179 | | Size of chunk | |
---|
1180 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1181 | |
---|
1182 | |
---|
1183 | Where "chunk" is the front of the chunk for the purpose of most of |
---|
1184 | the malloc code, but "mem" is the pointer that is returned to the |
---|
1185 | user. "Nextchunk" is the beginning of the next contiguous chunk. |
---|
1186 | |
---|
1187 | Chunks always begin on even word boundries, so the mem portion |
---|
1188 | (which is returned to the user) is also on an even word boundary, and |
---|
1189 | thus double-word aligned. |
---|
1190 | |
---|
1191 | Free chunks are stored in circular doubly-linked lists, and look like this: |
---|
1192 | |
---|
1193 | chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1194 | | Size of previous chunk | |
---|
1195 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1196 | `head:' | Size of chunk, in bytes |P| |
---|
1197 | mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1198 | | Forward pointer to next chunk in list | |
---|
1199 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1200 | | Back pointer to previous chunk in list | |
---|
1201 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1202 | | Unused space (may be 0 bytes long) . |
---|
1203 | . . |
---|
1204 | . | |
---|
1205 | nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1206 | `foot:' | Size of chunk, in bytes | |
---|
1207 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
---|
1208 | |
---|
1209 | The P (PREV_INUSE) bit, stored in the unused low-order bit of the |
---|
1210 | chunk size (which is always a multiple of two words), is an in-use |
---|
1211 | bit for the *previous* chunk. If that bit is *clear*, then the |
---|
1212 | word before the current chunk size contains the previous chunk |
---|
1213 | size, and can be used to find the front of the previous chunk. |
---|
1214 | (The very first chunk allocated always has this bit set, |
---|
1215 | preventing access to non-existent (or non-owned) memory.) |
---|
1216 | |
---|
1217 | Note that the `foot' of the current chunk is actually represented |
---|
1218 | as the prev_size of the NEXT chunk. (This makes it easier to |
---|
1219 | deal with alignments etc). |
---|
1220 | |
---|
1221 | The two exceptions to all this are |
---|
1222 | |
---|
1223 | 1. The special chunk `top', which doesn't bother using the |
---|
1224 | trailing size field since there is no |
---|
1225 | next contiguous chunk that would have to index off it. (After |
---|
1226 | initialization, `top' is forced to always exist. If it would |
---|
1227 | become less than MINSIZE bytes long, it is replenished via |
---|
1228 | malloc_extend_top.) |
---|
1229 | |
---|
1230 | 2. Chunks allocated via mmap, which have the second-lowest-order |
---|
1231 | bit (IS_MMAPPED) set in their size fields. Because they are |
---|
1232 | never merged or traversed from any other chunk, they have no |
---|
1233 | foot size or inuse information. |
---|
1234 | |
---|
1235 | Available chunks are kept in any of several places (all declared below): |
---|
1236 | |
---|
1237 | * `av': An array of chunks serving as bin headers for consolidated |
---|
1238 | chunks. Each bin is doubly linked. The bins are approximately |
---|
1239 | proportionally (log) spaced. There are a lot of these bins |
---|
1240 | (128). This may look excessive, but works very well in |
---|
1241 | practice. All procedures maintain the invariant that no |
---|
1242 | consolidated chunk physically borders another one. Chunks in |
---|
1243 | bins are kept in size order, with ties going to the |
---|
1244 | approximately least recently used chunk. |
---|
1245 | |
---|
1246 | The chunks in each bin are maintained in decreasing sorted order by |
---|
1247 | size. This is irrelevant for the small bins, which all contain |
---|
1248 | the same-sized chunks, but facilitates best-fit allocation for |
---|
1249 | larger chunks. (These lists are just sequential. Keeping them in |
---|
1250 | order almost never requires enough traversal to warrant using |
---|
1251 | fancier ordered data structures.) Chunks of the same size are |
---|
1252 | linked with the most recently freed at the front, and allocations |
---|
1253 | are taken from the back. This results in LRU or FIFO allocation |
---|
1254 | order, which tends to give each chunk an equal opportunity to be |
---|
1255 | consolidated with adjacent freed chunks, resulting in larger free |
---|
1256 | chunks and less fragmentation. |
---|
1257 | |
---|
1258 | * `top': The top-most available chunk (i.e., the one bordering the |
---|
1259 | end of available memory) is treated specially. It is never |
---|
1260 | included in any bin, is used only if no other chunk is |
---|
1261 | available, and is released back to the system if it is very |
---|
1262 | large (see M_TRIM_THRESHOLD). |
---|
1263 | |
---|
1264 | * `last_remainder': A bin holding only the remainder of the |
---|
1265 | most recently split (non-top) chunk. This bin is checked |
---|
1266 | before other non-fitting chunks, so as to provide better |
---|
1267 | locality for runs of sequentially allocated chunks. |
---|
1268 | |
---|
1269 | * Implicitly, through the host system's memory mapping tables. |
---|
1270 | If supported, requests greater than a threshold are usually |
---|
1271 | serviced via calls to mmap, and then later released via munmap. |
---|
1272 | |
---|
1273 | */ |
---|
1274 | |
---|
1275 | |
---|
1276 | |
---|
1277 | |
---|
1278 | |
---|
1279 | |
---|
1280 | /* sizes, alignments */ |
---|
1281 | |
---|
1282 | #define SIZE_SZ (sizeof(INTERNAL_SIZE_T)) |
---|
1283 | #define MALLOC_ALIGNMENT (SIZE_SZ + SIZE_SZ) |
---|
1284 | #define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1) |
---|
1285 | #define MINSIZE (sizeof(struct malloc_chunk)) |
---|
1286 | |
---|
1287 | /* conversion from malloc headers to user pointers, and back */ |
---|
1288 | |
---|
1289 | #define chunk2mem(p) ((Void_t*)((char*)(p) + 2*SIZE_SZ)) |
---|
1290 | #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - 2*SIZE_SZ)) |
---|
1291 | |
---|
1292 | /* pad request bytes into a usable size */ |
---|
1293 | |
---|
1294 | #define request2size(req) \ |
---|
1295 | (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \ |
---|
1296 | (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \ |
---|
1297 | (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK))) |
---|
1298 | |
---|
1299 | /* Check if m has acceptable alignment */ |
---|
1300 | |
---|
1301 | #define aligned_OK(m) (((unsigned long)((m)) & (MALLOC_ALIGN_MASK)) == 0) |
---|
1302 | |
---|
1303 | |
---|
1304 | |
---|
1305 | |
---|
1306 | /* |
---|
1307 | Physical chunk operations |
---|
1308 | */ |
---|
1309 | |
---|
1310 | |
---|
1311 | /* size field is or'ed with PREV_INUSE when previous adjacent chunk in use */ |
---|
1312 | |
---|
1313 | #define PREV_INUSE 0x1 |
---|
1314 | |
---|
1315 | /* size field is or'ed with IS_MMAPPED if the chunk was obtained with mmap() */ |
---|
1316 | |
---|
1317 | #define IS_MMAPPED 0x2 |
---|
1318 | |
---|
1319 | /* Bits to mask off when extracting size */ |
---|
1320 | |
---|
1321 | #define SIZE_BITS (PREV_INUSE|IS_MMAPPED) |
---|
1322 | |
---|
1323 | |
---|
1324 | /* Ptr to next physical malloc_chunk. */ |
---|
1325 | |
---|
1326 | #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->size & ~PREV_INUSE) )) |
---|
1327 | |
---|
1328 | /* Ptr to previous physical malloc_chunk */ |
---|
1329 | |
---|
1330 | #define prev_chunk(p)\ |
---|
1331 | ((mchunkptr)( ((char*)(p)) - ((p)->prev_size) )) |
---|
1332 | |
---|
1333 | |
---|
1334 | /* Treat space at ptr + offset as a chunk */ |
---|
1335 | |
---|
1336 | #define chunk_at_offset(p, s) ((mchunkptr)(((char*)(p)) + (s))) |
---|
1337 | |
---|
1338 | |
---|
1339 | |
---|
1340 | |
---|
1341 | /* |
---|
1342 | Dealing with use bits |
---|
1343 | */ |
---|
1344 | |
---|
1345 | /* extract p's inuse bit */ |
---|
1346 | |
---|
1347 | #define inuse(p)\ |
---|
1348 | ((((mchunkptr)(((char*)(p))+((p)->size & ~PREV_INUSE)))->size) & PREV_INUSE) |
---|
1349 | |
---|
1350 | /* extract inuse bit of previous chunk */ |
---|
1351 | |
---|
1352 | #define prev_inuse(p) ((p)->size & PREV_INUSE) |
---|
1353 | |
---|
1354 | /* check for mmap()'ed chunk */ |
---|
1355 | |
---|
1356 | #define chunk_is_mmapped(p) ((p)->size & IS_MMAPPED) |
---|
1357 | |
---|
1358 | /* set/clear chunk as in use without otherwise disturbing */ |
---|
1359 | |
---|
1360 | #define set_inuse(p)\ |
---|
1361 | ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size |= PREV_INUSE |
---|
1362 | |
---|
1363 | #define clear_inuse(p)\ |
---|
1364 | ((mchunkptr)(((char*)(p)) + ((p)->size & ~PREV_INUSE)))->size &= ~(PREV_INUSE) |
---|
1365 | |
---|
1366 | /* check/set/clear inuse bits in known places */ |
---|
1367 | |
---|
1368 | #define inuse_bit_at_offset(p, s)\ |
---|
1369 | (((mchunkptr)(((char*)(p)) + (s)))->size & PREV_INUSE) |
---|
1370 | |
---|
1371 | #define set_inuse_bit_at_offset(p, s)\ |
---|
1372 | (((mchunkptr)(((char*)(p)) + (s)))->size |= PREV_INUSE) |
---|
1373 | |
---|
1374 | #define clear_inuse_bit_at_offset(p, s)\ |
---|
1375 | (((mchunkptr)(((char*)(p)) + (s)))->size &= ~(PREV_INUSE)) |
---|
1376 | |
---|
1377 | |
---|
1378 | |
---|
1379 | |
---|
1380 | /* |
---|
1381 | Dealing with size fields |
---|
1382 | */ |
---|
1383 | |
---|
1384 | /* Get size, ignoring use bits */ |
---|
1385 | |
---|
1386 | #define chunksize(p) ((p)->size & ~(SIZE_BITS)) |
---|
1387 | |
---|
1388 | /* Set size at head, without disturbing its use bit */ |
---|
1389 | |
---|
1390 | #define set_head_size(p, s) ((p)->size = (((p)->size & PREV_INUSE) | (s))) |
---|
1391 | |
---|
1392 | /* Set size/use ignoring previous bits in header */ |
---|
1393 | |
---|
1394 | #define set_head(p, s) ((p)->size = (s)) |
---|
1395 | |
---|
1396 | /* Set size at footer (only when chunk is not in use) */ |
---|
1397 | |
---|
1398 | #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_size = (s)) |
---|
1399 | |
---|
1400 | |
---|
1401 | |
---|
1402 | |
---|
1403 | |
---|
1404 | /* |
---|
1405 | Bins |
---|
1406 | |
---|
1407 | The bins, `av_' are an array of pairs of pointers serving as the |
---|
1408 | heads of (initially empty) doubly-linked lists of chunks, laid out |
---|
1409 | in a way so that each pair can be treated as if it were in a |
---|
1410 | malloc_chunk. (This way, the fd/bk offsets for linking bin heads |
---|
1411 | and chunks are the same). |
---|
1412 | |
---|
1413 | Bins for sizes < 512 bytes contain chunks of all the same size, spaced |
---|
1414 | 8 bytes apart. Larger bins are approximately logarithmically |
---|
1415 | spaced. (See the table below.) The `av_' array is never mentioned |
---|
1416 | directly in the code, but instead via bin access macros. |
---|
1417 | |
---|
1418 | Bin layout: |
---|
1419 | |
---|
1420 | 64 bins of size 8 |
---|
1421 | 32 bins of size 64 |
---|
1422 | 16 bins of size 512 |
---|
1423 | 8 bins of size 4096 |
---|
1424 | 4 bins of size 32768 |
---|
1425 | 2 bins of size 262144 |
---|
1426 | 1 bin of size what's left |
---|
1427 | |
---|
1428 | There is actually a little bit of slop in the numbers in bin_index |
---|
1429 | for the sake of speed. This makes no difference elsewhere. |
---|
1430 | |
---|
1431 | The special chunks `top' and `last_remainder' get their own bins, |
---|
1432 | (this is implemented via yet more trickery with the av_ array), |
---|
1433 | although `top' is never properly linked to its bin since it is |
---|
1434 | always handled specially. |
---|
1435 | |
---|
1436 | */ |
---|
1437 | |
---|
1438 | #define NAV 128 /* number of bins */ |
---|
1439 | |
---|
1440 | typedef struct malloc_chunk* mbinptr; |
---|
1441 | |
---|
1442 | /* access macros */ |
---|
1443 | |
---|
1444 | #define bin_at(i) ((mbinptr)((char*)&(av_[2*(i) + 2]) - 2*SIZE_SZ)) |
---|
1445 | #define next_bin(b) ((mbinptr)((char*)(b) + 2 * sizeof(mbinptr))) |
---|
1446 | #define prev_bin(b) ((mbinptr)((char*)(b) - 2 * sizeof(mbinptr))) |
---|
1447 | |
---|
1448 | /* |
---|
1449 | The first 2 bins are never indexed. The corresponding av_ cells are instead |
---|
1450 | used for bookkeeping. This is not to save space, but to simplify |
---|
1451 | indexing, maintain locality, and avoid some initialization tests. |
---|
1452 | */ |
---|
1453 | |
---|
1454 | #define top (bin_at(0)->fd) /* The topmost chunk */ |
---|
1455 | #define last_remainder (bin_at(1)) /* remainder from last split */ |
---|
1456 | |
---|
1457 | |
---|
1458 | /* |
---|
1459 | Because top initially points to its own bin with initial |
---|
1460 | zero size, thus forcing extension on the first malloc request, |
---|
1461 | we avoid having any special code in malloc to check whether |
---|
1462 | it even exists yet. But we still need to in malloc_extend_top. |
---|
1463 | */ |
---|
1464 | |
---|
1465 | #define initial_top ((mchunkptr)(bin_at(0))) |
---|
1466 | |
---|
1467 | /* Helper macro to initialize bins */ |
---|
1468 | |
---|
1469 | #define IAV(i) bin_at(i), bin_at(i) |
---|
1470 | |
---|
1471 | static mbinptr av_[NAV * 2 + 2] = { |
---|
1472 | 0, 0, |
---|
1473 | IAV(0), IAV(1), IAV(2), IAV(3), IAV(4), IAV(5), IAV(6), IAV(7), |
---|
1474 | IAV(8), IAV(9), IAV(10), IAV(11), IAV(12), IAV(13), IAV(14), IAV(15), |
---|
1475 | IAV(16), IAV(17), IAV(18), IAV(19), IAV(20), IAV(21), IAV(22), IAV(23), |
---|
1476 | IAV(24), IAV(25), IAV(26), IAV(27), IAV(28), IAV(29), IAV(30), IAV(31), |
---|
1477 | IAV(32), IAV(33), IAV(34), IAV(35), IAV(36), IAV(37), IAV(38), IAV(39), |
---|
1478 | IAV(40), IAV(41), IAV(42), IAV(43), IAV(44), IAV(45), IAV(46), IAV(47), |
---|
1479 | IAV(48), IAV(49), IAV(50), IAV(51), IAV(52), IAV(53), IAV(54), IAV(55), |
---|
1480 | IAV(56), IAV(57), IAV(58), IAV(59), IAV(60), IAV(61), IAV(62), IAV(63), |
---|
1481 | IAV(64), IAV(65), IAV(66), IAV(67), IAV(68), IAV(69), IAV(70), IAV(71), |
---|
1482 | IAV(72), IAV(73), IAV(74), IAV(75), IAV(76), IAV(77), IAV(78), IAV(79), |
---|
1483 | IAV(80), IAV(81), IAV(82), IAV(83), IAV(84), IAV(85), IAV(86), IAV(87), |
---|
1484 | IAV(88), IAV(89), IAV(90), IAV(91), IAV(92), IAV(93), IAV(94), IAV(95), |
---|
1485 | IAV(96), IAV(97), IAV(98), IAV(99), IAV(100), IAV(101), IAV(102), IAV(103), |
---|
1486 | IAV(104), IAV(105), IAV(106), IAV(107), IAV(108), IAV(109), IAV(110), IAV(111), |
---|
1487 | IAV(112), IAV(113), IAV(114), IAV(115), IAV(116), IAV(117), IAV(118), IAV(119), |
---|
1488 | IAV(120), IAV(121), IAV(122), IAV(123), IAV(124), IAV(125), IAV(126), IAV(127) |
---|
1489 | }; |
---|
1490 | |
---|
1491 | |
---|
1492 | |
---|
1493 | /* field-extraction macros */ |
---|
1494 | |
---|
1495 | #define first(b) ((b)->fd) |
---|
1496 | #define last(b) ((b)->bk) |
---|
1497 | |
---|
1498 | /* |
---|
1499 | Indexing into bins |
---|
1500 | */ |
---|
1501 | |
---|
1502 | #define bin_index(sz) \ |
---|
1503 | (((((unsigned long)(sz)) >> 9) == 0) ? (((unsigned long)(sz)) >> 3): \ |
---|
1504 | ((((unsigned long)(sz)) >> 9) <= 4) ? 56 + (((unsigned long)(sz)) >> 6): \ |
---|
1505 | ((((unsigned long)(sz)) >> 9) <= 20) ? 91 + (((unsigned long)(sz)) >> 9): \ |
---|
1506 | ((((unsigned long)(sz)) >> 9) <= 84) ? 110 + (((unsigned long)(sz)) >> 12): \ |
---|
1507 | ((((unsigned long)(sz)) >> 9) <= 340) ? 119 + (((unsigned long)(sz)) >> 15): \ |
---|
1508 | ((((unsigned long)(sz)) >> 9) <= 1364) ? 124 + (((unsigned long)(sz)) >> 18): \ |
---|
1509 | 126) |
---|
1510 | /* |
---|
1511 | bins for chunks < 512 are all spaced 8 bytes apart, and hold |
---|
1512 | identically sized chunks. This is exploited in malloc. |
---|
1513 | */ |
---|
1514 | |
---|
1515 | #define MAX_SMALLBIN 63 |
---|
1516 | #define MAX_SMALLBIN_SIZE 512 |
---|
1517 | #define SMALLBIN_WIDTH 8 |
---|
1518 | |
---|
1519 | #define smallbin_index(sz) (((unsigned long)(sz)) >> 3) |
---|
1520 | |
---|
1521 | /* |
---|
1522 | Requests are `small' if both the corresponding and the next bin are small |
---|
1523 | */ |
---|
1524 | |
---|
1525 | #define is_small_request(nb) (nb < MAX_SMALLBIN_SIZE - SMALLBIN_WIDTH) |
---|
1526 | |
---|
1527 | |
---|
1528 | |
---|
1529 | /* |
---|
1530 | To help compensate for the large number of bins, a one-level index |
---|
1531 | structure is used for bin-by-bin searching. `binblocks' is a |
---|
1532 | one-word bitvector recording whether groups of BINBLOCKWIDTH bins |
---|
1533 | have any (possibly) non-empty bins, so they can be skipped over |
---|
1534 | all at once during during traversals. The bits are NOT always |
---|
1535 | cleared as soon as all bins in a block are empty, but instead only |
---|
1536 | when all are noticed to be empty during traversal in malloc. |
---|
1537 | */ |
---|
1538 | |
---|
1539 | #define BINBLOCKWIDTH 4 /* bins per block */ |
---|
1540 | |
---|
1541 | #define binblocks (bin_at(0)->size) /* bitvector of nonempty blocks */ |
---|
1542 | |
---|
1543 | /* bin<->block macros */ |
---|
1544 | |
---|
1545 | #define idx2binblock(ix) ((unsigned)1 << (ix / BINBLOCKWIDTH)) |
---|
1546 | #define mark_binblock(ii) (binblocks |= idx2binblock(ii)) |
---|
1547 | #define clear_binblock(ii) (binblocks &= ~(idx2binblock(ii))) |
---|
1548 | |
---|
1549 | |
---|
1550 | |
---|
1551 | |
---|
1552 | |
---|
1553 | /* Other static bookkeeping data */ |
---|
1554 | |
---|
1555 | /* variables holding tunable values */ |
---|
1556 | |
---|
1557 | static unsigned long trim_threshold = DEFAULT_TRIM_THRESHOLD; |
---|
1558 | static unsigned long top_pad = DEFAULT_TOP_PAD; |
---|
1559 | static unsigned int n_mmaps_max = DEFAULT_MMAP_MAX; |
---|
1560 | static unsigned long mmap_threshold = DEFAULT_MMAP_THRESHOLD; |
---|
1561 | |
---|
1562 | /* The first value returned from sbrk */ |
---|
1563 | static char* sbrk_base = (char*)(-1); |
---|
1564 | |
---|
1565 | /* The maximum memory obtained from system via sbrk */ |
---|
1566 | static unsigned long max_sbrked_mem = 0; |
---|
1567 | |
---|
1568 | /* The maximum via either sbrk or mmap */ |
---|
1569 | static unsigned long max_total_mem = 0; |
---|
1570 | |
---|
1571 | /* internal working copy of mallinfo */ |
---|
1572 | static struct mallinfo current_mallinfo = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; |
---|
1573 | |
---|
1574 | /* The total memory obtained from system via sbrk */ |
---|
1575 | #define sbrked_mem (current_mallinfo.arena) |
---|
1576 | |
---|
1577 | /* Tracking mmaps */ |
---|
1578 | |
---|
1579 | static unsigned int n_mmaps = 0; |
---|
1580 | static unsigned int max_n_mmaps = 0; |
---|
1581 | static unsigned long mmapped_mem = 0; |
---|
1582 | static unsigned long max_mmapped_mem = 0; |
---|
1583 | |
---|
1584 | |
---|
1585 | |
---|
1586 | /* |
---|
1587 | Debugging support |
---|
1588 | */ |
---|
1589 | |
---|
1590 | #if DEBUG |
---|
1591 | |
---|
1592 | |
---|
1593 | /* |
---|
1594 | These routines make a number of assertions about the states |
---|
1595 | of data structures that should be true at all times. If any |
---|
1596 | are not true, it's very likely that a user program has somehow |
---|
1597 | trashed memory. (It's also possible that there is a coding error |
---|
1598 | in malloc. In which case, please report it!) |
---|
1599 | */ |
---|
1600 | |
---|
1601 | #if __STD_C |
---|
1602 | static void do_check_chunk(mchunkptr p) |
---|
1603 | #else |
---|
1604 | static void do_check_chunk(p) mchunkptr p; |
---|
1605 | #endif |
---|
1606 | { |
---|
1607 | INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; |
---|
1608 | |
---|
1609 | /* No checkable chunk is mmapped */ |
---|
1610 | assert(!chunk_is_mmapped(p)); |
---|
1611 | |
---|
1612 | /* Check for legal address ... */ |
---|
1613 | assert((char*)p >= sbrk_base); |
---|
1614 | if (p != top) |
---|
1615 | assert((char*)p + sz <= (char*)top); |
---|
1616 | else |
---|
1617 | assert((char*)p + sz <= sbrk_base + sbrked_mem); |
---|
1618 | |
---|
1619 | } |
---|
1620 | |
---|
1621 | |
---|
1622 | #if __STD_C |
---|
1623 | static void do_check_free_chunk(mchunkptr p) |
---|
1624 | #else |
---|
1625 | static void do_check_free_chunk(p) mchunkptr p; |
---|
1626 | #endif |
---|
1627 | { |
---|
1628 | INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; |
---|
1629 | mchunkptr next = chunk_at_offset(p, sz); |
---|
1630 | |
---|
1631 | do_check_chunk(p); |
---|
1632 | |
---|
1633 | /* Check whether it claims to be free ... */ |
---|
1634 | assert(!inuse(p)); |
---|
1635 | |
---|
1636 | /* Unless a special marker, must have OK fields */ |
---|
1637 | if ((long)sz >= (long)MINSIZE) |
---|
1638 | { |
---|
1639 | assert((sz & MALLOC_ALIGN_MASK) == 0); |
---|
1640 | assert(aligned_OK(chunk2mem(p))); |
---|
1641 | /* ... matching footer field */ |
---|
1642 | assert(next->prev_size == sz); |
---|
1643 | /* ... and is fully consolidated */ |
---|
1644 | assert(prev_inuse(p)); |
---|
1645 | assert (next == top || inuse(next)); |
---|
1646 | |
---|
1647 | /* ... and has minimally sane links */ |
---|
1648 | assert(p->fd->bk == p); |
---|
1649 | assert(p->bk->fd == p); |
---|
1650 | } |
---|
1651 | else /* markers are always of size SIZE_SZ */ |
---|
1652 | assert(sz == SIZE_SZ); |
---|
1653 | } |
---|
1654 | |
---|
1655 | #if __STD_C |
---|
1656 | static void do_check_inuse_chunk(mchunkptr p) |
---|
1657 | #else |
---|
1658 | static void do_check_inuse_chunk(p) mchunkptr p; |
---|
1659 | #endif |
---|
1660 | { |
---|
1661 | mchunkptr next = next_chunk(p); |
---|
1662 | do_check_chunk(p); |
---|
1663 | |
---|
1664 | /* Check whether it claims to be in use ... */ |
---|
1665 | assert(inuse(p)); |
---|
1666 | |
---|
1667 | /* ... and is surrounded by OK chunks. |
---|
1668 | Since more things can be checked with free chunks than inuse ones, |
---|
1669 | if an inuse chunk borders them and debug is on, it's worth doing them. |
---|
1670 | */ |
---|
1671 | if (!prev_inuse(p)) |
---|
1672 | { |
---|
1673 | mchunkptr prv = prev_chunk(p); |
---|
1674 | assert(next_chunk(prv) == p); |
---|
1675 | do_check_free_chunk(prv); |
---|
1676 | } |
---|
1677 | if (next == top) |
---|
1678 | { |
---|
1679 | assert(prev_inuse(next)); |
---|
1680 | assert(chunksize(next) >= MINSIZE); |
---|
1681 | } |
---|
1682 | else if (!inuse(next)) |
---|
1683 | do_check_free_chunk(next); |
---|
1684 | |
---|
1685 | } |
---|
1686 | |
---|
1687 | #if __STD_C |
---|
1688 | static void do_check_malloced_chunk(mchunkptr p, INTERNAL_SIZE_T s) |
---|
1689 | #else |
---|
1690 | static void do_check_malloced_chunk(p, s) mchunkptr p; INTERNAL_SIZE_T s; |
---|
1691 | #endif |
---|
1692 | { |
---|
1693 | INTERNAL_SIZE_T sz = p->size & ~PREV_INUSE; |
---|
1694 | long room = sz - s; |
---|
1695 | |
---|
1696 | do_check_inuse_chunk(p); |
---|
1697 | |
---|
1698 | /* Legal size ... */ |
---|
1699 | assert((long)sz >= (long)MINSIZE); |
---|
1700 | assert((sz & MALLOC_ALIGN_MASK) == 0); |
---|
1701 | assert(room >= 0); |
---|
1702 | assert(room < (long)MINSIZE); |
---|
1703 | |
---|
1704 | /* ... and alignment */ |
---|
1705 | assert(aligned_OK(chunk2mem(p))); |
---|
1706 | |
---|
1707 | |
---|
1708 | /* ... and was allocated at front of an available chunk */ |
---|
1709 | assert(prev_inuse(p)); |
---|
1710 | |
---|
1711 | } |
---|
1712 | |
---|
1713 | |
---|
1714 | #define check_free_chunk(P) do_check_free_chunk(P) |
---|
1715 | #define check_inuse_chunk(P) do_check_inuse_chunk(P) |
---|
1716 | #define check_chunk(P) do_check_chunk(P) |
---|
1717 | #define check_malloced_chunk(P,N) do_check_malloced_chunk(P,N) |
---|
1718 | #else |
---|
1719 | #define check_free_chunk(P) |
---|
1720 | #define check_inuse_chunk(P) |
---|
1721 | #define check_chunk(P) |
---|
1722 | #define check_malloced_chunk(P,N) |
---|
1723 | #endif |
---|
1724 | |
---|
1725 | |
---|
1726 | |
---|
1727 | /* |
---|
1728 | Macro-based internal utilities |
---|
1729 | */ |
---|
1730 | |
---|
1731 | |
---|
1732 | /* |
---|
1733 | Linking chunks in bin lists. |
---|
1734 | Call these only with variables, not arbitrary expressions, as arguments. |
---|
1735 | */ |
---|
1736 | |
---|
1737 | /* |
---|
1738 | Place chunk p of size s in its bin, in size order, |
---|
1739 | putting it ahead of others of same size. |
---|
1740 | */ |
---|
1741 | |
---|
1742 | |
---|
1743 | #define frontlink(P, S, IDX, BK, FD) \ |
---|
1744 | { \ |
---|
1745 | if (S < MAX_SMALLBIN_SIZE) \ |
---|
1746 | { \ |
---|
1747 | IDX = smallbin_index(S); \ |
---|
1748 | mark_binblock(IDX); \ |
---|
1749 | BK = bin_at(IDX); \ |
---|
1750 | FD = BK->fd; \ |
---|
1751 | P->bk = BK; \ |
---|
1752 | P->fd = FD; \ |
---|
1753 | FD->bk = BK->fd = P; \ |
---|
1754 | } \ |
---|
1755 | else \ |
---|
1756 | { \ |
---|
1757 | IDX = bin_index(S); \ |
---|
1758 | BK = bin_at(IDX); \ |
---|
1759 | FD = BK->fd; \ |
---|
1760 | if (FD == BK) mark_binblock(IDX); \ |
---|
1761 | else \ |
---|
1762 | { \ |
---|
1763 | while (FD != BK && S < chunksize(FD)) FD = FD->fd; \ |
---|
1764 | BK = FD->bk; \ |
---|
1765 | } \ |
---|
1766 | P->bk = BK; \ |
---|
1767 | P->fd = FD; \ |
---|
1768 | FD->bk = BK->fd = P; \ |
---|
1769 | } \ |
---|
1770 | } |
---|
1771 | |
---|
1772 | |
---|
1773 | /* take a chunk off a list */ |
---|
1774 | |
---|
1775 | #define unlink(P, BK, FD) \ |
---|
1776 | { \ |
---|
1777 | BK = P->bk; \ |
---|
1778 | FD = P->fd; \ |
---|
1779 | FD->bk = BK; \ |
---|
1780 | BK->fd = FD; \ |
---|
1781 | } \ |
---|
1782 | |
---|
1783 | /* Place p as the last remainder */ |
---|
1784 | |
---|
1785 | #define link_last_remainder(P) \ |
---|
1786 | { \ |
---|
1787 | last_remainder->fd = last_remainder->bk = P; \ |
---|
1788 | P->fd = P->bk = last_remainder; \ |
---|
1789 | } |
---|
1790 | |
---|
1791 | /* Clear the last_remainder bin */ |
---|
1792 | |
---|
1793 | #define clear_last_remainder \ |
---|
1794 | (last_remainder->fd = last_remainder->bk = last_remainder) |
---|
1795 | |
---|
1796 | |
---|
1797 | |
---|
1798 | |
---|
1799 | |
---|
1800 | |
---|
1801 | /* Routines dealing with mmap(). */ |
---|
1802 | |
---|
1803 | #if HAVE_MMAP |
---|
1804 | |
---|
1805 | #if __STD_C |
---|
1806 | static mchunkptr mmap_chunk(size_t size) |
---|
1807 | #else |
---|
1808 | static mchunkptr mmap_chunk(size) size_t size; |
---|
1809 | #endif |
---|
1810 | { |
---|
1811 | size_t page_mask = malloc_getpagesize - 1; |
---|
1812 | mchunkptr p; |
---|
1813 | |
---|
1814 | #ifndef MAP_ANONYMOUS |
---|
1815 | static int fd = -1; |
---|
1816 | #endif |
---|
1817 | |
---|
1818 | if(n_mmaps >= n_mmaps_max) return 0; /* too many regions */ |
---|
1819 | |
---|
1820 | /* For mmapped chunks, the overhead is one SIZE_SZ unit larger, because |
---|
1821 | * there is no following chunk whose prev_size field could be used. |
---|
1822 | */ |
---|
1823 | size = (size + SIZE_SZ + page_mask) & ~page_mask; |
---|
1824 | |
---|
1825 | #ifdef MAP_ANONYMOUS |
---|
1826 | p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, |
---|
1827 | MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); |
---|
1828 | #else /* !MAP_ANONYMOUS */ |
---|
1829 | if (fd < 0) |
---|
1830 | { |
---|
1831 | fd = open("/dev/zero", O_RDWR); |
---|
1832 | if(fd < 0) return 0; |
---|
1833 | } |
---|
1834 | p = (mchunkptr)mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); |
---|
1835 | #endif |
---|
1836 | |
---|
1837 | if(p == (mchunkptr)-1) return 0; |
---|
1838 | |
---|
1839 | n_mmaps++; |
---|
1840 | if (n_mmaps > max_n_mmaps) max_n_mmaps = n_mmaps; |
---|
1841 | |
---|
1842 | /* We demand that eight bytes into a page must be 8-byte aligned. */ |
---|
1843 | assert(aligned_OK(chunk2mem(p))); |
---|
1844 | |
---|
1845 | /* The offset to the start of the mmapped region is stored |
---|
1846 | * in the prev_size field of the chunk; normally it is zero, |
---|
1847 | * but that can be changed in memalign(). |
---|
1848 | */ |
---|
1849 | p->prev_size = 0; |
---|
1850 | set_head(p, size|IS_MMAPPED); |
---|
1851 | |
---|
1852 | mmapped_mem += size; |
---|
1853 | if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) |
---|
1854 | max_mmapped_mem = mmapped_mem; |
---|
1855 | if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) |
---|
1856 | max_total_mem = mmapped_mem + sbrked_mem; |
---|
1857 | return p; |
---|
1858 | } |
---|
1859 | |
---|
1860 | #if __STD_C |
---|
1861 | static void munmap_chunk(mchunkptr p) |
---|
1862 | #else |
---|
1863 | static void munmap_chunk(p) mchunkptr p; |
---|
1864 | #endif |
---|
1865 | { |
---|
1866 | INTERNAL_SIZE_T size = chunksize(p); |
---|
1867 | int ret; |
---|
1868 | |
---|
1869 | assert (chunk_is_mmapped(p)); |
---|
1870 | assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem)); |
---|
1871 | assert((n_mmaps > 0)); |
---|
1872 | assert(((p->prev_size + size) & (malloc_getpagesize-1)) == 0); |
---|
1873 | |
---|
1874 | n_mmaps--; |
---|
1875 | mmapped_mem -= (size + p->prev_size); |
---|
1876 | |
---|
1877 | ret = munmap((char *)p - p->prev_size, size + p->prev_size); |
---|
1878 | |
---|
1879 | /* munmap returns non-zero on failure */ |
---|
1880 | assert(ret == 0); |
---|
1881 | } |
---|
1882 | |
---|
1883 | #if HAVE_MREMAP |
---|
1884 | |
---|
1885 | #if __STD_C |
---|
1886 | static mchunkptr mremap_chunk(mchunkptr p, size_t new_size) |
---|
1887 | #else |
---|
1888 | static mchunkptr mremap_chunk(p, new_size) mchunkptr p; size_t new_size; |
---|
1889 | #endif |
---|
1890 | { |
---|
1891 | size_t page_mask = malloc_getpagesize - 1; |
---|
1892 | INTERNAL_SIZE_T offset = p->prev_size; |
---|
1893 | INTERNAL_SIZE_T size = chunksize(p); |
---|
1894 | char *cp; |
---|
1895 | |
---|
1896 | assert (chunk_is_mmapped(p)); |
---|
1897 | assert(! ((char*)p >= sbrk_base && (char*)p < sbrk_base + sbrked_mem)); |
---|
1898 | assert((n_mmaps > 0)); |
---|
1899 | assert(((size + offset) & (malloc_getpagesize-1)) == 0); |
---|
1900 | |
---|
1901 | /* Note the extra SIZE_SZ overhead as in mmap_chunk(). */ |
---|
1902 | new_size = (new_size + offset + SIZE_SZ + page_mask) & ~page_mask; |
---|
1903 | |
---|
1904 | cp = (char *)mremap((char *)p - offset, size + offset, new_size, 1); |
---|
1905 | |
---|
1906 | if (cp == (char *)-1) return 0; |
---|
1907 | |
---|
1908 | p = (mchunkptr)(cp + offset); |
---|
1909 | |
---|
1910 | assert(aligned_OK(chunk2mem(p))); |
---|
1911 | |
---|
1912 | assert((p->prev_size == offset)); |
---|
1913 | set_head(p, (new_size - offset)|IS_MMAPPED); |
---|
1914 | |
---|
1915 | mmapped_mem -= size + offset; |
---|
1916 | mmapped_mem += new_size; |
---|
1917 | if ((unsigned long)mmapped_mem > (unsigned long)max_mmapped_mem) |
---|
1918 | max_mmapped_mem = mmapped_mem; |
---|
1919 | if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) |
---|
1920 | max_total_mem = mmapped_mem + sbrked_mem; |
---|
1921 | return p; |
---|
1922 | } |
---|
1923 | |
---|
1924 | #endif /* HAVE_MREMAP */ |
---|
1925 | |
---|
1926 | #endif /* HAVE_MMAP */ |
---|
1927 | |
---|
1928 | |
---|
1929 | |
---|
1930 | |
---|
1931 | /* |
---|
1932 | Extend the top-most chunk by obtaining memory from system. |
---|
1933 | Main interface to sbrk (but see also malloc_trim). |
---|
1934 | */ |
---|
1935 | |
---|
1936 | #if __STD_C |
---|
1937 | static void malloc_extend_top(INTERNAL_SIZE_T nb) |
---|
1938 | #else |
---|
1939 | static void malloc_extend_top(nb) INTERNAL_SIZE_T nb; |
---|
1940 | #endif |
---|
1941 | { |
---|
1942 | char* brk; /* return value from sbrk */ |
---|
1943 | INTERNAL_SIZE_T front_misalign; /* unusable bytes at front of sbrked space */ |
---|
1944 | INTERNAL_SIZE_T correction; /* bytes for 2nd sbrk call */ |
---|
1945 | char* new_brk; /* return of 2nd sbrk call */ |
---|
1946 | INTERNAL_SIZE_T top_size; /* new size of top chunk */ |
---|
1947 | |
---|
1948 | mchunkptr old_top = top; /* Record state of old top */ |
---|
1949 | INTERNAL_SIZE_T old_top_size = chunksize(old_top); |
---|
1950 | char* old_end = (char*)(chunk_at_offset(old_top, old_top_size)); |
---|
1951 | |
---|
1952 | /* Pad request with top_pad plus minimal overhead */ |
---|
1953 | |
---|
1954 | INTERNAL_SIZE_T sbrk_size = nb + top_pad + MINSIZE; |
---|
1955 | unsigned long pagesz = malloc_getpagesize; |
---|
1956 | |
---|
1957 | /* If not the first time through, round to preserve page boundary */ |
---|
1958 | /* Otherwise, we need to correct to a page size below anyway. */ |
---|
1959 | /* (We also correct below if an intervening foreign sbrk call.) */ |
---|
1960 | |
---|
1961 | if (sbrk_base != (char*)(-1)) |
---|
1962 | sbrk_size = (sbrk_size + (pagesz - 1)) & ~(pagesz - 1); |
---|
1963 | |
---|
1964 | brk = (char*)(MORECORE (sbrk_size)); |
---|
1965 | |
---|
1966 | /* Fail if sbrk failed or if a foreign sbrk call killed our space */ |
---|
1967 | if (brk == (char*)(MORECORE_FAILURE) || |
---|
1968 | (brk < old_end && old_top != initial_top)) |
---|
1969 | return; |
---|
1970 | |
---|
1971 | sbrked_mem += sbrk_size; |
---|
1972 | |
---|
1973 | if (brk == old_end) /* can just add bytes to current top */ |
---|
1974 | { |
---|
1975 | top_size = sbrk_size + old_top_size; |
---|
1976 | set_head(top, top_size | PREV_INUSE); |
---|
1977 | } |
---|
1978 | else |
---|
1979 | { |
---|
1980 | if (sbrk_base == (char*)(-1)) /* First time through. Record base */ |
---|
1981 | sbrk_base = brk; |
---|
1982 | else /* Someone else called sbrk(). Count those bytes as sbrked_mem. */ |
---|
1983 | sbrked_mem += brk - (char*)old_end; |
---|
1984 | |
---|
1985 | /* Guarantee alignment of first new chunk made from this space */ |
---|
1986 | front_misalign = (unsigned long)chunk2mem(brk) & MALLOC_ALIGN_MASK; |
---|
1987 | if (front_misalign > 0) |
---|
1988 | { |
---|
1989 | correction = (MALLOC_ALIGNMENT) - front_misalign; |
---|
1990 | brk += correction; |
---|
1991 | } |
---|
1992 | else |
---|
1993 | correction = 0; |
---|
1994 | |
---|
1995 | /* Guarantee the next brk will be at a page boundary */ |
---|
1996 | |
---|
1997 | correction += ((((unsigned long)(brk + sbrk_size))+(pagesz-1)) & |
---|
1998 | ~(pagesz - 1)) - ((unsigned long)(brk + sbrk_size)); |
---|
1999 | |
---|
2000 | /* Allocate correction */ |
---|
2001 | new_brk = (char*)(MORECORE (correction)); |
---|
2002 | if (new_brk == (char*)(MORECORE_FAILURE)) return; |
---|
2003 | |
---|
2004 | sbrked_mem += correction; |
---|
2005 | |
---|
2006 | top = (mchunkptr)brk; |
---|
2007 | top_size = new_brk - brk + correction; |
---|
2008 | set_head(top, top_size | PREV_INUSE); |
---|
2009 | |
---|
2010 | if (old_top != initial_top) |
---|
2011 | { |
---|
2012 | |
---|
2013 | /* There must have been an intervening foreign sbrk call. */ |
---|
2014 | /* A double fencepost is necessary to prevent consolidation */ |
---|
2015 | |
---|
2016 | /* If not enough space to do this, then user did something very wrong */ |
---|
2017 | if (old_top_size < MINSIZE) |
---|
2018 | { |
---|
2019 | set_head(top, PREV_INUSE); /* will force null return from malloc */ |
---|
2020 | return; |
---|
2021 | } |
---|
2022 | |
---|
2023 | /* Also keep size a multiple of MALLOC_ALIGNMENT */ |
---|
2024 | old_top_size = (old_top_size - 3*SIZE_SZ) & ~MALLOC_ALIGN_MASK; |
---|
2025 | set_head_size(old_top, old_top_size); |
---|
2026 | chunk_at_offset(old_top, old_top_size )->size = |
---|
2027 | SIZE_SZ|PREV_INUSE; |
---|
2028 | chunk_at_offset(old_top, old_top_size + SIZE_SZ)->size = |
---|
2029 | SIZE_SZ|PREV_INUSE; |
---|
2030 | /* If possible, release the rest. */ |
---|
2031 | if (old_top_size >= MINSIZE) |
---|
2032 | fREe(chunk2mem(old_top)); |
---|
2033 | } |
---|
2034 | } |
---|
2035 | |
---|
2036 | if ((unsigned long)sbrked_mem > (unsigned long)max_sbrked_mem) |
---|
2037 | max_sbrked_mem = sbrked_mem; |
---|
2038 | if ((unsigned long)(mmapped_mem + sbrked_mem) > (unsigned long)max_total_mem) |
---|
2039 | max_total_mem = mmapped_mem + sbrked_mem; |
---|
2040 | |
---|
2041 | /* We always land on a page boundary */ |
---|
2042 | assert(((unsigned long)((char*)top + top_size) & (pagesz - 1)) == 0); |
---|
2043 | } |
---|
2044 | |
---|
2045 | |
---|
2046 | |
---|
2047 | |
---|
2048 | /* Main public routines */ |
---|
2049 | |
---|
2050 | |
---|
2051 | /* |
---|
2052 | Malloc Algorthim: |
---|
2053 | |
---|
2054 | The requested size is first converted into a usable form, `nb'. |
---|
2055 | This currently means to add 4 bytes overhead plus possibly more to |
---|
2056 | obtain 8-byte alignment and/or to obtain a size of at least |
---|
2057 | MINSIZE (currently 16 bytes), the smallest allocatable size. |
---|
2058 | (All fits are considered `exact' if they are within MINSIZE bytes.) |
---|
2059 | |
---|
2060 | From there, the first successful of the following steps is taken: |
---|
2061 | |
---|
2062 | 1. The bin corresponding to the request size is scanned, and if |
---|
2063 | a chunk of exactly the right size is found, it is taken. |
---|
2064 | |
---|
2065 | 2. The most recently remaindered chunk is used if it is big |
---|
2066 | enough. This is a form of (roving) first fit, used only in |
---|
2067 | the absence of exact fits. Runs of consecutive requests use |
---|
2068 | the remainder of the chunk used for the previous such request |
---|
2069 | whenever possible. This limited use of a first-fit style |
---|
2070 | allocation strategy tends to give contiguous chunks |
---|
2071 | coextensive lifetimes, which improves locality and can reduce |
---|
2072 | fragmentation in the long run. |
---|
2073 | |
---|
2074 | 3. Other bins are scanned in increasing size order, using a |
---|
2075 | chunk big enough to fulfill the request, and splitting off |
---|
2076 | any remainder. This search is strictly by best-fit; i.e., |
---|
2077 | the smallest (with ties going to approximately the least |
---|
2078 | recently used) chunk that fits is selected. |
---|
2079 | |
---|
2080 | 4. If large enough, the chunk bordering the end of memory |
---|
2081 | (`top') is split off. (This use of `top' is in accord with |
---|
2082 | the best-fit search rule. In effect, `top' is treated as |
---|
2083 | larger (and thus less well fitting) than any other available |
---|
2084 | chunk since it can be extended to be as large as necessary |
---|
2085 | (up to system limitations). |
---|
2086 | |
---|
2087 | 5. If the request size meets the mmap threshold and the |
---|
2088 | system supports mmap, and there are few enough currently |
---|
2089 | allocated mmapped regions, and a call to mmap succeeds, |
---|
2090 | the request is allocated via direct memory mapping. |
---|
2091 | |
---|
2092 | 6. Otherwise, the top of memory is extended by |
---|
2093 | obtaining more space from the system (normally using sbrk, |
---|
2094 | but definable to anything else via the MORECORE macro). |
---|
2095 | Memory is gathered from the system (in system page-sized |
---|
2096 | units) in a way that allows chunks obtained across different |
---|
2097 | sbrk calls to be consolidated, but does not require |
---|
2098 | contiguous memory. Thus, it should be safe to intersperse |
---|
2099 | mallocs with other sbrk calls. |
---|
2100 | |
---|
2101 | |
---|
2102 | All allocations are made from the the `lowest' part of any found |
---|
2103 | chunk. (The implementation invariant is that prev_inuse is |
---|
2104 | always true of any allocated chunk; i.e., that each allocated |
---|
2105 | chunk borders either a previously allocated and still in-use chunk, |
---|
2106 | or the base of its memory arena.) |
---|
2107 | |
---|
2108 | */ |
---|
2109 | |
---|
2110 | #if __STD_C |
---|
2111 | Void_t* mALLOc(size_t bytes) |
---|
2112 | #else |
---|
2113 | Void_t* mALLOc(bytes) size_t bytes; |
---|
2114 | #endif |
---|
2115 | { |
---|
2116 | mchunkptr victim; /* inspected/selected chunk */ |
---|
2117 | INTERNAL_SIZE_T victim_size; /* its size */ |
---|
2118 | int idx; /* index for bin traversal */ |
---|
2119 | mbinptr bin; /* associated bin */ |
---|
2120 | mchunkptr remainder; /* remainder from a split */ |
---|
2121 | long remainder_size; /* its size */ |
---|
2122 | int remainder_index; /* its bin index */ |
---|
2123 | unsigned long block; /* block traverser bit */ |
---|
2124 | int startidx; /* first bin of a traversed block */ |
---|
2125 | mchunkptr fwd; /* misc temp for linking */ |
---|
2126 | mchunkptr bck; /* misc temp for linking */ |
---|
2127 | mbinptr q; /* misc temp */ |
---|
2128 | |
---|
2129 | INTERNAL_SIZE_T nb; |
---|
2130 | |
---|
2131 | if ((long)bytes < 0) return 0; |
---|
2132 | |
---|
2133 | nb = request2size(bytes); /* padded request size; */ |
---|
2134 | |
---|
2135 | /* Check for exact match in a bin */ |
---|
2136 | |
---|
2137 | if (is_small_request(nb)) /* Faster version for small requests */ |
---|
2138 | { |
---|
2139 | idx = smallbin_index(nb); |
---|
2140 | |
---|
2141 | /* No traversal or size check necessary for small bins. */ |
---|
2142 | |
---|
2143 | q = bin_at(idx); |
---|
2144 | victim = last(q); |
---|
2145 | |
---|
2146 | /* Also scan the next one, since it would have a remainder < MINSIZE */ |
---|
2147 | if (victim == q) |
---|
2148 | { |
---|
2149 | q = next_bin(q); |
---|
2150 | victim = last(q); |
---|
2151 | } |
---|
2152 | if (victim != q) |
---|
2153 | { |
---|
2154 | victim_size = chunksize(victim); |
---|
2155 | unlink(victim, bck, fwd); |
---|
2156 | set_inuse_bit_at_offset(victim, victim_size); |
---|
2157 | check_malloced_chunk(victim, nb); |
---|
2158 | return chunk2mem(victim); |
---|
2159 | } |
---|
2160 | |
---|
2161 | idx += 2; /* Set for bin scan below. We've already scanned 2 bins. */ |
---|
2162 | |
---|
2163 | } |
---|
2164 | else |
---|
2165 | { |
---|
2166 | idx = bin_index(nb); |
---|
2167 | bin = bin_at(idx); |
---|
2168 | |
---|
2169 | for (victim = last(bin); victim != bin; victim = victim->bk) |
---|
2170 | { |
---|
2171 | victim_size = chunksize(victim); |
---|
2172 | remainder_size = victim_size - nb; |
---|
2173 | |
---|
2174 | if (remainder_size >= (long)MINSIZE) /* too big */ |
---|
2175 | { |
---|
2176 | --idx; /* adjust to rescan below after checking last remainder */ |
---|
2177 | break; |
---|
2178 | } |
---|
2179 | |
---|
2180 | else if (remainder_size >= 0) /* exact fit */ |
---|
2181 | { |
---|
2182 | unlink(victim, bck, fwd); |
---|
2183 | set_inuse_bit_at_offset(victim, victim_size); |
---|
2184 | check_malloced_chunk(victim, nb); |
---|
2185 | return chunk2mem(victim); |
---|
2186 | } |
---|
2187 | } |
---|
2188 | |
---|
2189 | ++idx; |
---|
2190 | |
---|
2191 | } |
---|
2192 | |
---|
2193 | /* Try to use the last split-off remainder */ |
---|
2194 | |
---|
2195 | if ( (victim = last_remainder->fd) != last_remainder) |
---|
2196 | { |
---|
2197 | victim_size = chunksize(victim); |
---|
2198 | remainder_size = victim_size - nb; |
---|
2199 | |
---|
2200 | if (remainder_size >= (long)MINSIZE) /* re-split */ |
---|
2201 | { |
---|
2202 | remainder = chunk_at_offset(victim, nb); |
---|
2203 | set_head(victim, nb | PREV_INUSE); |
---|
2204 | link_last_remainder(remainder); |
---|
2205 | set_head(remainder, remainder_size | PREV_INUSE); |
---|
2206 | set_foot(remainder, remainder_size); |
---|
2207 | check_malloced_chunk(victim, nb); |
---|
2208 | return chunk2mem(victim); |
---|
2209 | } |
---|
2210 | |
---|
2211 | clear_last_remainder; |
---|
2212 | |
---|
2213 | if (remainder_size >= 0) /* exhaust */ |
---|
2214 | { |
---|
2215 | set_inuse_bit_at_offset(victim, victim_size); |
---|
2216 | check_malloced_chunk(victim, nb); |
---|
2217 | return chunk2mem(victim); |
---|
2218 | } |
---|
2219 | |
---|
2220 | /* Else place in bin */ |
---|
2221 | |
---|
2222 | frontlink(victim, victim_size, remainder_index, bck, fwd); |
---|
2223 | } |
---|
2224 | |
---|
2225 | /* |
---|
2226 | If there are any possibly nonempty big-enough blocks, |
---|
2227 | search for best fitting chunk by scanning bins in blockwidth units. |
---|
2228 | */ |
---|
2229 | |
---|
2230 | if ( (block = idx2binblock(idx)) <= binblocks) |
---|
2231 | { |
---|
2232 | |
---|
2233 | /* Get to the first marked block */ |
---|
2234 | |
---|
2235 | if ( (block & binblocks) == 0) |
---|
2236 | { |
---|
2237 | /* force to an even block boundary */ |
---|
2238 | idx = (idx & ~(BINBLOCKWIDTH - 1)) + BINBLOCKWIDTH; |
---|
2239 | block <<= 1; |
---|
2240 | while ((block & binblocks) == 0) |
---|
2241 | { |
---|
2242 | idx += BINBLOCKWIDTH; |
---|
2243 | block <<= 1; |
---|
2244 | } |
---|
2245 | } |
---|
2246 | |
---|
2247 | /* For each possibly nonempty block ... */ |
---|
2248 | for (;;) |
---|
2249 | { |
---|
2250 | startidx = idx; /* (track incomplete blocks) */ |
---|
2251 | q = bin = bin_at(idx); |
---|
2252 | |
---|
2253 | /* For each bin in this block ... */ |
---|
2254 | do |
---|
2255 | { |
---|
2256 | /* Find and use first big enough chunk ... */ |
---|
2257 | |
---|
2258 | for (victim = last(bin); victim != bin; victim = victim->bk) |
---|
2259 | { |
---|
2260 | victim_size = chunksize(victim); |
---|
2261 | remainder_size = victim_size - nb; |
---|
2262 | |
---|
2263 | if (remainder_size >= (long)MINSIZE) /* split */ |
---|
2264 | { |
---|
2265 | remainder = chunk_at_offset(victim, nb); |
---|
2266 | set_head(victim, nb | PREV_INUSE); |
---|
2267 | unlink(victim, bck, fwd); |
---|
2268 | link_last_remainder(remainder); |
---|
2269 | set_head(remainder, remainder_size | PREV_INUSE); |
---|
2270 | set_foot(remainder, remainder_size); |
---|
2271 | check_malloced_chunk(victim, nb); |
---|
2272 | return chunk2mem(victim); |
---|
2273 | } |
---|
2274 | |
---|
2275 | else if (remainder_size >= 0) /* take */ |
---|
2276 | { |
---|
2277 | set_inuse_bit_at_offset(victim, victim_size); |
---|
2278 | unlink(victim, bck, fwd); |
---|
2279 | check_malloced_chunk(victim, nb); |
---|
2280 | return chunk2mem(victim); |
---|
2281 | } |
---|
2282 | |
---|
2283 | } |
---|
2284 | |
---|
2285 | bin = next_bin(bin); |
---|
2286 | |
---|
2287 | } while ((++idx & (BINBLOCKWIDTH - 1)) != 0); |
---|
2288 | |
---|
2289 | /* Clear out the block bit. */ |
---|
2290 | |
---|
2291 | do /* Possibly backtrack to try to clear a partial block */ |
---|
2292 | { |
---|
2293 | if ((startidx & (BINBLOCKWIDTH - 1)) == 0) |
---|
2294 | { |
---|
2295 | binblocks &= ~block; |
---|
2296 | break; |
---|
2297 | } |
---|
2298 | --startidx; |
---|
2299 | q = prev_bin(q); |
---|
2300 | } while (first(q) == q); |
---|
2301 | |
---|
2302 | /* Get to the next possibly nonempty block */ |
---|
2303 | |
---|
2304 | if ( (block <<= 1) <= binblocks && (block != 0) ) |
---|
2305 | { |
---|
2306 | while ((block & binblocks) == 0) |
---|
2307 | { |
---|
2308 | idx += BINBLOCKWIDTH; |
---|
2309 | block <<= 1; |
---|
2310 | } |
---|
2311 | } |
---|
2312 | else |
---|
2313 | break; |
---|
2314 | } |
---|
2315 | } |
---|
2316 | |
---|
2317 | |
---|
2318 | /* Try to use top chunk */ |
---|
2319 | |
---|
2320 | /* Require that there be a remainder, ensuring top always exists */ |
---|
2321 | if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE) |
---|
2322 | { |
---|
2323 | |
---|
2324 | #if HAVE_MMAP |
---|
2325 | /* If big and would otherwise need to extend, try to use mmap instead */ |
---|
2326 | if ((unsigned long)nb >= (unsigned long)mmap_threshold && |
---|
2327 | (victim = mmap_chunk(nb)) != 0) |
---|
2328 | return chunk2mem(victim); |
---|
2329 | #endif |
---|
2330 | |
---|
2331 | /* Try to extend */ |
---|
2332 | malloc_extend_top(nb); |
---|
2333 | if ( (remainder_size = chunksize(top) - nb) < (long)MINSIZE) |
---|
2334 | return 0; /* propagate failure */ |
---|
2335 | } |
---|
2336 | |
---|
2337 | victim = top; |
---|
2338 | set_head(victim, nb | PREV_INUSE); |
---|
2339 | top = chunk_at_offset(victim, nb); |
---|
2340 | set_head(top, remainder_size | PREV_INUSE); |
---|
2341 | check_malloced_chunk(victim, nb); |
---|
2342 | return chunk2mem(victim); |
---|
2343 | |
---|
2344 | } |
---|
2345 | |
---|
2346 | |
---|
2347 | |
---|
2348 | |
---|
2349 | /* |
---|
2350 | |
---|
2351 | free() algorithm : |
---|
2352 | |
---|
2353 | cases: |
---|
2354 | |
---|
2355 | 1. free(0) has no effect. |
---|
2356 | |
---|
2357 | 2. If the chunk was allocated via mmap, it is release via munmap(). |
---|
2358 | |
---|
2359 | 3. If a returned chunk borders the current high end of memory, |
---|
2360 | it is consolidated into the top, and if the total unused |
---|
2361 | topmost memory exceeds the trim threshold, malloc_trim is |
---|
2362 | called. |
---|
2363 | |
---|
2364 | 4. Other chunks are consolidated as they arrive, and |
---|
2365 | placed in corresponding bins. (This includes the case of |
---|
2366 | consolidating with the current `last_remainder'). |
---|
2367 | |
---|
2368 | */ |
---|
2369 | |
---|
2370 | |
---|
2371 | #if __STD_C |
---|
2372 | void fREe(Void_t* mem) |
---|
2373 | #else |
---|
2374 | void fREe(mem) Void_t* mem; |
---|
2375 | #endif |
---|
2376 | { |
---|
2377 | mchunkptr p; /* chunk corresponding to mem */ |
---|
2378 | INTERNAL_SIZE_T hd; /* its head field */ |
---|
2379 | INTERNAL_SIZE_T sz; /* its size */ |
---|
2380 | int idx; /* its bin index */ |
---|
2381 | mchunkptr next; /* next contiguous chunk */ |
---|
2382 | INTERNAL_SIZE_T nextsz; /* its size */ |
---|
2383 | INTERNAL_SIZE_T prevsz; /* size of previous contiguous chunk */ |
---|
2384 | mchunkptr bck; /* misc temp for linking */ |
---|
2385 | mchunkptr fwd; /* misc temp for linking */ |
---|
2386 | int islr; /* track whether merging with last_remainder */ |
---|
2387 | |
---|
2388 | if (mem == 0) /* free(0) has no effect */ |
---|
2389 | return; |
---|
2390 | |
---|
2391 | p = mem2chunk(mem); |
---|
2392 | hd = p->size; |
---|
2393 | |
---|
2394 | #if HAVE_MMAP |
---|
2395 | if (hd & IS_MMAPPED) /* release mmapped memory. */ |
---|
2396 | { |
---|
2397 | munmap_chunk(p); |
---|
2398 | return; |
---|
2399 | } |
---|
2400 | #endif |
---|
2401 | |
---|
2402 | check_inuse_chunk(p); |
---|
2403 | |
---|
2404 | sz = hd & ~PREV_INUSE; |
---|
2405 | next = chunk_at_offset(p, sz); |
---|
2406 | nextsz = chunksize(next); |
---|
2407 | |
---|
2408 | if (next == top) /* merge with top */ |
---|
2409 | { |
---|
2410 | sz += nextsz; |
---|
2411 | |
---|
2412 | if (!(hd & PREV_INUSE)) /* consolidate backward */ |
---|
2413 | { |
---|
2414 | prevsz = p->prev_size; |
---|
2415 | p = chunk_at_offset(p, -((long) prevsz)); |
---|
2416 | sz += prevsz; |
---|
2417 | unlink(p, bck, fwd); |
---|
2418 | } |
---|
2419 | |
---|
2420 | set_head(p, sz | PREV_INUSE); |
---|
2421 | top = p; |
---|
2422 | if ((unsigned long)(sz) >= (unsigned long)trim_threshold) |
---|
2423 | malloc_trim(top_pad); |
---|
2424 | return; |
---|
2425 | } |
---|
2426 | |
---|
2427 | set_head(next, nextsz); /* clear inuse bit */ |
---|
2428 | |
---|
2429 | islr = 0; |
---|
2430 | |
---|
2431 | if (!(hd & PREV_INUSE)) /* consolidate backward */ |
---|
2432 | { |
---|
2433 | prevsz = p->prev_size; |
---|
2434 | p = chunk_at_offset(p, -((long) prevsz)); |
---|
2435 | sz += prevsz; |
---|
2436 | |
---|
2437 | if (p->fd == last_remainder) /* keep as last_remainder */ |
---|
2438 | islr = 1; |
---|
2439 | else |
---|
2440 | unlink(p, bck, fwd); |
---|
2441 | } |
---|
2442 | |
---|
2443 | if (!(inuse_bit_at_offset(next, nextsz))) /* consolidate forward */ |
---|
2444 | { |
---|
2445 | sz += nextsz; |
---|
2446 | |
---|
2447 | if (!islr && next->fd == last_remainder) /* re-insert last_remainder */ |
---|
2448 | { |
---|
2449 | islr = 1; |
---|
2450 | link_last_remainder(p); |
---|
2451 | } |
---|
2452 | else |
---|
2453 | unlink(next, bck, fwd); |
---|
2454 | } |
---|
2455 | |
---|
2456 | |
---|
2457 | set_head(p, sz | PREV_INUSE); |
---|
2458 | set_foot(p, sz); |
---|
2459 | if (!islr) |
---|
2460 | frontlink(p, sz, idx, bck, fwd); |
---|
2461 | } |
---|
2462 | |
---|
2463 | |
---|
2464 | |
---|
2465 | |
---|
2466 | |
---|
2467 | /* |
---|
2468 | |
---|
2469 | Realloc algorithm: |
---|
2470 | |
---|
2471 | Chunks that were obtained via mmap cannot be extended or shrunk |
---|
2472 | unless HAVE_MREMAP is defined, in which case mremap is used. |
---|
2473 | Otherwise, if their reallocation is for additional space, they are |
---|
2474 | copied. If for less, they are just left alone. |
---|
2475 | |
---|
2476 | Otherwise, if the reallocation is for additional space, and the |
---|
2477 | chunk can be extended, it is, else a malloc-copy-free sequence is |
---|
2478 | taken. There are several different ways that a chunk could be |
---|
2479 | extended. All are tried: |
---|
2480 | |
---|
2481 | * Extending forward into following adjacent free chunk. |
---|
2482 | * Shifting backwards, joining preceding adjacent space |
---|
2483 | * Both shifting backwards and extending forward. |
---|
2484 | * Extending into newly sbrked space |
---|
2485 | |
---|
2486 | Unless the #define REALLOC_ZERO_BYTES_FREES is set, realloc with a |
---|
2487 | size argument of zero (re)allocates a minimum-sized chunk. |
---|
2488 | |
---|
2489 | If the reallocation is for less space, and the new request is for |
---|
2490 | a `small' (<512 bytes) size, then the newly unused space is lopped |
---|
2491 | off and freed. |
---|
2492 | |
---|
2493 | The old unix realloc convention of allowing the last-free'd chunk |
---|
2494 | to be used as an argument to realloc is no longer supported. |
---|
2495 | I don't know of any programs still relying on this feature, |
---|
2496 | and allowing it would also allow too many other incorrect |
---|
2497 | usages of realloc to be sensible. |
---|
2498 | |
---|
2499 | |
---|
2500 | */ |
---|
2501 | |
---|
2502 | |
---|
2503 | #if __STD_C |
---|
2504 | Void_t* rEALLOc(Void_t* oldmem, size_t bytes) |
---|
2505 | #else |
---|
2506 | Void_t* rEALLOc(oldmem, bytes) Void_t* oldmem; size_t bytes; |
---|
2507 | #endif |
---|
2508 | { |
---|
2509 | INTERNAL_SIZE_T nb; /* padded request size */ |
---|
2510 | |
---|
2511 | mchunkptr oldp; /* chunk corresponding to oldmem */ |
---|
2512 | INTERNAL_SIZE_T oldsize; /* its size */ |
---|
2513 | |
---|
2514 | mchunkptr newp; /* chunk to return */ |
---|
2515 | INTERNAL_SIZE_T newsize; /* its size */ |
---|
2516 | Void_t* newmem; /* corresponding user mem */ |
---|
2517 | |
---|
2518 | mchunkptr next; /* next contiguous chunk after oldp */ |
---|
2519 | INTERNAL_SIZE_T nextsize; /* its size */ |
---|
2520 | |
---|
2521 | mchunkptr prev; /* previous contiguous chunk before oldp */ |
---|
2522 | INTERNAL_SIZE_T prevsize; /* its size */ |
---|
2523 | |
---|
2524 | mchunkptr remainder; /* holds split off extra space from newp */ |
---|
2525 | INTERNAL_SIZE_T remainder_size; /* its size */ |
---|
2526 | |
---|
2527 | mchunkptr bck; /* misc temp for linking */ |
---|
2528 | mchunkptr fwd; /* misc temp for linking */ |
---|
2529 | |
---|
2530 | #ifdef REALLOC_ZERO_BYTES_FREES |
---|
2531 | if (bytes == 0) { fREe(oldmem); return 0; } |
---|
2532 | #endif |
---|
2533 | |
---|
2534 | if ((long)bytes < 0) return 0; |
---|
2535 | |
---|
2536 | /* realloc of null is supposed to be same as malloc */ |
---|
2537 | if (oldmem == 0) return mALLOc(bytes); |
---|
2538 | |
---|
2539 | newp = oldp = mem2chunk(oldmem); |
---|
2540 | newsize = oldsize = chunksize(oldp); |
---|
2541 | |
---|
2542 | |
---|
2543 | nb = request2size(bytes); |
---|
2544 | |
---|
2545 | #if HAVE_MMAP |
---|
2546 | if (chunk_is_mmapped(oldp)) |
---|
2547 | { |
---|
2548 | #if HAVE_MREMAP |
---|
2549 | newp = mremap_chunk(oldp, nb); |
---|
2550 | if(newp) return chunk2mem(newp); |
---|
2551 | #endif |
---|
2552 | /* Note the extra SIZE_SZ overhead. */ |
---|
2553 | if(oldsize - SIZE_SZ >= nb) return oldmem; /* do nothing */ |
---|
2554 | /* Must alloc, copy, free. */ |
---|
2555 | newmem = mALLOc(bytes); |
---|
2556 | if (newmem == 0) return 0; /* propagate failure */ |
---|
2557 | MALLOC_COPY(newmem, oldmem, oldsize - 2*SIZE_SZ); |
---|
2558 | munmap_chunk(oldp); |
---|
2559 | return newmem; |
---|
2560 | } |
---|
2561 | #endif |
---|
2562 | |
---|
2563 | check_inuse_chunk(oldp); |
---|
2564 | |
---|
2565 | if ((long)(oldsize) < (long)(nb)) |
---|
2566 | { |
---|
2567 | |
---|
2568 | /* Try expanding forward */ |
---|
2569 | |
---|
2570 | next = chunk_at_offset(oldp, oldsize); |
---|
2571 | if (next == top || !inuse(next)) |
---|
2572 | { |
---|
2573 | nextsize = chunksize(next); |
---|
2574 | |
---|
2575 | /* Forward into top only if a remainder */ |
---|
2576 | if (next == top) |
---|
2577 | { |
---|
2578 | if ((long)(nextsize + newsize) >= (long)(nb + MINSIZE)) |
---|
2579 | { |
---|
2580 | newsize += nextsize; |
---|
2581 | top = chunk_at_offset(oldp, nb); |
---|
2582 | set_head(top, (newsize - nb) | PREV_INUSE); |
---|
2583 | set_head_size(oldp, nb); |
---|
2584 | return chunk2mem(oldp); |
---|
2585 | } |
---|
2586 | } |
---|
2587 | |
---|
2588 | /* Forward into next chunk */ |
---|
2589 | else if (((long)(nextsize + newsize) >= (long)(nb))) |
---|
2590 | { |
---|
2591 | unlink(next, bck, fwd); |
---|
2592 | newsize += nextsize; |
---|
2593 | goto split; |
---|
2594 | } |
---|
2595 | } |
---|
2596 | else |
---|
2597 | { |
---|
2598 | next = 0; |
---|
2599 | nextsize = 0; |
---|
2600 | } |
---|
2601 | |
---|
2602 | /* Try shifting backwards. */ |
---|
2603 | |
---|
2604 | if (!prev_inuse(oldp)) |
---|
2605 | { |
---|
2606 | prev = prev_chunk(oldp); |
---|
2607 | prevsize = chunksize(prev); |
---|
2608 | |
---|
2609 | /* try forward + backward first to save a later consolidation */ |
---|
2610 | |
---|
2611 | if (next != 0) |
---|
2612 | { |
---|
2613 | /* into top */ |
---|
2614 | if (next == top) |
---|
2615 | { |
---|
2616 | if ((long)(nextsize + prevsize + newsize) >= (long)(nb + MINSIZE)) |
---|
2617 | { |
---|
2618 | unlink(prev, bck, fwd); |
---|
2619 | newp = prev; |
---|
2620 | newsize += prevsize + nextsize; |
---|
2621 | newmem = chunk2mem(newp); |
---|
2622 | MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ); |
---|
2623 | top = chunk_at_offset(newp, nb); |
---|
2624 | set_head(top, (newsize - nb) | PREV_INUSE); |
---|
2625 | set_head_size(newp, nb); |
---|
2626 | return newmem; |
---|
2627 | } |
---|
2628 | } |
---|
2629 | |
---|
2630 | /* into next chunk */ |
---|
2631 | else if (((long)(nextsize + prevsize + newsize) >= (long)(nb))) |
---|
2632 | { |
---|
2633 | unlink(next, bck, fwd); |
---|
2634 | unlink(prev, bck, fwd); |
---|
2635 | newp = prev; |
---|
2636 | newsize += nextsize + prevsize; |
---|
2637 | newmem = chunk2mem(newp); |
---|
2638 | MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ); |
---|
2639 | goto split; |
---|
2640 | } |
---|
2641 | } |
---|
2642 | |
---|
2643 | /* backward only */ |
---|
2644 | if (prev != 0 && (long)(prevsize + newsize) >= (long)nb) |
---|
2645 | { |
---|
2646 | unlink(prev, bck, fwd); |
---|
2647 | newp = prev; |
---|
2648 | newsize += prevsize; |
---|
2649 | newmem = chunk2mem(newp); |
---|
2650 | MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ); |
---|
2651 | goto split; |
---|
2652 | } |
---|
2653 | } |
---|
2654 | |
---|
2655 | /* Must allocate */ |
---|
2656 | |
---|
2657 | newmem = mALLOc (bytes); |
---|
2658 | |
---|
2659 | if (newmem == 0) /* propagate failure */ |
---|
2660 | return 0; |
---|
2661 | |
---|
2662 | /* Avoid copy if newp is next chunk after oldp. */ |
---|
2663 | /* (This can only happen when new chunk is sbrk'ed.) */ |
---|
2664 | |
---|
2665 | if ( (newp = mem2chunk(newmem)) == next_chunk(oldp)) |
---|
2666 | { |
---|
2667 | newsize += chunksize(newp); |
---|
2668 | newp = oldp; |
---|
2669 | goto split; |
---|
2670 | } |
---|
2671 | |
---|
2672 | /* Otherwise copy, free, and exit */ |
---|
2673 | MALLOC_COPY(newmem, oldmem, oldsize - SIZE_SZ); |
---|
2674 | fREe(oldmem); |
---|
2675 | return newmem; |
---|
2676 | } |
---|
2677 | |
---|
2678 | |
---|
2679 | split: /* split off extra room in old or expanded chunk */ |
---|
2680 | |
---|
2681 | if (newsize - nb >= MINSIZE) /* split off remainder */ |
---|
2682 | { |
---|
2683 | remainder = chunk_at_offset(newp, nb); |
---|
2684 | remainder_size = newsize - nb; |
---|
2685 | set_head_size(newp, nb); |
---|
2686 | set_head(remainder, remainder_size | PREV_INUSE); |
---|
2687 | set_inuse_bit_at_offset(remainder, remainder_size); |
---|
2688 | fREe(chunk2mem(remainder)); /* let free() deal with it */ |
---|
2689 | } |
---|
2690 | else |
---|
2691 | { |
---|
2692 | set_head_size(newp, newsize); |
---|
2693 | set_inuse_bit_at_offset(newp, newsize); |
---|
2694 | } |
---|
2695 | |
---|
2696 | check_inuse_chunk(newp); |
---|
2697 | return chunk2mem(newp); |
---|
2698 | } |
---|
2699 | |
---|
2700 | |
---|
2701 | |
---|
2702 | |
---|
2703 | /* |
---|
2704 | |
---|
2705 | memalign algorithm: |
---|
2706 | |
---|
2707 | memalign requests more than enough space from malloc, finds a spot |
---|
2708 | within that chunk that meets the alignment request, and then |
---|
2709 | possibly frees the leading and trailing space. |
---|
2710 | |
---|
2711 | The alignment argument must be a power of two. This property is not |
---|
2712 | checked by memalign, so misuse may result in random runtime errors. |
---|
2713 | |
---|
2714 | 8-byte alignment is guaranteed by normal malloc calls, so don't |
---|
2715 | bother calling memalign with an argument of 8 or less. |
---|
2716 | |
---|
2717 | Overreliance on memalign is a sure way to fragment space. |
---|
2718 | |
---|
2719 | */ |
---|
2720 | |
---|
2721 | |
---|
2722 | #if __STD_C |
---|
2723 | Void_t* mEMALIGn(size_t alignment, size_t bytes) |
---|
2724 | #else |
---|
2725 | Void_t* mEMALIGn(alignment, bytes) size_t alignment; size_t bytes; |
---|
2726 | #endif |
---|
2727 | { |
---|
2728 | INTERNAL_SIZE_T nb; /* padded request size */ |
---|
2729 | char* m; /* memory returned by malloc call */ |
---|
2730 | mchunkptr p; /* corresponding chunk */ |
---|
2731 | char* brk; /* alignment point within p */ |
---|
2732 | mchunkptr newp; /* chunk to return */ |
---|
2733 | INTERNAL_SIZE_T newsize; /* its size */ |
---|
2734 | INTERNAL_SIZE_T leadsize; /* leading space befor alignment point */ |
---|
2735 | mchunkptr remainder; /* spare room at end to split off */ |
---|
2736 | long remainder_size; /* its size */ |
---|
2737 | |
---|
2738 | if ((long)bytes < 0) return 0; |
---|
2739 | |
---|
2740 | /* If need less alignment than we give anyway, just relay to malloc */ |
---|
2741 | |
---|
2742 | if (alignment <= MALLOC_ALIGNMENT) return mALLOc(bytes); |
---|
2743 | |
---|
2744 | /* Otherwise, ensure that it is at least a minimum chunk size */ |
---|
2745 | |
---|
2746 | if (alignment < MINSIZE) alignment = MINSIZE; |
---|
2747 | |
---|
2748 | /* Call malloc with worst case padding to hit alignment. */ |
---|
2749 | |
---|
2750 | nb = request2size(bytes); |
---|
2751 | m = (char*)(mALLOc(nb + alignment + MINSIZE)); |
---|
2752 | |
---|
2753 | if (m == 0) return 0; /* propagate failure */ |
---|
2754 | |
---|
2755 | p = mem2chunk(m); |
---|
2756 | |
---|
2757 | if ((((unsigned long)(m)) % alignment) == 0) /* aligned */ |
---|
2758 | { |
---|
2759 | #if HAVE_MMAP |
---|
2760 | if(chunk_is_mmapped(p)) |
---|
2761 | return chunk2mem(p); /* nothing more to do */ |
---|
2762 | #endif |
---|
2763 | } |
---|
2764 | else /* misaligned */ |
---|
2765 | { |
---|
2766 | /* |
---|
2767 | Find an aligned spot inside chunk. |
---|
2768 | Since we need to give back leading space in a chunk of at |
---|
2769 | least MINSIZE, if the first calculation places us at |
---|
2770 | a spot with less than MINSIZE leader, we can move to the |
---|
2771 | next aligned spot -- we've allocated enough total room so that |
---|
2772 | this is always possible. |
---|
2773 | */ |
---|
2774 | |
---|
2775 | brk = (char*)mem2chunk(((unsigned long)(m + alignment - 1)) & -((signed) alignment)); |
---|
2776 | if ((long)(brk - (char*)(p)) < MINSIZE) brk = brk + alignment; |
---|
2777 | |
---|
2778 | newp = (mchunkptr)brk; |
---|
2779 | leadsize = brk - (char*)(p); |
---|
2780 | newsize = chunksize(p) - leadsize; |
---|
2781 | |
---|
2782 | #if HAVE_MMAP |
---|
2783 | if(chunk_is_mmapped(p)) |
---|
2784 | { |
---|
2785 | newp->prev_size = p->prev_size + leadsize; |
---|
2786 | set_head(newp, newsize|IS_MMAPPED); |
---|
2787 | return chunk2mem(newp); |
---|
2788 | } |
---|
2789 | #endif |
---|
2790 | |
---|
2791 | /* give back leader, use the rest */ |
---|
2792 | |
---|
2793 | set_head(newp, newsize | PREV_INUSE); |
---|
2794 | set_inuse_bit_at_offset(newp, newsize); |
---|
2795 | set_head_size(p, leadsize); |
---|
2796 | fREe(chunk2mem(p)); |
---|
2797 | p = newp; |
---|
2798 | |
---|
2799 | assert (newsize >= nb && (((unsigned long)(chunk2mem(p))) % alignment) == 0); |
---|
2800 | } |
---|
2801 | |
---|
2802 | /* Also give back spare room at the end */ |
---|
2803 | |
---|
2804 | remainder_size = chunksize(p) - nb; |
---|
2805 | |
---|
2806 | if (remainder_size >= (long)MINSIZE) |
---|
2807 | { |
---|
2808 | remainder = chunk_at_offset(p, nb); |
---|
2809 | set_head(remainder, remainder_size | PREV_INUSE); |
---|
2810 | set_head_size(p, nb); |
---|
2811 | fREe(chunk2mem(remainder)); |
---|
2812 | } |
---|
2813 | |
---|
2814 | check_inuse_chunk(p); |
---|
2815 | return chunk2mem(p); |
---|
2816 | |
---|
2817 | } |
---|
2818 | |
---|
2819 | |
---|
2820 | |
---|
2821 | |
---|
2822 | /* |
---|
2823 | valloc just invokes memalign with alignment argument equal |
---|
2824 | to the page size of the system (or as near to this as can |
---|
2825 | be figured out from all the includes/defines above.) |
---|
2826 | */ |
---|
2827 | |
---|
2828 | #if __STD_C |
---|
2829 | Void_t* vALLOc(size_t bytes) |
---|
2830 | #else |
---|
2831 | Void_t* vALLOc(bytes) size_t bytes; |
---|
2832 | #endif |
---|
2833 | { |
---|
2834 | return mEMALIGn (malloc_getpagesize, bytes); |
---|
2835 | } |
---|
2836 | |
---|
2837 | /* |
---|
2838 | pvalloc just invokes valloc for the nearest pagesize |
---|
2839 | that will accommodate request |
---|
2840 | */ |
---|
2841 | |
---|
2842 | |
---|
2843 | #if __STD_C |
---|
2844 | Void_t* pvALLOc(size_t bytes) |
---|
2845 | #else |
---|
2846 | Void_t* pvALLOc(bytes) size_t bytes; |
---|
2847 | #endif |
---|
2848 | { |
---|
2849 | size_t pagesize = malloc_getpagesize; |
---|
2850 | return mEMALIGn (pagesize, (bytes + pagesize - 1) & ~(pagesize - 1)); |
---|
2851 | } |
---|
2852 | |
---|
2853 | /* |
---|
2854 | |
---|
2855 | calloc calls malloc, then zeroes out the allocated chunk. |
---|
2856 | |
---|
2857 | */ |
---|
2858 | |
---|
2859 | #if __STD_C |
---|
2860 | Void_t* cALLOc(size_t n, size_t elem_size) |
---|
2861 | #else |
---|
2862 | Void_t* cALLOc(n, elem_size) size_t n; size_t elem_size; |
---|
2863 | #endif |
---|
2864 | { |
---|
2865 | mchunkptr p; |
---|
2866 | INTERNAL_SIZE_T csz; |
---|
2867 | |
---|
2868 | INTERNAL_SIZE_T sz = n * elem_size; |
---|
2869 | |
---|
2870 | |
---|
2871 | /* check if expand_top called, in which case don't need to clear */ |
---|
2872 | #if MORECORE_CLEARS |
---|
2873 | mchunkptr oldtop = top; |
---|
2874 | INTERNAL_SIZE_T oldtopsize = chunksize(top); |
---|
2875 | #endif |
---|
2876 | Void_t* mem = mALLOc (sz); |
---|
2877 | |
---|
2878 | if ((long)n < 0) return 0; |
---|
2879 | |
---|
2880 | if (mem == 0) |
---|
2881 | return 0; |
---|
2882 | else |
---|
2883 | { |
---|
2884 | p = mem2chunk(mem); |
---|
2885 | |
---|
2886 | /* Two optional cases in which clearing not necessary */ |
---|
2887 | |
---|
2888 | |
---|
2889 | #if HAVE_MMAP |
---|
2890 | if (chunk_is_mmapped(p)) return mem; |
---|
2891 | #endif |
---|
2892 | |
---|
2893 | csz = chunksize(p); |
---|
2894 | |
---|
2895 | #if MORECORE_CLEARS |
---|
2896 | if (p == oldtop && csz > oldtopsize) |
---|
2897 | { |
---|
2898 | /* clear only the bytes from non-freshly-sbrked memory */ |
---|
2899 | csz = oldtopsize; |
---|
2900 | } |
---|
2901 | #endif |
---|
2902 | |
---|
2903 | MALLOC_ZERO(mem, csz - SIZE_SZ); |
---|
2904 | return mem; |
---|
2905 | } |
---|
2906 | } |
---|
2907 | |
---|
2908 | /* |
---|
2909 | |
---|
2910 | cfree just calls free. It is needed/defined on some systems |
---|
2911 | that pair it with calloc, presumably for odd historical reasons. |
---|
2912 | |
---|
2913 | */ |
---|
2914 | |
---|
2915 | #if !defined(INTERNAL_LINUX_C_LIB) || !defined(__ELF__) |
---|
2916 | #if __STD_C |
---|
2917 | void cfree(Void_t *mem) |
---|
2918 | #else |
---|
2919 | void cfree(mem) Void_t *mem; |
---|
2920 | #endif |
---|
2921 | { |
---|
2922 | fREe(mem); |
---|
2923 | } |
---|
2924 | #endif |
---|
2925 | |
---|
2926 | |
---|
2927 | |
---|
2928 | /* |
---|
2929 | |
---|
2930 | Malloc_trim gives memory back to the system (via negative |
---|
2931 | arguments to sbrk) if there is unused memory at the `high' end of |
---|
2932 | the malloc pool. You can call this after freeing large blocks of |
---|
2933 | memory to potentially reduce the system-level memory requirements |
---|
2934 | of a program. However, it cannot guarantee to reduce memory. Under |
---|
2935 | some allocation patterns, some large free blocks of memory will be |
---|
2936 | locked between two used chunks, so they cannot be given back to |
---|
2937 | the system. |
---|
2938 | |
---|
2939 | The `pad' argument to malloc_trim represents the amount of free |
---|
2940 | trailing space to leave untrimmed. If this argument is zero, |
---|
2941 | only the minimum amount of memory to maintain internal data |
---|
2942 | structures will be left (one page or less). Non-zero arguments |
---|
2943 | can be supplied to maintain enough trailing space to service |
---|
2944 | future expected allocations without having to re-obtain memory |
---|
2945 | from the system. |
---|
2946 | |
---|
2947 | Malloc_trim returns 1 if it actually released any memory, else 0. |
---|
2948 | |
---|
2949 | */ |
---|
2950 | |
---|
2951 | #if __STD_C |
---|
2952 | int malloc_trim(size_t pad) |
---|
2953 | #else |
---|
2954 | int malloc_trim(pad) size_t pad; |
---|
2955 | #endif |
---|
2956 | { |
---|
2957 | long top_size; /* Amount of top-most memory */ |
---|
2958 | long extra; /* Amount to release */ |
---|
2959 | char* current_brk; /* address returned by pre-check sbrk call */ |
---|
2960 | char* new_brk; /* address returned by negative sbrk call */ |
---|
2961 | |
---|
2962 | unsigned long pagesz = malloc_getpagesize; |
---|
2963 | |
---|
2964 | top_size = chunksize(top); |
---|
2965 | extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz; |
---|
2966 | |
---|
2967 | if (extra < (long)pagesz) /* Not enough memory to release */ |
---|
2968 | return 0; |
---|
2969 | |
---|
2970 | else |
---|
2971 | { |
---|
2972 | /* Test to make sure no one else called sbrk */ |
---|
2973 | current_brk = (char*)(MORECORE (0)); |
---|
2974 | if (current_brk != (char*)(top) + top_size) |
---|
2975 | return 0; /* Apparently we don't own memory; must fail */ |
---|
2976 | |
---|
2977 | else |
---|
2978 | { |
---|
2979 | new_brk = (char*)(MORECORE (-extra)); |
---|
2980 | |
---|
2981 | if (new_brk == (char*)(MORECORE_FAILURE)) /* sbrk failed? */ |
---|
2982 | { |
---|
2983 | /* Try to figure out what we have */ |
---|
2984 | current_brk = (char*)(MORECORE (0)); |
---|
2985 | top_size = current_brk - (char*)top; |
---|
2986 | if (top_size >= (long)MINSIZE) /* if not, we are very very dead! */ |
---|
2987 | { |
---|
2988 | sbrked_mem = current_brk - sbrk_base; |
---|
2989 | set_head(top, top_size | PREV_INUSE); |
---|
2990 | } |
---|
2991 | check_chunk(top); |
---|
2992 | return 0; |
---|
2993 | } |
---|
2994 | |
---|
2995 | else |
---|
2996 | { |
---|
2997 | /* Success. Adjust top accordingly. */ |
---|
2998 | set_head(top, (top_size - extra) | PREV_INUSE); |
---|
2999 | sbrked_mem -= extra; |
---|
3000 | check_chunk(top); |
---|
3001 | return 1; |
---|
3002 | } |
---|
3003 | } |
---|
3004 | } |
---|
3005 | } |
---|
3006 | |
---|
3007 | |
---|
3008 | |
---|
3009 | /* |
---|
3010 | malloc_usable_size: |
---|
3011 | |
---|
3012 | This routine tells you how many bytes you can actually use in an |
---|
3013 | allocated chunk, which may be more than you requested (although |
---|
3014 | often not). You can use this many bytes without worrying about |
---|
3015 | overwriting other allocated objects. Not a particularly great |
---|
3016 | programming practice, but still sometimes useful. |
---|
3017 | |
---|
3018 | */ |
---|
3019 | |
---|
3020 | #if __STD_C |
---|
3021 | size_t malloc_usable_size(Void_t* mem) |
---|
3022 | #else |
---|
3023 | size_t malloc_usable_size(mem) Void_t* mem; |
---|
3024 | #endif |
---|
3025 | { |
---|
3026 | mchunkptr p; |
---|
3027 | if (mem == 0) |
---|
3028 | return 0; |
---|
3029 | else |
---|
3030 | { |
---|
3031 | p = mem2chunk(mem); |
---|
3032 | if(!chunk_is_mmapped(p)) |
---|
3033 | { |
---|
3034 | if (!inuse(p)) return 0; |
---|
3035 | check_inuse_chunk(p); |
---|
3036 | return chunksize(p) - SIZE_SZ; |
---|
3037 | } |
---|
3038 | return chunksize(p) - 2*SIZE_SZ; |
---|
3039 | } |
---|
3040 | } |
---|
3041 | |
---|
3042 | |
---|
3043 | |
---|
3044 | |
---|
3045 | /* Utility to update current_mallinfo for malloc_stats and mallinfo() */ |
---|
3046 | |
---|
3047 | static void malloc_update_mallinfo() |
---|
3048 | { |
---|
3049 | int i; |
---|
3050 | mbinptr b; |
---|
3051 | mchunkptr p; |
---|
3052 | #if DEBUG |
---|
3053 | mchunkptr q; |
---|
3054 | #endif |
---|
3055 | |
---|
3056 | INTERNAL_SIZE_T avail = chunksize(top); |
---|
3057 | int navail = ((long)(avail) >= (long)MINSIZE)? 1 : 0; |
---|
3058 | |
---|
3059 | for (i = 1; i < NAV; ++i) |
---|
3060 | { |
---|
3061 | b = bin_at(i); |
---|
3062 | for (p = last(b); p != b; p = p->bk) |
---|
3063 | { |
---|
3064 | #if DEBUG |
---|
3065 | check_free_chunk(p); |
---|
3066 | for (q = next_chunk(p); |
---|
3067 | q < top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE; |
---|
3068 | q = next_chunk(q)) |
---|
3069 | check_inuse_chunk(q); |
---|
3070 | #endif |
---|
3071 | avail += chunksize(p); |
---|
3072 | navail++; |
---|
3073 | } |
---|
3074 | } |
---|
3075 | |
---|
3076 | current_mallinfo.ordblks = navail; |
---|
3077 | current_mallinfo.uordblks = sbrked_mem - avail; |
---|
3078 | current_mallinfo.fordblks = avail; |
---|
3079 | current_mallinfo.hblks = n_mmaps; |
---|
3080 | current_mallinfo.hblkhd = mmapped_mem; |
---|
3081 | current_mallinfo.keepcost = chunksize(top); |
---|
3082 | |
---|
3083 | } |
---|
3084 | |
---|
3085 | |
---|
3086 | |
---|
3087 | /* |
---|
3088 | |
---|
3089 | malloc_stats: |
---|
3090 | |
---|
3091 | Prints on stderr the amount of space obtain from the system (both |
---|
3092 | via sbrk and mmap), the maximum amount (which may be more than |
---|
3093 | current if malloc_trim and/or munmap got called), the maximum |
---|
3094 | number of simultaneous mmap regions used, and the current number |
---|
3095 | of bytes allocated via malloc (or realloc, etc) but not yet |
---|
3096 | freed. (Note that this is the number of bytes allocated, not the |
---|
3097 | number requested. It will be larger than the number requested |
---|
3098 | because of alignment and bookkeeping overhead.) |
---|
3099 | |
---|
3100 | */ |
---|
3101 | |
---|
3102 | void malloc_stats() |
---|
3103 | { |
---|
3104 | malloc_update_mallinfo(); |
---|
3105 | fprintf(stderr, "max system bytes = %10u\n", |
---|
3106 | (unsigned int)(max_total_mem)); |
---|
3107 | fprintf(stderr, "system bytes = %10u\n", |
---|
3108 | (unsigned int)(sbrked_mem + mmapped_mem)); |
---|
3109 | fprintf(stderr, "in use bytes = %10u\n", |
---|
3110 | (unsigned int)(current_mallinfo.uordblks + mmapped_mem)); |
---|
3111 | #if HAVE_MMAP |
---|
3112 | fprintf(stderr, "max mmap regions = %10u\n", |
---|
3113 | (unsigned int)max_n_mmaps); |
---|
3114 | #endif |
---|
3115 | } |
---|
3116 | |
---|
3117 | /* |
---|
3118 | mallinfo returns a copy of updated current mallinfo. |
---|
3119 | */ |
---|
3120 | |
---|
3121 | struct mallinfo mALLINFo() |
---|
3122 | { |
---|
3123 | malloc_update_mallinfo(); |
---|
3124 | return current_mallinfo; |
---|
3125 | } |
---|
3126 | |
---|
3127 | |
---|
3128 | |
---|
3129 | |
---|
3130 | /* |
---|
3131 | mallopt: |
---|
3132 | |
---|
3133 | mallopt is the general SVID/XPG interface to tunable parameters. |
---|
3134 | The format is to provide a (parameter-number, parameter-value) pair. |
---|
3135 | mallopt then sets the corresponding parameter to the argument |
---|
3136 | value if it can (i.e., so long as the value is meaningful), |
---|
3137 | and returns 1 if successful else 0. |
---|
3138 | |
---|
3139 | See descriptions of tunable parameters above. |
---|
3140 | |
---|
3141 | */ |
---|
3142 | |
---|
3143 | #if __STD_C |
---|
3144 | int mALLOPt(int param_number, int value) |
---|
3145 | #else |
---|
3146 | int mALLOPt(param_number, value) int param_number; int value; |
---|
3147 | #endif |
---|
3148 | { |
---|
3149 | switch(param_number) |
---|
3150 | { |
---|
3151 | case M_TRIM_THRESHOLD: |
---|
3152 | trim_threshold = value; return 1; |
---|
3153 | case M_TOP_PAD: |
---|
3154 | top_pad = value; return 1; |
---|
3155 | case M_MMAP_THRESHOLD: |
---|
3156 | mmap_threshold = value; return 1; |
---|
3157 | case M_MMAP_MAX: |
---|
3158 | #if HAVE_MMAP |
---|
3159 | n_mmaps_max = value; return 1; |
---|
3160 | #else |
---|
3161 | if (value != 0) return 0; else n_mmaps_max = value; return 1; |
---|
3162 | #endif |
---|
3163 | |
---|
3164 | default: |
---|
3165 | return 0; |
---|
3166 | } |
---|
3167 | } |
---|
3168 | |
---|
3169 | /* |
---|
3170 | |
---|
3171 | History: |
---|
3172 | |
---|
3173 | V2.6.6 Sun Dec 5 07:42:19 1999 Doug Lea (dl at gee) |
---|
3174 | * return null for negative arguments |
---|
3175 | * Added Several WIN32 cleanups from Martin C. Fong <mcfong@yahoo.com> |
---|
3176 | * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h' |
---|
3177 | (e.g. WIN32 platforms) |
---|
3178 | * Cleanup up header file inclusion for WIN32 platforms |
---|
3179 | * Cleanup code to avoid Microsoft Visual C++ compiler complaints |
---|
3180 | * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing |
---|
3181 | memory allocation routines |
---|
3182 | * Set 'malloc_getpagesize' for WIN32 platforms (needs more work) |
---|
3183 | * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to |
---|
3184 | usage of 'assert' in non-WIN32 code |
---|
3185 | * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to |
---|
3186 | avoid infinite loop |
---|
3187 | * Always call 'fREe()' rather than 'free()' |
---|
3188 | |
---|
3189 | V2.6.5 Wed Jun 17 15:57:31 1998 Doug Lea (dl at gee) |
---|
3190 | * Fixed ordering problem with boundary-stamping |
---|
3191 | |
---|
3192 | V2.6.3 Sun May 19 08:17:58 1996 Doug Lea (dl at gee) |
---|
3193 | * Added pvalloc, as recommended by H.J. Liu |
---|
3194 | * Added 64bit pointer support mainly from Wolfram Gloger |
---|
3195 | * Added anonymously donated WIN32 sbrk emulation |
---|
3196 | * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen |
---|
3197 | * malloc_extend_top: fix mask error that caused wastage after |
---|
3198 | foreign sbrks |
---|
3199 | * Add linux mremap support code from HJ Liu |
---|
3200 | |
---|
3201 | V2.6.2 Tue Dec 5 06:52:55 1995 Doug Lea (dl at gee) |
---|
3202 | * Integrated most documentation with the code. |
---|
3203 | * Add support for mmap, with help from |
---|
3204 | Wolfram Gloger (Gloger@lrz.uni-muenchen.de). |
---|
3205 | * Use last_remainder in more cases. |
---|
3206 | * Pack bins using idea from colin@nyx10.cs.du.edu |
---|
3207 | * Use ordered bins instead of best-fit threshhold |
---|
3208 | * Eliminate block-local decls to simplify tracing and debugging. |
---|
3209 | * Support another case of realloc via move into top |
---|
3210 | * Fix error occuring when initial sbrk_base not word-aligned. |
---|
3211 | * Rely on page size for units instead of SBRK_UNIT to |
---|
3212 | avoid surprises about sbrk alignment conventions. |
---|
3213 | * Add mallinfo, mallopt. Thanks to Raymond Nijssen |
---|
3214 | (raymond@es.ele.tue.nl) for the suggestion. |
---|
3215 | * Add `pad' argument to malloc_trim and top_pad mallopt parameter. |
---|
3216 | * More precautions for cases where other routines call sbrk, |
---|
3217 | courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de). |
---|
3218 | * Added macros etc., allowing use in linux libc from |
---|
3219 | H.J. Lu (hjl@gnu.ai.mit.edu) |
---|
3220 | * Inverted this history list |
---|
3221 | |
---|
3222 | V2.6.1 Sat Dec 2 14:10:57 1995 Doug Lea (dl at gee) |
---|
3223 | * Re-tuned and fixed to behave more nicely with V2.6.0 changes. |
---|
3224 | * Removed all preallocation code since under current scheme |
---|
3225 | the work required to undo bad preallocations exceeds |
---|
3226 | the work saved in good cases for most test programs. |
---|
3227 | * No longer use return list or unconsolidated bins since |
---|
3228 | no scheme using them consistently outperforms those that don't |
---|
3229 | given above changes. |
---|
3230 | * Use best fit for very large chunks to prevent some worst-cases. |
---|
3231 | * Added some support for debugging |
---|
3232 | |
---|
3233 | V2.6.0 Sat Nov 4 07:05:23 1995 Doug Lea (dl at gee) |
---|
3234 | * Removed footers when chunks are in use. Thanks to |
---|
3235 | Paul Wilson (wilson@cs.texas.edu) for the suggestion. |
---|
3236 | |
---|
3237 | V2.5.4 Wed Nov 1 07:54:51 1995 Doug Lea (dl at gee) |
---|
3238 | * Added malloc_trim, with help from Wolfram Gloger |
---|
3239 | (wmglo@Dent.MED.Uni-Muenchen.DE). |
---|
3240 | |
---|
3241 | V2.5.3 Tue Apr 26 10:16:01 1994 Doug Lea (dl at g) |
---|
3242 | |
---|
3243 | V2.5.2 Tue Apr 5 16:20:40 1994 Doug Lea (dl at g) |
---|
3244 | * realloc: try to expand in both directions |
---|
3245 | * malloc: swap order of clean-bin strategy; |
---|
3246 | * realloc: only conditionally expand backwards |
---|
3247 | * Try not to scavenge used bins |
---|
3248 | * Use bin counts as a guide to preallocation |
---|
3249 | * Occasionally bin return list chunks in first scan |
---|
3250 | * Add a few optimizations from colin@nyx10.cs.du.edu |
---|
3251 | |
---|
3252 | V2.5.1 Sat Aug 14 15:40:43 1993 Doug Lea (dl at g) |
---|
3253 | * faster bin computation & slightly different binning |
---|
3254 | * merged all consolidations to one part of malloc proper |
---|
3255 | (eliminating old malloc_find_space & malloc_clean_bin) |
---|
3256 | * Scan 2 returns chunks (not just 1) |
---|
3257 | * Propagate failure in realloc if malloc returns 0 |
---|
3258 | * Add stuff to allow compilation on non-ANSI compilers |
---|
3259 | from kpv@research.att.com |
---|
3260 | |
---|
3261 | V2.5 Sat Aug 7 07:41:59 1993 Doug Lea (dl at g.oswego.edu) |
---|
3262 | * removed potential for odd address access in prev_chunk |
---|
3263 | * removed dependency on getpagesize.h |
---|
3264 | * misc cosmetics and a bit more internal documentation |
---|
3265 | * anticosmetics: mangled names in macros to evade debugger strangeness |
---|
3266 | * tested on sparc, hp-700, dec-mips, rs6000 |
---|
3267 | with gcc & native cc (hp, dec only) allowing |
---|
3268 | Detlefs & Zorn comparison study (in SIGPLAN Notices.) |
---|
3269 | |
---|
3270 | Trial version Fri Aug 28 13:14:29 1992 Doug Lea (dl at g.oswego.edu) |
---|
3271 | * Based loosely on libg++-1.2X malloc. (It retains some of the overall |
---|
3272 | structure of old version, but most details differ.) |
---|
3273 | |
---|
3274 | */ |
---|
3275 | |
---|
3276 | |
---|