source: SVN/cambria/redboot/packages/language/c/libc/string/current/src/strncmp.cxx @ 1

Last change on this file since 1 was 1, checked in by Tim Harvey, 2 years ago

restored latest version of files from server backup

Signed-off-by: Tim Harvey <tharvey@…>

File size: 5.5 KB
Line 
1//===========================================================================
2//
3//      strncmp.cxx
4//
5//      ANSI standard strncmp() routine
6//
7//===========================================================================
8//####ECOSGPLCOPYRIGHTBEGIN####
9// -------------------------------------------
10// This file is part of eCos, the Embedded Configurable Operating System.
11// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
12//
13// eCos is free software; you can redistribute it and/or modify it under
14// the terms of the GNU General Public License as published by the Free
15// Software Foundation; either version 2 or (at your option) any later version.
16//
17// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
18// WARRANTY; without even the implied warranty of MERCHANTABILITY or
19// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
20// for more details.
21//
22// You should have received a copy of the GNU General Public License along
23// with eCos; if not, write to the Free Software Foundation, Inc.,
24// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25//
26// As a special exception, if other files instantiate templates or use macros
27// or inline functions from this file, or you compile this file and link it
28// with other works to produce a work based on this file, this file does not
29// by itself cause the resulting work to be covered by the GNU General Public
30// License. However the source code for this file must still be made available
31// in accordance with section (3) of the GNU General Public License.
32//
33// This exception does not invalidate any other reasons why a work based on
34// this file might be covered by the GNU General Public License.
35//
36// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
37// at http://sources.redhat.com/ecos/ecos-license/
38// -------------------------------------------
39//####ECOSGPLCOPYRIGHTEND####
40//===========================================================================
41//#####DESCRIPTIONBEGIN####
42//
43// Author(s):    jlarmour
44// Contributors:
45// Date:         2000-04-14
46// Purpose:     
47// Description:
48// Usage:       
49//
50//####DESCRIPTIONEND####
51//
52//===========================================================================
53
54// CONFIGURATION
55
56#include <pkgconf/libc_string.h>   // Configuration header
57
58// INCLUDES
59
60#include <cyg/infra/cyg_type.h>    // Common type definitions
61#include <cyg/infra/cyg_trac.h>    // Tracing support
62#include <cyg/infra/cyg_ass.h>     // Assertion support
63#include <string.h>                // Header for this file
64#include <stddef.h>         // Compiler definitions such as size_t, NULL etc.
65#include <cyg/libc/string/stringsupp.hxx> // Useful string function support and
66                                          // prototypes
67
68// EXPORTED SYMBOLS
69
70externC int 
71strncmp( const char *s1, const char *s2, size_t n ) \
72    CYGBLD_ATTRIB_WEAK_ALIAS(__strncmp);
73
74// FUNCTIONS
75
76int 
77__strncmp( const char *s1, const char *s2, size_t n )
78{
79    int retval;
80
81    CYG_REPORT_FUNCNAMETYPE( "__strncmp", "returning %d" );
82    CYG_REPORT_FUNCARG3( "s1=%08x, s2=%08x, n=%d", s1, s2, n );
83   
84    if (n == 0)
85    {
86        CYG_REPORT_RETVAL( 0 );
87        return 0;
88    }
89
90    CYG_CHECK_DATA_PTR( s1, "s1 is not a valid pointer!" );
91    CYG_CHECK_DATA_PTR( s2, "s2 is not a valid pointer!" );
92
93#if defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) || defined(__OPTIMIZE_SIZE__)
94    while (n-- != 0 && *s1 == *s2)
95    {
96        if (n == 0 || *s1 == '\0' || *s2 == '\0')
97            break;
98        s1++;
99        s2++;
100    }
101   
102    retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);
103
104    CYG_REPORT_RETVAL( retval );
105
106    return retval;
107#else
108    const CYG_WORD *aligned_s1;
109    const CYG_WORD *aligned_s2;
110   
111    // If s1 or s2 are unaligned, then compare bytes.
112    if (CYG_LIBC_STR_UNALIGNED2 (s1, s2))
113    { 
114        while (n-- != 0 && *s1 == *s2)
115        {
116            // If we've run out of bytes or hit a null, return zero
117            // since we already know *s1 == *s2.
118            if (n == 0 || *s1 == '\0')
119                return 0;
120            s1++;
121            s2++;
122        }
123        retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);
124
125        CYG_REPORT_RETVAL( retval );
126
127        return retval;
128    } //if
129   
130    // If s1 and s2 are word-aligned, compare them a word at a time.
131    aligned_s1 = (const CYG_WORD *)s1;
132    aligned_s2 = (const CYG_WORD *)s2;
133    while (n >= sizeof(CYG_WORD) && *aligned_s1 == *aligned_s2)
134    {
135        n -= sizeof (CYG_WORD);
136       
137        // If we've run out of bytes or hit a null, return zero
138        // since we already know *aligned_s1 == *aligned_s2.
139        if (n == 0 || CYG_LIBC_STR_DETECTNULL (*aligned_s1))
140        {
141            CYG_REPORT_RETVAL( 0 );
142            return 0;
143        } // if
144       
145        aligned_s1++;
146        aligned_s2++;
147    } // while
148   
149    // A difference was detected in last few bytes of s1, so search bytewise
150    s1 = (const char *)aligned_s1;
151    s2 = (const char *)aligned_s2;
152   
153    while (n-- > 0 && *s1 == *s2)
154    {
155        // If we've run out of bytes or hit a null, return zero
156        // since we already know *s1 == *s2.
157        if (n == 0 || *s1 == '\0')
158        {
159            CYG_REPORT_RETVAL( 0 );
160            return 0;
161        } // if
162        s1++;
163        s2++;
164    } // while
165
166    retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);
167
168    CYG_REPORT_RETVAL( retval );
169   
170    return retval;
171
172#endif // not defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) ||
173       //     defined(__OPTIMIZE_SIZE__)
174} // __strncmp()
175
176// EOF strncmp.cxx
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