1 //===========================================================================
5 // ANSI standard strncmp() routine
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.
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.
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
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.
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.
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.
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####
43 // Author(s): jlarmour
50 //####DESCRIPTIONEND####
52 //===========================================================================
56 #include <pkgconf/libc_string.h> // Configuration header
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
71 strncmp( const char *s1, const char *s2, size_t n ) \
72 CYGBLD_ATTRIB_WEAK_ALIAS(__strncmp);
77 __strncmp( const char *s1, const char *s2, size_t n )
81 CYG_REPORT_FUNCNAMETYPE( "__strncmp", "returning %d" );
82 CYG_REPORT_FUNCARG3( "s1=%08x, s2=%08x, n=%d", s1, s2, n );
86 CYG_REPORT_RETVAL( 0 );
90 CYG_CHECK_DATA_PTR( s1, "s1 is not a valid pointer!" );
91 CYG_CHECK_DATA_PTR( s2, "s2 is not a valid pointer!" );
93 #if defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) || defined(__OPTIMIZE_SIZE__)
94 while (n-- != 0 && *s1 == *s2)
96 if (n == 0 || *s1 == '\0' || *s2 == '\0')
102 retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);
104 CYG_REPORT_RETVAL( retval );
108 const CYG_WORD *aligned_s1;
109 const CYG_WORD *aligned_s2;
111 // If s1 or s2 are unaligned, then compare bytes.
112 if (CYG_LIBC_STR_UNALIGNED2 (s1, s2))
114 while (n-- != 0 && *s1 == *s2)
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')
123 retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);
125 CYG_REPORT_RETVAL( retval );
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)
135 n -= sizeof (CYG_WORD);
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))
141 CYG_REPORT_RETVAL( 0 );
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;
153 while (n-- > 0 && *s1 == *s2)
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')
159 CYG_REPORT_RETVAL( 0 );
166 retval = (*(unsigned char *) s1) - (*(unsigned char *) s2);
168 CYG_REPORT_RETVAL( retval );
172 #endif // not defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) ||
173 // defined(__OPTIMIZE_SIZE__)