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Diffstat (limited to 'lib/libutils/isoc/newlib/memcmp.c')
| -rw-r--r-- | lib/libutils/isoc/newlib/memcmp.c | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/lib/libutils/isoc/newlib/memcmp.c b/lib/libutils/isoc/newlib/memcmp.c new file mode 100644 index 0000000..eb29c54 --- /dev/null +++ b/lib/libutils/isoc/newlib/memcmp.c @@ -0,0 +1,135 @@ +/* + * Copyright (c) 1994-2009 Red Hat, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * 3. Neither the name of the copyright holder nor the names of its + * contributors may be used to endorse or promote products derived from this + * software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* +FUNCTION + <<memcmp>>---compare two memory areas + +INDEX + memcmp + +ANSI_SYNOPSIS + #include <string.h> + int memcmp(const void *<[s1]>, const void *<[s2]>, size_t <[n]>); + +TRAD_SYNOPSIS + #include <string.h> + int memcmp(<[s1]>, <[s2]>, <[n]>) + void *<[s1]>; + void *<[s2]>; + size_t <[n]>; + +DESCRIPTION + This function compares not more than <[n]> characters of the + object pointed to by <[s1]> with the object pointed to by <[s2]>. + +RETURNS + The function returns an integer greater than, equal to or + less than zero according to whether the object pointed to by + <[s1]> is greater than, equal to or less than the object + pointed to by <[s2]>. + +PORTABILITY +<<memcmp>> is ANSI C. + +<<memcmp>> requires no supporting OS subroutines. + +QUICKREF + memcmp ansi pure +*/ + +#include "_ansi.h" +#include <string.h> + +/* Nonzero if either X or Y is not aligned on a "long" boundary. */ +#define UNALIGNED(X, Y) \ + (((long)X & (sizeof(long) - 1)) | ((long)Y & (sizeof(long) - 1))) + +/* How many bytes are copied each iteration of the word copy loop. */ +#define LBLOCKSIZE (sizeof(long)) + +/* Threshhold for punting to the byte copier. */ +#define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE) + +int +_DEFUN(memcmp, (m1, m2, n), _CONST _PTR m1 _AND _CONST _PTR m2 _AND size_t n) +{ +#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) + unsigned char *s1 = (unsigned char *)m1; + unsigned char *s2 = (unsigned char *)m2; + + while (n--) { + if (*s1 != *s2) + return *s1 - *s2; + s1++; + s2++; + } + return 0; +#else + unsigned char *s1 = (unsigned char *)m1; + unsigned char *s2 = (unsigned char *)m2; + unsigned long *a1; + unsigned long *a2; + + /* If the size is too small, or either pointer is unaligned, + then we punt to the byte compare loop. Hopefully this will + not turn up in inner loops. */ + if (!TOO_SMALL(n) && !UNALIGNED(s1, s2)) { + /* + * Otherwise, load and compare the blocks of memory one word at + * a time. + */ + a1 = (unsigned long *)s1; + a2 = (unsigned long *)s2; + while (n >= LBLOCKSIZE) { + if (*a1 != *a2) + break; + a1++; + a2++; + n -= LBLOCKSIZE; + } + + /* check m mod LBLOCKSIZE remaining characters */ + + s1 = (unsigned char *)a1; + s2 = (unsigned char *)a2; + } + + while (n--) { + if (*s1 != *s2) + return *s1 - *s2; + s1++; + s2++; + } + + return 0; +#endif /* not PREFER_SIZE_OVER_SPEED */ +} |