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/*
* This string-include defines all string functions as inline
* functions. Use gcc. It also assumes ds=es=data space, this should be
* normal. Most of the string-functions are rather heavily hand-optimized,
* see especially strtok,strstr,str[c]spn. They should work, but are not
* very easy to understand. Everything is done entirely within the register
* set, making the functions fast and clean. String instructions have been
* used through-out, making for "slightly" unclear code :-)
*
* NO Copyright (C) 1991, 1992 Linus Torvalds,
* consider these trivial functions to be PD.
*/
/*
* Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org>
*
* Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
*/
/*
* Modified for uClibc by Erik Andersen <andersen@codepoet.org>
* These make no attempt to use nifty things like mmx/3dnow/etc.
* These are not inline, and will therefore not be as fast as
* modifying the headers to use inlines (and cannot therefore
* do tricky things when dealing with const memory). But they
* should (I hope!) be faster than their generic equivalents....
*
* More importantly, these should provide a good example for
* others to follow when adding arch specific optimizations.
* -Erik
*/
#include <string.h>
#undef strncpy
//#define strncpy TESTING
char *strncpy(char * dest, const char * src, size_t count)
{
int esi, edi, ecx, eax;
__asm__ __volatile__(
"1: subl $1, %%ecx\n" /* not dec! it doesnt set CF */
" jc 2f\n"
" lodsb\n"
" stosb\n"
" testb %%al, %%al\n"
" jnz 1b\n"
" rep; stosb\n"
"2:\n"
: "=&S" (esi), "=&D" (edi), "=&c" (ecx), "=&a" (eax)
: "0" (src), "1" (dest), "2" (count)
: "memory"
);
return dest;
}
#ifndef strncpy
libc_hidden_def(strncpy)
#else
/* Uncomment TESTING, gcc -D_GNU_SOURCE -m32 -Os strncpy.c -o strncpy
* and run ./strncpy
*/
int main()
{
static char str[99];
str[3] = '*'; str[4] = 0; strncpy(str, "abc", 3);
printf(strcmp(str, "abc*") == 0 ? "ok\n" : "BAD!\n");
str[4] = '*'; str[5] = '+'; strncpy(str, "abc", 5);
printf(strcmp(str, "abc") == 0 && str[4] == 0 && str[5] == '+' ?
"ok\n" : "BAD!\n");
strncpy(str, "abc", 0); /* should do nothing */
printf(strcmp(str, "abc") == 0 && str[4] == 0 && str[5] == '+' ?
"ok\n" : "BAD!\n");
}
#endif
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