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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 strncat
//#define strncat TESTING
char *strncat(char * dest, const char * src, size_t count)
{
int esi, edi, eax, ecx, edx;
__asm__ __volatile__(
" xorl %%eax, %%eax\n"
" incl %%edx\n"
" pushl %%edi\n" /* save dest */
" repne; scasb\n"
" decl %%edi\n" /* edi => NUL in dest */
/* count-- */
"1: decl %%edx\n"
/* if count reached 0, store NUL and bail out */
" movl %%edx, %%eax\n"
" jz 2f\n"
/* else copy a char */
" lodsb\n"
"2: stosb\n"
" testb %%al, %%al\n"
" jnz 1b\n"
/* end of loop */
" popl %%eax\n" /* restore dest into eax */
: "=&S" (esi), "=&D" (edi), "=&a" (eax), "=&c" (ecx), "=&d" (edx)
: "0" (src), "1" (dest), "3" (0xffffffff), "4" (count)
: "memory"
);
return (char *)eax;
}
#ifndef strncat
libc_hidden_def(strncat)
#else
/* Uncomment TESTING, gcc -m32 -Os strncat.c -o strncat
* and run ./strncat
*/
int main()
{
char buf[99];
strcpy(buf, "abc"); buf[4] = '*'; strncat(buf, "def", 0);
printf(strcmp(buf, "abc") == 0 && buf[4] == '*' ? "ok\n" : "BAD!\n");
strcpy(buf, "abc"); buf[6] = 1; buf[7] = '*'; strncat(buf, "def", 50);
printf(strcmp(buf, "abcdef") == 0 && buf[7] == '*' ? "ok\n" : "BAD!\n");
strcpy(buf, "abc"); buf[6] = 1; buf[7] = '*'; strncat(buf, "def", -1);
printf(strcmp(buf, "abcdef") == 0 && buf[7] == '*' ? "ok\n" : "BAD!\n");
strcpy(buf, "abc"); buf[6] = 1; buf[7] = '*'; strncat(buf, "def123", 3);
printf(strcmp(buf, "abcdef") == 0 && buf[7] == '*' ? "ok\n" : "BAD!\n");
}
#endif
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