/* * 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, "def", 0); /* should do nothing */ printf(strcmp(str, "abc") == 0 && str[4] == 0 && str[5] == '+' ? "ok\n" : "BAD!\n"); } #endif