/* * 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> #ifdef __USE_GNU #undef strnlen /*#define strnlen TESTING*/ size_t strnlen(const char *s, size_t count) { int edx; int eax; __asm__ __volatile__( " leal -1(%%ecx), %%eax\n" "1: incl %%eax\n" " decl %%edx\n" " jz 3f\n" " cmpb $0, (%%eax)\n" " jnz 1b\n" "3: subl %%ecx, %%eax" : "=a" (eax), "=&d" (edx) : "c" (s), "1" (count + 1) ); return eax; } #ifndef strnlen libc_hidden_def(strnlen) #else /* Uncomment TESTING, gcc -D_GNU_SOURCE -m32 -Os strnlen.c -o strnlen * and run ./strnlen */ int main() { printf(strnlen("abc\0def", -2) == 3 ? "ok\n" : "BAD!\n"); printf(strnlen("abc\0def", -1) == 3 ? "ok\n" : "BAD!\n"); printf(strnlen("abc\0def", 0) == 0 ? "ok\n" : "BAD!\n"); printf(strnlen("abc\0def", 1) == 1 ? "ok\n" : "BAD!\n"); printf(strnlen("abc\0def", 2) == 2 ? "ok\n" : "BAD!\n"); printf(strnlen("abc\0def", 3) == 3 ? "ok\n" : "BAD!\n"); printf(strnlen("abc\0def", 4) == 3 ? "ok\n" : "BAD!\n"); printf(strnlen("abc\0def", 5) == 3 ? "ok\n" : "BAD!\n"); } #endif #endif