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/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
/*
* string function definitions for NOLIBC
* Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
*/
#ifndef _NOLIBC_STRING_H
#define _NOLIBC_STRING_H
#include "std.h"
static void *malloc(size_t len);
/*
* As much as possible, please keep functions alphabetically sorted.
*/
static __attribute__((unused))
int memcmp(const void *s1, const void *s2, size_t n)
{
size_t ofs = 0;
int c1 = 0;
while (ofs < n && !(c1 = ((unsigned char *)s1)[ofs] - ((unsigned char *)s2)[ofs])) {
ofs++;
}
return c1;
}
static __attribute__((unused))
void *_nolibc_memcpy_up(void *dst, const void *src, size_t len)
{
size_t pos = 0;
while (pos < len) {
((char *)dst)[pos] = ((const char *)src)[pos];
pos++;
}
return dst;
}
static __attribute__((unused))
void *_nolibc_memcpy_down(void *dst, const void *src, size_t len)
{
while (len) {
len--;
((char *)dst)[len] = ((const char *)src)[len];
}
return dst;
}
/* might be ignored by the compiler without -ffreestanding, then found as
* missing.
*/
__attribute__((weak,unused,section(".text.nolibc_memmove")))
void *memmove(void *dst, const void *src, size_t len)
{
size_t dir, pos;
pos = len;
dir = -1;
if (dst < src) {
pos = -1;
dir = 1;
}
while (len) {
pos += dir;
((char *)dst)[pos] = ((const char *)src)[pos];
len--;
}
return dst;
}
/* must be exported, as it's used by libgcc on ARM */
__attribute__((weak,unused,section(".text.nolibc_memcpy")))
void *memcpy(void *dst, const void *src, size_t len)
{
return _nolibc_memcpy_up(dst, src, len);
}
/* might be ignored by the compiler without -ffreestanding, then found as
* missing.
*/
__attribute__((weak,unused,section(".text.nolibc_memset")))
void *memset(void *dst, int b, size_t len)
{
char *p = dst;
while (len--)
*(p++) = b;
return dst;
}
static __attribute__((unused))
char *strchr(const char *s, int c)
{
while (*s) {
if (*s == (char)c)
return (char *)s;
s++;
}
return NULL;
}
static __attribute__((unused))
int strcmp(const char *a, const char *b)
{
unsigned int c;
int diff;
while (!(diff = (unsigned char)*a++ - (c = (unsigned char)*b++)) && c)
;
return diff;
}
static __attribute__((unused))
char *strcpy(char *dst, const char *src)
{
char *ret = dst;
while ((*dst++ = *src++));
return ret;
}
/* this function is only used with arguments that are not constants or when
* it's not known because optimizations are disabled. Note that gcc 12
* recognizes an strlen() pattern and replaces it with a jump to strlen(),
* thus itself, hence the asm() statement below that's meant to disable this
* confusing practice.
*/
static __attribute__((unused))
size_t strlen(const char *str)
{
size_t len;
for (len = 0; str[len]; len++)
asm("");
return len;
}
/* do not trust __builtin_constant_p() at -O0, as clang will emit a test and
* the two branches, then will rely on an external definition of strlen().
*/
#if defined(__OPTIMIZE__)
#define nolibc_strlen(x) strlen(x)
#define strlen(str) ({ \
__builtin_constant_p((str)) ? \
__builtin_strlen((str)) : \
nolibc_strlen((str)); \
})
#endif
static __attribute__((unused))
size_t strnlen(const char *str, size_t maxlen)
{
size_t len;
for (len = 0; (len < maxlen) && str[len]; len++);
return len;
}
static __attribute__((unused))
char *strdup(const char *str)
{
size_t len;
char *ret;
len = strlen(str);
ret = malloc(len + 1);
if (__builtin_expect(ret != NULL, 1))
memcpy(ret, str, len + 1);
return ret;
}
static __attribute__((unused))
char *strndup(const char *str, size_t maxlen)
{
size_t len;
char *ret;
len = strnlen(str, maxlen);
ret = malloc(len + 1);
if (__builtin_expect(ret != NULL, 1)) {
memcpy(ret, str, len);
ret[len] = '\0';
}
return ret;
}
static __attribute__((unused))
size_t strlcat(char *dst, const char *src, size_t size)
{
size_t len;
char c;
for (len = 0; dst[len]; len++)
;
for (;;) {
c = *src;
if (len < size)
dst[len] = c;
if (!c)
break;
len++;
src++;
}
return len;
}
static __attribute__((unused))
size_t strlcpy(char *dst, const char *src, size_t size)
{
size_t len;
char c;
for (len = 0;;) {
c = src[len];
if (len < size)
dst[len] = c;
if (!c)
break;
len++;
}
return len;
}
static __attribute__((unused))
char *strncat(char *dst, const char *src, size_t size)
{
char *orig = dst;
while (*dst)
dst++;
while (size && (*dst = *src)) {
src++;
dst++;
size--;
}
*dst = 0;
return orig;
}
static __attribute__((unused))
int strncmp(const char *a, const char *b, size_t size)
{
unsigned int c;
int diff = 0;
while (size-- &&
!(diff = (unsigned char)*a++ - (c = (unsigned char)*b++)) && c)
;
return diff;
}
static __attribute__((unused))
char *strncpy(char *dst, const char *src, size_t size)
{
size_t len;
for (len = 0; len < size; len++)
if ((dst[len] = *src))
src++;
return dst;
}
static __attribute__((unused))
char *strrchr(const char *s, int c)
{
const char *ret = NULL;
while (*s) {
if (*s == (char)c)
ret = s;
s++;
}
return (char *)ret;
}
#endif /* _NOLIBC_STRING_H */
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