Files
2026-10-19 19:57:05 +02:00

142 lines
3.1 KiB
C

#include <zinnia/compiler.h>
#include <zinnia/utils.h>
#include <stddef.h>
#include <stdint.h>
[[__hot]]
size_t strlen(const char* str) {
size_t result = 0;
while (*str++) {
result++;
}
return result;
}
[[__hot]]
size_t strnlen(const char* str, size_t len) {
size_t result = 0;
while (result < len && *str++) {
result++;
}
return result;
}
[[__hot]]
int memcmp(const void* s1, const void* s2, size_t size) {
const uint8_t* s1ptr = s1;
const uint8_t* s2ptr = s2;
for (size_t i = 0; i < size; i++) {
if (s1ptr[i] != s2ptr[i])
return (int)s1ptr[i] - (int)s2ptr[i];
}
return 0;
}
typedef size_t word_t [[__may_alias]]
;
[[__hot]]
void* memcpy(void* restrict dest, const void* restrict src, size_t n) {
uint8_t* d = dest;
const uint8_t* s = src;
// Word copies are only possible if both pointers can be aligned at the same time.
if (((uintptr_t)d - (uintptr_t)s) % sizeof(word_t) == 0) {
while (n && (uintptr_t)d % sizeof(word_t) != 0) {
*d++ = *s++;
n--;
}
word_t* word_dest = (word_t*)d;
const word_t* word_src = (const word_t*)s;
for (; n >= sizeof(word_t); n -= sizeof(word_t))
*word_dest++ = *word_src++;
d = (uint8_t*)word_dest;
s = (const uint8_t*)word_src;
}
while (n--)
*d++ = *s++;
return dest;
}
[[__hot]]
void* memmove(void* dstptr, const void* srcptr, size_t size) {
uint8_t* dst = (uint8_t*)dstptr;
const uint8_t* src = (const uint8_t*)srcptr;
if ((uintptr_t)dst < (uintptr_t)src) {
for (size_t i = 0; i < size; i++)
dst[i] = src[i];
} else {
for (size_t i = size; i != 0; i--)
dst[i - 1] = src[i - 1];
}
return dstptr;
}
[[__hot]]
void* memset(void* dest, int value, size_t n) {
uint8_t* d = dest;
const uint8_t byte = (uint8_t)value;
while (n && (uintptr_t)d % sizeof(word_t) != 0) {
*d++ = byte;
n--;
}
const word_t word_value = (SIZE_MAX / 0xFF) * byte;
word_t* word_dest = (word_t*)d;
for (; n >= sizeof(word_t); n -= sizeof(word_t))
*word_dest++ = word_value;
d = (uint8_t*)word_dest;
while (n--)
*d++ = byte;
return dest;
}
char* strncpy(char* restrict dst, const char* restrict src, size_t len) {
size_t src_len = strnlen(src, len);
memcpy(dst, src, src_len);
memset(dst + src_len, 0, len - src_len);
return dst;
}
int strncmp(const char* str1, const char* str2, size_t len) {
while (len && *str1 && (*str1 == *str2)) {
++str1;
++str2;
--len;
}
if (len == 0) {
return 0;
} else {
return (*(unsigned char*)str1 - *(unsigned char*)str2);
}
}
int strcmp(const char* str1, const char* str2) {
while (*str1 && (*str1 == *str2)) {
++str1;
++str2;
}
return (*(unsigned char*)str1 - *(unsigned char*)str2);
}
char* strchr(const char* s, int c) {
char ch = (char)c;
while (true) {
char cur = *s;
if (cur == ch)
return (char*)s;
if (cur == 0)
return nullptr;
s++;
}
}