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118 lines
2.5 KiB
C++

#include "string.h"
extern "C" char *strchrnul(const char *s, int c) {
if (s != nullptr) {
while (*s != '\0') {
if (*s == c) {
break;
}
s++;
}
}
return const_cast<char *>(s);
}
extern "C" char *strchr(const char *s, int c) {
if (s != nullptr) {
s = strchrnul(s, c);
if (*s == c) {
return const_cast<char *>(s);
}
}
return nullptr;
}
extern "C" int strcmp(const char *s1, const char *s2) {
if (s1 == nullptr || s2 == nullptr) {
return 0;
}
while (*s1 == *s2++) {
if (*s1++ == '\0') {
return 0;
}
}
return static_cast<int>(*s1) - static_cast<int>(*(s2 - 1));
}
extern "C" int strncmp(const char *s1, const char *s2, size_t n) {
if (s1 != nullptr && s2 != nullptr) {
for (size_t i = 0; i < n; i++) {
if (s1[i] != s2[i]) {
return static_cast<int>(s1[i]) - static_cast<int>(s2[i]);
} else if (s1[i] == '\0') {
break;
}
}
}
return 0;
}
extern "C" size_t strlen(const char *s) {
size_t len = 0;
if (s != nullptr) {
while (*s++ != '\0') {
len++;
}
}
return len;
}
extern "C" char *strcpy(char *dest, const char *src) { // NOLINT
char *r = dest;
if (dest != nullptr && src != nullptr) {
while ((*dest++ = *src++) != '\0') {
}
}
return r;
}
extern "C" char *strncpy(char *dest, const char *src, size_t n) {
char *r = dest;
if (dest != nullptr && src != nullptr) {
while ((n--) != 0 && (*dest++ = *src++) != '\0') {
}
}
return r;
}
extern "C" void *memcpy(void *__restrict__ dest, void const *__restrict__ src,
size_t size) {
uint8_t *destination = reinterpret_cast<uint8_t *>(dest);
uint8_t const *source = (uint8_t const *)src;
for (size_t i = 0; i != size; ++i) {
destination[i] = source[i];
}
return dest;
}
extern "C" void *memmove(void *dest, void const *src, size_t size) {
uint8_t *destination = reinterpret_cast<uint8_t *>(dest);
uint8_t const *source = reinterpret_cast<uint8_t const *>(src);
if (source > destination) {
for (size_t i = 0; i != size; ++i) {
destination[i] = source[i];
}
} else {
for (size_t i = size; i != 0; --i) {
destination[i - 1] = source[i - 1];
}
}
return dest;
}
extern "C" void *memset(void *dest, int pattern, size_t size) {
uint8_t *destination = reinterpret_cast<uint8_t *>(dest);
for (size_t i = 0; i != size; ++i) {
destination[i] = static_cast<uint8_t>(pattern);
}
return dest;
}