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#include <cstdint>
#include <klibc/string.hpp>
void* klibc::memcpy(void *__restrict dest, const void *__restrict src, std::size_t n) {
#if defined(__x86_64__)
asm volatile(
"rep movsb"
: "+D"(dest), "+S"(src), "+c"(n)
:
: "memory"
);
return dest;
#else
std::uint8_t *__restrict pdest = static_cast<std::uint8_t *__restrict>(dest);
const std::uint8_t *__restrict psrc = static_cast<const std::uint8_t *__restrict>(src);
for (std::size_t i = 0; i < n; i++) {
pdest[i] = psrc[i];
}
return dest;
#endif
}
void* klibc::memset(void *s, int c, std::size_t n) {
#if defined(__x86_64__)
void* original_s = s;
asm volatile(
"rep stosb"
: "+D"(s), "+c"(n)
: "a"((std::uint8_t)c)
: "memory"
);
return original_s;
#else
std::uint8_t *p = static_cast<std::uint8_t *>(s);
for (std::size_t i = 0; i < n; i++) {
p[i] = static_cast<std::uint8_t>(c);
}
return s;
#endif
}
void* klibc::memmove(void *dest, const void *src, std::size_t n) {
std::uint8_t *pdest = static_cast<std::uint8_t *>(dest);
const std::uint8_t *psrc = static_cast<const std::uint8_t *>(src);
if (reinterpret_cast<std::uintptr_t>(src) > reinterpret_cast<std::uintptr_t>(dest)) {
for (std::size_t i = 0; i < n; i++) {
pdest[i] = psrc[i];
}
} else if (reinterpret_cast<std::uintptr_t>(src) < reinterpret_cast<std::uintptr_t>(dest)) {
for (std::size_t i = n; i > 0; i--) {
pdest[i-1] = psrc[i-1];
}
}
return dest;
}
int klibc::memcmp(const void *s1, const void *s2, std::size_t n) {
const std::uint8_t *p1 = static_cast<const std::uint8_t *>(s1);
const std::uint8_t *p2 = static_cast<const std::uint8_t *>(s2);
for (std::size_t i = 0; i < n; i++) {
if (p1[i] != p2[i]) {
return p1[i] < p2[i] ? -1 : 1;
}
}
return 0;
}
int klibc::strlen(const char *str) {
int len = 0;
while (str[len] != '\0') {
len++;
}
return len;
}
char* klibc::strchr(const char *s, int c) {
while (*s) {
if (*s == (char)c) return (char *)s;
s++;
}
return nullptr;
}
char* klibc::strtok(char **next,char *str, const char *delim) {
if (str) *next = str;
if (!*next) return nullptr;
char *start = *next;
while (*start && strchr(delim, *start)) {
start++;
}
if (!*start) {
*next = nullptr;
return nullptr;
}
char *end = start;
while (*end && !strchr(delim, *end)) {
end++;
}
if (*end) {
*end = '\0';
*next = end + 1;
} else {
*next = nullptr;
}
return start;
}
char* klibc::strrchr(const char* str, int ch) {
char* last_occurrence = 0;
while (*str) {
if (*str == ch) {
last_occurrence = (char*)str;
}
str++;
}
return last_occurrence;
}
char* klibc::strcat(char* dest, const char* src) {
char* ptr = dest;
while(*ptr != '\0') {
ptr++;
}
while(*src != '\0') {
*ptr = *src;
ptr++;
src++;
}
*ptr = '\0';
return dest;
}
int klibc::strncmp(const char *s1, const char *s2, std::size_t n) {
std::size_t i = 0;
while (i < n && s1[i] && (s1[i] == s2[i])) {
i++;
}
if (i == n) return 0;
return (unsigned char)s1[i] - (unsigned char)s2[i];
}
// tbh i dont remember from what i took this
int klibc::strcmp(const char *s1, const char *s2) {
const unsigned long *w1 = (const unsigned long *)s1;
const unsigned long *w2 = (const unsigned long *)s2;
const unsigned long himagic = 0x8080808080808080UL;
const unsigned long lomagic = 0x0101010101010101UL;
while (1) {
unsigned long word1 = *w1++;
unsigned long word2 = *w2++;
unsigned long diff = word1 ^ word2;
unsigned long zeros = (word1 - lomagic) & ~word1 & himagic;
if (diff != 0 || zeros != 0) {
const char *c1 = (const char *)(w1 - 1);
const char *c2 = (const char *)(w2 - 1);
do {
unsigned char ch1 = *c1++;
unsigned char ch2 = *c2++;
if (ch1 != ch2) return ch1 - ch2;
if (ch1 == 0) break;
} while (1);
return 0;
}
}
}
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