Files
my-kern/kernel/libc/string.c

121 lines
2.5 KiB
C

//
// Created by rick on 01-02-21.
//
#include <string.h>
#include <sys/param.h>
#include <sys/types.h>
int memcpy(void *dst, const void *src, size_t amount) {
for (size_t i = 0; i < amount; i++) {
((char *) dst)[i] = ((const char *) src)[i];
}
return 0;
}
int memset(void *dst, int data, size_t amount) {
for (size_t i = 0; i < amount; ++i) {
((char *) dst)[i] = (char) data;
}
return 0;
}
int strcpy(char *dst, const char *src) {
return memcpy(dst, src, strlen(src) + 1);
}
int strncpy(char *dst, const char *src, size_t n) {
return memcpy(dst, src, MIN(strlen(src), n) + 1);
}
size_t strlen(const char *str) {
int length = 0;
while (str[length] != 0) {
length++;
}
return length;
}
int strcmp(const char *s1, const char *s2) {
int len1 = strlen(s1);
int len2 = strlen(s2);
return strncmp(s1, s2, MAX(len1, len2));
}
const char *strchr(const char *s, char c) {
int index = 0;
while (1) {
if (s[index] == c) {
return &s[index];
}
if (s[index] == 0) {
return NULL;
}
index++;
}
}
const char *strrchr(const char *s, char c) {
int index = strlen(s);
while (1) {
if (s[index] == c) {
return &s[index];
}
if (index == 0) {
return NULL;
}
index--;
}
}
int memcmp(const void *s1, const void *s2, size_t n) {
uint8_t a, b;
for (size_t i = 0; i < n; ++i) {
a = ((uint8_t *) s1)[i];
b = ((uint8_t *) s2)[i];
if (a > b) return 1;
if (b < a) return -1;
}
return 0;
}
int strncmp(const char *s1, const char *s2, int n) {
for (int i = 0; i < n; ++i) {
if (s1[i] == 0 && s2[i] == 0) {
return 0;
}
if (s1[i] == 0) {
return -1;
}
if (s2[i] == 0) {
return 1;
}
if (s1[i] > s2[i]) {
return -1;
}
if (s1[i] < s2[i]) {
return 1;
}
}
return 0;
}
char *strcat(char *dest, const char *src) {
size_t count = strlen(src);
return strncat(dest, src, count);
}
char *strncat(char *dest, const char *src, size_t n) {
size_t start = strlen(dest);
for (size_t index = 0; index < n; index++) {
char val = src[index];
dest[start + index] = val;
if (val == 0) {
dest[start + index] = 0;
break;
}
}
return dest;
}