ciabatta/code/string.c

204 lines
3.8 KiB
C

#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
// TODO: rewrite memmove to not allocate anything
typedef unsigned char byte;
void *memcpy(void *restrict s1, const void *restrict s2, size_t n) {
const byte *restrict c2 = s2;
byte *restrict c1 = s1;
while (n--) {
*c1++ = *c2++;
}
return s1;
}
void *memmove(void *s1, const void *s2, size_t n)
{
void *buffer = malloc(n);
memcpy(buffer, s2, n);
memcpy(s1, buffer, n);
free(buffer);
return s1;
}
void *memset(void *s, int c, size_t n) {
byte *restrict buf = s;
while (n--) {
*buf++ = c;
}
return s;
}
char *strcpy(char *restrict s1, const char *restrict s2)
{
while(*s2 != 0) {
*s1++ = *s2++;
}
*s1 = 0;
return s1;
}
char *strncpy(char *restrict s1, const char *restrict s2, size_t n)
{
while(n-->0 && *s2 != 0) {
*s1++ = *s2++;
}
while(n-->0) {
*s1++ = 0;
}
return s1;
}
char *strncat(char *restrict s1, const char *restrict s2, size_t n)
{
size_t start = strlen(s1);
for(size_t i = 0; i != n && *s2 != 0; ++i) {
s1[start+i] = s2[i];
}
s1[start+n] = 0;
return s1;
}
int memcmp(const void *s1, const void *s2, size_t n) {
const byte *u1 = s1;
const byte *u2 = s2;
for (; n--; u1++, u2++) {
if (*u1 != *u2) return *u1 - *u2;
}
return 0;
}
int strcmp(const char *s1, const char *s2) {
int diff;
do {
diff = *s1 - *s2;
} while(diff != 0 && *s1 != 0 && *s2 != 0);
return diff;
}
int strncmp(const char *s1, const char *s2, size_t n)
{
int diff = 0;
size_t i = 0;
if(n != 0) do {
diff = *s1 - *s2;
} while(++i < n && diff != 0 && *s1 != 0 && *s2 != 0);
return diff;
}
// fuck locales
int strcoll(const char *s1, const char *s2)
{
return strcmp(s1, s2);
}
// fuck bad implementation of strcoll
size_t strxfrm(char *restrict s1, const char *restrict s2, size_t n)
{
size_t len = strlen(s2);
if(s1 != NULL && n != 0) {
for(size_t i = 0; i != n; ++i) {
*s1 = *s2;
}
}
return len;
}
void *memchr(const void *ptr, int c, size_t n)
{
const byte *s = ptr;
size_t i = 0;
for(; i != n && *s != c; ++i, ++s) {
++s;
}
if(i == n) return NULL;
return (void *)s; // fuck clang
}
char *strchr(const char *s, int c)
{
while(*s && *s != c) ++s;
if(*s != c) return NULL;
return (void *)s; // fuck clang
}
size_t strcspn(const char *s1, const char *s2)
{
size_t i = 0;
while(*s1) {
if(strchr(s2, *s1) != NULL) {
break;
}
++s1;
++i;
}
return i;
}
char *strpbrk(const char *s1, const char *s2)
{
while(*s1) {
if(strchr(s2, *s1) == NULL) {
break;
}
++s1;
}
return (char *)s1;
}
char *strstr(const char *s1, const char *s2)
{
if(!*s2) return (char *)s1;
size_t len = strlen(s2);
while(*s1 != 0) {
bool match = true;
for(size_t i = 0; i != len; ++i) {
if(!*s1 || s1[i] != s2[i]) {
match = false;
break;
}
}
++s1;
if(match) return (char *)s1;
}
return NULL;
}
char *strerror(int errnum)
{
switch(errnum) {
case 0: return "No errors";
case EDOM: return "Value is out of domain of the function";
case EILSEQ: return "Illegal byte sequence";
case ERANGE: return "Value is out of range";
}
return "Unkown error";
}
size_t strlen(const char *s) {
size_t i = 0;
while (s[i]) {
i++;
}
return i;
}
size_t strnlen_s(const char *s, size_t maxsize) {
if (s == NULL) return 0;
size_t i = 0;
while (s[i] && i < maxsize) {
i++;
}
return i;
}