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#include <ctype.h>
#include <errno.h>
#include <string.h>
long strtol(const char *restrict s, char **restrict end, int base) {
long res = 0;
int sign = 1;
while (isspace(*s)) s++;
if (*s == '+') {
s++;
} else if (*s == '-') {
s++;
sign = -1;
}
if (base == 0) {
if (*s == '0') {
s++;
if (*s == 'x' || *s == 'X') {
s++;
base = 16;
} else {
base = 8;
}
} else {
base = 10;
}
}
for (;;) {
unsigned char digit = *s;
if ('0' <= digit && digit <= '9') digit -= '0';
else if ('a' <= digit && digit <= 'z') digit -= 'a' - 10;
else if ('A' <= digit && digit <= 'Z') digit -= 'A' - 10;
else break;
if (digit >= base) break;
// TODO overflow check
res *= base;
res += digit;
s++;
}
if (end) *end = (void*)s;
return res * sign;
}
char *strchr(const char *s, int c) {
for (; *s; s++) {
if (*s == c) return (char*)s;
}
return NULL;
}
size_t strspn(const char *s, const char *accept) {
size_t l = 0;
for (; s[l] && strchr(accept, s[l]); l++);
return l;
}
size_t strcspn(const char *s, const char *reject) {
size_t l = 0;
for (; s[l] && !strchr(reject, s[l]); l++);
return l;
}
char *strtok(char *restrict s, const char *restrict sep) {
static char *state;
return strtok_r(s, sep, &state);
}
char *strtok_r(char *restrict s, const char *restrict sep, char **restrict state) {
char *end;
if (!s) s = *state;
s += strspn(s, sep); /* beginning of token */
if (!*s) return NULL;
end = s + strcspn(s, sep);
if (*end) {
*end = '\0';
*state = end + 1;
} else {
*state = end;
}
return s;
}
int strncmp(const char *s1, const char *s2, size_t n) {
while (n-- & *s1 && *s1 == *s2) {
s1++; s2++;
}
if (*s1 == *s2) return 0;
if (*s1 < *s2) return -1;
else return 1;
}
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