1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
/** String functions that don't depend on any external functions. */
#include <string.h>
char *strchr(const char *s, int c) {
for (; *s || c == 0; s++) {
if (*s == c) return (char *)s;
}
return NULL;
}
char *strrchr(const char *s, int c) {
for (int i = strlen(s) + 1; i >= 0; i--) {
if (s[i] == c) return (char *)s + i;
}
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 *strpbrk(const char *s1, const char *s2) {
for (; *s1; s1++) {
if (strchr(s2, *s1)) return (char*)s1;
}
return NULL;
}
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) {
for (size_t i = 0; i < n; i++) {
if (s1[i] < s2[i]) return -1;
if (s1[i] > s2[i]) return 1;
}
return 0;
}
int strcoll(const char *s1, const char *s2) {
return strcmp(s1, s2);
}
char *strstr(const char *s1, const char *s2) {
size_t l1 = strlen(s1), l2 = strlen(s2);
for (; l2 <= l1; s1++, l1--) {
if (memcmp(s1, s2, l2) == 0) return (char*)s1;
}
return NULL;
}
char *strcat(char *restrict dst, const char *restrict src) {
return strcpy(dst + strlen(dst), src);
}
char *strcpy(char *restrict s1, const char *restrict s2) {
char *ret = s1;
while (*s2) *s1++ = *s2++;
*s1 = *s2;
return ret;
}
char *strncpy(char *restrict dst, const char *restrict src, size_t n) {
for (size_t i = 0; i < n; i++) {
dst[i] = src[i];
if (dst[i] == '\0') return dst + i; // TODO fill with null bytes
}
return dst;
}
size_t strnlen(const char *s, size_t len) {
for (size_t i = 0; i < len; i++) {
if (!s[i]) {
return i;
}
}
return len;
}
|
