1 /* 2 * libc string functions 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU Library General Public License version 2. 6 */ 7 8 #include "libcflat.h" 9 10 unsigned long strlen(const char *buf) 11 { 12 unsigned long len = 0; 13 14 while (*buf++) 15 ++len; 16 return len; 17 } 18 19 char *strcat(char *dest, const char *src) 20 { 21 char *p = dest; 22 23 while (*p) 24 ++p; 25 while ((*p++ = *src++) != 0) 26 ; 27 return dest; 28 } 29 30 char *strcpy(char *dest, const char *src) 31 { 32 *dest = 0; 33 return strcat(dest, src); 34 } 35 36 int strncmp(const char *a, const char *b, size_t n) 37 { 38 for (; n--; ++a, ++b) 39 if (*a != *b || *a == '\0') 40 return *a - *b; 41 42 return 0; 43 } 44 45 int strcmp(const char *a, const char *b) 46 { 47 return strncmp(a, b, SIZE_MAX); 48 } 49 50 char *strchr(const char *s, int c) 51 { 52 while (*s != (char)c) 53 if (*s++ == '\0') 54 return NULL; 55 return (char *)s; 56 } 57 58 char *strstr(const char *s1, const char *s2) 59 { 60 size_t l1, l2; 61 62 l2 = strlen(s2); 63 if (!l2) 64 return (char *)s1; 65 l1 = strlen(s1); 66 while (l1 >= l2) { 67 l1--; 68 if (!memcmp(s1, s2, l2)) 69 return (char *)s1; 70 s1++; 71 } 72 return NULL; 73 } 74 75 void *memset(void *s, int c, size_t n) 76 { 77 size_t i; 78 char *a = s; 79 80 for (i = 0; i < n; ++i) 81 a[i] = c; 82 83 return s; 84 } 85 86 void *memcpy(void *dest, const void *src, size_t n) 87 { 88 size_t i; 89 char *a = dest; 90 const char *b = src; 91 92 for (i = 0; i < n; ++i) 93 a[i] = b[i]; 94 95 return dest; 96 } 97 98 int memcmp(const void *s1, const void *s2, size_t n) 99 { 100 const unsigned char *a = s1, *b = s2; 101 int ret = 0; 102 103 while (n--) { 104 ret = *a - *b; 105 if (ret) 106 break; 107 ++a, ++b; 108 } 109 return ret; 110 } 111 112 void *memmove(void *dest, const void *src, size_t n) 113 { 114 const unsigned char *s = src; 115 unsigned char *d = dest; 116 117 if (d <= s) { 118 while (n--) 119 *d++ = *s++; 120 } else { 121 d += n, s += n; 122 while (n--) 123 *--d = *--s; 124 } 125 return dest; 126 } 127 128 void *memchr(const void *s, int c, size_t n) 129 { 130 const unsigned char *str = s, chr = (unsigned char)c; 131 132 while (n--) 133 if (*str++ == chr) 134 return (void *)(str - 1); 135 return NULL; 136 } 137 138 long atol(const char *ptr) 139 { 140 long acc = 0; 141 const char *s = ptr; 142 int neg, c; 143 144 while (*s == ' ' || *s == '\t') 145 s++; 146 if (*s == '-'){ 147 neg = 1; 148 s++; 149 } else { 150 neg = 0; 151 if (*s == '+') 152 s++; 153 } 154 155 while (*s) { 156 if (*s < '0' || *s > '9') 157 break; 158 c = *s - '0'; 159 acc = acc * 10 + c; 160 s++; 161 } 162 163 if (neg) 164 acc = -acc; 165 166 return acc; 167 } 168 169 extern char **environ; 170 171 char *getenv(const char *name) 172 { 173 char **envp = environ, *delim; 174 175 while (*envp) { 176 delim = strchr(*envp, '='); 177 if (delim && strncmp(name, *envp, delim - *envp) == 0) 178 return delim + 1; 179 ++envp; 180 } 181 return NULL; 182 } 183