lib/string.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <types.h>
   4 #include <malloc.h>
   5
   6 int strcmp(const char *s1, const char *s2)
   7 {
   8         while ((*s1 == *s2) && *s1 != '\0') {
   9                 s1++;
  10                 s2++;
  11         }
  12
  13         return (*s1 - *s2);
  14 }
  15
  16 int strncmp(const char *s1, const char *s2, int n)
  17 {
  18         while ((--n) && (*s1 == *s2) && *s1 != '\0') {
  19                 s1++;
  20                 s2++;
  21         }
  22
  23         return (*s1 - *s2);
  24 }
  25
  26
  27 char *strcpy(char *dest, const char *src)
  28 {
  29         char *tmp = dest;
  30
  31         while ((*dest++ = *src++) != '\0')
  32                 /* nothing */;
  33         return tmp;
  34 }
  35
  36
  37 char *strcat(char *dest, const char *src)
  38 {
  39         char *tmp = dest;
  40
  41         while (*dest)
  42                 dest++;
  43         while ((*dest++ = *src++) != '\0')
  44                 ;
  45         return tmp;
  46 }
  47
  48
  49 size_t strlen(const char *s)
  50 {
  51         const char *sc;
  52
  53         for (sc = s; *sc; ++sc)
  54                 /* nothing */;
  55         return sc - s;
  56 }
  57
  58
  59 char *strchr (const char *s, int c)
  60 {
  61         while (*s) {
  62                 if (*s == c)
  63                         return (char *) s;
  64                 s++;
  65         }
  66
  67         return (void *)0;
  68 }
  69
  70 char *strrchr (char *s, int c)
  71 {
  72         char *end = s + strlen(s) - 1;
  73
  74         while (*end != c && end >= s)
  75                 end--;
  76         if (end < s)
  77                 return NULL;
  78         return end;
  79 }
  80
  81 char *strdup(const char *str)
  82 {
  83         char *s = malloc(strlen(str) + 1);
  84         if (!s)
  85                 return s;
  86         strcpy(s, str);
  87         return s;
  88 }
  89
  90 void *memset(void *s, int c, size_t count)
  91 {
  92         char *xs = s;
  93
  94         while (count--)
  95                 *xs++ = c;
  96         return s;
  97 }
  98
  99 void *memset_word(void *s, unsigned short word, size_t count)
 100 {
 101         unsigned short *xs = (unsigned short *)s;
 102
 103         while (count--)
 104                 *xs++ = word;
 105         return s;
 106 }
 107
 108 void *memcpy(void *dest, const void *src, size_t count)
 109 {
 110         char *tmp = dest;
 111         const char *s = src;
 112
 113         while (count--)
 114                 *tmp++ = *s++;
 115         return dest;
 116 }
 117
 118
 119 void *memmove(void *dest, const void *src, size_t count)
 120 {
 121         char *tmp;
 122         const char *s;
 123
 124         if (dest <= src) {
 125                 tmp = dest;
 126                 s = src;
 127                 while (count--)
 128                         *tmp++ = *s++;
 129         } else {
 130                 tmp = dest;
 131                 tmp += count;
 132                 s = src;
 133                 s += count;
 134                 while (count--)
 135                         *--tmp = *--s;
 136         }
 137         return dest;
 138 }
 139
 140
 141 int memcmp(const void *cs, const void *ct, size_t count)
 142 {
 143         const unsigned char *su1, *su2;
 144         int res = 0;
 145
 146         for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
 147                 if ((res = *su1 - *su2) != 0)
 148                         break;
 149         return res;
 150 }