user/string.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <types.h>
   4
   5 int strcmp(const char *s1, const char *s2)
   6 {
   7         while ((*s1 == *s2) && *s1 != '\0') {
   8                 s1++;
   9                 s2++;
  10         }
  11
  12         return (*s1 - *s2);
  13 }
  14
  15 int strncmp(const char *s1, const char *s2, int n)
  16 {
  17         while ((--n) && (*s1 == *s2) && *s1 != '\0') {
  18                 s1++;
  19                 s2++;
  20         }
  21
  22         return (*s1 - *s2);
  23 }
  24
  25
  26 char *strcpy(char *dest, const char *src)
  27 {
  28         char *tmp = dest;
  29
  30         while ((*dest++ = *src++) != '\0')
  31                 /* nothing */;
  32         return tmp;
  33 }
  34
  35
  36 char *strcat(char *dest, const char *src)
  37 {
  38         char *tmp = dest;
  39
  40         while (*dest)
  41                 dest++;
  42         while ((*dest++ = *src++) != '\0')
  43                 ;
  44         return tmp;
  45 }
  46
  47
  48 size_t strlen(const char *s)
  49 {
  50         const char *sc;
  51
  52         for (sc = s; *sc; ++sc)
  53                 /* nothing */;
  54         return sc - s;
  55 }
  56
  57
  58 char *strchr (const char *s, int c)
  59 {
  60         while (*s) {
  61                 if (*s == c)
  62                         return (char *) s;
  63                 s++;
  64         }
  65
  66         return (void *)0;
  67 }
  68
  69 char *strrchr (char *s, int c)
  70 {
  71         char *end = s + strlen(s) - 1;
  72
  73         while (*end != c && end >= s)
  74                 end--;
  75         if (end < s)
  76                 return NULL;
  77         return end;
  78 }
  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
  91 void *memset(void *s, int c, size_t count)
  92 {
  93         char *xs = s;
  94
  95         while (count--)
  96                 *xs++ = c;
  97         return s;
  98 }
  99
 100 void *memset_word(void *s, unsigned short word, size_t count)
 101 {
 102         unsigned short *xs = (unsigned short *)s;
 103
 104         while (count--)
 105                 *xs++ = word;
 106         return s;
 107 }
 108
 109 void *memcpy(void *dest, const void *src, size_t count)
 110 {
 111         char *tmp = dest;
 112         const char *s = src;
 113
 114         while (count--)
 115                 *tmp++ = *s++;
 116         return dest;
 117 }
 118
 119
 120 void *memmove(void *dest, const void *src, size_t count)
 121 {
 122         char *tmp;
 123         const char *s;
 124
 125         if (dest <= src) {
 126                 tmp = dest;
 127                 s = src;
 128                 while (count--)
 129                         *tmp++ = *s++;
 130         } else {
 131                 tmp = dest;
 132                 tmp += count;
 133                 s = src;
 134                 s += count;
 135                 while (count--)
 136                         *--tmp = *--s;
 137         }
 138         return dest;
 139 }
 140
 141
 142 int memcmp(const void *cs, const void *ct, size_t count)
 143 {
 144         const unsigned char *su1, *su2;
 145         int res = 0;
 146
 147         for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
 148                 if ((res = *su1 - *su2) != 0)
 149                         break;
 150         return res;
 151 }