str_extra.c

Extra string functions library for C
git clone git://git.finwo.net/lib/str_extra.c
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strnstr.c (569B)

      1 #include "string.h"
      2 
      3 #include "strnstr.h"
      4 
      5 // Origin: https://stackoverflow.com/a/25705264/2928176
      6 // Author: Chris Dodd (https://stackoverflow.com/users/16406/chris-dodd)
      7 char *strnstr(const char *haystack, const char *needle, size_t len) {
      8   int i;
      9   size_t needle_len;
     10 
     11   if (0 == (needle_len = strnlen(needle, len))) {
     12     return NULL;
     13   }
     14 
     15   for (i=0; i<=(int)(len-needle_len); i++) {
     16     if (
     17       (haystack[0] == needle[0]) &&
     18       (0 == strncmp(haystack, needle, needle_len))
     19     ) {
     20       return (char *)haystack;
     21     }
     22     haystack++;
     23   }
     24 
     25   return NULL;
     26 }