compat/memmem.c

   1 #include "../git-compat-util.h"
   2
   3 void *gitmemmem(const void *haystack, size_t haystack_len,
   4                 const void *needle, size_t needle_len)
   5 {
   6         const char *begin = haystack;
   7         const char *last_possible = begin + haystack_len - needle_len;
   8
   9         /*
  10          * The first occurrence of the empty string is deemed to occur at
  11          * the beginning of the string.
  12          */
  13         if (needle_len == 0)
  14                 return (void *)begin;
  15
  16         /*
  17          * Sanity check, otherwise the loop might search through the whole
  18          * memory.
  19          */
  20         if (haystack_len < needle_len)
  21                 return NULL;
  22
  23         for (; begin <= last_possible; begin++) {
  24                 if (!memcmp(begin, needle, needle_len))
  25                         return (void *)begin;
  26         }
  27
  28         return NULL;
  29 }