libiberty/memchr.c

   1 /*
   2 FUNCTION
   3         <<memchr>>---find character in memory
   4
   5 INDEX
   6         memchr
   7
   8 ANSI_SYNOPSIS
   9         #include <string.h>
  10         void *memchr(const void *<[src]>, int <[c]>, size_t <[length]>);
  11
  12 TRAD_SYNOPSIS
  13         #include <string.h>
  14         void *memchr(<[src]>, <[c]>, <[length]>)
  15         void *<[src]>;
  16         void *<[c]>;
  17         size_t <[length]>;
  18
  19 DESCRIPTION
  20         This function searches memory starting at <<*<[src]>>> for the
  21         character <[c]>.  The search only ends with the first
  22         occurrence of <[c]>, or after <[length]> characters; in
  23         particular, <<NULL>> does not terminate the search.
  24
  25 RETURNS
  26         If the character <[c]> is found within <[length]> characters
  27         of <<*<[src]>>>, a pointer to the character is returned. If
  28         <[c]> is not found, then <<NULL>> is returned.
  29
  30 PORTABILITY
  31 <<memchr>>  requires no supporting OS subroutines.
  32
  33 QUICKREF
  34         memchr ansi pure
  35
  36 */
  37
  38 #include <ansidecl.h>
  39 #ifdef __STDC__
  40 #include <stddef.h>
  41 #else
  42 #define size_t unsigned long
  43 #endif
  44
  45 PTR
  46 memchr (src_void, c, length)
  47      register const PTR src_void;
  48      int c;
  49      size_t length;
  50 {
  51   const unsigned char *src = (const unsigned char *)src_void;
  52
  53   while (--length >= 0)
  54   {
  55     if (*src == c)
  56      return (PTR)src;
  57     src++;
  58   }
  59   return NULL;
  60 }