compiler/stdc/strrchr.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     C99 function strrchr().
   6 */
   7
   8 #include <aros/macros.h>
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <string.h>
  14
  15         char * strrchr (
  16
  17 /*  SYNOPSIS */
  18         const char * str,
  19         int          c)
  20
  21 /*  FUNCTION
  22         Searches for the last character c in a string.
  23
  24     INPUTS
  25         str - Search this string
  26         c - Look for this character
  27
  28     RESULT
  29         A pointer to the first occurence of c in str or NULL if c is not
  30         found in str.
  31
  32     NOTES
  33
  34     EXAMPLE
  35         char buffer[64];
  36
  37         strcpy (buffer, "Hello ");
  38
  39         // This returns a pointer to the second l in buffer.
  40         strrchr (buffer, 'l');
  41
  42         // This returns NULL
  43         strrchr (buffer, 'x');
  44
  45     BUGS
  46
  47     SEE ALSO
  48         strrchr()
  49
  50     INTERNALS
  51         It might seem that the algorithm below is slower than one which
  52         first finds the end and then walks backwards but that would mean
  53         to process some characters twice - if the string doesn't contain
  54         c, it would mean to process every character twice.
  55
  56 ******************************************************************************/
  57 {
  58     char * p = NULL;
  59
  60     while (*str)
  61     {
  62         /* those casts are needed to compare chars > 127 */
  63         if ((unsigned char)*str == (unsigned char)c)
  64             p = (char *)str;
  65
  66         str ++;
  67     }
  68
  69     return p;
  70 } /* strrchr */