compiler/clib/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 #include <stdio.h>
  10
  11 /*****************************************************************************
  12
  13     NAME */
  14 #include <string.h>
  15
  16         char * strrchr (
  17
  18 /*  SYNOPSIS */
  19         const char * str,
  20         int          c)
  21
  22 /*  FUNCTION
  23         Searches for the last character c in a string.
  24
  25     INPUTS
  26         str - Search this string
  27         c - Look for this character
  28
  29     RESULT
  30         A pointer to the first occurence of c in str or NULL if c is not
  31         found in str.
  32
  33     NOTES
  34
  35     EXAMPLE
  36         char buffer[64];
  37
  38         strcpy (buffer, "Hello ");
  39
  40         // This returns a pointer to the second l in buffer.
  41         strrchr (buffer, 'l');
  42
  43         // This returns NULL
  44         strrchr (buffer, 'x');
  45
  46     BUGS
  47
  48     SEE ALSO
  49         strrchr()
  50
  51     INTERNALS
  52         It might seem that the algorithm below is slower than one which
  53         first finds the end and then walks backwards but that would mean
  54         to process some characters twice - if the string doesn't contain
  55         c, it would mean to process every character twice.
  56
  57 ******************************************************************************/
  58 {
  59     char * p = NULL;
  60
  61     while (*str)
  62     {
  63         /* those casts are needed to compare chars > 127 */
  64         if ((unsigned char)*str == (unsigned char)c)
  65             p = (char *)str;
  66
  67         str ++;
  68     }
  69
  70     return p;
  71 } /* strrchr */
  72
  73 AROS_MAKE_ALIAS(strrchr, rindex);