newlib/libc/argz/argz_replace.c

   1 /* Copyright (C) 2002 by  Red Hat, Incorporated. All rights reserved.
   2  *
   3  * Permission to use, copy, modify, and distribute this software
   4  * is freely granted, provided that this notice is preserved.
   5  */
   6
   7 #include <errno.h>
   8 #include <sys/types.h>
   9 #include <string.h>
  10 #include <stdlib.h>
  11 #include <argz.h>
  12
  13 #include "buf_findstr.h"
  14
  15 error_t
  16 argz_replace (char **argz,
  17        size_t *argz_len,
  18        const char *str,
  19        const char *with,
  20        unsigned *replace_count)
  21 {
  22   const int str_len = strlen(str);
  23   const int with_len = strlen(with);
  24   const int len_diff = with_len - str_len;
  25
  26   char *buf_iter = *argz;
  27   size_t buf_len = *argz_len;
  28   char *last_iter = NULL;
  29   char *new_argz = NULL;
  30   size_t new_argz_len = 0;
  31   char *new_argz_iter = NULL;
  32   char *argz_realloc = NULL;
  33
  34   *replace_count = 0;
  35   new_argz_len = *argz_len;
  36
  37   while(buf_len)
  38     {
  39       if(_buf_findstr(str, &buf_iter, &buf_len))
  40         {
  41           *replace_count += 1;
  42           new_argz_len += len_diff;
  43         }
  44     }
  45
  46   if (*replace_count)
  47     {
  48       if (!(new_argz = (char *)malloc(new_argz_len)))
  49         return ENOMEM;
  50
  51       buf_iter = *argz;
  52       buf_len = *argz_len;
  53       last_iter = buf_iter;
  54       new_argz_iter = new_argz;
  55
  56       while(buf_len)
  57         {
  58           if (_buf_findstr(str, &buf_iter, &buf_len))
  59             {
  60               /* copy everything up to, but not including str, from old argz to
  61                  new argz. */
  62               memcpy(new_argz_iter, last_iter, buf_iter - last_iter - str_len);
  63               new_argz_iter += (buf_iter - last_iter - str_len);
  64               /* copy replacement string. */
  65               memcpy(new_argz_iter, with, with_len);
  66               new_argz_iter += with_len;
  67               last_iter = buf_iter;
  68             }
  69         }
  70       /* copy everything after last occurrence of str. */
  71       memcpy(new_argz_iter, last_iter, *argz + *argz_len - last_iter);
  72
  73       /* reallocate argz, and copy over the new value. */
  74       if(!(argz_realloc = (char *)realloc(*argz, new_argz_len)))
  75         {
  76           free(new_argz);
  77           return ENOMEM;
  78         }
  79       *argz = argz_realloc;
  80
  81       memcpy(*argz, new_argz, new_argz_len);
  82       *argz_len = new_argz_len;
  83
  84       if (*argz_len == 0)
  85         {
  86           free(*argz);
  87           *argz = NULL;
  88         }
  89       free(new_argz);
  90     }
  91
  92   return 0;
  93 }