newlib/libc/argz/argz_insert.c

   1 /* Copyright (C) 2002, 2005 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 #define __need_ptrdiff_t
  13 #include <stddef.h>
  14
  15 error_t
  16 argz_insert (char **argz,
  17        size_t *argz_len,
  18        char *before,
  19        const char *entry)
  20 {
  21   int len = 0;
  22   ptrdiff_t delta;
  23
  24   if (before == NULL)
  25     return argz_add(argz, argz_len, entry);
  26
  27   if (before < *argz || before >= *argz + *argz_len)
  28     return EINVAL;
  29
  30   while (before != *argz && before[-1])
  31     before--;
  32
  33   /* delta will always be non-negative, and < *argz_len */
  34   delta = before - *argz;
  35
  36   len = strlen(entry) + 1;
  37
  38   if(!(*argz = (char *)realloc(*argz, *argz_len + len)))
  39     return ENOMEM;
  40
  41   memmove(*argz + delta + len, *argz + delta,  *argz_len - delta);
  42   memcpy(*argz + delta, entry, len);
  43
  44   *argz_len += len;
  45
  46   return 0;
  47 }