about summary refs log tree commit diff
path: root/string/argz-replace.c
blob: d08f3202ee3d9f21fcb4508445a9a9f62ff51f66 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
/* String replacement in an argz vector
   Copyright (C) 1997-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Written by Miles Bader <miles@gnu.ai.mit.edu>

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <stdlib.h>
#include <string.h>
#include <argz.h>

/* Append BUF, of length BUF_LEN to *TO, of length *TO_LEN, reallocating and
   updating *TO & *TO_LEN appropriately.  If an allocation error occurs,
   *TO's old value is freed, and *TO is set to 0.  */
static void
str_append (char **to, size_t *to_len, const char *buf, const size_t buf_len)
{
  size_t new_len = *to_len + buf_len;
  char *new_to = realloc (*to, new_len + 1);

  if (new_to)
    {
      *((char *) __mempcpy (new_to + *to_len, buf, buf_len)) = '\0';
      *to = new_to;
      *to_len = new_len;
    }
  else
    {
      free (*to);
      *to = 0;
    }
}

/* Replace any occurrences of the string STR in ARGZ with WITH, reallocating
   ARGZ as necessary.  If REPLACE_COUNT is non-zero, *REPLACE_COUNT will be
   incremented by number of replacements performed.  */
error_t
__argz_replace (char **argz, size_t *argz_len, const char *str, const char *with,
		unsigned *replace_count)
{
  error_t err = 0;

  if (str && *str)
    {
      char *arg = 0;
      char *src = *argz;
      size_t src_len = *argz_len;
      char *dst = 0;
      size_t dst_len = 0;
      int delayed_copy = 1;	/* True while we've avoided copying anything.  */
      size_t str_len = strlen (str), with_len = strlen (with);

      while (!err && (arg = argz_next (src, src_len, arg)))
	{
	  char *match = strstr (arg, str);
	  if (match)
	    {
	      char *from = match + str_len;
	      size_t to_len = match - arg;
	      char *to = __strndup (arg, to_len);

	      while (to && from)
		{
		  str_append (&to, &to_len, with, with_len);
		  if (to)
		    {
		      match = strstr (from, str);
		      if (match)
			{
			  str_append (&to, &to_len, from, match - from);
			  from = match + str_len;
			}
		      else
			{
			  str_append (&to, &to_len, from, strlen (from));
			  from = 0;
			}
		    }
		}

	      if (to)
		{
		  if (delayed_copy)
		    /* We avoided copying SRC to DST until we found a match;
                       now that we've done so, copy everything from the start
                       of SRC.  */
		    {
		      if (arg > src)
			err = __argz_append (&dst, &dst_len, src, (arg - src));
		      delayed_copy = 0;
		    }
		  if (! err)
		    err = __argz_add (&dst, &dst_len, to);
		  free (to);
		}
	      else
		err = ENOMEM;

	      if (replace_count)
		(*replace_count)++;
	    }
	  else if (! delayed_copy)
	    err = __argz_add (&dst, &dst_len, arg);
	}

      if (! err)
	{
	  if (! delayed_copy)
	    /* We never found any instances of str.  */
	    {
	      free (src);
	      *argz = dst;
	      *argz_len = dst_len;
	    }
	}
      else if (dst_len > 0)
	free (dst);
    }

  return err;
}
weak_alias (__argz_replace, argz_replace)