1/* readtokens0.c -- Read NUL-separated tokens from an input stream.
2
3   Copyright (C) 2004, 2006, 2009-2010 Free Software Foundation, Inc.
4
5   This program is free software: you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 3 of the License, or
8   (at your option) any later version.
9
10   This program is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with this program.  If not, see <http://www.gnu.org/licenses/>.
17
18   Written by Jim Meyering. */
19
20#include <config.h>
21
22#include <stdlib.h>
23
24#include "readtokens0.h"
25
26#define obstack_chunk_alloc malloc
27#define obstack_chunk_free free
28
29void
30readtokens0_init (struct Tokens *t)
31{
32  t->n_tok = 0;
33  t->tok = NULL;
34  t->tok_len = NULL;
35  obstack_init (&t->o_data);
36  obstack_init (&t->o_tok);
37  obstack_init (&t->o_tok_len);
38}
39
40void
41readtokens0_free (struct Tokens *t)
42{
43  obstack_free (&t->o_data, NULL);
44  obstack_free (&t->o_tok, NULL);
45  obstack_free (&t->o_tok_len, NULL);
46}
47
48/* Finalize (in the obstack_finish sense) the current token
49   and record its pointer and length.  */
50static void
51save_token (struct Tokens *t)
52{
53  /* Don't count the trailing NUL byte in the length.  */
54  size_t len = obstack_object_size (&t->o_data) - 1;
55  char const *s = obstack_finish (&t->o_data);
56  obstack_ptr_grow (&t->o_tok, s);
57  obstack_grow (&t->o_tok_len, &len, sizeof len);
58  t->n_tok++;
59}
60
61/* Read NUL-separated tokens from stream IN into T until EOF or error.
62   The final NUL is optional.  Always append a NULL pointer to the
63   resulting list of token pointers, but that pointer isn't counted
64   via t->n_tok.  Return true if successful.  */
65bool
66readtokens0 (FILE *in, struct Tokens *t)
67{
68
69  while (1)
70    {
71      int c = fgetc (in);
72      if (c == EOF)
73        {
74          size_t len = obstack_object_size (&t->o_data);
75          /* If the current object has nonzero length, then there
76             was no NUL byte at EOF -- or maybe there was an error,
77             in which case, we need to append a NUL byte to our buffer.  */
78          if (len)
79            {
80              obstack_1grow (&t->o_data, '\0');
81              save_token (t);
82            }
83
84          break;
85        }
86
87      obstack_1grow (&t->o_data, c);
88      if (c == '\0')
89        save_token (t);
90    }
91
92  /* Add a NULL pointer at the end, in case the caller (like du)
93     requires an argv-style array of strings.  */
94  obstack_ptr_grow (&t->o_tok, NULL);
95
96  t->tok = obstack_finish (&t->o_tok);
97  t->tok_len = obstack_finish (&t->o_tok_len);
98  return ! ferror (in);
99}
100