summaryrefslogtreecommitdiff
path: root/lib/getdelim.c
blob: beced051f19a2a246837fa7b0a866c3a88dc2b76 (plain)
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
135
136
137
138
139
140
141
142
143
144
145
146
147
/* getdelim.c --- Implementation of replacement getdelim function.
   Copyright (C) 1994, 1996-1998, 2001, 2003, 2005-2019 Free Software
   Foundation, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program 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
   General Public License for more details.

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

/* Ported from glibc by Simon Josefsson. */

/* Don't use __attribute__ __nonnull__ in this compilation unit.  Otherwise gcc
   optimizes away the lineptr == NULL || n == NULL || fp == NULL tests below.  */
#define _GL_ARG_NONNULL(params)

#include <config.h>

#include <stdio.h>

#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>

#ifndef SSIZE_MAX
# define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
#endif

#if USE_UNLOCKED_IO
# include "unlocked-io.h"
# define getc_maybe_unlocked(fp)        getc(fp)
#elif !HAVE_FLOCKFILE || !HAVE_FUNLOCKFILE || !HAVE_DECL_GETC_UNLOCKED
# undef flockfile
# undef funlockfile
# define flockfile(x) ((void) 0)
# define funlockfile(x) ((void) 0)
# define getc_maybe_unlocked(fp)        getc(fp)
#else
# define getc_maybe_unlocked(fp)        getc_unlocked(fp)
#endif

static void
alloc_failed (void)
{
#if defined _WIN32 && ! defined __CYGWIN__
  /* Avoid errno problem without using the realloc module; see:
     https://lists.gnu.org/r/bug-gnulib/2016-08/msg00025.html  */
  errno = ENOMEM;
#endif
}

/* Read up to (and including) a DELIMITER from FP into *LINEPTR (and
   NUL-terminate it).  *LINEPTR is a pointer returned from malloc (or
   NULL), pointing to *N characters of space.  It is realloc'ed as
   necessary.  Returns the number of characters read (not including
   the null terminator), or -1 on error or EOF.  */

ssize_t
getdelim (char **lineptr, size_t *n, int delimiter, FILE *fp)
{
  ssize_t result;
  size_t cur_len = 0;

  if (lineptr == NULL || n == NULL || fp == NULL)
    {
      errno = EINVAL;
      return -1;
    }

  flockfile (fp);

  if (*lineptr == NULL || *n == 0)
    {
      char *new_lineptr;
      *n = 120;
      new_lineptr = (char *) realloc (*lineptr, *n);
      if (new_lineptr == NULL)
        {
          alloc_failed ();
          result = -1;
          goto unlock_return;
        }
      *lineptr = new_lineptr;
    }

  for (;;)
    {
      int i;

      i = getc_maybe_unlocked (fp);
      if (i == EOF)
        {
          result = -1;
          break;
        }

      /* Make enough space for len+1 (for final NUL) bytes.  */
      if (cur_len + 1 >= *n)
        {
          size_t needed_max =
            SSIZE_MAX < SIZE_MAX ? (size_t) SSIZE_MAX + 1 : SIZE_MAX;
          size_t needed = 2 * *n + 1;   /* Be generous. */
          char *new_lineptr;

          if (needed_max < needed)
            needed = needed_max;
          if (cur_len + 1 >= needed)
            {
              result = -1;
              errno = EOVERFLOW;
              goto unlock_return;
            }

          new_lineptr = (char *) realloc (*lineptr, needed);
          if (new_lineptr == NULL)
            {
              alloc_failed ();
              result = -1;
              goto unlock_return;
            }

          *lineptr = new_lineptr;
          *n = needed;
        }

      (*lineptr)[cur_len] = i;
      cur_len++;

      if (i == delimiter)
        break;
    }
  (*lineptr)[cur_len] = '\0';
  result = cur_len ? cur_len : result;

 unlock_return:
  funlockfile (fp); /* doesn't set errno */

  return result;
}