1/* Copyright (C) 1995-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include "libioP.h"
19#include "strfile.h"
20#include <stdio.h>
21#include <stdlib.h>
22
23
24struct _IO_FILE_memstream
25{
26 _IO_strfile _sf;
27 char **bufloc;
28 size_t *sizeloc;
29};
30
31
32/* Open a stream that writes into a malloc'd buffer that is expanded as
33 necessary. *BUFLOC and *SIZELOC are updated with the buffer's location
34 and the number of characters written on fflush or fclose. */
35FILE *
36__open_memstream (char **bufloc, size_t *sizeloc)
37{
38 struct locked_FILE
39 {
40 struct _IO_FILE_memstream fp;
41#ifdef _IO_MTSAFE_IO
42 _IO_lock_t lock;
43#endif
44 struct _IO_wide_data wd;
45 } *new_f;
46 char *buf;
47
48 new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
49 if (new_f == NULL)
50 return NULL;
51#ifdef _IO_MTSAFE_IO
52 new_f->fp._sf._sbf._f._lock = &new_f->lock;
53#endif
54
55 buf = calloc (1, BUFSIZ);
56 if (buf == NULL)
57 {
58 free (new_f);
59 return NULL;
60 }
61 _IO_init_internal (&new_f->fp._sf._sbf._f, 0);
62 _IO_JUMPS_FILE_plus (&new_f->fp._sf._sbf) = &_IO_mem_jumps;
63 _IO_str_init_static_internal (&new_f->fp._sf, buf, BUFSIZ, buf);
64 new_f->fp._sf._sbf._f._flags &= ~_IO_USER_BUF;
65 new_f->fp._sf._s._allocate_buffer_unused = (_IO_alloc_type) malloc;
66 new_f->fp._sf._s._free_buffer_unused = (_IO_free_type) free;
67
68 new_f->fp.bufloc = bufloc;
69 new_f->fp.sizeloc = sizeloc;
70
71 /* Disable single thread optimization. BZ 21735. */
72 new_f->fp._sf._sbf._f._flags2 |= _IO_FLAGS2_NEED_LOCK;
73
74 return (FILE *) &new_f->fp._sf._sbf;
75}
76libc_hidden_def (__open_memstream)
77weak_alias (__open_memstream, open_memstream)
78
79
80int
81_IO_mem_sync (FILE *fp)
82{
83 struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
84
85 if (fp->_IO_write_ptr == fp->_IO_write_end)
86 {
87 _IO_str_overflow (fp, '\0');
88 --fp->_IO_write_ptr;
89 }
90
91 *mp->bufloc = fp->_IO_write_base;
92 *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
93
94 return 0;
95}
96
97
98void
99_IO_mem_finish (FILE *fp, int dummy)
100{
101 struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
102
103 *mp->bufloc = (char *) realloc (fp->_IO_write_base,
104 fp->_IO_write_ptr - fp->_IO_write_base + 1);
105 if (*mp->bufloc != NULL)
106 {
107 (*mp->bufloc)[fp->_IO_write_ptr - fp->_IO_write_base] = '\0';
108 *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
109
110 fp->_IO_buf_base = NULL;
111 }
112
113 _IO_str_finish (fp, 0);
114}
115