1 /* read-file.c -- read file contents into a string
2 Copyright (C) 2006, 2009, 2010 Free Software Foundation, Inc.
3 Written by Simon Josefsson and Bruno Haible.
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 2, or (at your option)
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.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
21 #include "read-file.h"
32 /* Get malloc, realloc, free. */
38 /* Read a STREAM and return a newly allocated string with the content,
39 and set *LENGTH to the length of the string. The string is
40 zero-terminated, but the terminating zero byte is not counted in
41 *LENGTH. On errors, *LENGTH is undefined, errno preserves the
42 values set by system functions (if any), and NULL is returned. */
44 fread_file (FILE * stream, size_t * length)
49 /* For a regular file, allocate a buffer that has exactly the right
50 size. This avoids the need to do dynamic reallocations later. */
54 if (fstat (fileno (stream), &st) >= 0 && S_ISREG (st.st_mode))
56 off_t pos = ftello (stream);
58 if (pos >= 0 && pos < st.st_size)
60 off_t alloc_off = st.st_size - pos;
62 if (SIZE_MAX <= alloc_off)
68 alloc = alloc_off + 1;
72 /* errno is ENOMEM. */
79 size_t size = 0; /* number of bytes read so far */
87 if (size + BUFSIZ + 1 > alloc)
90 size_t new_alloc = alloc + alloc / 2;
92 /* Check against overflow. */
93 if (new_alloc < alloc)
100 if (alloc < size + BUFSIZ + 1)
101 alloc = size + BUFSIZ + 1;
103 new_buf = realloc (buf, alloc);
113 requested = alloc - size - 1;
114 count = fread (buf + size, 1, requested, stream);
117 if (count != requested)
123 /* Shrink the allocated memory if possible. */
124 if (size + 1 < alloc)
126 char *smaller_buf = realloc (buf, size + 1);
127 if (smaller_buf != NULL)
144 internal_read_file (const char *filename, size_t * length, const char *mode)
146 FILE *stream = fopen (filename, mode);
153 out = fread_file (stream, length);
157 if (fclose (stream) != 0)
171 /* Open and read the contents of FILENAME, and return a newly
172 allocated string with the content, and set *LENGTH to the length of
173 the string. The string is zero-terminated, but the terminating
174 zero byte is not counted in *LENGTH. On errors, *LENGTH is
175 undefined, errno preserves the values set by system functions (if
176 any), and NULL is returned. */
178 read_file (const char *filename, size_t * length)
180 return internal_read_file (filename, length, "r");
183 /* Open (on non-POSIX systems, in binary mode) and read the contents
184 of FILENAME, and return a newly allocated string with the content,
185 and set LENGTH to the length of the string. The string is
186 zero-terminated, but the terminating zero byte is not counted in
187 the LENGTH variable. On errors, *LENGTH is undefined, errno
188 preserves the values set by system functions (if any), and NULL is
191 read_binary_file (const char *filename, size_t * length)
193 return internal_read_file (filename, length, "rb");