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[binutils.git] / bfd / compress.c
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1 /* ELF attributes support (based on ARM EABI attributes).
2 Copyright 2008
3 Free Software Foundation, Inc.
5 This file is part of BFD, the Binary File Descriptor library.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
22 #include "config.h"
23 #include "sysdep.h"
24 #include "bfd.h"
25 #include "libbfd.h"
26 #ifdef HAVE_ZLIB_H
27 #include <zlib.h>
28 #endif
31 FUNCTION
32 bfd_uncompress_section_contents
34 SYNOPSIS
35 bfd_boolean bfd_uncompress_section_contents
36 (bfd_byte **buffer, bfd_size_type *size);
38 DESCRIPTION
40 Uncompresses a section that was compressed using zlib, in place. At
41 the call to this function, *@var{buffer} and *@var{size} should point
42 to the section contents to be uncompressed. At the end of the
43 function, *@var{buffer} and *@var{size} will point to the uncompressed
44 contents. This function assumes *BUFFER was allocated using
45 bfd_malloc() or equivalent. If the section is not a valid compressed
46 section, or zlib is not installed on this machine, the input is
47 unmodified.
49 Returns @code{FALSE} if unable to uncompress successfully; in that case
50 the input is unmodified. Otherwise, returns @code{TRUE}.
53 bfd_boolean
54 bfd_uncompress_section_contents (bfd_byte **buffer, bfd_size_type *size)
56 #ifndef HAVE_ZLIB_H
57 /* These are just to quiet gcc. */
58 buffer = 0;
59 size = 0;
60 return FALSE;
61 #else
62 bfd_size_type compressed_size = *size;
63 bfd_byte *compressed_buffer = *buffer;
64 bfd_size_type uncompressed_size;
65 bfd_byte *uncompressed_buffer;
66 z_stream strm;
67 int rc;
68 bfd_size_type header_size = 12;
70 /* Read the zlib header. In this case, it should be "ZLIB" followed
71 by the uncompressed section size, 8 bytes in big-endian order. */
72 if (compressed_size < header_size
73 || ! CONST_STRNEQ ((char*) compressed_buffer, "ZLIB"))
74 return FALSE;
75 uncompressed_size = compressed_buffer[4]; uncompressed_size <<= 8;
76 uncompressed_size += compressed_buffer[5]; uncompressed_size <<= 8;
77 uncompressed_size += compressed_buffer[6]; uncompressed_size <<= 8;
78 uncompressed_size += compressed_buffer[7]; uncompressed_size <<= 8;
79 uncompressed_size += compressed_buffer[8]; uncompressed_size <<= 8;
80 uncompressed_size += compressed_buffer[9]; uncompressed_size <<= 8;
81 uncompressed_size += compressed_buffer[10]; uncompressed_size <<= 8;
82 uncompressed_size += compressed_buffer[11];
84 /* It is possible the section consists of several compressed
85 buffers concatenated together, so we uncompress in a loop. */
86 strm.zalloc = NULL;
87 strm.zfree = NULL;
88 strm.opaque = NULL;
89 strm.avail_in = compressed_size - header_size;
90 strm.next_in = (Bytef*) compressed_buffer + header_size;
91 strm.avail_out = uncompressed_size;
92 uncompressed_buffer = bfd_malloc (uncompressed_size);
93 if (! uncompressed_buffer)
94 return FALSE;
96 rc = inflateInit (&strm);
97 while (strm.avail_in > 0)
99 if (rc != Z_OK)
100 goto fail;
101 strm.next_out = ((Bytef*) uncompressed_buffer
102 + (uncompressed_size - strm.avail_out));
103 rc = inflate (&strm, Z_FINISH);
104 if (rc != Z_STREAM_END)
105 goto fail;
106 rc = inflateReset (&strm);
108 rc = inflateEnd (&strm);
109 if (rc != Z_OK
110 || strm.avail_out != 0)
111 goto fail;
113 free (compressed_buffer);
114 *buffer = uncompressed_buffer;
115 *size = uncompressed_size;
116 return TRUE;
118 fail:
119 free (uncompressed_buffer);
120 return FALSE;
121 #endif /* HAVE_ZLIB_H */