blob: 66cb5a7055ec83298de08e625902e1e229c9ce42 [file] [log] [blame]
Lasse Collin24fa0402011-01-12 17:01:22 -08001/*
2 * Definitions for handling the .xz file format
3 *
4 * Author: Lasse Collin <lasse.collin@tukaani.org>
5 *
6 * This file has been put into the public domain.
7 * You can do whatever you want with this file.
8 */
9
10#ifndef XZ_STREAM_H
11#define XZ_STREAM_H
12
13#if defined(__KERNEL__) && !XZ_INTERNAL_CRC32
14# include <linux/crc32.h>
15# undef crc32
16# define xz_crc32(buf, size, crc) \
17 (~crc32_le(~(uint32_t)(crc), buf, size))
18#endif
19
20/*
21 * See the .xz file format specification at
22 * http://tukaani.org/xz/xz-file-format.txt
23 * to understand the container format.
24 */
25
26#define STREAM_HEADER_SIZE 12
27
28#define HEADER_MAGIC "\3757zXZ"
29#define HEADER_MAGIC_SIZE 6
30
31#define FOOTER_MAGIC "YZ"
32#define FOOTER_MAGIC_SIZE 2
33
34/*
35 * Variable-length integer can hold a 63-bit unsigned integer or a special
36 * value indicating that the value is unknown.
37 *
38 * Experimental: vli_type can be defined to uint32_t to save a few bytes
39 * in code size (no effect on speed). Doing so limits the uncompressed and
40 * compressed size of the file to less than 256 MiB and may also weaken
41 * error detection slightly.
42 */
43typedef uint64_t vli_type;
44
45#define VLI_MAX ((vli_type)-1 / 2)
46#define VLI_UNKNOWN ((vli_type)-1)
47
48/* Maximum encoded size of a VLI */
49#define VLI_BYTES_MAX (sizeof(vli_type) * 8 / 7)
50
51/* Integrity Check types */
52enum xz_check {
53 XZ_CHECK_NONE = 0,
54 XZ_CHECK_CRC32 = 1,
55 XZ_CHECK_CRC64 = 4,
56 XZ_CHECK_SHA256 = 10
57};
58
59/* Maximum possible Check ID */
60#define XZ_CHECK_MAX 15
61
62#endif