1 /*
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 */
43 typedef 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 */
52 enum 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