| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 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 |