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 * https://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 63