lib/xz/xz_stream.h

24fa0402SLasse Collin/*
24fa0402SLasse Collin * Definitions for handling the .xz file format
24fa0402SLasse Collin *
24fa0402SLasse Collin * Author: Lasse Collin <lasse.collin@tukaani.org>
24fa0402SLasse Collin *
24fa0402SLasse Collin * This file has been put into the public domain.
24fa0402SLasse Collin * You can do whatever you want with this file.
24fa0402SLasse Collin */
24fa0402SLasse Collin
24fa0402SLasse Collin#ifndef XZ_STREAM_H
24fa0402SLasse Collin#define XZ_STREAM_H
24fa0402SLasse Collin
24fa0402SLasse Collin#if defined(__KERNEL__) && !XZ_INTERNAL_CRC32
24fa0402SLasse Collin#	include <linux/crc32.h>
24fa0402SLasse Collin#	undef crc32
24fa0402SLasse Collin#	define xz_crc32(buf, size, crc) \
24fa0402SLasse Collin		(~crc32_le(~(uint32_t)(crc), buf, size))
24fa0402SLasse Collin#endif
24fa0402SLasse Collin
24fa0402SLasse Collin/*
24fa0402SLasse Collin * See the .xz file format specification at
d89775fcSAlexander A. Klimov * https://tukaani.org/xz/xz-file-format.txt
24fa0402SLasse Collin * to understand the container format.
24fa0402SLasse Collin */
24fa0402SLasse Collin
24fa0402SLasse Collin#define STREAM_HEADER_SIZE 12
24fa0402SLasse Collin
24fa0402SLasse Collin#define HEADER_MAGIC "\3757zXZ"
24fa0402SLasse Collin#define HEADER_MAGIC_SIZE 6
24fa0402SLasse Collin
24fa0402SLasse Collin#define FOOTER_MAGIC "YZ"
24fa0402SLasse Collin#define FOOTER_MAGIC_SIZE 2
24fa0402SLasse Collin
24fa0402SLasse Collin/*
24fa0402SLasse Collin * Variable-length integer can hold a 63-bit unsigned integer or a special
24fa0402SLasse Collin * value indicating that the value is unknown.
24fa0402SLasse Collin *
24fa0402SLasse Collin * Experimental: vli_type can be defined to uint32_t to save a few bytes
24fa0402SLasse Collin * in code size (no effect on speed). Doing so limits the uncompressed and
24fa0402SLasse Collin * compressed size of the file to less than 256 MiB and may also weaken
24fa0402SLasse Collin * error detection slightly.
24fa0402SLasse Collin */
24fa0402SLasse Collintypedef uint64_t vli_type;
24fa0402SLasse Collin
24fa0402SLasse Collin#define VLI_MAX ((vli_type)-1 / 2)
24fa0402SLasse Collin#define VLI_UNKNOWN ((vli_type)-1)
24fa0402SLasse Collin
24fa0402SLasse Collin/* Maximum encoded size of a VLI */
24fa0402SLasse Collin#define VLI_BYTES_MAX (sizeof(vli_type) * 8 / 7)
24fa0402SLasse Collin
24fa0402SLasse Collin/* Integrity Check types */
24fa0402SLasse Collinenum xz_check {
24fa0402SLasse Collin	XZ_CHECK_NONE = 0,
24fa0402SLasse Collin	XZ_CHECK_CRC32 = 1,
24fa0402SLasse Collin	XZ_CHECK_CRC64 = 4,
24fa0402SLasse Collin	XZ_CHECK_SHA256 = 10
24fa0402SLasse Collin};
24fa0402SLasse Collin
24fa0402SLasse Collin/* Maximum possible Check ID */
24fa0402SLasse Collin#define XZ_CHECK_MAX 15
24fa0402SLasse Collin
24fa0402SLasse Collin#endif