lz4_decompress.c | Explore in Territory

/*
 * LZ4 - Fast LZ compression algorithm
 * Copyright (C) 2011 - 2016, Yann Collet.
 * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php)
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *	* Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 *	* Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * You can contact the author at :
 *	- LZ4 homepage : http://www.lz4.org
 *	- LZ4 source repository : https://github.com/lz4/lz4
 *
 *	Changed for kernel usage by:
 *	Sven Schmidt <[email protected]>
 */

/*-************************************
 *	Dependencies
 **************************************/
#include <linux/lz4.h>
#include "lz4defs.h"
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <asm/unaligned.h>

/*-*****************************
 *	Decompression functions
 *******************************/

#define DEBUGLOG(l, ...) …

#ifndef assert
#define assert(condition) …
#endif

/*
 * LZ4_decompress_generic() :
 * This generic decompression function covers all use cases.
 * It shall be instantiated several times, using different sets of directives.
 * Note that it is important for performance that this function really get inlined,
 * in order to remove useless branches during compilation optimization.
 */
static FORCE_INLINE int LZ4_decompress_generic(
	 const char * const src,
	 char * const dst,
	 int srcSize,
		/*
		 * If endOnInput == endOnInputSize,
		 * this value is `dstCapacity`
		 */
	 int outputSize,
	 /* endOnOutputSize, endOnInputSize */
	 endCondition_directive endOnInput,
	 /* full, partial */
	 earlyEnd_directive partialDecoding,
	 /* noDict, withPrefix64k, usingExtDict */
	 dict_directive dict,
	 /* always <= dst, == dst when no prefix */
	 const BYTE * const lowPrefix,
	 /* only if dict == usingExtDict */
	 const BYTE * const dictStart,
	 /* note : = 0 if noDict */
	 const size_t dictSize
	 )
{ … }

int LZ4_decompress_safe(const char *source, char *dest,
	int compressedSize, int maxDecompressedSize)
{ … }

int LZ4_decompress_safe_partial(const char *src, char *dst,
	int compressedSize, int targetOutputSize, int dstCapacity)
{ … }

int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
{ … }

/* ===== Instantiate a few more decoding cases, used more than once. ===== */

static int LZ4_decompress_safe_withPrefix64k(const char *source, char *dest,
				      int compressedSize, int maxOutputSize)
{ … }

static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest,
					       int compressedSize,
					       int maxOutputSize,
					       size_t prefixSize)
{ … }

static int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
					    int compressedSize, int maxOutputSize,
					    const void *dictStart, size_t dictSize)
{ … }

static int LZ4_decompress_fast_extDict(const char *source, char *dest,
				       int originalSize,
				       const void *dictStart, size_t dictSize)
{ … }

/*
 * The "double dictionary" mode, for use with e.g. ring buffers: the first part
 * of the dictionary is passed as prefix, and the second via dictStart + dictSize.
 * These routines are used only once, in LZ4_decompress_*_continue().
 */
static FORCE_INLINE
int LZ4_decompress_safe_doubleDict(const char *source, char *dest,
				   int compressedSize, int maxOutputSize,
				   size_t prefixSize,
				   const void *dictStart, size_t dictSize)
{ … }

static FORCE_INLINE
int LZ4_decompress_fast_doubleDict(const char *source, char *dest,
				   int originalSize, size_t prefixSize,
				   const void *dictStart, size_t dictSize)
{ … }

/* ===== streaming decompression functions ===== */

int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
	const char *dictionary, int dictSize)
{ … }

/*
 * *_continue() :
 * These decoding functions allow decompression of multiple blocks
 * in "streaming" mode.
 * Previously decoded blocks must still be available at the memory
 * position where they were decoded.
 * If it's not possible, save the relevant part of
 * decoded data into a safe buffer,
 * and indicate where it stands using LZ4_setStreamDecode()
 */
int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
	const char *source, char *dest, int compressedSize, int maxOutputSize)
{ … }

int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
	const char *source, char *dest, int originalSize)
{ … }

int LZ4_decompress_safe_usingDict(const char *source, char *dest,
				  int compressedSize, int maxOutputSize,
				  const char *dictStart, int dictSize)
{ … }

int LZ4_decompress_fast_usingDict(const char *source, char *dest,
				  int originalSize,
				  const char *dictStart, int dictSize)
{ … }

#ifndef STATIC
EXPORT_SYMBOL(…);
EXPORT_SYMBOL(…);
EXPORT_SYMBOL(…);
EXPORT_SYMBOL(…);
EXPORT_SYMBOL(…);
EXPORT_SYMBOL(…);
EXPORT_SYMBOL(…);
EXPORT_SYMBOL(…);

MODULE_LICENSE(…) …;
MODULE_DESCRIPTION(…) …;
#endif
linux/lib/lz4/lz4_decompress.c
