-#ifndef __LZ4_H__
-#define __LZ4_H__
-/*
- * LZ4 Kernel Interface
+/* LZ4 Kernel Interface
*
* Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
+ * Copyright (C) 2016, Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
+ *
+ * This file is based on the original header file
+ * for LZ4 - Fast LZ compression algorithm.
+ *
+ * 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
*/
-#define LZ4_MEM_COMPRESS (16384)
-#define LZ4HC_MEM_COMPRESS (262144 + (2 * sizeof(unsigned char *)))
+#ifndef __LZ4_H__
+#define __LZ4_H__
+
+#include <linux/types.h>
+#include <linux/string.h> /* memset, memcpy */
+
+/*-************************************************************************
+ * CONSTANTS
+ **************************************************************************/
/*
- * lz4_compressbound()
- * Provides the maximum size that LZ4 may output in a "worst case" scenario
- * (input data not compressible)
+ * LZ4_MEMORY_USAGE :
+ * Memory usage formula : N->2^N Bytes
+ * (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
+ * Increasing memory usage improves compression ratio
+ * Reduced memory usage can improve speed, due to cache effect
+ * Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
*/
-static inline size_t lz4_compressbound(size_t isize)
+#define LZ4_MEMORY_USAGE 14
+
+#define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */
+#define LZ4_COMPRESSBOUND(isize) (\
+ (unsigned int)(isize) > (unsigned int)LZ4_MAX_INPUT_SIZE \
+ ? 0 \
+ : (isize) + ((isize)/255) + 16)
+
+#define LZ4_ACCELERATION_DEFAULT 1
+#define LZ4_HASHLOG (LZ4_MEMORY_USAGE-2)
+#define LZ4_HASHTABLESIZE (1 << LZ4_MEMORY_USAGE)
+#define LZ4_HASH_SIZE_U32 (1 << LZ4_HASHLOG)
+
+#define LZ4HC_MIN_CLEVEL 3
+#define LZ4HC_DEFAULT_CLEVEL 9
+#define LZ4HC_MAX_CLEVEL 16
+
+#define LZ4HC_DICTIONARY_LOGSIZE 16
+#define LZ4HC_MAXD (1<<LZ4HC_DICTIONARY_LOGSIZE)
+#define LZ4HC_MAXD_MASK (LZ4HC_MAXD - 1)
+#define LZ4HC_HASH_LOG (LZ4HC_DICTIONARY_LOGSIZE - 1)
+#define LZ4HC_HASHTABLESIZE (1 << LZ4HC_HASH_LOG)
+#define LZ4HC_HASH_MASK (LZ4HC_HASHTABLESIZE - 1)
+
+/*-************************************************************************
+ * STREAMING CONSTANTS AND STRUCTURES
+ **************************************************************************/
+#define LZ4_STREAMSIZE_U64 ((1 << (LZ4_MEMORY_USAGE - 3)) + 4)
+#define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U64 * sizeof(unsigned long long))
+
+#define LZ4_STREAMHCSIZE 262192
+#define LZ4_STREAMHCSIZE_SIZET (262192 / sizeof(size_t))
+
+#define LZ4_STREAMDECODESIZE_U64 4
+#define LZ4_STREAMDECODESIZE (LZ4_STREAMDECODESIZE_U64 * \
+ sizeof(unsigned long long))
+
+/*
+ * LZ4_stream_t - information structure to track an LZ4 stream.
+ */
+typedef struct {
+ uint32_t hashTable[LZ4_HASH_SIZE_U32];
+ uint32_t currentOffset;
+ uint32_t initCheck;
+ const uint8_t *dictionary;
+ uint8_t *bufferStart;
+ uint32_t dictSize;
+} LZ4_stream_t_internal;
+typedef union {
+ unsigned long long table[LZ4_STREAMSIZE_U64];
+ LZ4_stream_t_internal internal_donotuse;
+} LZ4_stream_t;
+
+/*
+ * LZ4_streamHC_t - information structure to track an LZ4HC stream.
+ */
+typedef struct {
+ unsigned int hashTable[LZ4HC_HASHTABLESIZE];
+ unsigned short chainTable[LZ4HC_MAXD];
+ /* next block to continue on current prefix */
+ const unsigned char *end;
+ /* All index relative to this position */
+ const unsigned char *base;
+ /* alternate base for extDict */
+ const unsigned char *dictBase;
+ /* below that point, need extDict */
+ unsigned int dictLimit;
+ /* below that point, no more dict */
+ unsigned int lowLimit;
+ /* index from which to continue dict update */
+ unsigned int nextToUpdate;
+ unsigned int compressionLevel;
+} LZ4HC_CCtx_internal;
+typedef union {
+ size_t table[LZ4_STREAMHCSIZE_SIZET];
+ LZ4HC_CCtx_internal internal_donotuse;
+} LZ4_streamHC_t;
+
+/*
+ * LZ4_streamDecode_t - information structure to track an
+ * LZ4 stream during decompression.
+ *
+ * init this structure using LZ4_setStreamDecode (or memset()) before first use
+ */
+typedef struct {
+ const uint8_t *externalDict;
+ size_t extDictSize;
+ const uint8_t *prefixEnd;
+ size_t prefixSize;
+} LZ4_streamDecode_t_internal;
+typedef union {
+ unsigned long long table[LZ4_STREAMDECODESIZE_U64];
+ LZ4_streamDecode_t_internal internal_donotuse;
+} LZ4_streamDecode_t;
+
+/*-************************************************************************
+ * SIZE OF STATE
+ **************************************************************************/
+#define LZ4_MEM_COMPRESS LZ4_STREAMSIZE
+#define LZ4HC_MEM_COMPRESS LZ4_STREAMHCSIZE
+
+/*-************************************************************************
+ * Compression Functions
+ **************************************************************************/
+
+/**
+ * LZ4_compressBound() - Max. output size in worst case szenarios
+ * @isize: Size of the input data
+ *
+ * Return: Max. size LZ4 may output in a "worst case" szenario
+ * (data not compressible)
+ */
+static inline int LZ4_compressBound(size_t isize)
{
- return isize + (isize / 255) + 16;
+ return LZ4_COMPRESSBOUND(isize);
}
-/*
- * lz4_compress()
- * src : source address of the original data
- * src_len : size of the original data
- * dst : output buffer address of the compressed data
- * This requires 'dst' of size LZ4_COMPRESSBOUND.
- * dst_len : is the output size, which is returned after compress done
- * workmem : address of the working memory.
- * This requires 'workmem' of size LZ4_MEM_COMPRESS.
- * return : Success if return 0
- * Error if return (< 0)
- * note : Destination buffer and workmem must be already allocated with
- * the defined size.
- */
-int lz4_compress(const unsigned char *src, size_t src_len,
- unsigned char *dst, size_t *dst_len, void *wrkmem);
-
- /*
- * lz4hc_compress()
- * src : source address of the original data
- * src_len : size of the original data
- * dst : output buffer address of the compressed data
- * This requires 'dst' of size LZ4_COMPRESSBOUND.
- * dst_len : is the output size, which is returned after compress done
- * workmem : address of the working memory.
- * This requires 'workmem' of size LZ4HC_MEM_COMPRESS.
- * return : Success if return 0
- * Error if return (< 0)
- * note : Destination buffer and workmem must be already allocated with
- * the defined size.
- */
-int lz4hc_compress(const unsigned char *src, size_t src_len,
- unsigned char *dst, size_t *dst_len, void *wrkmem);
+/**
+ * lz4_compressbound() - For backwards compatibility; see LZ4_compressBound
+ * @isize: Size of the input data
+ *
+ * Return: Max. size LZ4 may output in a "worst case" szenario
+ * (data not compressible)
+ */
+static inline int lz4_compressbound(size_t isize)
+{
+ return LZ4_COMPRESSBOUND(isize);
+}
+
+/**
+ * LZ4_compress_default() - Compress data from source to dest
+ * @source: source address of the original data
+ * @dest: output buffer address of the compressed data
+ * @inputSize: size of the input data. Max supported value is LZ4_MAX_INPUT_SIZE
+ * @maxOutputSize: full or partial size of buffer 'dest'
+ * which must be already allocated
+ * @wrkmem: address of the working memory.
+ * This requires 'workmem' of LZ4_MEM_COMPRESS.
+ *
+ * Compresses 'sourceSize' bytes from buffer 'source'
+ * into already allocated 'dest' buffer of size 'maxOutputSize'.
+ * Compression is guaranteed to succeed if
+ * 'maxOutputSize' >= LZ4_compressBound(inputSize).
+ * It also runs faster, so it's a recommended setting.
+ * If the function cannot compress 'source' into a more limited 'dest' budget,
+ * compression stops *immediately*, and the function result is zero.
+ * As a consequence, 'dest' content is not valid.
+ *
+ * Return: Number of bytes written into buffer 'dest'
+ * (necessarily <= maxOutputSize) or 0 if compression fails
+ */
+int LZ4_compress_default(const char *source, char *dest, int inputSize,
+ int maxOutputSize, void *wrkmem);
+
+/**
+ * LZ4_compress_fast() - As LZ4_compress_default providing an acceleration param
+ * @source: source address of the original data
+ * @dest: output buffer address of the compressed data
+ * @inputSize: size of the input data. Max supported value is LZ4_MAX_INPUT_SIZE
+ * @maxOutputSize: full or partial size of buffer 'dest'
+ * which must be already allocated
+ * @acceleration: acceleration factor
+ * @wrkmem: address of the working memory.
+ * This requires 'workmem' of LZ4_MEM_COMPRESS.
+ *
+ * Same as LZ4_compress_default(), but allows to select an "acceleration"
+ * factor. The larger the acceleration value, the faster the algorithm,
+ * but also the lesser the compression. It's a trade-off. It can be fine tuned,
+ * with each successive value providing roughly +~3% to speed.
+ * An acceleration value of "1" is the same as regular LZ4_compress_default()
+ * Values <= 0 will be replaced by LZ4_ACCELERATION_DEFAULT, which is 1.
+ *
+ * Return: Number of bytes written into buffer 'dest'
+ * (necessarily <= maxOutputSize) or 0 if compression fails
+ */
+int LZ4_compress_fast(const char *source, char *dest, int inputSize,
+ int maxOutputSize, int acceleration, void *wrkmem);
+
+/**
+ * LZ4_compress_destSize() - Compress as much data as possible
+ * from source to dest
+ * @source: source address of the original data
+ * @dest: output buffer address of the compressed data
+ * @sourceSizePtr: will be modified to indicate how many bytes where read
+ * from 'source' to fill 'dest'. New value is necessarily <= old value.
+ * @targetDestSize: Size of buffer 'dest' which must be already allocated
+ * @wrkmem: address of the working memory.
+ * This requires 'workmem' of LZ4_MEM_COMPRESS.
+ *
+ * Reverse the logic, by compressing as much data as possible
+ * from 'source' buffer into already allocated buffer 'dest'
+ * of size 'targetDestSize'.
+ * This function either compresses the entire 'source' content into 'dest'
+ * if it's large enough, or fill 'dest' buffer completely with as much data as
+ * possible from 'source'.
+ *
+ * Return: Number of bytes written into 'dest' (necessarily <= targetDestSize)
+ * or 0 if compression fails
+ */
+int LZ4_compress_destSize(const char *source, char *dest, int *sourceSizePtr,
+ int targetDestSize, void *wrkmem);
/*
- * lz4_decompress()
- * src : source address of the compressed data
- * src_len : is the input size, whcih is returned after decompress done
- * dest : output buffer address of the decompressed data
- * actual_dest_len: is the size of uncompressed data, supposing it's known
- * return : Success if return 0
- * Error if return (< 0)
- * note : Destination buffer must be already allocated.
- * slightly faster than lz4_decompress_unknownoutputsize()
+ * lz4_compress() - For backward compatibility, see LZ4_compress_default
+ * @src: source address of the original data
+ * @src_len: size of the original data
+ * @dst: output buffer address of the compressed data. This requires 'dst'
+ * of size LZ4_COMPRESSBOUND
+ * @dst_len: is the output size, which is returned after compress done
+ * @workmem: address of the working memory.
+ *
+ * Return: Success if return 0, Error if return < 0
*/
-int lz4_decompress(const unsigned char *src, size_t *src_len,
- unsigned char *dest, size_t actual_dest_len);
+int lz4_compress(const unsigned char *src, size_t src_len, unsigned char *dst,
+ size_t *dst_len, void *wrkmem);
+
+/*-************************************************************************
+ * Decompression Functions
+ **************************************************************************/
+
+/**
+ * LZ4_decompress_fast() - Decompresses data from 'source' into 'dest'
+ * @source: source address of the compressed data
+ * @dest: output buffer address of the uncompressed data
+ * which must be already allocated with 'originalSize' bytes
+ * @originalSize: is the original and therefore uncompressed size
+ *
+ * Decompresses data from 'source' into 'dest'.
+ * This function fully respect memory boundaries for properly formed
+ * compressed data.
+ * It is a bit faster than LZ4_decompress_safe().
+ * However, it does not provide any protection against intentionally
+ * modified data stream (malicious input).
+ * Use this function in trusted environment only
+ * (data to decode comes from a trusted source).
+ *
+ * Return: number of bytes read from the source buffer
+ * or a negative result if decompression fails.
+ */
+int LZ4_decompress_fast(const char *source, char *dest, int originalSize);
+
+/**
+ * LZ4_decompress_safe() - Decompression protected against buffer overflow
+ * @source: source address of the compressed data
+ * @dest: output buffer address of the uncompressed data
+ * which must be already allocated
+ * @compressedSize: is the precise full size of the compressed block
+ * @maxDecompressedSize: is the size of 'dest' buffer
+ *
+ * Decompresses data fom 'source' into 'dest'.
+ * If the source stream is detected malformed, the function will
+ * stop decoding and return a negative result.
+ * This function is protected against buffer overflow exploits,
+ * including malicious data packets. It never writes outside output buffer,
+ * nor reads outside input buffer.
+ *
+ * Return: number of bytes decompressed into destination buffer
+ * (necessarily <= maxDecompressedSize)
+ * or a negative result in case of error
+ */
+int LZ4_decompress_safe(const char *source, char *dest, int compressedSize,
+ int maxDecompressedSize);
+
+/**
+ * LZ4_decompress_safe_partial() - Decompress a block of size 'compressedSize'
+ * at position 'source' into buffer 'dest'
+ * @source: source address of the compressed data
+ * @dest: output buffer address of the decompressed data which must be
+ * already allocated
+ * @compressedSize: is the precise full size of the compressed block.
+ * @targetOutputSize: the decompression operation will try
+ * to stop as soon as 'targetOutputSize' has been reached
+ * @maxDecompressedSize: is the size of destination buffer
+ *
+ * This function decompresses a compressed block of size 'compressedSize'
+ * at position 'source' into destination buffer 'dest'
+ * of size 'maxDecompressedSize'.
+ * The function tries to stop decompressing operation as soon as
+ * 'targetOutputSize' has been reached, reducing decompression time.
+ * This function never writes outside of output buffer,
+ * and never reads outside of input buffer.
+ * It is therefore protected against malicious data packets.
+ *
+ * Return: the number of bytes decoded in the destination buffer
+ * (necessarily <= maxDecompressedSize)
+ * or a negative result in case of error
+ *
+ */
+int LZ4_decompress_safe_partial(const char *source, char *dest,
+ int compressedSize, int targetOutputSize, int maxDecompressedSize);
/*
- * lz4_decompress_unknownoutputsize()
- * src : source address of the compressed data
- * src_len : is the input size, therefore the compressed size
- * dest : output buffer address of the decompressed data
- * dest_len: is the max size of the destination buffer, which is
- * returned with actual size of decompressed data after
- * decompress done
- * return : Success if return 0
- * Error if return (< 0)
- * note : Destination buffer must be already allocated.
+ * lz4_decompress_unknownoutputsize() - For backwards compatibility,
+ * see LZ4_decompress_safe
+ * @src: source address of the compressed data
+ * @src_len: is the input size, therefore the compressed size
+ * @dest: output buffer address of the decompressed data
+ * which must be already allocated
+ * @dest_len: is the max size of the destination buffer, which is
+ * returned with actual size of decompressed data after decompress done
+ *
+ * Return: Success if return 0, Error if return (< 0)
*/
int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
- unsigned char *dest, size_t *dest_len);
+ unsigned char *dest, size_t *dest_len);
+
+/**
+ * lz4_decompress() - For backwards cocmpatibility, see LZ4_decompress_fast
+ * @src: source address of the compressed data
+ * @src_len: is the input size, which is returned after decompress done
+ * @dest: output buffer address of the decompressed data,
+ * which must be already allocated
+ * @actual_dest_len: is the size of uncompressed data, supposing it's known
+ *
+ * Return: Success if return 0, Error if return (< 0)
+ */
+int lz4_decompress(const unsigned char *src, size_t *src_len,
+ unsigned char *dest, size_t actual_dest_len);
+
+/*-************************************************************************
+ * LZ4 HC Compression
+ **************************************************************************/
+
+/**
+ * LZ4_compress_HC() - Compress data from `src` into `dst`, using HC algorithm
+ * @src: source address of the original data
+ * @dst: output buffer address of the compressed data
+ * @srcSize: size of the input data. Max supported value is LZ4_MAX_INPUT_SIZE
+ * @dstCapacity: full or partial size of buffer 'dst',
+ * which must be already allocated
+ * @compressionLevel: Recommended values are between 4 and 9, although any
+ * value between 1 and LZ4HC_MAX_CLEVEL will work.
+ * Values >LZ4HC_MAX_CLEVEL behave the same as 16.
+ * @wrkmem: address of the working memory.
+ * This requires 'wrkmem' of size LZ4HC_MEM_COMPRESS.
+ *
+ * Compress data from 'src' into 'dst', using the more powerful
+ * but slower "HC" algorithm. Compression is guaranteed to succeed if
+ * `dstCapacity >= LZ4_compressBound(srcSize)
+ *
+ * Return : the number of bytes written into 'dst' or 0 if compression fails.
+ */
+int LZ4_compress_HC(const char *src, char *dst, int srcSize, int dstCapacity,
+ int compressionLevel, void *wrkmem);
+
+/**
+ * lz4hc_compress() - For backwards compatibility, see LZ4_compress_HC
+ * @src: source address of the original data
+ * @src_len: size of the original data
+ * @dst: output buffer address of the compressed data. This requires 'dst'
+ * of size LZ4_COMPRESSBOUND.
+ * @dst_len: is the output size, which is returned after compress done
+ * @wrkmem: address of the working memory.
+ * This requires 'workmem' of size LZ4HC_MEM_COMPRESS.
+ *
+ * Return : Success if return 0, Error if return (< 0)
+ */
+int lz4hc_compress(const unsigned char *src, size_t src_len, unsigned char *dst,
+ size_t *dst_len, void *wrkmem);
+
+/**
+ * LZ4_resetStreamHC() - Init an allocated 'LZ4_streamHC_t' structure
+ * @streamHCPtr: pointer to the 'LZ4_streamHC_t' structure
+ * @compressionLevel: Recommended values are between 4 and 9, although any
+ * value between 1 and LZ4HC_MAX_CLEVEL will work.
+ * Values >LZ4HC_MAX_CLEVEL behave the same as 16.
+ *
+ * An LZ4_streamHC_t structure can be allocated once
+ * and re-used multiple times.
+ * Use this function to init an allocated `LZ4_streamHC_t` structure
+ * and start a new compression.
+ */
+void LZ4_resetStreamHC(LZ4_streamHC_t *streamHCPtr, int compressionLevel);
+
+/**
+ * LZ4_loadDictHC() - Load a static dictionary into LZ4_streamHC
+ * @streamHCPtr: pointer to the LZ4HC_stream_t
+ * @dictionary: dictionary to load
+ * @dictSize: size of dictionary
+ *
+ * Use this function to load a static dictionary into LZ4HC_stream.
+ * Any previous data will be forgotten, only 'dictionary'
+ * will remain in memory.
+ * Loading a size of 0 is allowed.
+ *
+ * Return : dictionary size, in bytes (necessarily <= 64 KB)
+ */
+int LZ4_loadDictHC(LZ4_streamHC_t *streamHCPtr, const char *dictionary,
+ int dictSize);
+
+/**
+ * LZ4_compress_HC_continue() - Compress 'src' using data from previously
+ * compressed blocks as a dictionary using the HC algorithm
+ * @streamHCPtr: Pointer to the previous 'LZ4_streamHC_t' structure
+ * @src: source address of the original data
+ * @dst: output buffer address of the compressed data,
+ * which must be already allocated
+ * @srcSize: size of the input data. Max supported value is LZ4_MAX_INPUT_SIZE
+ * @maxDstSize: full or partial size of buffer 'dest'
+ * which must be already allocated
+ *
+ * These functions compress data in successive blocks of any size, using
+ * previous blocks as dictionary. One key assumption is that previous
+ * blocks (up to 64 KB) remain read-accessible while
+ * compressing next blocks. There is an exception for ring buffers,
+ * which can be smaller than 64 KB.
+ * Ring buffers scenario is automatically detected and handled by
+ * LZ4_compress_HC_continue().
+ * Before starting compression, state must be properly initialized,
+ * using LZ4_resetStreamHC().
+ * A first "fictional block" can then be designated as
+ * initial dictionary, using LZ4_loadDictHC() (Optional).
+ * Then, use LZ4_compress_HC_continue()
+ * to compress each successive block. Previous memory blocks
+ * (including initial dictionary when present) must remain accessible
+ * and unmodified during compression.
+ * 'dst' buffer should be sized to handle worst case scenarios, using
+ * LZ4_compressBound(), to ensure operation success.
+ * If, for any reason, previous data blocks can't be preserved unmodified
+ * in memory during next compression block,
+ * you must save it to a safer memory space, using LZ4_saveDictHC().
+ * Return value of LZ4_saveDictHC() is the size of dictionary
+ * effectively saved into 'safeBuffer'.
+ *
+ * Return: Number of bytes written into buffer 'dst' or 0 if compression fails
+ */
+int LZ4_compress_HC_continue(LZ4_streamHC_t *streamHCPtr, const char *src,
+ char *dst, int srcSize, int maxDstSize);
+
+/**
+ * LZ4_saveDictHC() - Save static dictionary from LZ4HC_stream
+ * @streamHCPtr: pointer to the 'LZ4HC_stream_t' structure
+ * @safeBuffer: buffer to save dictionary to, must be already allocated
+ * @maxDictSize: size of 'safeBuffer'
+ *
+ * If previously compressed data block is not guaranteed
+ * to remain available at its memory location,
+ * save it into a safer place (char *safeBuffer).
+ * Note : you don't need to call LZ4_loadDictHC() afterwards,
+ * dictionary is immediately usable, you can therefore call
+ * LZ4_compress_HC_continue().
+ *
+ * Return : saved dictionary size in bytes (necessarily <= maxDictSize),
+ * or 0 if error.
+ */
+int LZ4_saveDictHC(LZ4_streamHC_t *streamHCPtr, char *safeBuffer,
+ int maxDictSize);
+
+/*-*********************************************
+ * Streaming Compression Functions
+ ***********************************************/
+
+/**
+ * LZ4_resetStream() - Init an allocated 'LZ4_stream_t' structure
+ * @LZ4_stream: pointer to the 'LZ4_stream_t' structure
+ *
+ * An LZ4_stream_t structure can be allocated once
+ * and re-used multiple times.
+ * Use this function to init an allocated `LZ4_stream_t` structure
+ * and start a new compression.
+ */
+void LZ4_resetStream(LZ4_stream_t *LZ4_stream);
+
+/**
+ * LZ4_loadDict() - Load a static dictionary into LZ4_stream
+ * @streamPtr: pointer to the LZ4_stream_t
+ * @dictionary: dictionary to load
+ * @dictSize: size of dictionary
+ *
+ * Use this function to load a static dictionary into LZ4_stream.
+ * Any previous data will be forgotten, only 'dictionary'
+ * will remain in memory.
+ * Loading a size of 0 is allowed.
+ *
+ * Return : dictionary size, in bytes (necessarily <= 64 KB)
+ */
+int LZ4_loadDict(LZ4_stream_t *streamPtr, const char *dictionary,
+ int dictSize);
+
+/**
+ * LZ4_saveDict() - Save static dictionary from LZ4_stream
+ * @streamPtr: pointer to the 'LZ4_stream_t' structure
+ * @safeBuffer: buffer to save dictionary to, must be already allocated
+ * @dictSize: size of 'safeBuffer'
+ *
+ * If previously compressed data block is not guaranteed
+ * to remain available at its memory location,
+ * save it into a safer place (char *safeBuffer).
+ * Note : you don't need to call LZ4_loadDict() afterwards,
+ * dictionary is immediately usable, you can therefore call
+ * LZ4_compress_fast_continue().
+ *
+ * Return : saved dictionary size in bytes (necessarily <= dictSize),
+ * or 0 if error.
+ */
+int LZ4_saveDict(LZ4_stream_t *streamPtr, char *safeBuffer, int dictSize);
+
+/**
+ * LZ4_compress_fast_continue() - Compress 'src' using data from previously
+ * compressed blocks as a dictionary
+ * @streamPtr: Pointer to the previous 'LZ4_stream_t' structure
+ * @src: source address of the original data
+ * @dst: output buffer address of the compressed data,
+ * which must be already allocated
+ * @srcSize: size of the input data. Max supported value is LZ4_MAX_INPUT_SIZE
+ * @maxDstSize: full or partial size of buffer 'dest'
+ * which must be already allocated
+ * @acceleration: acceleration factor
+ *
+ * Compress buffer content 'src', using data from previously compressed blocks
+ * as dictionary to improve compression ratio.
+ * Important : Previous data blocks are assumed to still
+ * be present and unmodified !
+ * If maxDstSize >= LZ4_compressBound(srcSize),
+ * compression is guaranteed to succeed, and runs faster.
+ *
+ * Return: Number of bytes written into buffer 'dst' or 0 if compression fails
+ */
+int LZ4_compress_fast_continue(LZ4_stream_t *streamPtr, const char *src,
+ char *dst, int srcSize, int maxDstSize, int acceleration);
+
+/**
+ * LZ4_setStreamDecode() - Instruct where to find dictionary
+ * @LZ4_streamDecode: the 'LZ4_streamDecode_t' structure
+ * @dictionary: dictionary to use
+ * @dictSize: size of dictionary
+ *
+ * Use this function to instruct where to find the dictionary.
+ * Setting a size of 0 is allowed (same effect as reset).
+ *
+ * Return: 1 if OK, 0 if error
+ */
+int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
+ const char *dictionary, int dictSize);
+
+/**
+ * LZ4_decompress_fast_continue() - Decompress blocks in streaming mode
+ * @LZ4_streamDecode: the 'LZ4_streamDecode_t' structure
+ * @source: source address of the compressed data
+ * @dest: output buffer address of the uncompressed data
+ * which must be already allocated
+ * @compressedSize: is the precise full size of the compressed block
+ * @maxDecompressedSize: is the size of 'dest' buffer
+ *
+ * These decoding function allows decompression of multiple blocks
+ * in "streaming" mode.
+ * Previously decoded blocks *must* remain available at the memory position
+ * where they were decoded (up to 64 KB)
+ * In the case of a ring buffers, decoding buffer must be either :
+ * - Exactly same size as encoding buffer, with same update rule
+ * (block boundaries at same positions) In which case,
+ * the decoding & encoding ring buffer can have any size,
+ * including very small ones ( < 64 KB).
+ * - Larger than encoding buffer, by a minimum of maxBlockSize more bytes.
+ * maxBlockSize is implementation dependent.
+ * It's the maximum size you intend to compress into a single block.
+ * In which case, encoding and decoding buffers do not need
+ * to be synchronized, and encoding ring buffer can have any size,
+ * including small ones ( < 64 KB).
+ * - _At least_ 64 KB + 8 bytes + maxBlockSize.
+ * In which case, encoding and decoding buffers do not need to be
+ * synchronized, and encoding ring buffer can have any size,
+ * including larger than decoding buffer. W
+ * Whenever these conditions are not possible, save the last 64KB of decoded
+ * data into a safe buffer, and indicate where it is saved
+ * using LZ4_setStreamDecode()
+ *
+ * Return: number of bytes decompressed into destination buffer
+ * (necessarily <= maxDecompressedSize)
+ * or a negative result in case of error
+ */
+int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
+ const char *source, char *dest, int compressedSize,
+ int maxDecompressedSize);
+
+/**
+ * LZ4_decompress_fast_continue() - Decompress blocks in streaming mode
+ * @LZ4_streamDecode: the 'LZ4_streamDecode_t' structure
+ * @source: source address of the compressed data
+ * @dest: output buffer address of the uncompressed data
+ * which must be already allocated with 'originalSize' bytes
+ * @originalSize: is the original and therefore uncompressed size
+ *
+ * These decoding function allows decompression of multiple blocks
+ * in "streaming" mode.
+ * Previously decoded blocks *must* remain available at the memory position
+ * where they were decoded (up to 64 KB)
+ * In the case of a ring buffers, decoding buffer must be either :
+ * - Exactly same size as encoding buffer, with same update rule
+ * (block boundaries at same positions) In which case,
+ * the decoding & encoding ring buffer can have any size,
+ * including very small ones ( < 64 KB).
+ * - Larger than encoding buffer, by a minimum of maxBlockSize more bytes.
+ * maxBlockSize is implementation dependent.
+ * It's the maximum size you intend to compress into a single block.
+ * In which case, encoding and decoding buffers do not need
+ * to be synchronized, and encoding ring buffer can have any size,
+ * including small ones ( < 64 KB).
+ * - _At least_ 64 KB + 8 bytes + maxBlockSize.
+ * In which case, encoding and decoding buffers do not need to be
+ * synchronized, and encoding ring buffer can have any size,
+ * including larger than decoding buffer. W
+ * Whenever these conditions are not possible, save the last 64KB of decoded
+ * data into a safe buffer, and indicate where it is saved
+ * using LZ4_setStreamDecode()
+ *
+ * Return: number of bytes decompressed into destination buffer
+ * (necessarily <= maxDecompressedSize)
+ * or a negative result in case of error
+ */
+int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
+ const char *source, char *dest, int originalSize);
+
+/**
+ * LZ4_decompress_safe_usingDict() - Same as LZ4_setStreamDecode()
+ * followed by LZ4_decompress_safe_continue()
+ * @source: source address of the compressed data
+ * @dest: output buffer address of the uncompressed data
+ * which must be already allocated
+ * @compressedSize: is the precise full size of the compressed block
+ * @maxDecompressedSize: is the size of 'dest' buffer
+ * @dictStart: pointer to the start of the dictionary in memory
+ * @dictSize: size of dictionary
+ *
+ * These decoding function works the same as
+ * a combination of LZ4_setStreamDecode() followed by
+ * LZ4_decompress_safe_continue()
+ * It is stand-alone, and don'tn eed a LZ4_streamDecode_t structure.
+ *
+ * Return: number of bytes decompressed into destination buffer
+ * (necessarily <= maxDecompressedSize)
+ * or a negative result in case of error
+ */
+int LZ4_decompress_safe_usingDict(const char *source, char *dest,
+ int compressedSize, int maxDecompressedSize, const char *dictStart,
+ int dictSize);
+
+/**
+ * LZ4_decompress_fast_usingDict() - Same as LZ4_setStreamDecode()
+ * followed by LZ4_decompress_fast_continue()
+ * @source: source address of the compressed data
+ * @dest: output buffer address of the uncompressed data
+ * which must be already allocated with 'originalSize' bytes
+ * @originalSize: is the original and therefore uncompressed size
+ * @dictStart: pointer to the start of the dictionary in memory
+ * @dictSize: size of dictionary
+ *
+ * These decoding function works the same as
+ * a combination of LZ4_setStreamDecode() followed by
+ * LZ4_decompress_safe_continue()
+ * It is stand-alone, and don'tn eed a LZ4_streamDecode_t structure.
+ *
+ * Return: number of bytes decompressed into destination buffer
+ * (necessarily <= maxDecompressedSize)
+ * or a negative result in case of error
+ */
+int LZ4_decompress_fast_usingDict(const char *source, char *dest,
+ int originalSize, const char *dictStart, int dictSize);
+
#endif
projects / linux-2.6-block.git / blobdiff