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linux-hardened/include/linux/lz4.h
Sven Schmidt 69c78423b8 lib/lz4: remove back-compat wrappers 
Remove the functions introduced as wrappers for providing backwards
compatibility to the prior LZ4 version.  They're not needed anymore
since there's no callers left.

Link: http://lkml.kernel.org/r/1486321748-19085-6-git-send-email-4sschmid@informatik.uni-hamburg.de
Signed-off-by: Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
Cc: Bongkyu Kim <bongkyu.kim@lge.com>
Cc: Rui Salvaterra <rsalvaterra@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David S. Miller <davem@davemloft.net>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:57 -08:00

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/* 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
*/
#ifndef __LZ4_H__
#define __LZ4_H__
#include <linux/types.h>
#include <linux/string.h> /* memset, memcpy */
/*-************************************************************************
* CONSTANTS
**************************************************************************/
/*
* 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
*/
#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 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);
/*-************************************************************************
* 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 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);
/**
* 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
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