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-/* ******************************************************************
- FSE : Finite State Entropy codec
- Public Prototypes declaration
- Copyright (C) 2013-2016, 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 :
- - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
-****************************************************************** */
-
-#if defined (__cplusplus)
-extern "C" {
-#endif
-
-#ifndef FSE_H
-#define FSE_H
-
-
-/*-*****************************************
-* Dependencies
-******************************************/
-#include <stddef.h> /* size_t, ptrdiff_t */
-
-
-/*-*****************************************
-* FSE_PUBLIC_API : control library symbols visibility
-******************************************/
-#if defined(FSE_DLL_EXPORT) && (FSE_DLL_EXPORT==1) && defined(__GNUC__) && (__GNUC__ >= 4)
-# define FSE_PUBLIC_API __attribute__ ((visibility ("default")))
-#elif defined(FSE_DLL_EXPORT) && (FSE_DLL_EXPORT==1) /* Visual expected */
-# define FSE_PUBLIC_API __declspec(dllexport)
-#elif defined(FSE_DLL_IMPORT) && (FSE_DLL_IMPORT==1)
-# define FSE_PUBLIC_API __declspec(dllimport) /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/
-#else
-# define FSE_PUBLIC_API
-#endif
-
-/*------ Version ------*/
-#define FSE_VERSION_MAJOR 0
-#define FSE_VERSION_MINOR 9
-#define FSE_VERSION_RELEASE 0
-
-#define FSE_LIB_VERSION FSE_VERSION_MAJOR.FSE_VERSION_MINOR.FSE_VERSION_RELEASE
-#define FSE_QUOTE(str) #str
-#define FSE_EXPAND_AND_QUOTE(str) FSE_QUOTE(str)
-#define FSE_VERSION_STRING FSE_EXPAND_AND_QUOTE(FSE_LIB_VERSION)
-
-#define FSE_VERSION_NUMBER (FSE_VERSION_MAJOR *100*100 + FSE_VERSION_MINOR *100 + FSE_VERSION_RELEASE)
-FSE_PUBLIC_API unsigned FSE_versionNumber(void); /**< library version number; to be used when checking dll version */
-
-
-/*-****************************************
-* FSE simple functions
-******************************************/
-/*! FSE_compress() :
- Compress content of buffer 'src', of size 'srcSize', into destination buffer 'dst'.
- 'dst' buffer must be already allocated. Compression runs faster is dstCapacity >= FSE_compressBound(srcSize).
- @return : size of compressed data (<= dstCapacity).
- Special values : if return == 0, srcData is not compressible => Nothing is stored within dst !!!
- if return == 1, srcData is a single byte symbol * srcSize times. Use RLE compression instead.
- if FSE_isError(return), compression failed (more details using FSE_getErrorName())
-*/
-FSE_PUBLIC_API size_t FSE_compress(void* dst, size_t dstCapacity,
- const void* src, size_t srcSize);
-
-/*! FSE_decompress():
- Decompress FSE data from buffer 'cSrc', of size 'cSrcSize',
- into already allocated destination buffer 'dst', of size 'dstCapacity'.
- @return : size of regenerated data (<= maxDstSize),
- or an error code, which can be tested using FSE_isError() .
-
- ** Important ** : FSE_decompress() does not decompress non-compressible nor RLE data !!!
- Why ? : making this distinction requires a header.
- Header management is intentionally delegated to the user layer, which can better manage special cases.
-*/
-FSE_PUBLIC_API size_t FSE_decompress(void* dst, size_t dstCapacity,
- const void* cSrc, size_t cSrcSize);
-
-
-/*-*****************************************
-* Tool functions
-******************************************/
-FSE_PUBLIC_API size_t FSE_compressBound(size_t size); /* maximum compressed size */
-
-/* Error Management */
-FSE_PUBLIC_API unsigned FSE_isError(size_t code); /* tells if a return value is an error code */
-FSE_PUBLIC_API const char* FSE_getErrorName(size_t code); /* provides error code string (useful for debugging) */
-
-
-/*-*****************************************
-* FSE advanced functions
-******************************************/
-/*! FSE_compress2() :
- Same as FSE_compress(), but allows the selection of 'maxSymbolValue' and 'tableLog'
- Both parameters can be defined as '0' to mean : use default value
- @return : size of compressed data
- Special values : if return == 0, srcData is not compressible => Nothing is stored within cSrc !!!
- if return == 1, srcData is a single byte symbol * srcSize times. Use RLE compression.
- if FSE_isError(return), it's an error code.
-*/
-FSE_PUBLIC_API size_t FSE_compress2 (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog);
-
-
-/*-*****************************************
-* FSE detailed API
-******************************************/
-/*!
-FSE_compress() does the following:
-1. count symbol occurrence from source[] into table count[] (see hist.h)
-2. normalize counters so that sum(count[]) == Power_of_2 (2^tableLog)
-3. save normalized counters to memory buffer using writeNCount()
-4. build encoding table 'CTable' from normalized counters
-5. encode the data stream using encoding table 'CTable'
-
-FSE_decompress() does the following:
-1. read normalized counters with readNCount()
-2. build decoding table 'DTable' from normalized counters
-3. decode the data stream using decoding table 'DTable'
-
-The following API allows targeting specific sub-functions for advanced tasks.
-For example, it's possible to compress several blocks using the same 'CTable',
-or to save and provide normalized distribution using external method.
-*/
-
-/* *** COMPRESSION *** */
-
-/*! FSE_optimalTableLog():
- dynamically downsize 'tableLog' when conditions are met.
- It saves CPU time, by using smaller tables, while preserving or even improving compression ratio.
- @return : recommended tableLog (necessarily <= 'maxTableLog') */
-FSE_PUBLIC_API unsigned FSE_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue);
-
-/*! FSE_normalizeCount():
- normalize counts so that sum(count[]) == Power_of_2 (2^tableLog)
- 'normalizedCounter' is a table of short, of minimum size (maxSymbolValue+1).
- @return : tableLog,
- or an errorCode, which can be tested using FSE_isError() */
-FSE_PUBLIC_API size_t FSE_normalizeCount(short* normalizedCounter, unsigned tableLog,
- const unsigned* count, size_t srcSize, unsigned maxSymbolValue);
-
-/*! FSE_NCountWriteBound():
- Provides the maximum possible size of an FSE normalized table, given 'maxSymbolValue' and 'tableLog'.
- Typically useful for allocation purpose. */
-FSE_PUBLIC_API size_t FSE_NCountWriteBound(unsigned maxSymbolValue, unsigned tableLog);
-
-/*! FSE_writeNCount():
- Compactly save 'normalizedCounter' into 'buffer'.
- @return : size of the compressed table,
- or an errorCode, which can be tested using FSE_isError(). */
-FSE_PUBLIC_API size_t FSE_writeNCount (void* buffer, size_t bufferSize,
- const short* normalizedCounter,
- unsigned maxSymbolValue, unsigned tableLog);
-
-/*! Constructor and Destructor of FSE_CTable.
- Note that FSE_CTable size depends on 'tableLog' and 'maxSymbolValue' */
-typedef unsigned FSE_CTable; /* don't allocate that. It's only meant to be more restrictive than void* */
-FSE_PUBLIC_API FSE_CTable* FSE_createCTable (unsigned maxSymbolValue, unsigned tableLog);
-FSE_PUBLIC_API void FSE_freeCTable (FSE_CTable* ct);
-
-/*! FSE_buildCTable():
- Builds `ct`, which must be already allocated, using FSE_createCTable().
- @return : 0, or an errorCode, which can be tested using FSE_isError() */
-FSE_PUBLIC_API size_t FSE_buildCTable(FSE_CTable* ct, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog);
-
-/*! FSE_compress_usingCTable():
- Compress `src` using `ct` into `dst` which must be already allocated.
- @return : size of compressed data (<= `dstCapacity`),
- or 0 if compressed data could not fit into `dst`,
- or an errorCode, which can be tested using FSE_isError() */
-FSE_PUBLIC_API size_t FSE_compress_usingCTable (void* dst, size_t dstCapacity, const void* src, size_t srcSize, const FSE_CTable* ct);
-
-/*!
-Tutorial :
-----------
-The first step is to count all symbols. FSE_count() does this job very fast.
-Result will be saved into 'count', a table of unsigned int, which must be already allocated, and have 'maxSymbolValuePtr[0]+1' cells.
-'src' is a table of bytes of size 'srcSize'. All values within 'src' MUST be <= maxSymbolValuePtr[0]
-maxSymbolValuePtr[0] will be updated, with its real value (necessarily <= original value)
-FSE_count() will return the number of occurrence of the most frequent symbol.
-This can be used to know if there is a single symbol within 'src', and to quickly evaluate its compressibility.
-If there is an error, the function will return an ErrorCode (which can be tested using FSE_isError()).
-
-The next step is to normalize the frequencies.
-FSE_normalizeCount() will ensure that sum of frequencies is == 2 ^'tableLog'.
-It also guarantees a minimum of 1 to any Symbol with frequency >= 1.
-You can use 'tableLog'==0 to mean "use default tableLog value".
-If you are unsure of which tableLog value to use, you can ask FSE_optimalTableLog(),
-which will provide the optimal valid tableLog given sourceSize, maxSymbolValue, and a user-defined maximum (0 means "default").
-
-The result of FSE_normalizeCount() will be saved into a table,
-called 'normalizedCounter', which is a table of signed short.
-'normalizedCounter' must be already allocated, and have at least 'maxSymbolValue+1' cells.
-The return value is tableLog if everything proceeded as expected.
-It is 0 if there is a single symbol within distribution.
-If there is an error (ex: invalid tableLog value), the function will return an ErrorCode (which can be tested using FSE_isError()).
-
-'normalizedCounter' can be saved in a compact manner to a memory area using FSE_writeNCount().
-'buffer' must be already allocated.
-For guaranteed success, buffer size must be at least FSE_headerBound().
-The result of the function is the number of bytes written into 'buffer'.
-If there is an error, the function will return an ErrorCode (which can be tested using FSE_isError(); ex : buffer size too small).
-
-'normalizedCounter' can then be used to create the compression table 'CTable'.
-The space required by 'CTable' must be already allocated, using FSE_createCTable().
-You can then use FSE_buildCTable() to fill 'CTable'.
-If there is an error, both functions will return an ErrorCode (which can be tested using FSE_isError()).
-
-'CTable' can then be used to compress 'src', with FSE_compress_usingCTable().
-Similar to FSE_count(), the convention is that 'src' is assumed to be a table of char of size 'srcSize'
-The function returns the size of compressed data (without header), necessarily <= `dstCapacity`.
-If it returns '0', compressed data could not fit into 'dst'.
-If there is an error, the function will return an ErrorCode (which can be tested using FSE_isError()).
-*/
-
-
-/* *** DECOMPRESSION *** */
-
-/*! FSE_readNCount():
- Read compactly saved 'normalizedCounter' from 'rBuffer'.
- @return : size read from 'rBuffer',
- or an errorCode, which can be tested using FSE_isError().
- maxSymbolValuePtr[0] and tableLogPtr[0] will also be updated with their respective values */
-FSE_PUBLIC_API size_t FSE_readNCount (short* normalizedCounter,
- unsigned* maxSymbolValuePtr, unsigned* tableLogPtr,
- const void* rBuffer, size_t rBuffSize);
-
-/*! Constructor and Destructor of FSE_DTable.
- Note that its size depends on 'tableLog' */
-typedef unsigned FSE_DTable; /* don't allocate that. It's just a way to be more restrictive than void* */
-FSE_PUBLIC_API FSE_DTable* FSE_createDTable(unsigned tableLog);
-FSE_PUBLIC_API void FSE_freeDTable(FSE_DTable* dt);
-
-/*! FSE_buildDTable():
- Builds 'dt', which must be already allocated, using FSE_createDTable().
- return : 0, or an errorCode, which can be tested using FSE_isError() */
-FSE_PUBLIC_API size_t FSE_buildDTable (FSE_DTable* dt, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog);
-
-/*! FSE_decompress_usingDTable():
- Decompress compressed source `cSrc` of size `cSrcSize` using `dt`
- into `dst` which must be already allocated.
- @return : size of regenerated data (necessarily <= `dstCapacity`),
- or an errorCode, which can be tested using FSE_isError() */
-FSE_PUBLIC_API size_t FSE_decompress_usingDTable(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize, const FSE_DTable* dt);
-
-/*!
-Tutorial :
-----------
-(Note : these functions only decompress FSE-compressed blocks.
- If block is uncompressed, use memcpy() instead
- If block is a single repeated byte, use memset() instead )
-
-The first step is to obtain the normalized frequencies of symbols.
-This can be performed by FSE_readNCount() if it was saved using FSE_writeNCount().
-'normalizedCounter' must be already allocated, and have at least 'maxSymbolValuePtr[0]+1' cells of signed short.
-In practice, that means it's necessary to know 'maxSymbolValue' beforehand,
-or size the table to handle worst case situations (typically 256).
-FSE_readNCount() will provide 'tableLog' and 'maxSymbolValue'.
-The result of FSE_readNCount() is the number of bytes read from 'rBuffer'.
-Note that 'rBufferSize' must be at least 4 bytes, even if useful information is less than that.
-If there is an error, the function will return an error code, which can be tested using FSE_isError().
-
-The next step is to build the decompression tables 'FSE_DTable' from 'normalizedCounter'.
-This is performed by the function FSE_buildDTable().
-The space required by 'FSE_DTable' must be already allocated using FSE_createDTable().
-If there is an error, the function will return an error code, which can be tested using FSE_isError().
-
-`FSE_DTable` can then be used to decompress `cSrc`, with FSE_decompress_usingDTable().
-`cSrcSize` must be strictly correct, otherwise decompression will fail.
-FSE_decompress_usingDTable() result will tell how many bytes were regenerated (<=`dstCapacity`).
-If there is an error, the function will return an error code, which can be tested using FSE_isError(). (ex: dst buffer too small)
-*/
-
-#endif /* FSE_H */
-
-#if defined(FSE_STATIC_LINKING_ONLY) && !defined(FSE_H_FSE_STATIC_LINKING_ONLY)
-#define FSE_H_FSE_STATIC_LINKING_ONLY
-
-/* *** Dependency *** */
-#include "bitstream.h"
-
-
-/* *****************************************
-* Static allocation
-*******************************************/
-/* FSE buffer bounds */
-#define FSE_NCOUNTBOUND 512
-#define FSE_BLOCKBOUND(size) (size + (size>>7))
-#define FSE_COMPRESSBOUND(size) (FSE_NCOUNTBOUND + FSE_BLOCKBOUND(size)) /* Macro version, useful for static allocation */
-
-/* It is possible to statically allocate FSE CTable/DTable as a table of FSE_CTable/FSE_DTable using below macros */
-#define FSE_CTABLE_SIZE_U32(maxTableLog, maxSymbolValue) (1 + (1<<(maxTableLog-1)) + ((maxSymbolValue+1)*2))
-#define FSE_DTABLE_SIZE_U32(maxTableLog) (1 + (1<<maxTableLog))
-
-/* or use the size to malloc() space directly. Pay attention to alignment restrictions though */
-#define FSE_CTABLE_SIZE(maxTableLog, maxSymbolValue) (FSE_CTABLE_SIZE_U32(maxTableLog, maxSymbolValue) * sizeof(FSE_CTable))
-#define FSE_DTABLE_SIZE(maxTableLog) (FSE_DTABLE_SIZE_U32(maxTableLog) * sizeof(FSE_DTable))
-
-
-/* *****************************************
- * FSE advanced API
- ***************************************** */
-
-unsigned FSE_optimalTableLog_internal(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue, unsigned minus);
-/**< same as FSE_optimalTableLog(), which used `minus==2` */
-
-/* FSE_compress_wksp() :
- * Same as FSE_compress2(), but using an externally allocated scratch buffer (`workSpace`).
- * FSE_WKSP_SIZE_U32() provides the minimum size required for `workSpace` as a table of FSE_CTable.
- */
-#define FSE_WKSP_SIZE_U32(maxTableLog, maxSymbolValue) ( FSE_CTABLE_SIZE_U32(maxTableLog, maxSymbolValue) + ((maxTableLog > 12) ? (1 << (maxTableLog - 2)) : 1024) )
-size_t FSE_compress_wksp (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog, void* workSpace, size_t wkspSize);
-
-size_t FSE_buildCTable_raw (FSE_CTable* ct, unsigned nbBits);
-/**< build a fake FSE_CTable, designed for a flat distribution, where each symbol uses nbBits */
-
-size_t FSE_buildCTable_rle (FSE_CTable* ct, unsigned char symbolValue);
-/**< build a fake FSE_CTable, designed to compress always the same symbolValue */
-
-/* FSE_buildCTable_wksp() :
- * Same as FSE_buildCTable(), but using an externally allocated scratch buffer (`workSpace`).
- * `wkspSize` must be >= `(1<<tableLog)`.
- */
-size_t FSE_buildCTable_wksp(FSE_CTable* ct, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog, void* workSpace, size_t wkspSize);
-
-size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits);
-/**< build a fake FSE_DTable, designed to read a flat distribution where each symbol uses nbBits */
-
-size_t FSE_buildDTable_rle (FSE_DTable* dt, unsigned char symbolValue);
-/**< build a fake FSE_DTable, designed to always generate the same symbolValue */
-
-size_t FSE_decompress_wksp(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize, FSE_DTable* workSpace, unsigned maxLog);
-/**< same as FSE_decompress(), using an externally allocated `workSpace` produced with `FSE_DTABLE_SIZE_U32(maxLog)` */
-
-typedef enum {
- FSE_repeat_none, /**< Cannot use the previous table */
- FSE_repeat_check, /**< Can use the previous table but it must be checked */
- FSE_repeat_valid /**< Can use the previous table and it is assumed to be valid */
- } FSE_repeat;
-
-/* *****************************************
-* FSE symbol compression API
-*******************************************/
-/*!
- This API consists of small unitary functions, which highly benefit from being inlined.
- Hence their body are included in next section.
-*/
-typedef struct {
- ptrdiff_t value;
- const void* stateTable;
- const void* symbolTT;
- unsigned stateLog;
-} FSE_CState_t;
-
-static void FSE_initCState(FSE_CState_t* CStatePtr, const FSE_CTable* ct);
-
-static void FSE_encodeSymbol(BIT_CStream_t* bitC, FSE_CState_t* CStatePtr, unsigned symbol);
-
-static void FSE_flushCState(BIT_CStream_t* bitC, const FSE_CState_t* CStatePtr);
-
-/**<
-These functions are inner components of FSE_compress_usingCTable().
-They allow the creation of custom streams, mixing multiple tables and bit sources.
-
-A key property to keep in mind is that encoding and decoding are done **in reverse direction**.
-So the first symbol you will encode is the last you will decode, like a LIFO stack.
-
-You will need a few variables to track your CStream. They are :
-
-FSE_CTable ct; // Provided by FSE_buildCTable()
-BIT_CStream_t bitStream; // bitStream tracking structure
-FSE_CState_t state; // State tracking structure (can have several)
-
-
-The first thing to do is to init bitStream and state.
- size_t errorCode = BIT_initCStream(&bitStream, dstBuffer, maxDstSize);
- FSE_initCState(&state, ct);
-
-Note that BIT_initCStream() can produce an error code, so its result should be tested, using FSE_isError();
-You can then encode your input data, byte after byte.
-FSE_encodeSymbol() outputs a maximum of 'tableLog' bits at a time.
-Remember decoding will be done in reverse direction.
- FSE_encodeByte(&bitStream, &state, symbol);
-
-At any time, you can also add any bit sequence.
-Note : maximum allowed nbBits is 25, for compatibility with 32-bits decoders
- BIT_addBits(&bitStream, bitField, nbBits);
-
-The above methods don't commit data to memory, they just store it into local register, for speed.
-Local register size is 64-bits on 64-bits systems, 32-bits on 32-bits systems (size_t).
-Writing data to memory is a manual operation, performed by the flushBits function.
- BIT_flushBits(&bitStream);
-
-Your last FSE encoding operation shall be to flush your last state value(s).
- FSE_flushState(&bitStream, &state);
-
-Finally, you must close the bitStream.
-The function returns the size of CStream in bytes.
-If data couldn't fit into dstBuffer, it will return a 0 ( == not compressible)
-If there is an error, it returns an errorCode (which can be tested using FSE_isError()).
- size_t size = BIT_closeCStream(&bitStream);
-*/
-
-
-/* *****************************************
-* FSE symbol decompression API
-*******************************************/
-typedef struct {
- size_t state;
- const void* table; /* precise table may vary, depending on U16 */
-} FSE_DState_t;
-
-
-static void FSE_initDState(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD, const FSE_DTable* dt);
-
-static unsigned char FSE_decodeSymbol(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD);
-
-static unsigned FSE_endOfDState(const FSE_DState_t* DStatePtr);
-
-/**<
-Let's now decompose FSE_decompress_usingDTable() into its unitary components.
-You will decode FSE-encoded symbols from the bitStream,
-and also any other bitFields you put in, **in reverse order**.
-
-You will need a few variables to track your bitStream. They are :
-
-BIT_DStream_t DStream; // Stream context
-FSE_DState_t DState; // State context. Multiple ones are possible
-FSE_DTable* DTablePtr; // Decoding table, provided by FSE_buildDTable()
-
-The first thing to do is to init the bitStream.
- errorCode = BIT_initDStream(&DStream, srcBuffer, srcSize);
-
-You should then retrieve your initial state(s)
-(in reverse flushing order if you have several ones) :
- errorCode = FSE_initDState(&DState, &DStream, DTablePtr);
-
-You can then decode your data, symbol after symbol.
-For information the maximum number of bits read by FSE_decodeSymbol() is 'tableLog'.
-Keep in mind that symbols are decoded in reverse order, like a LIFO stack (last in, first out).
- unsigned char symbol = FSE_decodeSymbol(&DState, &DStream);
-
-You can retrieve any bitfield you eventually stored into the bitStream (in reverse order)
-Note : maximum allowed nbBits is 25, for 32-bits compatibility
- size_t bitField = BIT_readBits(&DStream, nbBits);
-
-All above operations only read from local register (which size depends on size_t).
-Refueling the register from memory is manually performed by the reload method.
- endSignal = FSE_reloadDStream(&DStream);
-
-BIT_reloadDStream() result tells if there is still some more data to read from DStream.
-BIT_DStream_unfinished : there is still some data left into the DStream.
-BIT_DStream_endOfBuffer : Dstream reached end of buffer. Its container may no longer be completely filled.
-BIT_DStream_completed : Dstream reached its exact end, corresponding in general to decompression completed.
-BIT_DStream_tooFar : Dstream went too far. Decompression result is corrupted.
-
-When reaching end of buffer (BIT_DStream_endOfBuffer), progress slowly, notably if you decode multiple symbols per loop,
-to properly detect the exact end of stream.
-After each decoded symbol, check if DStream is fully consumed using this simple test :
- BIT_reloadDStream(&DStream) >= BIT_DStream_completed
-
-When it's done, verify decompression is fully completed, by checking both DStream and the relevant states.
-Checking if DStream has reached its end is performed by :
- BIT_endOfDStream(&DStream);
-Check also the states. There might be some symbols left there, if some high probability ones (>50%) are possible.
- FSE_endOfDState(&DState);
-*/
-
-
-/* *****************************************
-* FSE unsafe API
-*******************************************/
-static unsigned char FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD);
-/* faster, but works only if nbBits is always >= 1 (otherwise, result will be corrupted) */
-
-
-/* *****************************************
-* Implementation of inlined functions
-*******************************************/
-typedef struct {
- int deltaFindState;
- U32 deltaNbBits;
-} FSE_symbolCompressionTransform; /* total 8 bytes */
-
-MEM_STATIC void FSE_initCState(FSE_CState_t* statePtr, const FSE_CTable* ct)
-{
- const void* ptr = ct;
- const U16* u16ptr = (const U16*) ptr;
- const U32 tableLog = MEM_read16(ptr);
- statePtr->value = (ptrdiff_t)1<<tableLog;
- statePtr->stateTable = u16ptr+2;
- statePtr->symbolTT = ct + 1 + (tableLog ? (1<<(tableLog-1)) : 1);
- statePtr->stateLog = tableLog;
-}
-
-
-/*! FSE_initCState2() :
-* Same as FSE_initCState(), but the first symbol to include (which will be the last to be read)
-* uses the smallest state value possible, saving the cost of this symbol */
-MEM_STATIC void FSE_initCState2(FSE_CState_t* statePtr, const FSE_CTable* ct, U32 symbol)
-{
- FSE_initCState(statePtr, ct);
- { const FSE_symbolCompressionTransform symbolTT = ((const FSE_symbolCompressionTransform*)(statePtr->symbolTT))[symbol];
- const U16* stateTable = (const U16*)(statePtr->stateTable);
- U32 nbBitsOut = (U32)((symbolTT.deltaNbBits + (1<<15)) >> 16);
- statePtr->value = (nbBitsOut << 16) - symbolTT.deltaNbBits;
- statePtr->value = stateTable[(statePtr->value >> nbBitsOut) + symbolTT.deltaFindState];
- }
-}
-
-MEM_STATIC void FSE_encodeSymbol(BIT_CStream_t* bitC, FSE_CState_t* statePtr, unsigned symbol)
-{
- FSE_symbolCompressionTransform const symbolTT = ((const FSE_symbolCompressionTransform*)(statePtr->symbolTT))[symbol];
- const U16* const stateTable = (const U16*)(statePtr->stateTable);
- U32 const nbBitsOut = (U32)((statePtr->value + symbolTT.deltaNbBits) >> 16);
- BIT_addBits(bitC, statePtr->value, nbBitsOut);
- statePtr->value = stateTable[ (statePtr->value >> nbBitsOut) + symbolTT.deltaFindState];
-}
-
-MEM_STATIC void FSE_flushCState(BIT_CStream_t* bitC, const FSE_CState_t* statePtr)
-{
- BIT_addBits(bitC, statePtr->value, statePtr->stateLog);
- BIT_flushBits(bitC);
-}
-
-
-/* FSE_getMaxNbBits() :
- * Approximate maximum cost of a symbol, in bits.
- * Fractional get rounded up (i.e : a symbol with a normalized frequency of 3 gives the same result as a frequency of 2)
- * note 1 : assume symbolValue is valid (<= maxSymbolValue)
- * note 2 : if freq[symbolValue]==0, @return a fake cost of tableLog+1 bits */
-MEM_STATIC U32 FSE_getMaxNbBits(const void* symbolTTPtr, U32 symbolValue)
-{
- const FSE_symbolCompressionTransform* symbolTT = (const FSE_symbolCompressionTransform*) symbolTTPtr;
- return (symbolTT[symbolValue].deltaNbBits + ((1<<16)-1)) >> 16;
-}
-
-/* FSE_bitCost() :
- * Approximate symbol cost, as fractional value, using fixed-point format (accuracyLog fractional bits)
- * note 1 : assume symbolValue is valid (<= maxSymbolValue)
- * note 2 : if freq[symbolValue]==0, @return a fake cost of tableLog+1 bits */
-MEM_STATIC U32 FSE_bitCost(const void* symbolTTPtr, U32 tableLog, U32 symbolValue, U32 accuracyLog)
-{
- const FSE_symbolCompressionTransform* symbolTT = (const FSE_symbolCompressionTransform*) symbolTTPtr;
- U32 const minNbBits = symbolTT[symbolValue].deltaNbBits >> 16;
- U32 const threshold = (minNbBits+1) << 16;
- assert(tableLog < 16);
- assert(accuracyLog < 31-tableLog); /* ensure enough room for renormalization double shift */
- { U32 const tableSize = 1 << tableLog;
- U32 const deltaFromThreshold = threshold - (symbolTT[symbolValue].deltaNbBits + tableSize);
- U32 const normalizedDeltaFromThreshold = (deltaFromThreshold << accuracyLog) >> tableLog; /* linear interpolation (very approximate) */
- U32 const bitMultiplier = 1 << accuracyLog;
- assert(symbolTT[symbolValue].deltaNbBits + tableSize <= threshold);
- assert(normalizedDeltaFromThreshold <= bitMultiplier);
- return (minNbBits+1)*bitMultiplier - normalizedDeltaFromThreshold;
- }
-}
-
-
-/* ====== Decompression ====== */
-
-typedef struct {
- U16 tableLog;
- U16 fastMode;
-} FSE_DTableHeader; /* sizeof U32 */
-
-typedef struct
-{
- unsigned short newState;
- unsigned char symbol;
- unsigned char nbBits;
-} FSE_decode_t; /* size == U32 */
-
-MEM_STATIC void FSE_initDState(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD, const FSE_DTable* dt)
-{
- const void* ptr = dt;
- const FSE_DTableHeader* const DTableH = (const FSE_DTableHeader*)ptr;
- DStatePtr->state = BIT_readBits(bitD, DTableH->tableLog);
- BIT_reloadDStream(bitD);
- DStatePtr->table = dt + 1;
-}
-
-MEM_STATIC BYTE FSE_peekSymbol(const FSE_DState_t* DStatePtr)
-{
- FSE_decode_t const DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
- return DInfo.symbol;
-}
-
-MEM_STATIC void FSE_updateState(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
-{
- FSE_decode_t const DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
- U32 const nbBits = DInfo.nbBits;
- size_t const lowBits = BIT_readBits(bitD, nbBits);
- DStatePtr->state = DInfo.newState + lowBits;
-}
-
-MEM_STATIC BYTE FSE_decodeSymbol(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
-{
- FSE_decode_t const DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
- U32 const nbBits = DInfo.nbBits;
- BYTE const symbol = DInfo.symbol;
- size_t const lowBits = BIT_readBits(bitD, nbBits);
-
- DStatePtr->state = DInfo.newState + lowBits;
- return symbol;
-}
-
-/*! FSE_decodeSymbolFast() :
- unsafe, only works if no symbol has a probability > 50% */
-MEM_STATIC BYTE FSE_decodeSymbolFast(FSE_DState_t* DStatePtr, BIT_DStream_t* bitD)
-{
- FSE_decode_t const DInfo = ((const FSE_decode_t*)(DStatePtr->table))[DStatePtr->state];
- U32 const nbBits = DInfo.nbBits;
- BYTE const symbol = DInfo.symbol;
- size_t const lowBits = BIT_readBitsFast(bitD, nbBits);
-
- DStatePtr->state = DInfo.newState + lowBits;
- return symbol;
-}
-
-MEM_STATIC unsigned FSE_endOfDState(const FSE_DState_t* DStatePtr)
-{
- return DStatePtr->state == 0;
-}
-
-
-
-#ifndef FSE_COMMONDEFS_ONLY
-
-/* **************************************************************
-* Tuning parameters
-****************************************************************/
-/*!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
-* Recommended max value is 14, for 16KB, which nicely fits into Intel x86 L1 cache */
-#ifndef FSE_MAX_MEMORY_USAGE
-# define FSE_MAX_MEMORY_USAGE 14
-#endif
-#ifndef FSE_DEFAULT_MEMORY_USAGE
-# define FSE_DEFAULT_MEMORY_USAGE 13
-#endif
-
-/*!FSE_MAX_SYMBOL_VALUE :
-* Maximum symbol value authorized.
-* Required for proper stack allocation */
-#ifndef FSE_MAX_SYMBOL_VALUE
-# define FSE_MAX_SYMBOL_VALUE 255
-#endif
-
-/* **************************************************************
-* template functions type & suffix
-****************************************************************/
-#define FSE_FUNCTION_TYPE BYTE
-#define FSE_FUNCTION_EXTENSION
-#define FSE_DECODE_TYPE FSE_decode_t
-
-
-#endif /* !FSE_COMMONDEFS_ONLY */
-
-
-/* ***************************************************************
-* Constants
-*****************************************************************/
-#define FSE_MAX_TABLELOG (FSE_MAX_MEMORY_USAGE-2)
-#define FSE_MAX_TABLESIZE (1U<<FSE_MAX_TABLELOG)
-#define FSE_MAXTABLESIZE_MASK (FSE_MAX_TABLESIZE-1)
-#define FSE_DEFAULT_TABLELOG (FSE_DEFAULT_MEMORY_USAGE-2)
-#define FSE_MIN_TABLELOG 5
-
-#define FSE_TABLELOG_ABSOLUTE_MAX 15
-#if FSE_MAX_TABLELOG > FSE_TABLELOG_ABSOLUTE_MAX
-# error "FSE_MAX_TABLELOG > FSE_TABLELOG_ABSOLUTE_MAX is not supported"
-#endif
-
-#define FSE_TABLESTEP(tableSize) ((tableSize>>1) + (tableSize>>3) + 3)
-
-
-#endif /* FSE_STATIC_LINKING_ONLY */
-
-
-#if defined (__cplusplus)
-}
-#endif