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author | Anton Samokhvalov <pg83@yandex.ru> | 2022-02-10 16:45:15 +0300 |
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committer | Daniil Cherednik <dcherednik@yandex-team.ru> | 2022-02-10 16:45:15 +0300 |
commit | 72cb13b4aff9bc9cf22e49251bc8fd143f82538f (patch) | |
tree | da2c34829458c7d4e74bdfbdf85dff449e9e7fb8 /contrib/libs/zstd06/common/fse_static.h | |
parent | 778e51ba091dc39e7b7fcab2b9cf4dbedfb6f2b5 (diff) | |
download | ydb-72cb13b4aff9bc9cf22e49251bc8fd143f82538f.tar.gz |
Restoring authorship annotation for Anton Samokhvalov <pg83@yandex.ru>. Commit 1 of 2.
Diffstat (limited to 'contrib/libs/zstd06/common/fse_static.h')
-rw-r--r-- | contrib/libs/zstd06/common/fse_static.h | 682 |
1 files changed, 341 insertions, 341 deletions
diff --git a/contrib/libs/zstd06/common/fse_static.h b/contrib/libs/zstd06/common/fse_static.h index d09589efee..9ecb0b2cb9 100644 --- a/contrib/libs/zstd06/common/fse_static.h +++ b/contrib/libs/zstd06/common/fse_static.h @@ -1,340 +1,340 @@ #include <contrib/libs/zstd06/renames.h> -/* ****************************************************************** - FSE : Finite State Entropy coder - header file for static linking (only) - Copyright (C) 2013-2015, 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 - - Public forum : https://groups.google.com/forum/#!forum/lz4c -****************************************************************** */ -#ifndef FSE_STATIC_H -#define FSE_STATIC_H - -#if defined (__cplusplus) -extern "C" { -#endif - - -/* ***************************************** -* Dependencies -*******************************************/ -#include "fse.h" -#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 unsigned 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)) - - -/* ***************************************** -* FSE advanced API -*******************************************/ -size_t FSE_countFast(unsigned* count, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize); -/* same as FSE_count(), but blindly trusts that all byte values within src are <= *maxSymbolValuePtr */ - -size_t FSE_buildCTable_raw (FSE_CTable* ct, unsigned nbBits); -/* build a fake FSE_CTable, designed to not compress an input, 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 */ - -size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits); -/* build a fake FSE_DTable, designed to read an uncompressed bitstream 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 */ - - -/* ***************************************** -* FSE symbol compression API -*******************************************/ -/*! - This API consists of small unitary functions, which highly benefit from being inlined. - You will want to enable link-time-optimization to ensure these functions are properly inlined in your binary. - Visual seems to do it automatically. - For gcc or clang, you'll need to add -flto flag at compilation and linking stages. - If none of these solutions is applicable, include "fse.c" directly. -*/ -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 = ((const U32*)ct + 1 + (tableLog ? (1<<(tableLog-1)) : 1)); - statePtr->stateLog = tableLog; -} - -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, U32 symbol) -{ - const FSE_symbolCompressionTransform symbolTT = ((const FSE_symbolCompressionTransform*)(statePtr->symbolTT))[symbol]; - const U16* const stateTable = (const U16*)(statePtr->stateTable); - U32 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); -} - -/*<===== 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; -} - - +/* ****************************************************************** + FSE : Finite State Entropy coder + header file for static linking (only) + Copyright (C) 2013-2015, 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 + - Public forum : https://groups.google.com/forum/#!forum/lz4c +****************************************************************** */ +#ifndef FSE_STATIC_H +#define FSE_STATIC_H + +#if defined (__cplusplus) +extern "C" { +#endif + + +/* ***************************************** +* Dependencies +*******************************************/ +#include "fse.h" +#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 unsigned 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)) + + +/* ***************************************** +* FSE advanced API +*******************************************/ +size_t FSE_countFast(unsigned* count, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize); +/* same as FSE_count(), but blindly trusts that all byte values within src are <= *maxSymbolValuePtr */ + +size_t FSE_buildCTable_raw (FSE_CTable* ct, unsigned nbBits); +/* build a fake FSE_CTable, designed to not compress an input, 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 */ + +size_t FSE_buildDTable_raw (FSE_DTable* dt, unsigned nbBits); +/* build a fake FSE_DTable, designed to read an uncompressed bitstream 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 */ + + +/* ***************************************** +* FSE symbol compression API +*******************************************/ +/*! + This API consists of small unitary functions, which highly benefit from being inlined. + You will want to enable link-time-optimization to ensure these functions are properly inlined in your binary. + Visual seems to do it automatically. + For gcc or clang, you'll need to add -flto flag at compilation and linking stages. + If none of these solutions is applicable, include "fse.c" directly. +*/ +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 = ((const U32*)ct + 1 + (tableLog ? (1<<(tableLog-1)) : 1)); + statePtr->stateLog = tableLog; +} + +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, U32 symbol) +{ + const FSE_symbolCompressionTransform symbolTT = ((const FSE_symbolCompressionTransform*)(statePtr->symbolTT))[symbol]; + const U16* const stateTable = (const U16*)(statePtr->stateTable); + U32 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); +} + +/*<===== 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 @@ -383,8 +383,8 @@ MEM_STATIC unsigned FSE_endOfDState(const FSE_DState_t* DStatePtr) #define FSE_TABLESTEP(tableSize) ((tableSize>>1) + (tableSize>>3) + 3) -#if defined (__cplusplus) -} -#endif - -#endif /* FSE_STATIC_H */ +#if defined (__cplusplus) +} +#endif + +#endif /* FSE_STATIC_H */ |