/*-**************************************************************
* FSE Compression Code
****************************************************************/
-/*!
-FSE_CTable is a variable size structure which contains :
- U16 tableLog;
- U16 maxSymbolValue;
- U16 nextStateNumber[1 << tableLog]; // This size is variable
- FSE_symbolCompressionTransform symbolTT[maxSymbolValue+1]; // This size is variable
+/*! FSE_sizeof_CTable() :
+ FSE_CTable is a variable size structure which contains :
+ `U16 tableLog;`
+ `U16 maxSymbolValue;`
+ `U16 nextStateNumber[1 << tableLog];` // This size is variable
+ `FSE_symbolCompressionTransform symbolTT[maxSymbolValue+1];` // This size is variable
Allocation is manual, since C standard does not support variable-size structures.
*/
return (FSE_CTable*)malloc(size);
}
-void FSE_freeCTable (FSE_CTable* ct)
-{
- free(ct);
-}
+void FSE_freeCTable (FSE_CTable* ct) { free(ct); }
/* provides the minimum logSize to safely represent a distribution */
static unsigned FSE_minTableLog(size_t srcSize, unsigned maxSymbolValue)
const FSE_CTable* ct, const unsigned fast)
{
const BYTE* const istart = (const BYTE*) src;
- const BYTE* ip;
const BYTE* const iend = istart + srcSize;
+ const BYTE* ip=iend;
size_t errorCode;
BIT_CStream_t bitC;
FSE_CState_t CState1, CState2;
-
/* init */
+ if (srcSize <= 2) return 0;
errorCode = BIT_initCStream(&bitC, dst, dstSize);
if (FSE_isError(errorCode)) return 0;
- FSE_initCState(&CState1, ct);
- CState2 = CState1;
-
- ip=iend;
#define FSE_FLUSHBITS(s) (fast ? BIT_flushBitsFast(s) : BIT_flushBits(s))
- /* join to even */
if (srcSize & 1) {
+ FSE_initCState2(&CState1, ct, *--ip);
+ FSE_initCState2(&CState2, ct, *--ip);
FSE_encodeSymbol(&bitC, &CState1, *--ip);
FSE_FLUSHBITS(&bitC);
+ } else {
+ FSE_initCState2(&CState2, ct, *--ip);
+ FSE_initCState2(&CState1, ct, *--ip);
}
/* join to mod 4 */
+ srcSize -= 2;
if ((sizeof(bitC.bitContainer)*8 > FSE_MAX_TABLELOG*4+7 ) && (srcSize & 2)) { /* test bit 2 */
FSE_encodeSymbol(&bitC, &CState2, *--ip);
FSE_encodeSymbol(&bitC, &CState1, *--ip);
/* tail */
/* note : BIT_reloadDStream(&bitD) >= FSE_DStream_partiallyFilled; Ends at exactly BIT_DStream_completed */
while (1) {
- if ( (BIT_reloadDStream(&bitD)>BIT_DStream_completed) || (op==omax) || (BIT_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state1))) )
- break;
+ if (op>(omax-2)) return ERROR(dstSize_tooSmall);
*op++ = FSE_GETSYMBOL(&state1);
- if ( (BIT_reloadDStream(&bitD)>BIT_DStream_completed) || (op==omax) || (BIT_endOfDStream(&bitD) && (fast || FSE_endOfDState(&state2))) )
+ if (BIT_reloadDStream(&bitD)==BIT_DStream_overflow) {
+ *op++ = FSE_GETSYMBOL(&state2);
break;
+ }
- *op++ = FSE_GETSYMBOL(&state2);
- }
+ if (op>(omax-2)) return ERROR(dstSize_tooSmall);
- /* end ? */
- if (BIT_endOfDStream(&bitD) && FSE_endOfDState(&state1) && FSE_endOfDState(&state2))
- return op-ostart;
+ *op++ = FSE_GETSYMBOL(&state2);
- if (op==omax) return ERROR(dstSize_tooSmall); /* dst buffer is full, but cSrc unfinished */
+ if (BIT_reloadDStream(&bitD)==BIT_DStream_overflow) {
+ *op++ = FSE_GETSYMBOL(&state1);
+ break;
+ } }
- return ERROR(corruption_detected);
+ return op-ostart;
}
/* ******************************************************************
- FSE : Finite State Entropy coder
- header file
- Copyright (C) 2013-2015, Yann Collet.
+ 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)
You can contact the author at :
- Source repository : https://github.com/Cyan4973/FiniteStateEntropy
- - Public forum : https://groups.google.com/forum/#!forum/lz4c
****************************************************************** */
#ifndef FSE_H
#define FSE_H
#endif
-/* *****************************************
-* Includes
+/*-*****************************************
+* Dependencies
******************************************/
#include <stddef.h> /* size_t, ptrdiff_t */
/*-****************************************
* FSE simple functions
******************************************/
-size_t FSE_compress(void* dst, size_t maxDstSize,
- const void* src, size_t srcSize);
-size_t FSE_decompress(void* dst, size_t maxDstSize,
- const void* cSrc, size_t cSrcSize);
-/*!
-FSE_compress():
+/*! FSE_compress() :
Compress content of buffer 'src', of size 'srcSize', into destination buffer 'dst'.
- 'dst' buffer must be already allocated. Compression runs faster is maxDstSize >= FSE_compressBound(srcSize)
- return : size of compressed data (<= maxDstSize)
+ '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())
+*/
+size_t FSE_compress(void* dst, size_t dstCapacity,
+ const void* src, size_t srcSize);
-FSE_decompress():
+/*! FSE_decompress():
Decompress FSE data from buffer 'cSrc', of size 'cSrcSize',
- into already allocated destination buffer 'dst', of size 'maxDstSize'.
- return : size of regenerated data (<= maxDstSize)
- or an error code, which can be tested using FSE_isError()
+ 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() doesn't decompress non-compressible nor RLE data !!!
+ ** 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.
*/
+size_t FSE_decompress(void* dst, size_t dstCapacity,
+ const void* cSrc, size_t cSrcSize);
-/* *****************************************
+/*-*****************************************
* Tool functions
******************************************/
size_t FSE_compressBound(size_t size); /* maximum compressed size */
const char* FSE_getErrorName(size_t code); /* provides error code string (useful for debugging) */
-/* *****************************************
+/*-*****************************************
* FSE advanced functions
******************************************/
-/*!
-FSE_compress2():
+/*! 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
+ @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.
size_t FSE_compress2 (void* dst, size_t dstSize, const void* src, size_t srcSize, unsigned maxSymbolValue, unsigned tableLog);
-/* *****************************************
+/*-*****************************************
* FSE detailed API
******************************************/
/*!
/* *** COMPRESSION *** */
-/*!
-FSE_count():
- Provides the precise count of each byte within a table 'count'
- 'count' is a table of unsigned int, of minimum size (*maxSymbolValuePtr+1).
- *maxSymbolValuePtr will be updated if detected smaller than initial value.
- @return : the count of the most frequent symbol (which is not identified)
- if return == srcSize, there is only one symbol.
- Can also return an error code, which can be tested with FSE_isError() */
+/*! FSE_count():
+ Provides the precise count of each byte within a table 'count'.
+ 'count' is a table of unsigned int, of minimum size (*maxSymbolValuePtr+1).
+ *maxSymbolValuePtr will be updated if detected smaller than initial value.
+ @return : the count of the most frequent symbol (which is not identified).
+ if return == srcSize, there is only one symbol.
+ Can also return an error code, which can be tested with FSE_isError(). */
size_t FSE_count(unsigned* count, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize);
-/*!
-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 <= initial 'tableLog') */
+/*! 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 <= initial 'tableLog') */
unsigned FSE_optimalTableLog(unsigned tableLog, size_t srcSize, unsigned maxSymbolValue);
-/*!
-FSE_normalizeCount():
- normalize counters 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_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() */
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_NCountWriteBound():
+ Provides the maximum possible size of an FSE normalized table, given 'maxSymbolValue' and 'tableLog'.
+ Typically useful for allocation purpose. */
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_writeNCount():
+ Compactly save 'normalizedCounter' into 'buffer'.
+ @return : size of the compressed table,
+ or an errorCode, which can be tested using FSE_isError(). */
size_t FSE_writeNCount (void* buffer, size_t bufferSize, const short* normalizedCounter, unsigned maxSymbolValue, unsigned tableLog);
-/*!
-Constructor and Destructor of type FSE_CTable
- Note that its size depends on 'tableLog' and 'maxSymbolValue' */
+/*! 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_CTable* FSE_createCTable (unsigned tableLog, unsigned maxSymbolValue);
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_buildCTable():
+ Builds `ct`, which must be already allocated, using FSE_createCTable().
+ @return : 0, or an errorCode, which can be tested using FSE_isError() */
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_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() */
size_t FSE_compress_usingCTable (void* dst, size_t dstCapacity, const void* src, size_t srcSize, const FSE_CTable* ct);
/*!
'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.
+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_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 */
size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSymbolValuePtr, unsigned* tableLogPtr, const void* rBuffer, size_t rBuffSize);
-/*!
-Constructor and Destructor of type FSE_DTable
+/*! 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_DTable* FSE_createDTable(unsigned tableLog);
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_buildDTable():
+ Builds 'dt', which must be already allocated, using FSE_createDTable().
+ return : 0, or an errorCode, which can be tested using FSE_isError() */
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_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() */
size_t FSE_decompress_usingDTable(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize, const FSE_DTable* dt);
/*!
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 (<=maxDstSize).
+`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)
*/
projects / thirdparty / zstd.git / commitdiff
