path: root/lz4.c

/*

   LZ4 - Fast LZ compression algorithm

   Copyright (C) 2011-2013, 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://fastcompression.blogspot.com/p/lz4.html

   - LZ4 source repository : http://code.google.com/p/lz4/

*/

/*

Note : this source file requires "lz4_encoder.h" and "lz4_decoder.h"

*/

//**************************************

// 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

// Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache

#define MEMORY_USAGE 14


// HEAPMODE :

// Select if compression algorithm will allocate space for its tables

// in memory stack (0:default, fastest), or in memory heap (1:requires memory allocation (malloc)).

// Default allocation strategy is to use stack (HEAPMODE 0)

#define HEAPMODE 0


// BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE :

// This will provide a small boost to performance for big endian cpu, but the resulting compressed stream will be incompatible with little-endian CPU.

// You can set this option to 1 in situations where data will remain within closed environment

// This option is useless on Little_Endian CPU (such as x86)

//#define BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE 1




//**************************************

// CPU Feature Detection

//**************************************

// 32 or 64 bits ?

#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) )   // Detects 64 bits mode

#  define LZ4_ARCH64 1

#else

#  define LZ4_ARCH64 0

#endif


// Little Endian or Big Endian ?

// Overwrite the #define below if you know your architecture endianess

#if defined (__GLIBC__)

#  include <endian.h>

#  if (__BYTE_ORDER == __BIG_ENDIAN)

#     define LZ4_BIG_ENDIAN 1

#  endif

#elif (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN)) && !(defined(__LITTLE_ENDIAN__) || defined(__LITTLE_ENDIAN) || defined(_LITTLE_ENDIAN))

#  define LZ4_BIG_ENDIAN 1

#elif defined(__sparc) || defined(__sparc__) \

   || defined(__ppc__) || defined(_POWER) || defined(__powerpc__) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) \
   || defined(__hpux)  || defined(__hppa) \
   || defined(_MIPSEB) || defined(__s390__)
#  define LZ4_BIG_ENDIAN 1

#else

// Little Endian assumed. PDP Endian and other very rare endian format are unsupported.

#endif


// Unaligned memory access is automatically enabled for "common" CPU, such as x86.

// For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected

// If you know your target CPU supports unaligned memory access, you want to force this option manually to improve performance

#if defined(__ARM_FEATURE_UNALIGNED)

#  define LZ4_FORCE_UNALIGNED_ACCESS 1

#endif


// Define this parameter if your target system or compiler does not support hardware bit count

#if defined(_MSC_VER) && defined(_WIN32_WCE)            // Visual Studio for Windows CE does not support Hardware bit count

#  define LZ4_FORCE_SW_BITCOUNT

#endif



//**************************************

// Compiler Options

//**************************************

#if __STDC_VERSION__ >= 199901L   // C99

/* "restrict" is a known keyword */
#else

#  define restrict // Disable restrict

#endif


#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)


#ifdef _MSC_VER  // Visual Studio

#  include <intrin.h>   // For Visual 2005

#  if LZ4_ARCH64	// 64-bit

#    pragma intrinsic(_BitScanForward64) // For Visual 2005

#    pragma intrinsic(_BitScanReverse64) // For Visual 2005

#  else

#    pragma intrinsic(_BitScanForward)   // For Visual 2005

#    pragma intrinsic(_BitScanReverse)   // For Visual 2005

#  endif

#  pragma warning(disable : 4127)        // disable: C4127: conditional expression is constant

#endif


#ifdef _MSC_VER

#  define lz4_bswap16(x) _byteswap_ushort(x)

#else

#  define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))

#endif


#if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)

#  define expect(expr,value)    (__builtin_expect ((expr),(value)) )

#else

#  define expect(expr,value)    (expr)

#endif


#define likely(expr)     expect((expr) != 0, 1)

#define unlikely(expr)   expect((expr) != 0, 0)



//**************************************

// Includes

//**************************************

#include <stdlib.h>   // for malloc

#include <string.h>   // for memset

#include "lz4.h"



//**************************************

// Basic Types

//**************************************

#if defined(_MSC_VER)    // Visual Studio does not support 'stdint' natively

#  define BYTE	unsigned __int8

#  define U16	unsigned __int16

#  define U32	unsigned __int32

#  define S32	__int32

#  define U64	unsigned __int64

#else

#  include <stdint.h>

#  define BYTE	uint8_t

#  define U16	uint16_t

#  define U32	uint32_t

#  define S32	int32_t

#  define U64	uint64_t

#endif


#ifndef LZ4_FORCE_UNALIGNED_ACCESS

#  pragma pack(push, 1)

#endif


typedef struct _U16_S { U16 v; } U16_S;
typedef struct _U32_S { U32 v; } U32_S;
typedef struct _U64_S { U64 v; } U64_S;

#ifndef LZ4_FORCE_UNALIGNED_ACCESS

#  pragma pack(pop)

#endif


#define A64(x) (((U64_S *)(x))->v)

#define A32(x) (((U32_S *)(x))->v)

#define A16(x) (((U16_S *)(x))->v)



//**************************************

// Constants

//**************************************

#define HASHTABLESIZE (1 << MEMORY_USAGE)


#define MINMATCH 4


#define COPYLENGTH 8

#define LASTLITERALS 5

#define MFLIMIT (COPYLENGTH+MINMATCH)

#define MINLENGTH (MFLIMIT+1)


#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT-1))

#define SKIPSTRENGTH 6     // Increasing this value will make the compression run slower on incompressible data


#define MAXD_LOG 16

#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)


#define ML_BITS  4

#define ML_MASK  ((1U<<ML_BITS)-1)

#define RUN_BITS (8-ML_BITS)

#define RUN_MASK ((1U<<RUN_BITS)-1)



//**************************************

// Architecture-specific macros

//**************************************

#if LZ4_ARCH64	// 64-bit

#  define STEPSIZE 8

#  define UARCH U64

#  define AARCH A64

#  define LZ4_COPYSTEP(s,d)       A64(d) = A64(s); d+=8; s+=8;

#  define LZ4_COPYPACKET(s,d)     LZ4_COPYSTEP(s,d)

#  define LZ4_SECURECOPY(s,d,e)   if (d<e) LZ4_WILDCOPY(s,d,e)

#  define HTYPE                   U32

#  define INITBASE(base)          const BYTE* const base = ip

#else		// 32-bit

#  define STEPSIZE 4

#  define UARCH U32

#  define AARCH A32

#  define LZ4_COPYSTEP(s,d)       A32(d) = A32(s); d+=4; s+=4;

#  define LZ4_COPYPACKET(s,d)     LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d);

#  define LZ4_SECURECOPY          LZ4_WILDCOPY

#  define HTYPE                   const BYTE*

#  define INITBASE(base)          const int base = 0

#endif


#if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))

#  define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }

#  define LZ4_WRITE_LITTLEENDIAN_16(p,i)  { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; }

#else		// Little Endian

#  define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }

#  define LZ4_WRITE_LITTLEENDIAN_16(p,v)  { A16(p) = v; p+=2; }

#endif



//**************************************

// Macros

//**************************************

#define LZ4_WILDCOPY(s,d,e)		do { LZ4_COPYPACKET(s,d) } while (d<e);

#define LZ4_BLINDCOPY(s,d,l)	{ BYTE* e=(d)+l; LZ4_WILDCOPY(s,d,e); d=e; }



//****************************

// Private functions

//****************************

#if LZ4_ARCH64


static inline int LZ4_NbCommonBytes (register U64 val)
{
#if defined(LZ4_BIG_ENDIAN)

    #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)

    unsigned long r = 0;
    _BitScanReverse64( &r, val );
    return (int)(r>>3);
    #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)

    return (__builtin_clzll(val) >> 3);
    #else

    int r;
    if (!(val>>32)) { r=4; } else { r=0; val>>=32; }
    if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
    r += (!val);
    return r;
    #endif

#else

    #if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)

    unsigned long r = 0;
    _BitScanForward64( &r, val );
    return (int)(r>>3);
    #elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)

    return (__builtin_ctzll(val) >> 3);
    #else

    static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
    return DeBruijnBytePos[((U64)((val & -val) * 0x0218A392CDABBD3F)) >> 58];
    #endif

#endif

}

#else


static inline int LZ4_NbCommonBytes (register U32 val)
{
#if defined(LZ4_BIG_ENDIAN)

#  if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)

    unsigned long r = 0;
    _BitScanReverse( &r, val );
    return (int)(r>>3);
#  elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)

    return (__builtin_clz(val) >> 3);
#  else

    int r;
    if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
    r += (!val);
    return r;
#  endif

#else

#  if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)

    unsigned long r;
    _BitScanForward( &r, val );
    return (int)(r>>3);
#  elif defined(__GNUC__) && (GCC_VERSION >= 304) && !defined(LZ4_FORCE_SW_BITCOUNT)

    return (__builtin_ctz(val) >> 3);
#  else

    static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
    return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
#  endif

#endif

}

#endif




//******************************

// Compression functions

//******************************


/*

int LZ4_compress_stack(

                 const char* source,

                 char* dest,

                 int inputSize)



Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.

Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).

return : the number of bytes written in buffer 'dest'

*/
#define FUNCTION_NAME LZ4_compress_stack

#include "lz4_encoder.h"



/*

int LZ4_compress_stack_limitedOutput(

                 const char* source,

                 char* dest,

                 int inputSize,

                 int maxOutputSize)



Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.

If it cannot achieve it, compression will stop, and result of the function will be zero.

return : the number of bytes written in buffer 'dest', or 0 if the compression fails

*/
#define FUNCTION_NAME LZ4_compress_stack_limitedOutput

#define LIMITED_OUTPUT

#include "lz4_encoder.h"



/*

int LZ4_compress64k_stack(

                 const char* source,

                 char* dest,

                 int inputSize)



Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.

This function compresses better than LZ4_compress_stack(), on the condition that

'inputSize' must be < to LZ4_64KLIMIT, or the function will fail.

Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).

return : the number of bytes written in buffer 'dest', or 0 if compression fails

*/
#define FUNCTION_NAME LZ4_compress64k_stack

#define COMPRESS_64K

#include "lz4_encoder.h"



/*

int LZ4_compress64k_stack_limitedOutput(

                 const char* source,

                 char* dest,

                 int inputSize,

                 int maxOutputSize)



Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.

This function compresses better than LZ4_compress_stack_limitedOutput(), on the condition that

'inputSize' must be < to LZ4_64KLIMIT, or the function will fail.

If it cannot achieve it, compression will stop, and result of the function will be zero.

return : the number of bytes written in buffer 'dest', or 0 if the compression fails

*/
#define FUNCTION_NAME LZ4_compress64k_stack_limitedOutput

#define COMPRESS_64K

#define LIMITED_OUTPUT

#include "lz4_encoder.h"



/*

void* LZ4_createHeapMemory();

int LZ4_freeHeapMemory(void* ctx);



Used to allocate and free hashTable memory 

to be used by the LZ4_compress_heap* family of functions.

LZ4_createHeapMemory() returns NULL is memory allocation fails.

*/
void* LZ4_create() { return malloc(HASHTABLESIZE); }
int LZ4_free(void* ctx) { free(ctx); return 0; }


/*

int LZ4_compress_heap(

                 void* ctx,

                 const char* source,

                 char* dest,

                 int inputSize)



Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.

The memory used for compression must be created by LZ4_createHeapMemory() and provided by pointer 'ctx'.

Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).

return : the number of bytes written in buffer 'dest'

*/
#define FUNCTION_NAME LZ4_compress_heap

#define USE_HEAPMEMORY

#include "lz4_encoder.h"



/*

int LZ4_compress_heap_limitedOutput(

                 void* ctx,

                 const char* source,

                 char* dest,

                 int inputSize,

                 int maxOutputSize)



Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.

If it cannot achieve it, compression will stop, and result of the function will be zero.

The memory used for compression must be created by LZ4_createHeapMemory() and provided by pointer 'ctx'.

return : the number of bytes written in buffer 'dest', or 0 if the compression fails

*/
#define FUNCTION_NAME LZ4_compress_heap_limitedOutput

#define LIMITED_OUTPUT

#define USE_HEAPMEMORY

#include "lz4_encoder.h"



/*

int LZ4_compress64k_heap(

                 void* ctx,

                 const char* source,

                 char* dest,

                 int inputSize)



Compress 'inputSize' bytes from 'source' into an output buffer 'dest'.

The memory used for compression must be created by LZ4_createHeapMemory() and provided by pointer 'ctx'.

'inputSize' must be < to LZ4_64KLIMIT, or the function will fail.

Destination buffer must be already allocated, and sized at a minimum of LZ4_compressBound(inputSize).

return : the number of bytes written in buffer 'dest'

*/
#define FUNCTION_NAME LZ4_compress64k_heap

#define COMPRESS_64K

#define USE_HEAPMEMORY

#include "lz4_encoder.h"



/*

int LZ4_compress64k_heap_limitedOutput(

                 void* ctx,

                 const char* source,

                 char* dest,

                 int inputSize,

                 int maxOutputSize)



Compress 'inputSize' bytes from 'source' into an output buffer 'dest' of maximum size 'maxOutputSize'.

If it cannot achieve it, compression will stop, and result of the function will be zero.

The memory used for compression must be created by LZ4_createHeapMemory() and provided by pointer 'ctx'.

'inputSize' must be < to LZ4_64KLIMIT, or the function will fail.

return : the number of bytes written in buffer 'dest', or 0 if the compression fails

*/
#define FUNCTION_NAME LZ4_compress64k_heap_limitedOutput

#define COMPRESS_64K

#define LIMITED_OUTPUT

#define USE_HEAPMEMORY

#include "lz4_encoder.h"



int LZ4_compress(const char* source, char* dest, int inputSize)
{
#if HEAPMODE

    void* ctx = LZ4_create();
    int result;
    if (ctx == NULL) return 0;    // Failed allocation => compression not done

    if (inputSize < LZ4_64KLIMIT)
        result = LZ4_compress64k_heap(ctx, source, dest, inputSize);
    else result = LZ4_compress_heap(ctx, source, dest, inputSize);
    LZ4_free(ctx);
    return result;
#else

    if (inputSize < (int)LZ4_64KLIMIT) return LZ4_compress64k_stack(source, dest, inputSize);
    return LZ4_compress_stack(source, dest, inputSize);
#endif

}


int LZ4_compress_limitedOutput(const char* source, char* dest, int inputSize, int maxOutputSize)
{
#if HEAPMODE

    void* ctx = LZ4_create();
    int result;
    if (ctx == NULL) return 0;    // Failed allocation => compression not done

    if (inputSize < LZ4_64KLIMIT)
        result = LZ4_compress64k_heap_limitedOutput(ctx, source, dest, inputSize, maxOutputSize);
    else result = LZ4_compress_heap_limitedOutput(ctx, source, dest, inputSize, maxOutputSize);
    LZ4_free(ctx);
    return result;
#else

    if (inputSize < (int)LZ4_64KLIMIT) return LZ4_compress64k_stack_limitedOutput(source, dest, inputSize, maxOutputSize);
    return LZ4_compress_stack_limitedOutput(source, dest, inputSize, maxOutputSize);
#endif

}


//****************************

// Decompression functions

//****************************


/*

int LZ4_decompress_safe(const char* source,

                        char* dest,

                        int inputSize,

                        int maxOutputSize);



LZ4_decompress_safe() guarantees it will never write nor read outside of the provided output buffers.

This function is safe against "buffer overflow" attacks.

A corrupted input will produce an error result, a negative int.

*/
#define FUNCTION_NAME LZ4_decompress_safe

#define EXITCONDITION_INPUTSIZE

#include "lz4_decoder.h"



/*

int LZ4_decompress_safe_withPrefix64k(

                        const char* source,

                        char* dest,

                        int inputSize,

                        int maxOutputSize);



Same as LZ4_decompress_safe(), but will also use 64K of memory before the beginning of input buffer.

Typically used to decode streams of inter-dependant blocks.

Note : the 64K of memory before pointer 'source' must be allocated and read-allowed.

*/
#define FUNCTION_NAME LZ4_decompress_safe_withPrefix64k

#define EXITCONDITION_INPUTSIZE

#define PREFIX_64K

#include "lz4_decoder.h"



/*

int LZ4_decompress_safe_partial(

                        const char* source,

                        char* dest,

                        int inputSize,

                        int targetOutputSize,

                        int maxOutputSize);



LZ4_decompress_safe_partial() objective is to decompress only a part of the compressed input block provided.

The decoding process stops as soon as 'targetOutputSize' bytes have been decoded, reducing decoding time.

The result of the function is the number of bytes decoded.

LZ4_decompress_safe_partial() may decode less than 'targetOutputSize' if input doesn't contain enough bytes to decode.

Always verify how many bytes were decoded to ensure there are as many as wanted into the output buffer 'dest'.

A corrupted input will produce an error result, a negative int.

*/
#define FUNCTION_NAME LZ4_decompress_safe_partial

#define EXITCONDITION_INPUTSIZE

#define PARTIAL_DECODING

#include "lz4_decoder.h"



/*

int LZ4_decompress_fast(const char* source,

                        char* dest,

                        int outputSize);



This function is faster than LZ4_decompress_safe().

LZ4_decompress_fast() guarantees it will never write nor read outside of output buffer.

Since LZ4_decompress_fast() doesn't know the size of input buffer.

it can only guarantee that it will never write into the input buffer, and will never read before its beginning.

To be used preferably in a controlled environment (when the compressed data to be decoded is from a trusted source).

A detected corrupted input will produce an error result, a negative int.

*/
#define FUNCTION_NAME LZ4_decompress_fast

#include "lz4_decoder.h"



/*

int LZ4_decompress_fast_withPrefix64k(

                        const char* source,

                        char* dest,

                        int inputSize

                        int maxOutputSize);



Same as LZ4_decompress_fast(), but will use the 64K of memory before the beginning of input buffer.

Typically used to decode streams of dependant inter-blocks.

Note : the 64K of memory before pointer 'source' must be allocated and read-allowed.

*/
#define FUNCTION_NAME LZ4_decompress_fast_withPrefix64k

#define PREFIX_64K

#include "lz4_decoder.h"