UXP/mfbt/lz4.h

/*
 *  LZ4 - Fast LZ compression algorithm
 *  Header File
 *  Copyright (C) 2011-2017, Yann Collet.

   BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are
   met:

       * Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
       * Redistributions in binary form must reproduce the above
   copyright notice, this list of conditions and the following disclaimer
   in the documentation and/or other materials provided with the
   distribution.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   You can contact the author at :
    - LZ4 homepage : http://www.lz4.org
    - LZ4 source repository : https://github.com/lz4/lz4
*/
#if defined (__cplusplus)
extern "C" {
#endif

#ifndef LZ4_H_2983827168210
#define LZ4_H_2983827168210

/* --- Dependency --- */
#include <stddef.h>   /* size_t */


/**
  Introduction

  LZ4 is lossless compression algorithm, providing compression speed at 400 MB/s per core,
  scalable with multi-cores CPU. It features an extremely fast decoder, with speed in
  multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.

  The LZ4 compression library provides in-memory compression and decompression functions.
  Compression can be done in:
    - a single step (described as Simple Functions)
    - a single step, reusing a context (described in Advanced Functions)
    - unbounded multiple steps (described as Streaming compression)

  lz4.h provides block compression functions. It gives full buffer control to user.
  Decompressing an lz4-compressed block also requires metadata (such as compressed size).
  Each application is free to encode such metadata in whichever way it wants.

  An additional format, called LZ4 frame specification (doc/lz4_Frame_format.md),
  take care of encoding standard metadata alongside LZ4-compressed blocks.
  If your application requires interoperability, it's recommended to use it.
  A library is provided to take care of it, see lz4frame.h.
*/

/*^***************************************************************
*  Export parameters
*****************************************************************/
/*
*  LZ4_DLL_EXPORT :
*  Enable exporting of functions when building a Windows DLL
*  LZ4LIB_API :
*  Control library symbols visibility.
*/
#if defined(LZ4_DLL_EXPORT) && (LZ4_DLL_EXPORT==1)
#  define LZ4LIB_API __declspec(dllexport)
#elif defined(LZ4_DLL_IMPORT) && (LZ4_DLL_IMPORT==1)
#  define LZ4LIB_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.*/
#elif defined(__GNUC__) && (__GNUC__ >= 4)
#  define LZ4LIB_API __attribute__ ((__visibility__ ("default")))
#else
#  define LZ4LIB_API
#endif


/*------   Version   ------*/
#define LZ4_VERSION_MAJOR    1    /* for breaking interface changes  */
#define LZ4_VERSION_MINOR    8    /* for new (non-breaking) interface capabilities */
#define LZ4_VERSION_RELEASE  0    /* for tweaks, bug-fixes, or development */

#define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE)

#define LZ4_LIB_VERSION LZ4_VERSION_MAJOR.LZ4_VERSION_MINOR.LZ4_VERSION_RELEASE
#define LZ4_QUOTE(str) #str
#define LZ4_EXPAND_AND_QUOTE(str) LZ4_QUOTE(str)
#define LZ4_VERSION_STRING LZ4_EXPAND_AND_QUOTE(LZ4_LIB_VERSION)

LZ4LIB_API int LZ4_versionNumber (void);  /**< library version number; to be used when checking dll version */
LZ4LIB_API const char* LZ4_versionString (void);   /**< library version string; to be used when checking dll version */


/*-************************************
*  Tuning parameter
**************************************/
/*!
 * LZ4_MEMORY_USAGE :
 * Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
 * Increasing memory usage improves compression ratio
 * Reduced memory usage can improve speed, due to cache effect
 * Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
 */
#ifndef LZ4_MEMORY_USAGE
# define LZ4_MEMORY_USAGE 14
#endif

/*-************************************
*  Simple Functions
**************************************/
/*! LZ4_compress_default() :
    Compresses 'sourceSize' bytes from buffer 'source'
    into already allocated 'dest' buffer of size 'maxDestSize'.
    Compression is guaranteed to succeed if 'maxDestSize' >= LZ4_compressBound(sourceSize).
    It also runs faster, so it's a recommended setting.
    If the function cannot compress 'source' into a more limited 'dest' budget,
    compression stops *immediately*, and the function result is zero.
    As a consequence, 'dest' content is not valid.
    This function never writes outside 'dest' buffer, nor read outside 'source' buffer.
        sourceSize  : Max supported value is LZ4_MAX_INPUT_VALUE
        maxDestSize : full or partial size of buffer 'dest' (which must be already allocated)
        return : the number of bytes written into buffer 'dest' (necessarily <= maxOutputSize)
              or 0 if compression fails */
LZ4LIB_API int LZ4_compress_default(const char* source, char* dest, int sourceSize, int maxDestSize);

/*! LZ4_decompress_safe() :
    compressedSize : is the precise full size of the compressed block.
    maxDecompressedSize : is the size of destination buffer, which must be already allocated.
    return : the number of bytes decompressed into destination buffer (necessarily <= maxDecompressedSize)
             If destination buffer is not large enough, decoding will stop and output an error code (<0).
             If the source stream is detected malformed, the function will stop decoding and return a negative result.
             This function is protected against buffer overflow exploits, including malicious data packets.
             It never writes outside output buffer, nor reads outside input buffer.
*/
LZ4LIB_API int LZ4_decompress_safe (const char* source, char* dest, int compressedSize, int maxDecompressedSize);


/*-************************************
*  Advanced Functions
**************************************/
#define LZ4_MAX_INPUT_SIZE        0x7E000000   /* 2 113 929 216 bytes */
#define LZ4_COMPRESSBOUND(isize)  ((unsigned)(isize) > (unsigned)LZ4_MAX_INPUT_SIZE ? 0 : (isize) + ((isize)/255) + 16)

/*!
LZ4_compressBound() :
    Provides the maximum size that LZ4 compression may output in a "worst case" scenario (input data not compressible)
    This function is primarily useful for memory allocation purposes (destination buffer size).
    Macro LZ4_COMPRESSBOUND() is also provided for compilation-time evaluation (stack memory allocation for example).
    Note that LZ4_compress_default() compress faster when dest buffer size is >= LZ4_compressBound(srcSize)
        inputSize  : max supported value is LZ4_MAX_INPUT_SIZE
        return : maximum output size in a "worst case" scenario
              or 0, if input size is too large ( > LZ4_MAX_INPUT_SIZE)
*/
LZ4LIB_API int LZ4_compressBound(int inputSize);

/*!
LZ4_compress_fast() :
    Same as LZ4_compress_default(), but allows to select an "acceleration" factor.
    The larger the acceleration value, the faster the algorithm, but also the lesser the compression.
    It's a trade-off. It can be fine tuned, with each successive value providing roughly +~3% to speed.
    An acceleration value of "1" is the same as regular LZ4_compress_default()
    Values <= 0 will be replaced by ACCELERATION_DEFAULT (see lz4.c), which is 1.
*/
LZ4LIB_API int LZ4_compress_fast (const char* source, char* dest, int sourceSize, int maxDestSize, int acceleration);


/*!
LZ4_compress_fast_extState() :
    Same compression function, just using an externally allocated memory space to store compression state.
    Use LZ4_sizeofState() to know how much memory must be allocated,
    and allocate it on 8-bytes boundaries (using malloc() typically).
    Then, provide it as 'void* state' to compression function.
*/
LZ4LIB_API int LZ4_sizeofState(void);
LZ4LIB_API int LZ4_compress_fast_extState (void* state, const char* source, char* dest, int inputSize, int maxDestSize, int acceleration);


/*!
LZ4_compress_destSize() :
    Reverse the logic, by compressing as much data as possible from 'source' buffer
    into already allocated buffer 'dest' of size 'targetDestSize'.
    This function either compresses the entire 'source' content into 'dest' if it's large enough,
    or fill 'dest' buffer completely with as much data as possible from 'source'.
        *sourceSizePtr : will be modified to indicate how many bytes where read from 'source' to fill 'dest'.
                         New value is necessarily <= old value.
        return : Nb bytes written into 'dest' (necessarily <= targetDestSize)
              or 0 if compression fails
*/
LZ4LIB_API int LZ4_compress_destSize (const char* source, char* dest, int* sourceSizePtr, int targetDestSize);


/*!
LZ4_decompress_fast() :
    originalSize : is the original and therefore uncompressed size
    return : the number of bytes read from the source buffer (in other words, the compressed size)
             If the source stream is detected malformed, the function will stop decoding and return a negative result.
             Destination buffer must be already allocated. Its size must be a minimum of 'originalSize' bytes.
    note : This function fully respect memory boundaries for properly formed compressed data.
           It is a bit faster than LZ4_decompress_safe().
           However, it does not provide any protection against intentionally modified data stream (malicious input).
           Use this function in trusted environment only (data to decode comes from a trusted source).
*/
LZ4LIB_API int LZ4_decompress_fast (const char* source, char* dest, int originalSize);

/*!
LZ4_decompress_safe_partial() :
    This function decompress a compressed block of size 'compressedSize' at position 'source'
    into destination buffer 'dest' of size 'maxDecompressedSize'.
    The function tries to stop decompressing operation as soon as 'targetOutputSize' has been reached,
    reducing decompression time.
    return : the number of bytes decoded in the destination buffer (necessarily <= maxDecompressedSize)
       Note : this number can be < 'targetOutputSize' should the compressed block to decode be smaller.
             Always control how many bytes were decoded.
             If the source stream is detected malformed, the function will stop decoding and return a negative result.
             This function never writes outside of output buffer, and never reads outside of input buffer. It is therefore protected against malicious data packets
*/
LZ4LIB_API int LZ4_decompress_safe_partial (const char* source, char* dest, int compressedSize, int targetOutputSize, int maxDecompressedSize);


/*-*********************************************
*  Streaming Compression Functions
***********************************************/
typedef union LZ4_stream_u LZ4_stream_t;   /* incomplete type (defined later) */

/*! LZ4_createStream() and LZ4_freeStream() :
 *  LZ4_createStream() will allocate and initialize an `LZ4_stream_t` structure.
 *  LZ4_freeStream() releases its memory.
 */
LZ4LIB_API LZ4_stream_t* LZ4_createStream(void);
LZ4LIB_API int           LZ4_freeStream (LZ4_stream_t* streamPtr);

/*! LZ4_resetStream() :
 *  An LZ4_stream_t structure can be allocated once and re-used multiple times.
 *  Use this function to init an allocated `LZ4_stream_t` structure and start a new compression.
 */
LZ4LIB_API void LZ4_resetStream (LZ4_stream_t* streamPtr);

/*! LZ4_loadDict() :
 *  Use this function to load a static dictionary into LZ4_stream.
 *  Any previous data will be forgotten, only 'dictionary' will remain in memory.
 *  Loading a size of 0 is allowed.
 *  Return : dictionary size, in bytes (necessarily <= 64 KB)
 */
LZ4LIB_API int LZ4_loadDict (LZ4_stream_t* streamPtr, const char* dictionary, int dictSize);

/*! LZ4_compress_fast_continue() :
 *  Compress buffer content 'src', using data from previously compressed blocks as dictionary to improve compression ratio.
 *  Important : Previous data blocks are assumed to remain present and unmodified !
 *  'dst' buffer must be already allocated.
 *  If dstCapacity >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster.
 *  If not, and if compressed data cannot fit into 'dst' buffer size, compression stops, and function @return==0.
 *  After an error, the stream status is invalid, it can only be reset or freed.
 */
LZ4LIB_API int LZ4_compress_fast_continue (LZ4_stream_t* streamPtr, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);

/*! LZ4_saveDict() :
 *  If previously compressed data block is not guaranteed to remain available at its current memory location,
 *  save it into a safer place (char* safeBuffer).
 *  Note : it's not necessary to call LZ4_loadDict() after LZ4_saveDict(), dictionary is immediately usable.
 *  @return : saved dictionary size in bytes (necessarily <= dictSize), or 0 if error.
 */
LZ4LIB_API int LZ4_saveDict (LZ4_stream_t* streamPtr, char* safeBuffer, int dictSize);


/*-**********************************************
*  Streaming Decompression Functions
*  Bufferless synchronous API
************************************************/
typedef union LZ4_streamDecode_u LZ4_streamDecode_t;   /* incomplete type (defined later) */

/*! LZ4_createStreamDecode() and LZ4_freeStreamDecode() :
 *  creation / destruction of streaming decompression tracking structure */
LZ4LIB_API LZ4_streamDecode_t* LZ4_createStreamDecode(void);
LZ4LIB_API int                 LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream);

/*! LZ4_setStreamDecode() :
 *  Use this function to instruct where to find the dictionary.
 *  Setting a size of 0 is allowed (same effect as reset).
 *  @return : 1 if OK, 0 if error
 */
LZ4LIB_API int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize);

/*! LZ4_decompress_*_continue() :
 *  These decoding functions allow decompression of multiple blocks in "streaming" mode.
 *  Previously decoded blocks *must* remain available at the memory position where they were decoded (up to 64 KB)
 *  In the case of a ring buffers, decoding buffer must be either :
 *  - Exactly same size as encoding buffer, with same update rule (block boundaries at same positions)
 *    In which case, the decoding & encoding ring buffer can have any size, including very small ones ( < 64 KB).
 *  - Larger than encoding buffer, by a minimum of maxBlockSize more bytes.
 *    maxBlockSize is implementation dependent. It's the maximum size you intend to compress into a single block.
 *    In which case, encoding and decoding buffers do not need to be synchronized,
 *    and encoding ring buffer can have any size, including small ones ( < 64 KB).
 *  - _At least_ 64 KB + 8 bytes + maxBlockSize.
 *    In which case, encoding and decoding buffers do not need to be synchronized,
 *    and encoding ring buffer can have any size, including larger than decoding buffer.
 *  Whenever these conditions are not possible, save the last 64KB of decoded data into a safe buffer,
 *  and indicate where it is saved using LZ4_setStreamDecode()
*/
LZ4LIB_API int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxDecompressedSize);
LZ4LIB_API int LZ4_decompress_fast_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int originalSize);


/*! LZ4_decompress_*_usingDict() :
 *  These decoding functions work the same as
 *  a combination of LZ4_setStreamDecode() followed by LZ4_decompress_*_continue()
 *  They are stand-alone, and don't need an LZ4_streamDecode_t structure.
 */
LZ4LIB_API int LZ4_decompress_safe_usingDict (const char* source, char* dest, int compressedSize, int maxDecompressedSize, const char* dictStart, int dictSize);
LZ4LIB_API int LZ4_decompress_fast_usingDict (const char* source, char* dest, int originalSize, const char* dictStart, int dictSize);


/*^**********************************************
 * !!!!!!   STATIC LINKING ONLY   !!!!!!
 ***********************************************/
/*-************************************
 *  Private definitions
 **************************************
 * Do not use these definitions.
 * They are exposed to allow static allocation of `LZ4_stream_t` and `LZ4_streamDecode_t`.
 * Using these definitions will expose code to API and/or ABI break in future versions of the library.
 **************************************/
#define LZ4_HASHLOG   (LZ4_MEMORY_USAGE-2)
#define LZ4_HASHTABLESIZE (1 << LZ4_MEMORY_USAGE)
#define LZ4_HASH_SIZE_U32 (1 << LZ4_HASHLOG)       /* required as macro for static allocation */

#if defined(__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
#include <stdint.h>

typedef struct {
    uint32_t hashTable[LZ4_HASH_SIZE_U32];
    uint32_t currentOffset;
    uint32_t initCheck;
    const uint8_t* dictionary;
    uint8_t* bufferStart;   /* obsolete, used for slideInputBuffer */
    uint32_t dictSize;
} LZ4_stream_t_internal;

typedef struct {
    const uint8_t* externalDict;
    size_t extDictSize;
    const uint8_t* prefixEnd;
    size_t prefixSize;
} LZ4_streamDecode_t_internal;

#else

typedef struct {
    unsigned int hashTable[LZ4_HASH_SIZE_U32];
    unsigned int currentOffset;
    unsigned int initCheck;
    const unsigned char* dictionary;
    unsigned char* bufferStart;   /* obsolete, used for slideInputBuffer */
    unsigned int dictSize;
} LZ4_stream_t_internal;

typedef struct {
    const unsigned char* externalDict;
    size_t extDictSize;
    const unsigned char* prefixEnd;
    size_t prefixSize;
} LZ4_streamDecode_t_internal;

#endif

/*!
 * LZ4_stream_t :
 * information structure to track an LZ4 stream.
 * init this structure before first use.
 * note : only use in association with static linking !
 *        this definition is not API/ABI safe,
 *        it may change in a future version !
 */
#define LZ4_STREAMSIZE_U64 ((1 << (LZ4_MEMORY_USAGE-3)) + 4)
#define LZ4_STREAMSIZE     (LZ4_STREAMSIZE_U64 * sizeof(unsigned long long))
union LZ4_stream_u {
    unsigned long long table[LZ4_STREAMSIZE_U64];
    LZ4_stream_t_internal internal_donotuse;
} ;  /* previously typedef'd to LZ4_stream_t */


/*!
 * LZ4_streamDecode_t :
 * information structure to track an LZ4 stream during decompression.
 * init this structure  using LZ4_setStreamDecode (or memset()) before first use
 * note : only use in association with static linking !
 *        this definition is not API/ABI safe,
 *        and may change in a future version !
 */
#define LZ4_STREAMDECODESIZE_U64  4
#define LZ4_STREAMDECODESIZE     (LZ4_STREAMDECODESIZE_U64 * sizeof(unsigned long long))
union LZ4_streamDecode_u {
    unsigned long long table[LZ4_STREAMDECODESIZE_U64];
    LZ4_streamDecode_t_internal internal_donotuse;
} ;   /* previously typedef'd to LZ4_streamDecode_t */


/*-************************************
*  Obsolete Functions
**************************************/

/*! Deprecation warnings
   Should deprecation warnings be a problem,
   it is generally possible to disable them,
   typically with -Wno-deprecated-declarations for gcc
   or _CRT_SECURE_NO_WARNINGS in Visual.
   Otherwise, it's also possible to define LZ4_DISABLE_DEPRECATE_WARNINGS */
#ifdef LZ4_DISABLE_DEPRECATE_WARNINGS
#  define LZ4_DEPRECATED(message)   /* disable deprecation warnings */
#else
#  define LZ4_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
#  if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */
#    define LZ4_DEPRECATED(message) [[deprecated(message)]]
#  elif (LZ4_GCC_VERSION >= 405) || defined(__clang__)
#    define LZ4_DEPRECATED(message) __attribute__((deprecated(message)))
#  elif (LZ4_GCC_VERSION >= 301)
#    define LZ4_DEPRECATED(message) __attribute__((deprecated))
#  elif defined(_MSC_VER)
#    define LZ4_DEPRECATED(message) __declspec(deprecated(message))
#  else
#    pragma message("WARNING: You need to implement LZ4_DEPRECATED for this compiler")
#    define LZ4_DEPRECATED(message)
#  endif
#endif /* LZ4_DISABLE_DEPRECATE_WARNINGS */

/* Obsolete compression functions */
LZ4LIB_API LZ4_DEPRECATED("use LZ4_compress_default() instead") int LZ4_compress               (const char* source, char* dest, int sourceSize);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_compress_default() instead") int LZ4_compress_limitedOutput (const char* source, char* dest, int sourceSize, int maxOutputSize);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_compress_fast_extState() instead") int LZ4_compress_withState               (void* state, const char* source, char* dest, int inputSize);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_compress_fast_extState() instead") int LZ4_compress_limitedOutput_withState (void* state, const char* source, char* dest, int inputSize, int maxOutputSize);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_compress_fast_continue() instead") int LZ4_compress_continue                (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_compress_fast_continue() instead") int LZ4_compress_limitedOutput_continue  (LZ4_stream_t* LZ4_streamPtr, const char* source, char* dest, int inputSize, int maxOutputSize);

/* Obsolete decompression functions */
LZ4LIB_API LZ4_DEPRECATED("use LZ4_decompress_fast() instead") int LZ4_uncompress (const char* source, char* dest, int outputSize);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_decompress_safe() instead") int LZ4_uncompress_unknownOutputSize (const char* source, char* dest, int isize, int maxOutputSize);

/* Obsolete streaming functions; use new streaming interface whenever possible */
LZ4LIB_API LZ4_DEPRECATED("use LZ4_createStream() instead") void* LZ4_create (char* inputBuffer);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_createStream() instead") int   LZ4_sizeofStreamState(void);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_resetStream() instead")  int   LZ4_resetStreamState(void* state, char* inputBuffer);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_saveDict() instead")     char* LZ4_slideInputBuffer (void* state);

/* Obsolete streaming decoding functions */
LZ4LIB_API LZ4_DEPRECATED("use LZ4_decompress_safe_usingDict() instead") int LZ4_decompress_safe_withPrefix64k (const char* src, char* dst, int compressedSize, int maxDstSize);
LZ4LIB_API LZ4_DEPRECATED("use LZ4_decompress_fast_usingDict() instead") int LZ4_decompress_fast_withPrefix64k (const char* src, char* dst, int originalSize);

#endif /* LZ4_H_2983827168210 */


#if defined (__cplusplus)
}
#endif