/*

  LZ4io.c - LZ4 File/Stream Interface

  Copyright (C) Yann Collet 2011-2015

  GPL v2 License

  This program is free software; you can redistribute it and/or modify

  it under the terms of the GNU General Public License as published by

  the Free Software Foundation; either version 2 of the License, or

  (at your option) any later version.

  This program is distributed in the hope that it will be useful,

  but WITHOUT ANY WARRANTY; without even the implied warranty of

  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License along

  with this program; if not, write to the Free Software Foundation, Inc.,

  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

  You can contact the author at :

  - LZ4 source repository : https://github.com/Cyan4973/lz4

  - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c

*/

/*

  Note : this is stand-alone program.

  It is not part of LZ4 compression library, it is a user code of the LZ4 library.

  - The license of LZ4 library is BSD.

  - The license of xxHash library is BSD.

  - The license of this source file is GPLv2.

*/

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

*  Compiler Options

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

#ifdef _MSC_VER    /* Visual Studio */

#  define _CRT_SECURE_NO_WARNINGS

#  define _CRT_SECURE_NO_DEPRECATE     /* VS2005 */

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

#endif

#define _LARGE_FILES           /* Large file support on 32-bits AIX */

#define _FILE_OFFSET_BITS 64   /* Large file support on 32-bits unix */

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

*  Includes

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

#include <stdio.h>     /* fprintf, fopen, fread, stdin, stdout, fflush, getchar */</stdio.h>

#include <stdlib.h>    /* malloc, free */</stdlib.h>

#include <string.h>    /* strcmp, strlen */</string.h>

#include <time.h>      /* clock */</time.h>

#include <sys types.h=""> /* stat64 */</sys>

#include <sys stat.h="">  /* stat64 */</sys>

#include "lz4io.h"

#include "lz4.h"       /* still required for legacy format */

#include "lz4hc.h"     /* still required for legacy format */

#include "lz4frame.h"

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

*  OS-specific Includes

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

#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(_WIN32)

#  include <fcntl.h>   /* _O_BINARY */</fcntl.h>

#  include <io.h>      /* _setmode, _fileno, _get_osfhandle */</io.h>

#  if !defined(__DJGPP__)

#    define SET_BINARY_MODE(file) { int unused=_setmode(_fileno(file), _O_BINARY); (void)unused; }

#    include <windows.h> /* DeviceIoControl, HANDLE, FSCTL_SET_SPARSE */</windows.h>

#    define SET_SPARSE_FILE_MODE(file) { DWORD dw; DeviceIoControl((HANDLE) _get_osfhandle(_fileno(file)), FSCTL_SET_SPARSE, 0, 0, 0, 0, &dw, 0); }

#    if defined(_MSC_VER) && (_MSC_VER >= 1400)  /* Avoid MSVC fseek()'s 2GiB barrier */

#      define fseek _fseeki64

#    endif

#  else

#    define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)

#    define SET_SPARSE_FILE_MODE(file)

#  endif

#else

#  define SET_BINARY_MODE(file)

#  define SET_SPARSE_FILE_MODE(file)

#endif

#if !defined(S_ISREG)

#  define S_ISREG(x) (((x) & S_IFMT) == S_IFREG)

#endif

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

*  Constants

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

#define KB *(1 <<10)

#define MB *(1 <<20)

#define GB *(1U<<30)

#define _1BIT  0x01

#define _2BITS 0x03

#define _3BITS 0x07

#define _4BITS 0x0F

#define _8BITS 0xFF

#define MAGICNUMBER_SIZE    4

#define LZ4IO_MAGICNUMBER   0x184D2204

#define LZ4IO_SKIPPABLE0    0x184D2A50

#define LZ4IO_SKIPPABLEMASK 0xFFFFFFF0

#define LEGACY_MAGICNUMBER  0x184C2102

#define CACHELINE 64

#define LEGACY_BLOCKSIZE   (8 MB)

#define MIN_STREAM_BUFSIZE (192 KB)

#define LZ4IO_BLOCKSIZEID_DEFAULT 7

#define sizeT sizeof(size_t)

#define maskT (sizeT - 1)

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

*  Macros

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

#define DISPLAY(...)         fprintf(stderr, __VA_ARGS__)

#define DISPLAYLEVEL(l, ...) if (g_displayLevel>=l) { DISPLAY(__VA_ARGS__); }

static int g_displayLevel = 0;   /* 0 : no display  ; 1: errors  ; 2 : + result + interaction + warnings ; 3 : + progression; 4 : + information */

#define DISPLAYUPDATE(l, ...) if (g_displayLevel>=l) { \

            if ((LZ4IO_GetMilliSpan(g_time) > refreshRate) || (g_displayLevel>=4)) \

            { g_time = clock(); DISPLAY(__VA_ARGS__); \

            if (g_displayLevel>=4) fflush(stdout); } }

static const unsigned refreshRate = 150;

static clock_t g_time = 0;

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

*  Local Parameters

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

static int g_overwrite = 1;

static int g_blockSizeId = LZ4IO_BLOCKSIZEID_DEFAULT;

static int g_blockChecksum = 0;

static int g_streamChecksum = 1;

static int g_blockIndependence = 1;

static int g_sparseFileSupport = 1;

static int g_contentSizeFlag = 0;

static const int minBlockSizeID = 4;

static const int maxBlockSizeID = 7;

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

*  Exceptions

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

#define DEBUG 0

#define DEBUGOUTPUT(...) if (DEBUG) DISPLAY(__VA_ARGS__);

#define EXM_THROW(error, ...)                                             \

{                                                                         \

    DEBUGOUTPUT("Error defined at %s, line %i : \n", __FILE__, __LINE__); \

    DISPLAYLEVEL(1, "Error %i : ", error);                                \

    DISPLAYLEVEL(1, __VA_ARGS__);                                         \

    DISPLAYLEVEL(1, "\n");                                                \

    exit(error);                                                          \

}

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

*  Version modifiers

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

#define EXTENDED_ARGUMENTS

#define EXTENDED_HELP

#define EXTENDED_FORMAT

#define DEFAULT_DECOMPRESSOR LZ4IO_decompressLZ4F

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

/* ****************** Parameters ******************** */

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

/* Default setting : overwrite = 1; return : overwrite mode (0/1) */

int LZ4IO_setOverwrite(int yes)

{

   g_overwrite = (yes!=0);

   return g_overwrite;

}

/* blockSizeID : valid values : 4-5-6-7 */

int LZ4IO_setBlockSizeID(int bsid)

{

    static const int blockSizeTable[] = { 64 KB, 256 KB, 1 MB, 4 MB };

    if ((bsid < minBlockSizeID) || (bsid > maxBlockSizeID)) return -1;

    g_blockSizeId = bsid;

    return blockSizeTable[g_blockSizeId-minBlockSizeID];

}

int LZ4IO_setBlockMode(LZ4IO_blockMode_t blockMode)

{

    g_blockIndependence = (blockMode == LZ4IO_blockIndependent);

    return g_blockIndependence;

}

/* Default setting : no checksum */

int LZ4IO_setBlockChecksumMode(int xxhash)

{

    g_blockChecksum = (xxhash != 0);

    return g_blockChecksum;

}

/* Default setting : checksum enabled */

int LZ4IO_setStreamChecksumMode(int xxhash)

{

    g_streamChecksum = (xxhash != 0);

    return g_streamChecksum;

}

/* Default setting : 0 (no notification) */

int LZ4IO_setNotificationLevel(int level)

{

    g_displayLevel = level;

    return g_displayLevel;

}

/* Default setting : 0 (disabled) */

int LZ4IO_setSparseFile(int enable)

{

    g_sparseFileSupport = (enable!=0);

    return g_sparseFileSupport;

}

/* Default setting : 0 (disabled) */

int LZ4IO_setContentSize(int enable)

{

    g_contentSizeFlag = (enable!=0);

    return g_contentSizeFlag;

}

static unsigned LZ4IO_GetMilliSpan(clock_t nPrevious)

{

    clock_t nCurrent = clock();

    unsigned nSpan = (unsigned)(((nCurrent - nPrevious) * 1000) / CLOCKS_PER_SEC);

    return nSpan;

}

static unsigned long long LZ4IO_GetFileSize(const char* infilename)

{

    int r;

#if defined(_MSC_VER)

    struct _stat64 statbuf;

    r = _stat64(infilename, &statbuf);

#else

    struct stat statbuf;

    r = stat(infilename, &statbuf);

#endif

    if (r || !S_ISREG(statbuf.st_mode)) return 0;   /* failure, or is not a regular file */

    return (unsigned long long)statbuf.st_size;

}

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

** ********************** LZ4 File / Pipe compression ********************* **

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

static int LZ4IO_GetBlockSize_FromBlockId (int id) { return (1 << (8 + (2 * id))); }

static int LZ4IO_isSkippableMagicNumber(unsigned int magic) { return (magic & LZ4IO_SKIPPABLEMASK) == LZ4IO_SKIPPABLE0; }

static int LZ4IO_getFiles(const char* input_filename, const char* output_filename, FILE** pfinput, FILE** pfoutput)

{

    if (!strcmp (input_filename, stdinmark))

    {

        DISPLAYLEVEL(4,"Using stdin for input\n");

        *pfinput = stdin;

        SET_BINARY_MODE(stdin);

    }

    else

    {

        *pfinput = fopen(input_filename, "rb");

    }

    if ( *pfinput==0 )

    {

        DISPLAYLEVEL(1, "Unable to access file for processing: %s\n", input_filename);

        return 1;

    }

    if (!strcmp (output_filename, stdoutmark))

    {

        DISPLAYLEVEL(4,"Using stdout for output\n");

        *pfoutput = stdout;

        SET_BINARY_MODE(stdout);

        if (g_sparseFileSupport==1)

        {

            g_sparseFileSupport = 0;

            DISPLAYLEVEL(4, "Sparse File Support is automatically disabled on stdout ; try --sparse \n");

        }

    }

    else

    {

        /* Check if destination file already exists */

        *pfoutput=0;

        if (output_filename != nulmark) *pfoutput = fopen( output_filename, "rb" );

        if (*pfoutput!=0)

        {

            fclose(*pfoutput);

            if (!g_overwrite)

            {

                int ch = 'Y';

                DISPLAYLEVEL(2, "Warning : %s already exists\n", output_filename);

                if ((g_displayLevel <= 1) || (*pfinput == stdin))

                    EXM_THROW(11, "Operation aborted : %s already exists", output_filename);   /* No interaction possible */

                DISPLAYLEVEL(2, "Overwrite ? (Y/n) : ");

                while((ch = getchar()) != '\n' && ch != EOF)   /* flush integrated */

                if ((ch!='Y') && (ch!='y')) EXM_THROW(12, "No. Operation aborted : %s already exists", output_filename);

            }

        }

        *pfoutput = fopen( output_filename, "wb" );

    }

    if (*pfoutput==0) EXM_THROW(13, "Pb opening %s", output_filename);

    return 0;

}

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

*   Legacy Compression

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

/* unoptimized version; solves endianess & alignment issues */

static void LZ4IO_writeLE32 (void* p, unsigned value32)

{

    unsigned char* dstPtr = (unsigned char*)p;

    dstPtr[0] = (unsigned char)value32;

    dstPtr[1] = (unsigned char)(value32 >> 8);

    dstPtr[2] = (unsigned char)(value32 >> 16);

    dstPtr[3] = (unsigned char)(value32 >> 24);

}

static int LZ4IO_LZ4_compress(const char* src, char* dst, int srcSize, int dstSize, int cLevel)

{

    (void)cLevel;

    return LZ4_compress_fast(src, dst, srcSize, dstSize, 1);

}

/* LZ4IO_compressFilename_Legacy :

 * This function is intentionally "hidden" (not published in .h)

 * It generates compressed streams using the old 'legacy' format */

int LZ4IO_compressFilename_Legacy(const char* input_filename, const char* output_filename, int compressionlevel)

{

    int (*compressionFunction)(const char* src, char* dst, int srcSize, int dstSize, int cLevel);

    unsigned long long filesize = 0;

    unsigned long long compressedfilesize = MAGICNUMBER_SIZE;

    char* in_buff;

    char* out_buff;

    const int outBuffSize = LZ4_compressBound(LEGACY_BLOCKSIZE);

    FILE* finput;

    FILE* foutput;

    clock_t start, end;

    size_t sizeCheck;

    /* Init */

    start = clock();

    if (compressionlevel < 3) compressionFunction = LZ4IO_LZ4_compress; else compressionFunction = LZ4_compress_HC;

    if (LZ4IO_getFiles(input_filename, output_filename, &finput, &foutput))

        EXM_THROW(20, "File error");

    /* Allocate Memory */

    in_buff = (char*)malloc(LEGACY_BLOCKSIZE);

    out_buff = (char*)malloc(outBuffSize);

    if (!in_buff || !out_buff) EXM_THROW(21, "Allocation error : not enough memory");

    /* Write Archive Header */

    LZ4IO_writeLE32(out_buff, LEGACY_MAGICNUMBER);

    sizeCheck = fwrite(out_buff, 1, MAGICNUMBER_SIZE, foutput);

    if (sizeCheck!=MAGICNUMBER_SIZE) EXM_THROW(22, "Write error : cannot write header");

    /* Main Loop */

    while (1)

    {

        unsigned int outSize;

        /* Read Block */

        int inSize = (int) fread(in_buff, (size_t)1, (size_t)LEGACY_BLOCKSIZE, finput);

        if( inSize<=0 ) break;

        filesize += inSize;

        /* Compress Block */

        outSize = compressionFunction(in_buff, out_buff+4, inSize, outBuffSize, compressionlevel);

        compressedfilesize += outSize+4;

        DISPLAYUPDATE(2, "\rRead : %i MB  ==> %.2f%%   ", (int)(filesize>>20), (double)compressedfilesize/filesize*100);

        /* Write Block */

        LZ4IO_writeLE32(out_buff, outSize);

        sizeCheck = fwrite(out_buff, 1, outSize+4, foutput);

        if (sizeCheck!=(size_t)(outSize+4)) EXM_THROW(23, "Write error : cannot write compressed block");

    }

    /* Status */

    end = clock();

    DISPLAYLEVEL(2, "\r%79s\r", "");

    filesize += !filesize;   /* avoid divide by zero */

    DISPLAYLEVEL(2,"Compressed %llu bytes into %llu bytes ==> %.2f%%\n",

        (unsigned long long) filesize, (unsigned long long) compressedfilesize, (double)compressedfilesize/filesize*100);

    {

        double seconds = (double)(end - start)/CLOCKS_PER_SEC;

        DISPLAYLEVEL(4,"Done in %.2f s ==> %.2f MB/s\n", seconds, (double)filesize / seconds / 1024 / 1024);

    }

    /* Close & Free */

    free(in_buff);

    free(out_buff);

    fclose(finput);

    fclose(foutput);

    return 0;

}

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

*  Compression using Frame format

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

typedef struct {

    void*  srcBuffer;

    size_t srcBufferSize;

    void*  dstBuffer;

    size_t dstBufferSize;

    LZ4F_compressionContext_t ctx;

} cRess_t;

static cRess_t LZ4IO_createCResources(void)

{

    const size_t blockSize = (size_t)LZ4IO_GetBlockSize_FromBlockId (g_blockSizeId);

    cRess_t ress;

    LZ4F_errorCode_t errorCode;

    errorCode = LZ4F_createCompressionContext(&(ress.ctx), LZ4F_VERSION);

    if (LZ4F_isError(errorCode)) EXM_THROW(30, "Allocation error : can't create LZ4F context : %s", LZ4F_getErrorName(errorCode));

    /* Allocate Memory */

    ress.srcBuffer = malloc(blockSize);

    ress.srcBufferSize = blockSize;

    ress.dstBufferSize = LZ4F_compressFrameBound(blockSize, NULL);   /* cover worst case */

    ress.dstBuffer = malloc(ress.dstBufferSize);

    if (!ress.srcBuffer || !ress.dstBuffer) EXM_THROW(31, "Allocation error : not enough memory");

    return ress;

}

static void LZ4IO_freeCResources(cRess_t ress)

{

    LZ4F_errorCode_t errorCode;

    free(ress.srcBuffer);

    free(ress.dstBuffer);

    errorCode = LZ4F_freeCompressionContext(ress.ctx);

    if (LZ4F_isError(errorCode)) EXM_THROW(38, "Error : can't free LZ4F context resource : %s", LZ4F_getErrorName(errorCode));

}

/*

 * LZ4IO_compressFilename_extRess()

 * result : 0 : compression completed correctly

 *          1 : missing or pb opening srcFileName

 */

static int LZ4IO_compressFilename_extRess(cRess_t ress, const char* srcFileName, const char* dstFileName, int compressionLevel)

{

    unsigned long long filesize = 0;

    unsigned long long compressedfilesize = 0;

    FILE* srcFile;

    FILE* dstFile;

    void* const srcBuffer = ress.srcBuffer;

    void* const dstBuffer = ress.dstBuffer;

    const size_t dstBufferSize = ress.dstBufferSize;

    const size_t blockSize = (size_t)LZ4IO_GetBlockSize_FromBlockId (g_blockSizeId);

    size_t sizeCheck, headerSize, readSize;

    LZ4F_compressionContext_t ctx = ress.ctx;   /* just a pointer */

    LZ4F_preferences_t prefs;

    /* Init */

    memset(&prefs, 0, sizeof(prefs));

    /* File check */

    if (LZ4IO_getFiles(srcFileName, dstFileName, &srcFile, &dstFile)) return 1;

    /* Set compression parameters */

    prefs.autoFlush = 1;

    prefs.compressionLevel = compressionLevel;

    prefs.frameInfo.blockMode = (LZ4F_blockMode_t)g_blockIndependence;

    prefs.frameInfo.blockSizeID = (LZ4F_blockSizeID_t)g_blockSizeId;

    prefs.frameInfo.contentChecksumFlag = (LZ4F_contentChecksum_t)g_streamChecksum;

    if (g_contentSizeFlag)

    {

      unsigned long long fileSize = LZ4IO_GetFileSize(srcFileName);

      prefs.frameInfo.contentSize = fileSize;   /* == 0 if input == stdin */

      if (fileSize==0)

          DISPLAYLEVEL(3, "Warning : cannot determine uncompressed frame content size \n");

    }

    /* read first block */

    readSize  = fread(srcBuffer, (size_t)1, blockSize, srcFile);

    filesize += readSize;

    /* single-block file */

    if (readSize < blockSize)

    {

        /* Compress in single pass */

        size_t cSize = LZ4F_compressFrame(dstBuffer, dstBufferSize, srcBuffer, readSize, &prefs);

        if (LZ4F_isError(cSize)) EXM_THROW(34, "Compression failed : %s", LZ4F_getErrorName(cSize));

        compressedfilesize += cSize;

        DISPLAYUPDATE(2, "\rRead : %u MB   ==> %.2f%%   ",

                      (unsigned)(filesize>>20), (double)compressedfilesize/(filesize+!filesize)*100);   /* avoid division by zero */

        /* Write Block */

        sizeCheck = fwrite(dstBuffer, 1, cSize, dstFile);

        if (sizeCheck!=cSize) EXM_THROW(35, "Write error : cannot write compressed block");

    }

    else

    /* multiple-blocks file */

    {

        /* Write Archive Header */

        headerSize = LZ4F_compressBegin(ctx, dstBuffer, dstBufferSize, &prefs);

        if (LZ4F_isError(headerSize)) EXM_THROW(32, "File header generation failed : %s", LZ4F_getErrorName(headerSize));

        sizeCheck = fwrite(dstBuffer, 1, headerSize, dstFile);

        if (sizeCheck!=headerSize) EXM_THROW(33, "Write error : cannot write header");

        compressedfilesize += headerSize;

        /* Main Loop */

        while (readSize>0)

        {

            size_t outSize;

            /* Compress Block */

            outSize = LZ4F_compressUpdate(ctx, dstBuffer, dstBufferSize, srcBuffer, readSize, NULL);

            if (LZ4F_isError(outSize)) EXM_THROW(34, "Compression failed : %s", LZ4F_getErrorName(outSize));

            compressedfilesize += outSize;

            DISPLAYUPDATE(2, "\rRead : %u MB   ==> %.2f%%   ", (unsigned)(filesize>>20), (double)compressedfilesize/filesize*100);

            /* Write Block */

            sizeCheck = fwrite(dstBuffer, 1, outSize, dstFile);

            if (sizeCheck!=outSize) EXM_THROW(35, "Write error : cannot write compressed block");

            /* Read next block */

            readSize  = fread(srcBuffer, (size_t)1, (size_t)blockSize, srcFile);

            filesize += readSize;

        }

        /* End of Stream mark */

        headerSize = LZ4F_compressEnd(ctx, dstBuffer, dstBufferSize, NULL);

        if (LZ4F_isError(headerSize)) EXM_THROW(36, "End of file generation failed : %s", LZ4F_getErrorName(headerSize));

        sizeCheck = fwrite(dstBuffer, 1, headerSize, dstFile);

        if (sizeCheck!=headerSize) EXM_THROW(37, "Write error : cannot write end of stream");

        compressedfilesize += headerSize;

    }

    /* Release files */

    fclose (srcFile);

    fclose (dstFile);

    /* Final Status */

    DISPLAYLEVEL(2, "\r%79s\r", "");

    DISPLAYLEVEL(2, "Compressed %llu bytes into %llu bytes ==> %.2f%%\n",

        filesize, compressedfilesize, (double)compressedfilesize/(filesize + !filesize)*100);   /* avoid division by zero */

    return 0;

}

int LZ4IO_compressFilename(const char* srcFileName, const char* dstFileName, int compressionLevel)

{

    clock_t start, end;

    cRess_t ress;

    int issueWithSrcFile = 0;

    /* Init */

    start = clock();

    ress = LZ4IO_createCResources();

    /* Compress File */

    issueWithSrcFile += LZ4IO_compressFilename_extRess(ress, srcFileName, dstFileName, compressionLevel);

    /* Free resources */

    LZ4IO_freeCResources(ress);

    /* Final Status */

    end = clock();

    {

        double seconds = (double)(end - start) / CLOCKS_PER_SEC;

        DISPLAYLEVEL(4, "Completed in %.2f sec \n", seconds);

    }

    return issueWithSrcFile;

}

#define FNSPACE 30

int LZ4IO_compressMultipleFilenames(const char** inFileNamesTable, int ifntSize, const char* suffix, int compressionLevel)

{

    int i;

    int missed_files = 0;

    char* dstFileName = (char*)malloc(FNSPACE);

    size_t ofnSize = FNSPACE;

    const size_t suffixSize = strlen(suffix);

    cRess_t ress;

    /* init */

    ress = LZ4IO_createCResources();

    /* loop on each file */

    for (i=0; i

    {

        size_t ifnSize = strlen(inFileNamesTable[i]);

        if (ofnSize <= ifnSize+suffixSize+1) { free(dstFileName); ofnSize = ifnSize + 20; dstFileName = (char*)malloc(ofnSize); }

        strcpy(dstFileName, inFileNamesTable[i]);

        strcat(dstFileName, suffix);

        missed_files += LZ4IO_compressFilename_extRess(ress, inFileNamesTable[i], dstFileName, compressionLevel);

    }

    /* Close & Free */

    LZ4IO_freeCResources(ress);

    free(dstFileName);

    return missed_files;

}

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

/* ********************** LZ4 file-stream Decompression **************** */

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

static unsigned LZ4IO_readLE32 (const void* s)

{

    const unsigned char* srcPtr = (const unsigned char*)s;

    unsigned value32 = srcPtr[0];

    value32 += (srcPtr[1]<<8);

    value32 += (srcPtr[2]<<16);

    value32 += ((unsigned)srcPtr[3])<<24;

    return value32;

}

static unsigned LZ4IO_fwriteSparse(FILE* file, const void* buffer, size_t bufferSize, unsigned storedSkips)

{

    const size_t* const bufferT = (const size_t*)buffer;   /* Buffer is supposed malloc'ed, hence aligned on size_t */

    const size_t* ptrT = bufferT;

    size_t  bufferSizeT = bufferSize / sizeT;

    const size_t* const bufferTEnd = bufferT + bufferSizeT;

    static const size_t segmentSizeT = (32 KB) / sizeT;

    if (!g_sparseFileSupport)   /* normal write */

    {

        size_t sizeCheck = fwrite(buffer, 1, bufferSize, file);

        if (sizeCheck != bufferSize) EXM_THROW(70, "Write error : cannot write decoded block");

        return 0;

    }

    /* avoid int overflow */

    if (storedSkips > 1 GB)

    {

        int seekResult = fseek(file, 1 GB, SEEK_CUR);

        if (seekResult != 0) EXM_THROW(71, "1 GB skip error (sparse file support)");

        storedSkips -= 1 GB;

    }

    while (ptrT < bufferTEnd)

    {

        size_t seg0SizeT = segmentSizeT;

        size_t nb0T;

        int seekResult;

        /* count leading zeros */

        if (seg0SizeT > bufferSizeT) seg0SizeT = bufferSizeT;

        bufferSizeT -= seg0SizeT;

        for (nb0T=0; (nb0T < seg0SizeT) && (ptrT[nb0T] == 0); nb0T++) ;

        storedSkips += (unsigned)(nb0T * sizeT);

        if (nb0T != seg0SizeT)   /* not all 0s */

        {

            size_t sizeCheck;

            seekResult = fseek(file, storedSkips, SEEK_CUR);

            if (seekResult) EXM_THROW(72, "Sparse skip error ; try --no-sparse");

            storedSkips = 0;

            seg0SizeT -= nb0T;

            ptrT += nb0T;

            sizeCheck = fwrite(ptrT, sizeT, seg0SizeT, file);

            if (sizeCheck != seg0SizeT) EXM_THROW(73, "Write error : cannot write decoded block");

        }

        ptrT += seg0SizeT;

    }

    if (bufferSize & maskT)   /* size not multiple of sizeT : implies end of block */

    {

        const char* const restStart = (const char*)bufferTEnd;

        const char* restPtr = restStart;

        size_t  restSize =  bufferSize & maskT;

        const char* const restEnd = restStart + restSize;

        for (; (restPtr < restEnd) && (*restPtr == 0); restPtr++) ;

        storedSkips += (unsigned) (restPtr - restStart);

        if (restPtr != restEnd)

        {

            size_t sizeCheck;

            int seekResult = fseek(file, storedSkips, SEEK_CUR);

            if (seekResult) EXM_THROW(74, "Sparse skip error ; try --no-sparse");

            storedSkips = 0;

            sizeCheck = fwrite(restPtr, 1, restEnd - restPtr, file);

            if (sizeCheck != (size_t)(restEnd - restPtr)) EXM_THROW(75, "Write error : cannot write decoded end of block");

        }

    }

    return storedSkips;

}

static void LZ4IO_fwriteSparseEnd(FILE* file, unsigned storedSkips)

{

    char lastZeroByte[1] = { 0 };

    if (storedSkips>0)   /* implies g_sparseFileSupport */

    {

        int seekResult;

        size_t sizeCheck;

        storedSkips --;

        seekResult = fseek(file, storedSkips, SEEK_CUR);

        if (seekResult != 0) EXM_THROW(69, "Final skip error (sparse file)\n");

        sizeCheck = fwrite(lastZeroByte, 1, 1, file);

        if (sizeCheck != 1) EXM_THROW(69, "Write error : cannot write last zero\n");

    }

}

static unsigned g_magicRead = 0;

static unsigned long long LZ4IO_decodeLegacyStream(FILE* finput, FILE* foutput)

{

    unsigned long long filesize = 0;

    char* in_buff;

    char* out_buff;

    unsigned storedSkips = 0;

    /* Allocate Memory */

    in_buff = (char*)malloc(LZ4_compressBound(LEGACY_BLOCKSIZE));

    out_buff = (char*)malloc(LEGACY_BLOCKSIZE);

    if (!in_buff || !out_buff) EXM_THROW(51, "Allocation error : not enough memory");

    /* Main Loop */

    while (1)

    {

        int decodeSize;

        size_t sizeCheck;

        unsigned int blockSize;

        /* Block Size */

        sizeCheck = fread(in_buff, 1, 4, finput);

        if (sizeCheck==0) break;                   /* Nothing to read : file read is completed */

        blockSize = LZ4IO_readLE32(in_buff);       /* Convert to Little Endian */

        if (blockSize > LZ4_COMPRESSBOUND(LEGACY_BLOCKSIZE))

        {   /* Cannot read next block : maybe new stream ? */

            g_magicRead = blockSize;

            break;

        }

        /* Read Block */

        sizeCheck = fread(in_buff, 1, blockSize, finput);

        if (sizeCheck!=blockSize) EXM_THROW(52, "Read error : cannot access compressed block !");

        /* Decode Block */

        decodeSize = LZ4_decompress_safe(in_buff, out_buff, blockSize, LEGACY_BLOCKSIZE);

        if (decodeSize < 0) EXM_THROW(53, "Decoding Failed ! Corrupted input detected !");

        filesize += decodeSize;

        /* Write Block */

        storedSkips = LZ4IO_fwriteSparse(foutput, out_buff, decodeSize, storedSkips);

    }

    LZ4IO_fwriteSparseEnd(foutput, storedSkips);

    /* Free */

    free(in_buff);

    free(out_buff);

    return filesize;

}

typedef struct {

    void*  srcBuffer;

    size_t srcBufferSize;

    void*  dstBuffer;

    size_t dstBufferSize;

    LZ4F_decompressionContext_t dCtx;

} dRess_t;

static const size_t LZ4IO_dBufferSize = 64 KB;

static dRess_t LZ4IO_createDResources(void)

{

    dRess_t ress;

    LZ4F_errorCode_t errorCode;

    /* init */

    errorCode = LZ4F_createDecompressionContext(&ress.dCtx, LZ4F_VERSION);

    if (LZ4F_isError(errorCode)) EXM_THROW(60, "Can't create LZ4F context : %s", LZ4F_getErrorName(errorCode));

    /* Allocate Memory */

    ress.srcBufferSize = LZ4IO_dBufferSize;

    ress.srcBuffer = malloc(ress.srcBufferSize);

    ress.dstBufferSize = LZ4IO_dBufferSize;

    ress.dstBuffer = malloc(ress.dstBufferSize);

    if (!ress.srcBuffer || !ress.dstBuffer) EXM_THROW(61, "Allocation error : not enough memory");

    return ress;

}

static void LZ4IO_freeDResources(dRess_t ress)

{

    LZ4F_errorCode_t errorCode = LZ4F_freeDecompressionContext(ress.dCtx);

    if (LZ4F_isError(errorCode)) EXM_THROW(69, "Error : can't free LZ4F context resource : %s", LZ4F_getErrorName(errorCode));

    free(ress.srcBuffer);

    free(ress.dstBuffer);

}

static unsigned long long LZ4IO_decompressLZ4F(dRess_t ress, FILE* srcFile, FILE* dstFile)

{

    unsigned long long filesize = 0;

    LZ4F_errorCode_t nextToLoad;

    unsigned storedSkips = 0;

    /* Init feed with magic number (already consumed from FILE*  sFile) */

    {

        size_t inSize = MAGICNUMBER_SIZE;

        size_t outSize= 0;

        LZ4IO_writeLE32(ress.srcBuffer, LZ4IO_MAGICNUMBER);

        nextToLoad = LZ4F_decompress(ress.dCtx, ress.dstBuffer, &outSize, ress.srcBuffer, &inSize, NULL);

        if (LZ4F_isError(nextToLoad)) EXM_THROW(62, "Header error : %s", LZ4F_getErrorName(nextToLoad));

    }

    /* Main Loop */

    for (;nextToLoad;)

    {

        size_t readSize;

        size_t pos = 0;

        size_t decodedBytes = ress.dstBufferSize;

        /* Read input */

        if (nextToLoad > ress.srcBufferSize) nextToLoad = ress.srcBufferSize;

        readSize = fread(ress.srcBuffer, 1, nextToLoad, srcFile);

        if (!readSize)

            break;   /* empty file or stream */

        while ((pos < readSize) || (decodedBytes == ress.dstBufferSize))   /* still to read, or still to flush */

        {

            /* Decode Input (at least partially) */

            size_t remaining = readSize - pos;

            decodedBytes = ress.dstBufferSize;

            nextToLoad = LZ4F_decompress(ress.dCtx, ress.dstBuffer, &decodedBytes, (char*)(ress.srcBuffer)+pos, &remaining, NULL);

            if (LZ4F_isError(nextToLoad)) EXM_THROW(66, "Decompression error : %s", LZ4F_getErrorName(nextToLoad));

            pos += remaining;

            if (decodedBytes)

            {

                /* Write Block */

                filesize += decodedBytes;

                DISPLAYUPDATE(2, "\rDecompressed : %u MB  ", (unsigned)(filesize>>20));

                storedSkips = LZ4IO_fwriteSparse(dstFile, ress.dstBuffer, decodedBytes, storedSkips);

            }

            if (!nextToLoad) break;

        }

    }

    LZ4IO_fwriteSparseEnd(dstFile, storedSkips);

    if (nextToLoad!=0)

        EXM_THROW(67, "Unfinished stream");

    return filesize;

}