Merge pull request #61 from Cyan4973/dev

Dev

1 files changed, 290 insertions, 129 deletions

diff --git a/programs/lz4io.c b/programs/lz4io.c
index fa1f0f9..f5c5e98 100644
--- a/programs/lz4io.c
+++ b/programs/lz4io.c
@@ -1,6 +1,7 @@
 /*
   LZ4io.c - LZ4 File/Stream Interface
-  Copyright (C) Yann Collet 2011-2014
+  Copyright (C) Yann Collet 2011-2015
+
   GPL v2 License
 
   This program is free software; you can redistribute it and/or modify
@@ -18,7 +19,7 @@
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
   You can contact the author at :
-  - LZ4 source repository : http://code.google.com/p/lz4/
+  - LZ4 source repository : https://github.com/Cyan4973/lz4
   - LZ4 public forum : https://groups.google.com/forum/#!forum/lz4c
 */
 /*
@@ -31,56 +32,51 @@
 
 /**************************************
 *  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 GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
-#ifdef __GNUC__
-#  pragma GCC diagnostic ignored "-Wmissing-braces"   /* GCC bug 53119 : doesn't accept { 0 } as initializer (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53119) */
-#  pragma GCC diagnostic ignored "-Wmissing-field-initializers"   /* GCC bug 53119 : doesn't accept { 0 } as initializer (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53119) */
-#endif
-
 #define _LARGE_FILES           /* Large file support on 32-bits AIX */
 #define _FILE_OFFSET_BITS 64   /* Large file support on 32-bits unix */
-#define _POSIX_SOURCE 1        /* for fileno() within <stdio.h> on unix */
 
 
-/****************************
+/*****************************
 *  Includes
 *****************************/
-#include <stdio.h>    /* fprintf, fopen, fread, _fileno, stdin, stdout */
-#include <stdlib.h>   /* malloc, free */
-#include <string.h>   /* strcmp, strlen */
-#include <time.h>     /* clock */
+#include <stdio.h>     /* fprintf, fopen, fread, stdin, stdout */
+#include <stdlib.h>    /* malloc, free */
+#include <string.h>    /* strcmp, strlen */
+#include <time.h>      /* clock */
+#include <sys/types.h> /* stat64 */
+#include <sys/stat.h>  /* stat64 */
 #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) || defined(__CYGWIN__)
 #  include <fcntl.h>   /* _O_BINARY */
-#  include <io.h>      /* _setmode, _isatty */
-#  ifdef __MINGW32__
-   int _fileno(FILE *stream);   /* MINGW somehow forgets to include this windows declaration into <stdio.h> */
-#  endif
+#  include <io.h>      /* _setmode, _fileno, _get_osfhandle */
 #  define SET_BINARY_MODE(file) _setmode(_fileno(file), _O_BINARY)
-#  define IS_CONSOLE(stdStream) _isatty(_fileno(stdStream))
+#  include <Windows.h> /* DeviceIoControl, HANDLE, FSCTL_SET_SPARSE */
+#  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
-#  include <unistd.h>  /* isatty */
 #  define SET_BINARY_MODE(file)
-#  define IS_CONSOLE(stdStream) isatty(fileno(stdStream))
+#  define SET_SPARSE_FILE_MODE(file)
 #endif
 
 
-/****************************
+/*****************************
 *  Constants
 *****************************/
 #define KB *(1 <<10)
@@ -93,43 +89,46 @@
 #define _4BITS 0x0F
 #define _8BITS 0xFF
 
-#define MAGICNUMBER_SIZE   4
-#define LZ4S_MAGICNUMBER   0x184D2204
-#define LZ4S_SKIPPABLE0    0x184D2A50
-#define LZ4S_SKIPPABLEMASK 0xFFFFFFF0
-#define LEGACY_MAGICNUMBER 0x184C2102
+#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 LZ4S_BLOCKSIZEID_DEFAULT 7
-#define LZ4S_CHECKSUM_SEED 0
-#define LZ4S_EOS 0
-#define LZ4S_MAXHEADERSIZE (MAGICNUMBER_SIZE+2+8+4+1)
+#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 (displayLevel>=l) { DISPLAY(__VA_ARGS__); }
-#define DISPLAYUPDATE(l, ...) if (displayLevel>=l) { \
-            if ((LZ4IO_GetMilliSpan(g_time) > refreshRate) || (displayLevel>=4)) \
+#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 (displayLevel>=4) fflush(stdout); } }
+            if (g_displayLevel>=4) fflush(stdout); } }
 static const unsigned refreshRate = 150;
 static clock_t g_time = 0;
 
 
 /**************************************
 *  Local Parameters
-***************************************/
-static int displayLevel = 0;   /* 0 : no display  ; 1: errors  ; 2 : + result + interaction + warnings ; 3 : + progression; 4 : + information */
-static int overwrite = 1;
-static int globalBlockSizeId = LZ4S_BLOCKSIZEID_DEFAULT;
-static int blockChecksum = 0;
-static int streamChecksum = 1;
-static int blockIndependence = 1;
+**************************************/
+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 = 0;
+static int g_contentSizeFlag = 0;
 
 static const int minBlockSizeID = 4;
 static const int maxBlockSizeID = 7;
@@ -152,11 +151,10 @@ static const int maxBlockSizeID = 7;
 
 /**************************************
 *  Version modifiers
-***************************************/
+**************************************/
 #define EXTENDED_ARGUMENTS
 #define EXTENDED_HELP
 #define EXTENDED_FORMAT
-#define DEFAULT_COMPRESSOR   compress_file
 #define DEFAULT_DECOMPRESSOR decodeLZ4S
 
 
@@ -167,8 +165,8 @@ static const int maxBlockSizeID = 7;
 /* Default setting : overwrite = 1; return : overwrite mode (0/1) */
 int LZ4IO_setOverwrite(int yes)
 {
-   overwrite = (yes!=0);
-   return overwrite;
+   g_overwrite = (yes!=0);
+   return g_overwrite;
 }
 
 /* blockSizeID : valid values : 4-5-6-7 */
@@ -176,35 +174,49 @@ int LZ4IO_setBlockSizeID(int bsid)
 {
     static const int blockSizeTable[] = { 64 KB, 256 KB, 1 MB, 4 MB };
     if ((bsid < minBlockSizeID) || (bsid > maxBlockSizeID)) return -1;
-    globalBlockSizeId = bsid;
-    return blockSizeTable[globalBlockSizeId-minBlockSizeID];
+    g_blockSizeId = bsid;
+    return blockSizeTable[g_blockSizeId-minBlockSizeID];
 }
 
 int LZ4IO_setBlockMode(LZ4IO_blockMode_t blockMode)
 {
-    blockIndependence = (blockMode == LZ4IO_blockIndependent);
-    return blockIndependence;
+    g_blockIndependence = (blockMode == LZ4IO_blockIndependent);
+    return g_blockIndependence;
 }
 
 /* Default setting : no checksum */
 int LZ4IO_setBlockChecksumMode(int xxhash)
 {
-    blockChecksum = (xxhash != 0);
-    return blockChecksum;
+    g_blockChecksum = (xxhash != 0);
+    return g_blockChecksum;
 }
 
 /* Default setting : checksum enabled */
 int LZ4IO_setStreamChecksumMode(int xxhash)
 {
-    streamChecksum = (xxhash != 0);
-    return streamChecksum;
+    g_streamChecksum = (xxhash != 0);
+    return g_streamChecksum;
 }
 
 /* Default setting : 0 (no notification) */
 int LZ4IO_setNotificationLevel(int level)
 {
-    displayLevel = level;
-    return displayLevel;
+    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)
@@ -214,16 +226,30 @@ static unsigned LZ4IO_GetMilliSpan(clock_t nPrevious)
     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;   /* No good... */
+    return (unsigned long long)statbuf.st_size;
+}
+
 
-/* ************************************************************************ */
-/* ********************** LZ4 File / Pipe compression ********************* */
-/* ************************************************************************ */
+/* ************************************************************************ **
+** ********************** LZ4 File / Pipe compression ********************* **
+** ************************************************************************ */
 
-static int          LZ4S_GetBlockSize_FromBlockId (int id) { return (1 << (8 + (2 * id))); }
-static int          LZ4S_isSkippableMagicNumber(unsigned int magic) { return (magic & LZ4S_SKIPPABLEMASK) == LZ4S_SKIPPABLE0; }
+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 get_fileHandle(char* input_filename, char* output_filename, FILE** pfinput, FILE** pfoutput)
+static int get_fileHandle(const char* input_filename, const char* output_filename, FILE** pfinput, FILE** pfoutput)
 {
 
     if (!strcmp (input_filename, stdinmark))
@@ -251,12 +277,12 @@ static int get_fileHandle(char* input_filename, char* output_filename, FILE** pf
         if (*pfoutput!=0)
         {
             fclose(*pfoutput);
-            if (!overwrite)
+            if (!g_overwrite)
             {
                 char ch;
                 DISPLAYLEVEL(2, "Warning : %s already exists\n", output_filename);
                 DISPLAYLEVEL(2, "Overwrite ? (Y/N) : ");
-                if (displayLevel <= 1) EXM_THROW(11, "Operation aborted : %s already exists", output_filename);   /* No interaction possible */
+                if (g_displayLevel <= 1) EXM_THROW(11, "Operation aborted : %s already exists", output_filename);   /* No interaction possible */
                 ch = (char)getchar();
                 if ((ch!='Y') && (ch!='y')) EXM_THROW(11, "Operation aborted : %s already exists", output_filename);
             }
@@ -272,15 +298,14 @@ static int get_fileHandle(char* input_filename, char* output_filename, FILE** pf
 
 
 
-
 /***************************************
- *   Legacy Compression
- * *************************************/
+*   Legacy Compression
+***************************************/
 
 /* unoptimized version; solves endianess & alignment issues */
 static void LZ4IO_writeLE32 (void* p, unsigned value32)
 {
-    unsigned char* dstPtr = p;
+    unsigned char* dstPtr = (unsigned char*)p;
     dstPtr[0] = (unsigned char)value32;
     dstPtr[1] = (unsigned char)(value32 >> 8);
     dstPtr[2] = (unsigned char)(value32 >> 16);
@@ -290,7 +315,7 @@ static void LZ4IO_writeLE32 (void* p, unsigned value32)
 /* 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(char* input_filename, char* output_filename, int compressionlevel)
+int LZ4IO_compressFilename_Legacy(const char* input_filename, const char* output_filename, int compressionlevel)
 {
     int (*compressionFunction)(const char*, char*, int);
     unsigned long long filesize = 0;
@@ -308,7 +333,7 @@ int LZ4IO_compressFilename_Legacy(char* input_filename, char* output_filename, i
     if (compressionlevel < 3) compressionFunction = LZ4_compress; else compressionFunction = LZ4_compressHC;
 
     get_fileHandle(input_filename, output_filename, &finput, &foutput);
-    if ((displayLevel==2) && (compressionlevel==1)) displayLevel=3;
+    if ((g_displayLevel==2) && (compressionlevel==1)) g_displayLevel=3;
 
     /* Allocate Memory */
     in_buff = (char*)malloc(LEGACY_BLOCKSIZE);
@@ -360,11 +385,11 @@ int LZ4IO_compressFilename_Legacy(char* input_filename, char* output_filename, i
 }
 
 
-/***********************************************
- *   Compression using Frame format
- * ********************************************/
+/*********************************************
+*  Compression using Frame format
+*********************************************/
 
-int LZ4IO_compressFilename(char* input_filename, char* output_filename, int compressionLevel)
+int LZ4IO_compressFilename(const char* input_filename, const char* output_filename, int compressionLevel)
 {
     unsigned long long filesize = 0;
     unsigned long long compressedfilesize = 0;
@@ -377,23 +402,29 @@ int LZ4IO_compressFilename(char* input_filename, char* output_filename, int comp
     size_t sizeCheck, headerSize, readSize, outBuffSize;
     LZ4F_compressionContext_t ctx;
     LZ4F_errorCode_t errorCode;
-    LZ4F_preferences_t prefs = {0};
+    LZ4F_preferences_t prefs;
 
 
     /* Init */
     start = clock();
-    if ((displayLevel==2) && (compressionLevel>=3)) displayLevel=3;
+    memset(&prefs, 0, sizeof(prefs));
+    if ((g_displayLevel==2) && (compressionLevel>=3)) g_displayLevel=3;
     errorCode = LZ4F_createCompressionContext(&ctx, LZ4F_VERSION);
     if (LZ4F_isError(errorCode)) EXM_THROW(30, "Allocation error : can't create LZ4F context : %s", LZ4F_getErrorName(errorCode));
     get_fileHandle(input_filename, output_filename, &finput, &foutput);
-    blockSize = LZ4S_GetBlockSize_FromBlockId (globalBlockSizeId);
+    blockSize = LZ4IO_GetBlockSize_FromBlockId (g_blockSizeId);
 
     /* Set compression parameters */
     prefs.autoFlush = 1;
     prefs.compressionLevel = compressionLevel;
-    prefs.frameInfo.blockMode = blockIndependence;
-    prefs.frameInfo.blockSizeID = globalBlockSizeId;
-    prefs.frameInfo.contentChecksumFlag = streamChecksum;
+    prefs.frameInfo.blockMode = (blockMode_t)g_blockIndependence;
+    prefs.frameInfo.blockSizeID = (blockSizeID_t)g_blockSizeId;
+    prefs.frameInfo.contentChecksumFlag = (contentChecksum_t)g_streamChecksum;
+    if (g_contentSizeFlag)
+    {
+      unsigned long long fileSize = LZ4IO_GetFileSize(input_filename);
+      prefs.frameInfo.frameOSize = fileSize;   /* == 0 if input == stdin */
+    }
 
     /* Allocate Memory */
     in_buff  = (char*)malloc(blockSize);
@@ -462,13 +493,34 @@ int LZ4IO_compressFilename(char* input_filename, char* output_filename, int comp
 }
 
 
+#define FNSPACE 30
+int LZ4IO_compressMultipleFilenames(const char** inFileNamesTable, int ifntSize, const char* suffix, int compressionlevel)
+{
+    int i;
+    char* outFileName = (char*)malloc(FNSPACE);
+    size_t ofnSize = FNSPACE;
+    const size_t suffixSize = strlen(suffix);
+
+    for (i=0; i<ifntSize; i++)
+    {
+        size_t ifnSize = strlen(inFileNamesTable[i]);
+        if (ofnSize <= ifnSize+suffixSize+1) { free(outFileName); ofnSize = ifnSize + 20; outFileName = (char*)malloc(ofnSize); }
+        strcpy(outFileName, inFileNamesTable[i]);
+        strcat(outFileName, suffix);
+        LZ4IO_compressFilename(inFileNamesTable[i], outFileName, compressionlevel);
+    }
+    free(outFileName);
+    return 0;
+}
+
+
 /* ********************************************************************* */
-/* ********************** LZ4 File / Stream decoding ******************* */
+/* ********************** LZ4 file-stream Decompression **************** */
 /* ********************************************************************* */
 
 static unsigned LZ4IO_readLE32 (const void* s)
 {
-    const unsigned char* srcPtr = s;
+    const unsigned char* srcPtr = (const unsigned char*)s;
     unsigned value32 = srcPtr[0];
     value32 += (srcPtr[1]<<8);
     value32 += (srcPtr[2]<<16);
@@ -506,15 +558,16 @@ static unsigned long long decodeLegacyStream(FILE* finput, FILE* foutput)
 
         /* 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(52, "Decoding Failed ! Corrupted input detected !");
+        if (decodeSize < 0) EXM_THROW(53, "Decoding Failed ! Corrupted input detected !");
         filesize += decodeSize;
 
         /* Write Block */
         sizeCheck = fwrite(out_buff, 1, decodeSize, foutput);
-        if (sizeCheck != (size_t)decodeSize) EXM_THROW(53, "Write error : cannot write decoded block into output\n");
+        if (sizeCheck != (size_t)decodeSize) EXM_THROW(54, "Write error : cannot write decoded block into output\n");
     }
 
     /* Free */
@@ -528,57 +581,131 @@ static unsigned long long decodeLegacyStream(FILE* finput, FILE* foutput)
 static unsigned long long decodeLZ4S(FILE* finput, FILE* foutput)
 {
     unsigned long long filesize = 0;
-    char* inBuff;
-    char* outBuff;
+    void* inBuff;
+    void* outBuff;
 #   define HEADERMAX 20
     char  headerBuff[HEADERMAX];
-    size_t sizeCheck, nextToRead, outBuffSize, inBuffSize;
+    size_t sizeCheck;
+    const size_t inBuffSize = 256 KB;
+    const size_t outBuffSize = 256 KB;
     LZ4F_decompressionContext_t ctx;
     LZ4F_errorCode_t errorCode;
-    LZ4F_frameInfo_t frameInfo;
+    unsigned storedSkips = 0;
 
     /* init */
     errorCode = LZ4F_createDecompressionContext(&ctx, LZ4F_VERSION);
-    if (LZ4F_isError(errorCode)) EXM_THROW(60, "Allocation error : can't create context : %s", LZ4F_getErrorName(errorCode));
-    LZ4IO_writeLE32(headerBuff, LZ4S_MAGICNUMBER);   /* regenerated here, as it was already read from finput */
-
-    /* Decode stream descriptor */
-    outBuffSize = 0; inBuffSize = 0; sizeCheck = MAGICNUMBER_SIZE;
-    nextToRead = LZ4F_decompress(ctx, NULL, &outBuffSize, headerBuff, &sizeCheck, NULL);
-    if (LZ4F_isError(nextToRead)) EXM_THROW(61, "Decompression error : %s", LZ4F_getErrorName(nextToRead));
-    if (nextToRead > HEADERMAX) EXM_THROW(62, "Header too large (%i>%i)", (int)nextToRead, HEADERMAX);
-    sizeCheck = fread(headerBuff, 1, nextToRead, finput);
-    if (sizeCheck!=nextToRead) EXM_THROW(63, "Read error ");
-    nextToRead = LZ4F_decompress(ctx, NULL, &outBuffSize, headerBuff, &sizeCheck, NULL);
-    errorCode = LZ4F_getFrameInfo(ctx, &frameInfo, NULL, &inBuffSize);
-    if (LZ4F_isError(errorCode)) EXM_THROW(64, "can't decode frame header : %s", LZ4F_getErrorName(errorCode));
+    if (LZ4F_isError(errorCode)) EXM_THROW(60, "Can't create context : %s", LZ4F_getErrorName(errorCode));
+    LZ4IO_writeLE32(headerBuff, LZ4IO_MAGICNUMBER);   /* regenerated here, as it was already read from finput */
 
     /* Allocate Memory */
-    outBuffSize = LZ4IO_setBlockSizeID(frameInfo.blockSizeID);
-    inBuffSize = outBuffSize + 4;
-    inBuff = (char*)malloc(inBuffSize);
-    outBuff = (char*)malloc(outBuffSize);
-    if (!inBuff || !outBuff) EXM_THROW(65, "Allocation error : not enough memory");
+    inBuff = malloc(256 KB);
+    outBuff = malloc(256 KB);
+    if (!inBuff || !outBuff) EXM_THROW(61, "Allocation error : not enough memory");
+
+    /* Init feed with magic number (already consumed from FILE) */
+    {
+        size_t inSize = 4;
+        size_t outSize=0;
+        LZ4IO_writeLE32(inBuff, LZ4IO_MAGICNUMBER);
+        errorCode = LZ4F_decompress(ctx, outBuff, &outSize, inBuff, &inSize, NULL);
+        if (LZ4F_isError(errorCode)) EXM_THROW(62, "Header error : %s", LZ4F_getErrorName(errorCode));
+    }
+
 
     /* Main Loop */
-    while (nextToRead != 0)
+    for (;;)
     {
-        size_t decodedBytes = outBuffSize;
+        size_t readSize;
+        size_t pos = 0;
 
-        /* Read Block */
-        sizeCheck = fread(inBuff, 1, nextToRead, finput);
-        if (sizeCheck!=nextToRead) EXM_THROW(66, "Read error ");
+        /* Read input */
+        readSize = fread(inBuff, 1, inBuffSize, finput);
+        if (!readSize) break;   /* empty file or stream */
 
-        /* Decode Block */
-        errorCode = LZ4F_decompress(ctx, outBuff, &decodedBytes, inBuff, &sizeCheck, NULL);
-        if (LZ4F_isError(errorCode)) EXM_THROW(67, "Decompression error : %s", LZ4F_getErrorName(errorCode));
-        if (sizeCheck!=nextToRead) EXM_THROW(67, "Synchronization error");
-        nextToRead = errorCode;
-        filesize += decodedBytes;
+        while (pos < readSize)
+        {
+            /* Decode Input (at least partially) */
+            size_t remaining = readSize - pos;
+            size_t decodedBytes = outBuffSize;
+            errorCode = LZ4F_decompress(ctx, outBuff, &decodedBytes, (char*)inBuff+pos, &remaining, NULL);
+            if (LZ4F_isError(errorCode)) EXM_THROW(66, "Decompression error : %s", LZ4F_getErrorName(errorCode));
+            pos += remaining;
+
+            if (decodedBytes)
+            {
+                /* Write Block */
+                filesize += decodedBytes;
+                if (g_sparseFileSupport)
+                {
+                    size_t* const oBuffStartT = (size_t*)outBuff;   /* since outBuff is malloc'ed, it's aligned on size_t */
+                    size_t* oBuffPosT = oBuffStartT;
+                    size_t  oBuffSizeT = decodedBytes / sizeT;
+                    size_t* const oBuffEndT = oBuffStartT + oBuffSizeT;
+                    static const size_t bs0T = (32 KB) / sizeT;
+                    while (oBuffPosT < oBuffEndT)
+                    {
+                        size_t seg0SizeT = bs0T;
+                        size_t nb0T;
+                        int seekResult;
+                        if (seg0SizeT > oBuffSizeT) seg0SizeT = oBuffSizeT;
+                        oBuffSizeT -= seg0SizeT;
+                        for (nb0T=0; (nb0T < seg0SizeT) && (oBuffPosT[nb0T] == 0); nb0T++) ;
+                        storedSkips += (unsigned)(nb0T * sizeT);
+                        if (storedSkips > 1 GB)   /* avoid int overflow */
+                        {
+                            seekResult = fseek(foutput, 1 GB, SEEK_CUR);
+                            if (seekResult != 0) EXM_THROW(68, "1 GB skip error (sparse file)");
+                            storedSkips -= 1 GB;
+                        }
+                        if (nb0T != seg0SizeT)   /* not all 0s */
+                        {
+                            seekResult = fseek(foutput, storedSkips, SEEK_CUR);
+                            if (seekResult) EXM_THROW(68, "Skip error (sparse file)");
+                            storedSkips = 0;
+                            seg0SizeT -= nb0T;
+                            oBuffPosT += nb0T;
+                            sizeCheck = fwrite(oBuffPosT, sizeT, seg0SizeT, foutput);
+                            if (sizeCheck != seg0SizeT) EXM_THROW(68, "Write error : cannot write decoded block");
+                        }
+                        oBuffPosT += seg0SizeT;
+                    }
+                    if (decodedBytes & maskT)   /* size not multiple of sizeT (necessarily end of block) */
+                    {
+                        const char* const restStart = (char*)oBuffEndT;
+                        const char* restPtr = restStart;
+                        size_t  restSize =  decodedBytes & maskT;
+                        const char* const restEnd = restStart + restSize;
+                        for (; (restPtr < restEnd) && (*restPtr == 0); restPtr++) ;
+                        storedSkips += (unsigned) (restPtr - restStart);
+                        if (restPtr != restEnd)
+                        {
+                            int seekResult = fseek(foutput, storedSkips, SEEK_CUR);
+                            if (seekResult) EXM_THROW(68, "Skip error (end of block)");
+                            storedSkips = 0;
+                            sizeCheck = fwrite(restPtr, 1, restEnd - restPtr, foutput);
+                            if (sizeCheck != (size_t)(restEnd - restPtr)) EXM_THROW(68, "Write error : cannot write decoded end of block");
+                        }
+                    }
+                }
+                else
+                {
+                    sizeCheck = fwrite(outBuff, 1, decodedBytes, foutput);
+                    if (sizeCheck != decodedBytes) EXM_THROW(68, "Write error : cannot write decoded block");
+                }
+            }
+        }
 
-        /* Write Block */
-        sizeCheck = fwrite(outBuff, 1, decodedBytes, foutput);
-        if (sizeCheck != decodedBytes) EXM_THROW(68, "Write error : cannot write decoded block\n");
+    }
+
+    if ((g_sparseFileSupport) && (storedSkips>0))
+    {
+        int seekResult;
+        storedSkips --;
+        seekResult = fseek(foutput, storedSkips, SEEK_CUR);
+        if (seekResult != 0) EXM_THROW(69, "Final skip error (sparse file)\n");
+        memset(outBuff, 0, 1);
+        sizeCheck = fwrite(outBuff, 1, 1, foutput);
+        if (sizeCheck != 1) EXM_THROW(69, "Write error : cannot write last zero\n");
     }
 
     /* Free */
@@ -591,6 +718,28 @@ static unsigned long long decodeLZ4S(FILE* finput, FILE* foutput)
 }
 
 
+static unsigned long long LZ4IO_passThrough(FILE* finput, FILE* foutput, unsigned char U32store[MAGICNUMBER_SIZE])
+{
+    void* buffer = malloc(64 KB);
+    size_t read = 1, sizeCheck;
+    unsigned long long total = MAGICNUMBER_SIZE;
+
+    sizeCheck = fwrite(U32store, 1, MAGICNUMBER_SIZE, foutput);
+    if (sizeCheck != MAGICNUMBER_SIZE) EXM_THROW(50, "Pass-through error at start");
+
+    while (read)
+    {
+        read = fread(buffer, 1, 64 KB, finput);
+        total += read;
+        sizeCheck = fwrite(buffer, 1, read, foutput);
+        if (sizeCheck != read) EXM_THROW(50, "Pass-through error");
+    }
+
+    free(buffer);
+    return total;
+}
+
+
 #define ENDOFSTREAM ((unsigned long long)-1)
 static unsigned long long selectDecoder( FILE* finput,  FILE* foutput)
 {
@@ -598,22 +747,26 @@ static unsigned long long selectDecoder( FILE* finput,  FILE* foutput)
     unsigned magicNumber, size;
     int errorNb;
     size_t nbReadBytes;
+    static unsigned nbCalls = 0;
+
+    /* init */
+    nbCalls++;
 
     /* Check Archive Header */
     nbReadBytes = fread(U32store, 1, MAGICNUMBER_SIZE, finput);
     if (nbReadBytes==0) return ENDOFSTREAM;                  /* EOF */
     if (nbReadBytes != MAGICNUMBER_SIZE) EXM_THROW(40, "Unrecognized header : Magic Number unreadable");
     magicNumber = LZ4IO_readLE32(U32store);   /* Little Endian format */
-    if (LZ4S_isSkippableMagicNumber(magicNumber)) magicNumber = LZ4S_SKIPPABLE0;  /* fold skippable magic numbers */
+    if (LZ4IO_isSkippableMagicNumber(magicNumber)) magicNumber = LZ4IO_SKIPPABLE0;  /* fold skippable magic numbers */
 
     switch(magicNumber)
     {
-    case LZ4S_MAGICNUMBER:
+    case LZ4IO_MAGICNUMBER:
         return DEFAULT_DECOMPRESSOR(finput, foutput);
     case LEGACY_MAGICNUMBER:
         DISPLAYLEVEL(4, "Detected : Legacy format \n");
         return decodeLegacyStream(finput, foutput);
-    case LZ4S_SKIPPABLE0:
+    case LZ4IO_SKIPPABLE0:
         DISPLAYLEVEL(4, "Skipping detected skippable area \n");
         nbReadBytes = fread(U32store, 1, 4, finput);
         if (nbReadBytes != 4) EXM_THROW(42, "Stream error : skippable size unreadable");
@@ -623,14 +776,19 @@ static unsigned long long selectDecoder( FILE* finput,  FILE* foutput)
         return selectDecoder(finput, foutput);
     EXTENDED_FORMAT;
     default:
-        if (ftell(finput) == MAGICNUMBER_SIZE) EXM_THROW(44,"Unrecognized header : file cannot be decoded");   /* Wrong magic number at the beginning of 1st stream */
+        if (nbCalls == 1)   /* just started */
+        {
+            if (g_overwrite)
+                return LZ4IO_passThrough(finput, foutput, U32store);
+            EXM_THROW(44,"Unrecognized header : file cannot be decoded");   /* Wrong magic number at the beginning of 1st stream */
+        }
         DISPLAYLEVEL(2, "Stream followed by unrecognized data\n");
         return ENDOFSTREAM;
     }
 }
 
 
-int LZ4IO_decompressFilename(char* input_filename, char* output_filename)
+int LZ4IO_decompressFilename(const char* input_filename, const char* output_filename)
 {
     unsigned long long filesize = 0, decodedSize=0;
     FILE* finput;
@@ -642,6 +800,9 @@ int LZ4IO_decompressFilename(char* input_filename, char* output_filename)
     start = clock();
     get_fileHandle(input_filename, output_filename, &finput, &foutput);
 
+    /* sparse file */
+    if (g_sparseFileSupport && foutput) { SET_SPARSE_FILE_MODE(foutput); }
+
     /* Loop over multiple streams */
     do
     {