Changes for 0.13.0

- Update lz4 to v1.8.3

CHANGELOG

@@ -1,3 +1,6 @@
+0.13.0
+- Updated lz4 to v1.8.3 (data corruption fix for v1.8.2)
+
 0.12.0
 - Updated lz4 to v1.8.2
 - Confirmed compatibility with Python 3.7

lz4/lz4.h

@@ -1,7 +1,7 @@
 /*
  *  LZ4 - Fast LZ compression algorithm
  *  Header File
- *  Copyright (C) 2011-2017, Yann Collet.
+ *  Copyright (C) 2011-present, Yann Collet.
 
    BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
 
@@ -46,7 +46,7 @@ extern "C" {
 /**
   Introduction
 
-  LZ4 is lossless compression algorithm, providing compression speed at 400 MB/s per core,
+  LZ4 is lossless compression algorithm, providing compression speed at 500 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.
 
@@ -62,8 +62,8 @@ extern "C" {
 
   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.
+  Frame format is required for interoperability.
+  It is delivered through a companion API, declared in lz4frame.h.
 */
 
 /*^***************************************************************
@@ -93,7 +93,7 @@ extern "C" {
 /*------   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  2    /* for tweaks, bug-fixes, or development */
+#define LZ4_VERSION_RELEASE  3    /* for tweaks, bug-fixes, or development */
 
 #define LZ4_VERSION_NUMBER (LZ4_VERSION_MAJOR *100*100 + LZ4_VERSION_MINOR *100 + LZ4_VERSION_RELEASE)
 
@@ -183,55 +183,72 @@ 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.
+    Then, provide this buffer as 'void* state' to compression function.
 */
 LZ4LIB_API int LZ4_sizeofState(void);
 LZ4LIB_API int LZ4_compress_fast_extState (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
 
 
-/*!
-LZ4_compress_destSize() :
-    Reverse the logic : compresses as much data as possible from 'src' buffer
-    into already allocated buffer 'dst' of size 'targetDestSize'.
-    This function either compresses the entire 'src' content into 'dst' if it's large enough,
-    or fill 'dst' buffer completely with as much data as possible from 'src'.
-        *srcSizePtr : will be modified to indicate how many bytes where read from 'src' to fill 'dst'.
-                      New value is necessarily <= old value.
-        return : Nb bytes written into 'dst' (necessarily <= targetDestSize)
-                 or 0 if compression fails
+/*! LZ4_compress_destSize() :
+ *  Reverse the logic : compresses as much data as possible from 'src' buffer
+ *  into already allocated buffer 'dst', of size >= 'targetDestSize'.
+ *  This function either compresses the entire 'src' content into 'dst' if it's large enough,
+ *  or fill 'dst' buffer completely with as much data as possible from 'src'.
+ *  note: acceleration parameter is fixed to "default".
+ *
+ * *srcSizePtr : will be modified to indicate how many bytes where read from 'src' to fill 'dst'.
+ *               New value is necessarily <= input value.
+ * @return : Nb bytes written into 'dst' (necessarily <= targetDestSize)
+ *           or 0 if compression fails.
 */
 LZ4LIB_API int LZ4_compress_destSize (const char* src, char* dst, int* srcSizePtr, int targetDstSize);
 
 
-/*!
-LZ4_decompress_fast() : **unsafe!**
-This function is a bit faster than LZ4_decompress_safe(),
-but it may misbehave on malformed input because it doesn't perform full validation of compressed data.
-    originalSize : is the uncompressed size to regenerate
-                   Destination buffer must be already allocated, and its size must be >= 'originalSize' bytes.
-    return : number of bytes read from source buffer (== compressed size).
-             If the source stream is detected malformed, the function stops decoding and return a negative result.
-    note : This function is only usable if the originalSize of uncompressed data is known in advance.
-           The caller should also check that all the compressed input has been consumed properly,
-           i.e. that the return value matches the size of the buffer with compressed input.
-           The function never writes past the output buffer.  However, since it doesn't know its 'src' size,
-           it may read past the intended input.  Also, because match offsets are not validated during decoding,
-           reads from 'src' may underflow.  Use this function in trusted environment **only**.
-*/
+/*! LZ4_decompress_fast() : **unsafe!**
+ *  This function used to be a bit faster than LZ4_decompress_safe(),
+ *  though situation has changed in recent versions,
+ *  and now `LZ4_decompress_safe()` can be as fast and sometimes faster than `LZ4_decompress_fast()`.
+ *  Moreover, LZ4_decompress_fast() is not protected vs malformed input, as it doesn't perform full validation of compressed data.
+ *  As a consequence, this function is no longer recommended, and may be deprecated in future versions.
+ *  It's only remaining specificity is that it can decompress data without knowing its compressed size.
+ *
+ *  originalSize : is the uncompressed size to regenerate.
+ *                 `dst` must be already allocated, its size must be >= 'originalSize' bytes.
+ * @return : number of bytes read from source buffer (== compressed size).
+ *           If the source stream is detected malformed, the function stops decoding and returns a negative result.
+ *  note : This function requires uncompressed originalSize to be known in advance.
+ *         The function never writes past the output buffer.
+ *         However, since it doesn't know its 'src' size, it may read past the intended input.
+ *         Also, because match offsets are not validated during decoding,
+ *         reads from 'src' may underflow.
+ *         Use this function in trusted environment **only**.
+ */
 LZ4LIB_API int LZ4_decompress_fast (const char* src, char* dst, int originalSize);
 
-/*!
-LZ4_decompress_safe_partial() :
-    This function decompress a compressed block of size 'srcSize' at position 'src'
-    into destination buffer 'dst' of size 'dstCapacity'.
-    The function will decompress a minimum of 'targetOutputSize' bytes, and stop after that.
-    However, it's not accurate, and may write more than 'targetOutputSize' (but always <= dstCapacity).
-   @return : the number of bytes decoded in the destination buffer (necessarily <= dstCapacity)
-        Note : this number can also be < targetOutputSize, if compressed block contains less data.
-            Therefore, always control how many bytes were decoded.
-            If source stream is detected malformed, function returns a negative result.
-            This function is protected against malicious data packets.
-*/
+/*! LZ4_decompress_safe_partial() :
+ *  Decompress an LZ4 compressed block, of size 'srcSize' at position 'src',
+ *  into destination buffer 'dst' of size 'dstCapacity'.
+ *  Up to 'targetOutputSize' bytes will be decoded.
+ *  The function stops decoding on reaching this objective,
+ *  which can boost performance when only the beginning of a block is required.
+ *
+ * @return : the number of bytes decoded in `dst` (necessarily <= dstCapacity)
+ *           If source stream is detected malformed, function returns a negative result.
+ *
+ *  Note : @return can be < targetOutputSize, if compressed block contains less data.
+ *
+ *  Note 2 : this function features 2 parameters, targetOutputSize and dstCapacity,
+ *           and expects targetOutputSize <= dstCapacity.
+ *           It effectively stops decoding on reaching targetOutputSize,
+ *           so dstCapacity is kind of redundant.
+ *           This is because in a previous version of this function,
+ *           decoding operation would not "break" a sequence in the middle.
+ *           As a consequence, there was no guarantee that decoding would stop at exactly targetOutputSize,
+ *           it could write more bytes, though only up to dstCapacity.
+ *           Some "margin" used to be required for this operation to work properly.
+ *           This is no longer necessary.
+ *           The function nonetheless keeps its signature, in an effort to not break API.
+ */
 LZ4LIB_API int LZ4_decompress_safe_partial (const char* src, char* dst, int srcSize, int targetOutputSize, int dstCapacity);
 
 
@@ -266,16 +283,23 @@ LZ4LIB_API int LZ4_loadDict (LZ4_stream_t* streamPtr, const char* dictionary, in
  *  'dst' buffer must be already allocated.
  *  If dstCapacity >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster.
  *
- *  Important : The previous 64KB of compressed data is assumed to remain present and unmodified in memory!
- *
- *  Special 1 : When input is a double-buffer, they can have any size, including < 64 KB.
- *              Make sure that buffers are separated by at least one byte.
- *              This way, each block only depends on previous block.
- *  Special 2 : If input buffer is a ring-buffer, it can have any size, including < 64 KB.
- *
  * @return : size of compressed block
  *           or 0 if there is an error (typically, cannot fit into 'dst').
- *  After an error, the stream status is invalid, it can only be reset or freed.
+ *
+ *  Note 1 : Each invocation to LZ4_compress_fast_continue() generates a new block.
+ *           Each block has precise boundaries.
+ *           It's not possible to append blocks together and expect a single invocation of LZ4_decompress_*() to decompress them together.
+ *           Each block must be decompressed separately, calling LZ4_decompress_*() with associated metadata.
+ *
+ *  Note 2 : The previous 64KB of source data is __assumed__ to remain present, unmodified, at same address in memory!
+ *
+ *  Note 3 : When input is structured as a double-buffer, each buffer can have any size, including < 64 KB.
+ *           Make sure that buffers are separated, by at least one byte.
+ *           This construction ensures that each block only depends on previous block.
+ *
+ *  Note 4 : If input buffer is a ring-buffer, it can have any size, including < 64 KB.
+ *
+ *  Note 5 : 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);
 
@@ -305,7 +329,7 @@ LZ4LIB_API int                 LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_str
 /*! LZ4_setStreamDecode() :
  *  An LZ4_streamDecode_t context can be allocated once and re-used multiple times.
  *  Use this function to start decompression of a new stream of blocks.
- *  A dictionary can optionnally be set. Use NULL or size 0 for a reset order.
+ *  A dictionary can optionally be set. Use NULL or size 0 for a reset order.
  *  Dictionary is presumed stable : it must remain accessible and unmodified during next decompression.
  * @return : 1 if OK, 0 if error
  */

lz4/lz4frame.c

@@ -738,7 +738,7 @@ static size_t LZ4F_makeBlock(void* dst, const void* src, size_t srcSize,
 
 static int LZ4F_compressBlock(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
 {
-    int const acceleration = (level < -1) ? -level : 1;
+    int const acceleration = (level < 0) ? -level + 1 : 1;
     LZ4F_initStream(ctx, cdict, level, LZ4F_blockIndependent);
     if (cdict) {
         return LZ4_compress_fast_continue((LZ4_stream_t*)ctx, src, dst, srcSize, dstCapacity, acceleration);
@@ -749,7 +749,7 @@ static int LZ4F_compressBlock(void* ctx, const char* src, char* dst, int srcSize
 
 static int LZ4F_compressBlock_continue(void* ctx, const char* src, char* dst, int srcSize, int dstCapacity, int level, const LZ4F_CDict* cdict)
 {
-    int const acceleration = (level < -1) ? -level : 1;
+    int const acceleration = (level < 0) ? -level + 1 : 1;
     (void)cdict; /* init once at beginning of frame */
     return LZ4_compress_fast_continue((LZ4_stream_t*)ctx, src, dst, srcSize, dstCapacity, acceleration);
 }

lz4/lz4frame.h

@@ -33,9 +33,10 @@
 */
 
 /* LZ4F is a stand-alone API to create LZ4-compressed frames
- * conformant with specification v1.5.1.
+ * conformant with specification v1.6.1.
  * It also offers streaming capabilities.
- * lz4.h is not required when using lz4frame.h.
+ * lz4.h is not required when using lz4frame.h,
+ * except to get constant such as LZ4_VERSION_NUMBER.
  * */
 
 #ifndef LZ4F_H_09782039843
@@ -159,8 +160,9 @@ typedef LZ4F_contentChecksum_t contentChecksum_t;
 
 /*! LZ4F_frameInfo_t :
  *  makes it possible to set or read frame parameters.
- *  It's not required to set all fields, as long as the structure was initially memset() to zero.
- *  For all fields, 0 sets it to default value */
+ *  Structure must be first init to 0, using memset() or LZ4F_INIT_FRAMEINFO,
+ *  setting all parameters to default.
+ *  It's then possible to update selectively some parameters */
 typedef struct {
   LZ4F_blockSizeID_t     blockSizeID;         /* max64KB, max256KB, max1MB, max4MB; 0 == default */
   LZ4F_blockMode_t       blockMode;           /* LZ4F_blockLinked, LZ4F_blockIndependent; 0 == default */
@@ -171,24 +173,30 @@ typedef struct {
   LZ4F_blockChecksum_t   blockChecksumFlag;   /* 1: each block followed by a checksum of block's compressed data; 0: disabled (default) */
 } LZ4F_frameInfo_t;
 
+#define LZ4F_INIT_FRAMEINFO   { 0, 0, 0, 0, 0, 0, 0 }    /* v1.8.3+ */
+
 /*! LZ4F_preferences_t :
- *  makes it possible to supply detailed compression parameters to the stream interface.
- *  Structure is presumed initially memset() to zero, representing default settings.
+ *  makes it possible to supply advanced compression instructions to streaming interface.
+ *  Structure must be first init to 0, using memset() or LZ4F_INIT_PREFERENCES,
+ *  setting all parameters to default.
  *  All reserved fields must be set to zero. */
 typedef struct {
   LZ4F_frameInfo_t frameInfo;
   int      compressionLevel;    /* 0: default (fast mode); values > LZ4HC_CLEVEL_MAX count as LZ4HC_CLEVEL_MAX; values < 0 trigger "fast acceleration" */
-  unsigned autoFlush;           /* 1: always flush, to reduce usage of internal buffers */
-  unsigned favorDecSpeed;       /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4LZ4HC_CLEVEL_OPT_MIN) */  /* >= v1.8.2 */
+  unsigned autoFlush;           /* 1: always flush; reduces usage of internal buffers */
+  unsigned favorDecSpeed;       /* 1: parser favors decompression speed vs compression ratio. Only works for high compression modes (>= LZ4HC_CLEVEL_OPT_MIN) */  /* v1.8.2+ */
   unsigned reserved[3];         /* must be zero for forward compatibility */
 } LZ4F_preferences_t;
 
-LZ4FLIB_API int LZ4F_compressionLevel_max(void);
+#define LZ4F_INIT_PREFERENCES   { LZ4F_INIT_FRAMEINFO, 0, 0, 0, { 0, 0, 0 } }    /* v1.8.3+ */
 
 
 /*-*********************************
 *  Simple compression function
 ***********************************/
+
+LZ4FLIB_API int LZ4F_compressionLevel_max(void);
+
 /*! LZ4F_compressFrameBound() :
  *  Returns the maximum possible compressed size with LZ4F_compressFrame() given srcSize and preferences.
  * `preferencesPtr` is optional. It can be replaced by NULL, in which case, the function will assume default preferences.
@@ -222,8 +230,9 @@ typedef struct {
 
 /*---   Resource Management   ---*/
 
-#define LZ4F_VERSION 100
+#define LZ4F_VERSION 100    /* This number can be used to check for an incompatible API breaking change */
 LZ4FLIB_API unsigned LZ4F_getVersion(void);
+
 /*! LZ4F_createCompressionContext() :
  * The first thing to do is to create a compressionContext object, which will be used in all compression operations.
  * This is achieved using LZ4F_createCompressionContext(), which takes as argument a version.

lz4/lz4hc.c

@@ -327,6 +327,8 @@ LZ4HC_InsertAndGetWiderMatch (
                             if (lookBackLength==0) {  /* no back possible */
                                 size_t const maxML = MIN(currentSegmentLength, srcPatternLength);
                                 if ((size_t)longest < maxML) {
+                                    assert(base + matchIndex < ip);
+                                    if (ip - (base+matchIndex) > MAX_DISTANCE) break;
                                     assert(maxML < 2 GB);
                                     longest = (int)maxML;
                                     *matchpos = base + matchIndex;   /* virtual pos, relative to ip, to retrieve offset */
@@ -450,6 +452,7 @@ LZ4_FORCE_INLINE int LZ4HC_encodeSequence (
     *op += length;
 
     /* Encode Offset */
+    assert( (*ip - match) <= MAX_DISTANCE );   /* note : consider providing offset as a value, rather than as a pointer difference */
     LZ4_writeLE16(*op, (U16)(*ip-match)); *op += 2;
 
     /* Encode MatchLength */

lz4/lz4hc.h

@@ -246,6 +246,10 @@ LZ4_DEPRECATED("use LZ4_resetStreamHC() instead") LZ4LIB_API  int   LZ4_resetStr
 #ifndef LZ4_HC_SLO_098092834
 #define LZ4_HC_SLO_098092834
 
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
 /*! LZ4_compress_HC_destSize() : v1.8.0 (experimental)
  *  Will try to compress as much data from `src` as possible
  *  that can fit into `targetDstSize` budget.
@@ -343,5 +347,9 @@ int LZ4_compress_HC_extStateHC_fastReset (void* state, const char* src, char* ds
  */
 LZ4LIB_API void LZ4_attach_HC_dictionary(LZ4_streamHC_t *working_stream, const LZ4_streamHC_t *dictionary_stream);
 
+#if defined (__cplusplus)
+}
+#endif
+
 #endif   /* LZ4_HC_SLO_098092834 */
 #endif   /* LZ4_HC_STATIC_LINKING_ONLY */