diff options
| -rw-r--r-- | lib/lz4frame.c | 6 | ||||
| -rw-r--r-- | lib/lz4frame.h | 14 | ||||
| -rw-r--r-- | lib/lz4frame_static.h | 9 |
3 files changed, 24 insertions, 5 deletions
diff --git a/lib/lz4frame.c b/lib/lz4frame.c index 518194d..1184a0f 100644 --- a/lib/lz4frame.c +++ b/lib/lz4frame.c @@ -792,6 +792,12 @@ typedef enum { dstage_skipSkippable } dStage_t; +LZ4F_errorCode_t LZ4F_resetDecompressionContext(LZ4F_dctx* dctx) +{ + dctx->dStage = dstage_getHeader; + return 0; +} + /*! LZ4F_headerSize() : * @return : size of frame header diff --git a/lib/lz4frame.h b/lib/lz4frame.h index 7c33464..76b4e69 100644 --- a/lib/lz4frame.h +++ b/lib/lz4frame.h @@ -300,7 +300,7 @@ typedef struct { * That is, it should be == 0 if decompression has been completed fully and correctly. */ LZ4FLIB_API LZ4F_errorCode_t LZ4F_createDecompressionContext(LZ4F_dctx** dctxPtr, unsigned version); -LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* const dctx); +LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx); /*-*********************************** @@ -309,12 +309,15 @@ LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* const dctx /*! LZ4F_getFrameInfo() : * This function extracts frame parameters (such as max blockSize, frame checksum, etc.). - * Its usage is optional. The objective is to provide relevant information for allocation purposes. + * Its usage is optional. Extracted information can be useful for allocation purposes, typically. * This function works in 2 situations : * - At the beginning of a new frame, in which case it will decode this information from `srcBuffer`, and start the decoding process. - * Amount of input data provided must be large enough to successfully decode the frame header. - * A header size is variable, but is guaranteed to be <= LZ4F_HEADER_SIZE_MAX bytes. It's possible to provide more input data than this minimum. - * - After decoding has been started. In which case, no input is read, frame parameters are extracted from dctx. + * Input size must be large enough to successfully decode the entire frame header. + * Frame header size is variable, but is guaranteed to be <= LZ4F_HEADER_SIZE_MAX bytes. + * It's allowed to provide more input data than this minimum. + * - After decoding has been started. + * In which case, no input is read, frame parameters are extracted from dctx. + * If decoding has just started, but not yet extracted information from header, LZ4F_getFrameInfo() will fail. * The number of bytes consumed from srcBuffer will be updated within *srcSizePtr (necessarily <= original value). * Decompression must resume from (srcBuffer + *srcSizePtr). * @return : an hint about how many srcSize bytes LZ4F_decompress() expects for next call, @@ -348,6 +351,7 @@ LZ4FLIB_API size_t LZ4F_getFrameInfo(LZ4F_dctx* dctx, * If decompression failed, @return is an error code, which can be tested using LZ4F_isError(). * * After a frame is fully decoded, dctx can be used again to decompress another frame. + * After a decompression error, use LZ4F_resetDecompressionContext() before re-using dctx, to return to clean state. */ LZ4FLIB_API size_t LZ4F_decompress(LZ4F_dctx* dctx, void* dstBuffer, size_t* dstSizePtr, diff --git a/lib/lz4frame_static.h b/lib/lz4frame_static.h index d3bae82..8ea496d 100644 --- a/lib/lz4frame_static.h +++ b/lib/lz4frame_static.h @@ -50,6 +50,15 @@ extern "C" { #include "lz4frame.h" +/* --- Experimental functions --- */ +/* LZ4F_resetDecompressionContext() : + * LZ4F_decompress() does not guarantee to leave dctx in clean state in case of errors. + * In order to re-use a dctx after a decompression error, + * use LZ4F_resetDecompressionContext() first. + * dctx will be able to start decompression on a new frame */ +LZ4FLIB_API LZ4F_errorCode_t LZ4F_resetDecompressionContext(LZ4F_dctx* dctx); + + /* --- Error List --- */ #define LZ4F_LIST_ERRORS(ITEM) \ ITEM(OK_NoError) \ |