Compress-LZ4

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src/lz4.c  view on Meta::CPAN

            while (op<cpy) *op++ = *match++;
        } else {
            LZ4_copy8(op, match);
            if (length>16) LZ4_wildCopy(op+8, match+8, cpy);
        }
        op=cpy;   /* correction */
    }

    /* end of decoding */
    if (endOnInput)
       return (int) (((char*)op)-dest);     /* Nb of output bytes decoded */
    else
       return (int) (((const char*)ip)-source);   /* Nb of input bytes read */

    /* Overflow error detected */
_output_error:
    return (int) (-(((const char*)ip)-source))-1;
}


int LZ4_decompress_safe(const char* source, char* dest, int compressedSize, int maxDecompressedSize)

src/lz4.c  view on Meta::CPAN

int LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream)
{
    FREEMEM(LZ4_stream);
    return 0;
}

/*!
 * LZ4_setStreamDecode() :
 * Use this function to instruct where to find the dictionary.
 * This function is not necessary if previous data is still available where it was decoded.
 * Loading a size of 0 is allowed (same effect as no dictionary).
 * Return : 1 if OK, 0 if error
 */
int LZ4_setStreamDecode (LZ4_streamDecode_t* LZ4_streamDecode, const char* dictionary, int dictSize)
{
    LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
    lz4sd->prefixSize = (size_t) dictSize;
    lz4sd->prefixEnd = (const BYTE*) dictionary + dictSize;
    lz4sd->externalDict = NULL;
    lz4sd->extDictSize  = 0;
    return 1;
}

/*
*_continue() :
    These decoding functions allow decompression of multiple blocks in "streaming" mode.
    Previously decoded blocks must still be available at the memory position where they were decoded.
    If it's not possible, save the relevant part of decoded data into a safe buffer,
    and indicate where it stands using LZ4_setStreamDecode()
*/
int LZ4_decompress_safe_continue (LZ4_streamDecode_t* LZ4_streamDecode, const char* source, char* dest, int compressedSize, int maxOutputSize)
{
    LZ4_streamDecode_t_internal* lz4sd = &LZ4_streamDecode->internal_donotuse;
    int result;

    if (lz4sd->prefixEnd == (BYTE*)dest) {
        result = LZ4_decompress_generic(source, dest, compressedSize, maxOutputSize,
                                        endOnInputSize, full, 0,

src/lz4.h  view on Meta::CPAN

           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) */

src/lz4.h  view on Meta::CPAN

/*! 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.