EncodeLZ77

Performs LZ77 encoding.

Syntax

IppStatus ippsEncodeLZ77_8u (Ipp8u** ppSrc, int* pSrcLen, IppLZ77Pair** ppDst, int* pDstLen, IppLZ77Flush flush, IppLZ77State_8u* pLZ77State);

Parameters

ppSrc	Double pointer to the source buffer.
pSrcLen	Pointer to the length of the source buffer.
ppDst	Double pointer to the destination buffer.
pDstLen	Pointer to the length of the destination buffer.
flush	Specifies the encoding mode for data blocks (see flush Parameter).
pLZ77State	Pointer to the LZ77 encoding state structure.

Description

The function ippsEncodeLZ77 is declared in the ippdc.h file. This function performs ZLIB encoding [ Ziv77 ] using the sliding wind ow technique in accordance with the RFC1951 specification.

The function uses the LZ77 encoding state structure pLZ77State that must be previously initialized by the function ippsEncodeLZ77InitAlloc or ippsEncodeLZ77Init.

The output data are of IppLZ 77Pair type that is defined as follows:

typedef struct IppLZ77Pairs {

Ipp16u length;

Ipp16u offset;

} IppLZ77Pair;

where length is a match length, and offset is a distance between the far-left position of the look-ahead buffer and the first literal of the string match in the sliding window. If the match is not found, the offset field contains 0 and the length field contains a single-literal code.

Code example demonstrates how to use the function ippsEncodeLZ77.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error if one of the specified pointers is NULL.
ippStsSizeErr	Indicates an error if dstLen is less than or equal to 0.
ippStsDstSizeLessExpected	Indicates a warning that the size of the destination buffer is insufficient for completing the operation.