Example of Using Intel IPP ZLIB Coding Functions

The following code example demonstrates how the model of a compressor can be implemented using the Intel IPP ZLIB functions ippsEncodeLZ77_8u and ippsDecodeLZ77_8u and an arbitrary bit encoding/decoding methods for the pairs.

Using the ippsEncodeLZ77 and ippsDecodeLZ77 functions

#include <stdio.h>
#include <stdlib.h>
#include "ippdc.h"
#define BUFLEN 1000

...............

int

main(int argc, char* argv[])

    int len;

    int lenr;

    Ipp8u* pSrc;

    int srcLen;

    IppLZ77Pair* pDst;

    int dstLen;

    IppLZ77Pair* pSrcr;

    int srcLenr;

    Ipp8u* pDstr;

    int dstLenr;

    IppStatus status;

    IppLZ77State_8u* pLZ77State;

    ....................

    /* LZ77 encoding */

    status = ippsEncodeLZ77InitAlloc_8u(IppLZ77FastCompr, IppLZ77CRC32,

                                            &pLZ77State);

    /* Reading the srcLen bytes of input data from the input data file to pSrc */

    ....................

    len = dstLen;

    status = ippsEncodeLZ77_8u(&pSrc, &srcLen, &pDst, &dstLen,

                                 IppLZ77FinishFlush, pLZ77State);

    /* Here we have the array of Pairs in pDst of (len - dstLen)  */

    /* In this point the arbitrary bit coding method can be used, */

    /* for example LZSS algorithm.                                */

    ....................

    ....................

    /* Writing the compressed data to the output file             */

    ippsLZ77Free_8u(pLZ77State);

    /* LZ77 decoding */

    status = ippsDecodeLZ77InitAlloc_8u(IppLZ77CRC32, &pLZ77State);

    /* Reading the compressed data from the file                  */

    ....................

    /* On this point the bit decoding method, corresponding to the above   */

    /* selected bit encoding method (LZSS for example) must be used        */

    ....................

    ....................

    /* After bit decoding the pairs restored placed to the pSrcr of srcLenr */

    /*  for further performing of LZ77 decoding                             */

    lenr = dstLenr;

    status = ippsDecodeLZ77_8u(&pSrcr, &srcLenr, &pDstr, &dstLenr,

                                 IppLZ77FinishFlush, pLZ77State);

    /* Writing the (lenr - dstLenr) bytes of decompressed data to the output file */

    ippsLZ77Free_8u(pLZ77State);

    return 0;

} /* main */