C++

Compress Large Binary File in Blocks

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Compresses a large binary file in blocks. C++

#include <CkFileAccess.h>
#include <CkCompression.h>
#include <CkByteData.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  This example assumes the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    CkFileAccess facSrc;
    CkFileAccess facDest;

    //  Open a large binary file for reading.
    success = facSrc.OpenForRead("qa_data/bmp/big.bmp");
    if (success == false) {
        std::cout << facSrc.lastErrorText() << "\r\n";
        return;
    }

    //  If we compress in 64K chunks, find out how many blocks there will be.
    int blockSize = 65536;
    int numBlocks = facSrc.GetNumBlocks(blockSize);

    //  Open an output file for the compressed data.
    success = facDest.OpenForWrite("c:/temp/qa_output/compressedBmp.dat");
    if (success == false) {
        std::cout << facDest.lastErrorText() << "\r\n";
        return;
    }

    CkCompression compress;
    compress.put_Algorithm("deflate");

    CkByteData fileBytes;
    CkByteData compressedBytes;

    //  Assuming numBlocks > 1
    compress.put_FirstChunk(true);
    compress.put_LastChunk(false);

    int i = 0;
    while (i < numBlocks) {
        success = facSrc.ReadBlock(i,blockSize,fileBytes);
        success = compress.CompressBytes(fileBytes,compressedBytes);

        facDest.FileWrite(compressedBytes);

        i = i + 1;

        compress.put_FirstChunk(false);
        if (i == (numBlocks - 1)) {
            compress.put_LastChunk(true);
        }

    }

    facSrc.FileClose();
    facDest.FileClose();

    std::cout << "Finished compressing file." << "\r\n";
    }