Unicode C

Streaming Compression

See more Compression Examples

Compress and decompress using a stream. Unicode C

#include <C_CkFileAccessW.h>
#include <C_CkCompressionW.h>
#include <C_CkStreamW.h>
#include <C_CkTaskW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkFileAccessW fac;
    HCkCompressionW compress;
    HCkStreamW streamC;
    HCkStreamW streamD;
    BOOL bFilesEqual;
    HCkStreamW streamA;
    HCkTaskW task;
    const wchar_t *decompressedText;

    success = FALSE;

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

    fac = CkFileAccessW_Create();
    compress = CkCompressionW_Create();
    CkCompressionW_putAlgorithm(compress,L"deflate");

    streamC = CkStreamW_Create();

    // This example sets the source and sink of the stream to files.
    // A stream can have use other streams as a source or sink,
    // or the application can itself be the source/sink by directly
    // reading or writing a stream.  (See below for an example of this..)
    CkStreamW_putSourceFile(streamC,L"qa_data/hamlet.xml");
    CkStreamW_putSinkFile(streamC,L"qa_output/hamlet_compressed.dat");

    // Compress from source to sink.
    success = CkCompressionW_CompressStream(compress,streamC);
    if (success != TRUE) {
        wprintf(L"%s\n",CkCompressionW_lastErrorText(compress));
        CkFileAccessW_Dispose(fac);
        CkCompressionW_Dispose(compress);
        CkStreamW_Dispose(streamC);
        return;
    }

    wprintf(L"File-to-file deflate compression successful.\n");
    // Note: The FileSize method returns a signed 32-bit integer.  If the file is potentially larger than 2GB, call FileSizeStr instead to return
    // the size of the file as a string, then convert to an integer value.
    wprintf(L"Original size = %d\n",CkFileAccessW_FileSize(fac,CkStreamW_sourceFile(streamC)));
    wprintf(L"Compressed size = %d\n",CkFileAccessW_FileSize(fac,CkStreamW_sinkFile(streamC)));

    // Now do file-to-file decompression
    streamD = CkStreamW_Create();
    CkStreamW_putSourceFile(streamD,L"qa_output/hamlet_compressed.dat");
    CkStreamW_putSinkFile(streamD,L"qa_output/hamlet_restored.xml");

    // Decompress from source to sink.
    success = CkCompressionW_DecompressStream(compress,streamD);
    if (success != TRUE) {
        wprintf(L"%s\n",CkCompressionW_lastErrorText(compress));
        CkFileAccessW_Dispose(fac);
        CkCompressionW_Dispose(compress);
        CkStreamW_Dispose(streamC);
        CkStreamW_Dispose(streamD);
        return;
    }

    wprintf(L"File-to-file deflate decompression successful.\n");

    // Let's double-check to see that the files are equal in size and content:

    bFilesEqual = CkFileAccessW_FileContentsEqual(fac,CkStreamW_sourceFile(streamC),CkStreamW_sinkFile(streamD));
    if (bFilesEqual != TRUE) {
        wprintf(L"The output file is not equal to the input file!\n");
    }
    else {
        wprintf(L"The file was successfully compressed and decompressed.\n");
    }

    // ---------------------------------------------------------------------
    // Now let's decompress again, but this time w/ the application reading
    // the decompressed data directly from a stream.
    streamA = CkStreamW_Create();

    CkStreamW_putSourceFile(streamA,L"qa_output/hamlet_compressed.dat");

    // Start decompressing in a background thread.
    task = CkCompressionW_DecompressStreamAsync(compress,streamA);
    success = CkTaskW_Run(task);

    // Read decompressed data from streamA:

    while ((CkStreamW_getEndOfStream(streamA) != TRUE)) {
        if (CkStreamW_getDataAvailable(streamA) == TRUE) {
            decompressedText = CkStreamW_readString(streamA);
            wprintf(L"%s\n",decompressedText);
        }

    }

    // Let's make sure the background task finished and that the decompress was successful.
    // It should already be the case that the task is finished.
    while ((CkTaskW_getFinished(task) != TRUE)) {
        CkTaskW_SleepMs(task,20);
    }

    // The decompressor may have finished, but it is possible that data
    // remains to be flushed.  
    if (CkStreamW_getDataAvailable(streamA) == TRUE) {
        decompressedText = CkStreamW_readString(streamA);
        wprintf(L"%s\n",decompressedText);
    }

    // Did streamA succeed in reading the entire file?
    if (CkTaskW_getTaskSuccess(task) != TRUE) {
        wprintf(L"async decompress failed:\n");
        wprintf(L"%s\n",CkTaskW_resultErrorText(task));
        success = FALSE;
    }

    wprintf(L"The async decompress was successful.\n");


    CkFileAccessW_Dispose(fac);
    CkCompressionW_Dispose(compress);
    CkStreamW_Dispose(streamC);
    CkStreamW_Dispose(streamD);
    CkStreamW_Dispose(streamA);

    }