C

Unzip One File to a Stream

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Demonstrates how to unzip a particular file contained within a .zip archive to a Chilkat stream. C

#include <C_CkZip.h>
#include <C_CkZipEntry.h>
#include <C_CkStream.h>
#include <C_CkTask.h>
#include <C_CkStringBuilder.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkZip zip;
    HCkZipEntry entry;
    HCkStream streamA;
    HCkStream streamB;
    HCkTask unzipTask;
    HCkStringBuilder sb;
    HCkStream streamC;
    const char *s;

    success = FALSE;

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

    zip = CkZip_Create();

    // First open a .zip.
    success = CkZip_OpenZip(zip,"qa_data/hamlet.zip");
    if (success == FALSE) {
        printf("%s\n",CkZip_lastErrorText(zip));
        CkZip_Dispose(zip);
        return;
    }

    // Find the entry to be unzipped to a stream..
    entry = CkZipEntry_Create();
    success = CkZip_EntryMatching(zip,"*hamlet.xml",entry);
    if (success == FALSE) {
        printf("%s\n",CkZip_lastErrorText(zip));
        CkZip_Dispose(zip);
        CkZipEntry_Dispose(entry);
        return;
    }

    // There are three ways we can unzip (inflate) to a stream.
    // 
    // 1) Set a sink file on the stream object and call UnzipToStream synchronously.
    //    This unzips to the stream's sink (which is to simply unzip to a file in the filesystem).
    // 
    // 2) Create a stream object and call UnzipToStreamAsync.  This starts the unzip in a background
    //    thread (after Task.Run is called).  Your application can then read the unzipped (inflated) file
    //    directly from the stream.
    // 
    // 3) (not shown in this example) Unzip to a stream object that is the source of something else.
    //    

    // ----------------------------------------------------------------
    // Case 1: Unzip to a file by setting the sink of streamA to a file.
    streamA = CkStream_Create();
    CkStream_putSinkFile(streamA,"qa_output/hamletA.xml");

    success = CkZipEntry_UnzipToStream(entry,streamA);
    if (success != TRUE) {
        printf("%s\n",CkZipEntry_lastErrorText(entry));
        CkZip_Dispose(zip);
        CkZipEntry_Dispose(entry);
        CkStream_Dispose(streamA);
        return;
    }

    // Close the stream to close the output file.
    success = CkStream_WriteClose(streamA);

    // ----------------------------------------------------------------
    // Case 2a: Uzip to a stream asynchronously. 
    streamB = CkStream_Create();

    unzipTask = CkZipEntry_UnzipToStreamAsync(entry,streamB);
    if (CkZipEntry_getLastMethodSuccess(entry) != TRUE) {
        printf("%s\n",CkZipEntry_lastErrorText(entry));
        CkZip_Dispose(zip);
        CkZipEntry_Dispose(entry);
        CkStream_Dispose(streamA);
        CkStream_Dispose(streamB);
        return;
    }

    // Start the background unzip thread.
    CkTask_Run(unzipTask);

    // Read the stream.  (this is reading the unzipped file data)
    sb = CkStringBuilder_Create();
    while (CkStream_getEndOfStream(streamB) != TRUE) {
        // Each call to ReadSb appends to the contents of sb.
        CkStream_ReadSb(streamB,sb);
    }

    CkStringBuilder_WriteFile(sb,"qa_output/hamletB.xml","utf-8",FALSE);

    CkTask_Dispose(unzipTask);
    printf("Success.\n");

    // ----------------------------------------------------------------
    // Case 2b: Uzip to a stream asynchronously and emit output while reading. 
    streamC = CkStream_Create();

    unzipTask = CkZipEntry_UnzipToStreamAsync(entry,streamC);
    if (CkZipEntry_getLastMethodSuccess(entry) != TRUE) {
        printf("%s\n",CkZipEntry_lastErrorText(entry));
        CkZip_Dispose(zip);
        CkZipEntry_Dispose(entry);
        CkStream_Dispose(streamA);
        CkStream_Dispose(streamB);
        CkStringBuilder_Dispose(sb);
        CkStream_Dispose(streamC);
        return;
    }

    CkTask_Run(unzipTask);

    while (CkStream_getEndOfStream(streamC) != TRUE) {
        s = CkStream_readString(streamC);
        printf("%s\n",s);
    }

    CkTask_Dispose(unzipTask);
    printf("Success.\n");


    CkZip_Dispose(zip);
    CkZipEntry_Dispose(entry);
    CkStream_Dispose(streamA);
    CkStream_Dispose(streamB);
    CkStringBuilder_Dispose(sb);
    CkStream_Dispose(streamC);

    }