(Objective-C) Unzip Binary File to Stream

Demonstrates how to unzip a large binary file to a stream to allow the application to process the uncompressed bytes chunk by chunk.

Note: This example requires Chilkat v9.5.0.67 or greater.

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#import <CkoZip.h>
#import <CkoZipEntry.h>
#import <CkoStream.h>
#import <CkoTask.h>
#import <CkoFileAccess.h>
#import <CkoBinData.h>

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

CkoZip *zip = [[CkoZip alloc] init];

// First open a .zip.
BOOL success = [zip OpenZip: @"qa_data/zips/big.zip"];
if (success != YES) {
    NSLog(@"%@",zip.LastErrorText);
    return;
}

// Get the entry to be unzipped to a stream..
CkoZipEntry *entry = [zip GetEntryByIndex: [NSNumber numberWithInt: 0]];
if (zip.LastMethodSuccess != YES) {
    NSLog(@"%@",zip.LastErrorText);
    return;
}

CkoStream *dataStream = [[CkoStream alloc] init];

CkoTask *unzipTask = [entry UnzipToStreamAsync: dataStream];
if (entry.LastMethodSuccess != YES) {
    NSLog(@"%@",entry.LastErrorText);

    return;
}

// Start the background unzip thread.
[unzipTask Run];

// We'll read the uncompressed data chunk-by-chunk and write to an output file.
CkoFileAccess *fac = [[CkoFileAccess alloc] init];
success = [fac OpenForWrite: @"qa_output/out.dat"];
if (success != YES) {
    NSLog(@"%@",fac.LastErrorText);

    return;
}

// Read the stream.  (this is reading the unzipped file data)
CkoBinData *bd = [[CkoBinData alloc] init];
while (dataStream.EndOfStream != YES) {
    // Get the next chunk of decompressed bytes.
    [dataStream ReadBd: bd];
    // Do something with it..
    // In this simple example, we'll just write to the file.
    [fac FileWriteBd: bd offset: [NSNumber numberWithInt: 0] numBytes: [NSNumber numberWithInt: 0]];
    // Clear for the next read.
    [bd Clear];
}

[fac FileClose];

NSLog(@"%@",@"Success.");