Objective-C

Unzip One File to a Stream

See more Zip Examples

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

#import <CkoZip.h>
#import <CkoZipEntry.h>
#import <CkoStream.h>
#import <CkoTask.h>
#import <CkoStringBuilder.h>
#import <NSString.h>

BOOL success = NO;

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

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

// First open a .zip.
success = [zip OpenZip: @"qa_data/hamlet.zip"];
if (success == NO) {
    NSLog(@"%@",zip.LastErrorText);
    return;
}

// Find the entry to be unzipped to a stream..
CkoZipEntry *entry = [[CkoZipEntry alloc] init];
success = [zip EntryMatching: @"*hamlet.xml" entry: entry];
if (success == NO) {
    NSLog(@"%@",zip.LastErrorText);
    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.
CkoStream *streamA = [[CkoStream alloc] init];
streamA.SinkFile = @"qa_output/hamletA.xml";

success = [entry UnzipToStream: streamA];
if (success != YES) {
    NSLog(@"%@",entry.LastErrorText);
    return;
}

// Close the stream to close the output file.
success = [streamA WriteClose];

// ----------------------------------------------------------------
// Case 2a: Uzip to a stream asynchronously. 
CkoStream *streamB = [[CkoStream alloc] init];

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

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

// Read the stream.  (this is reading the unzipped file data)
CkoStringBuilder *sb = [[CkoStringBuilder alloc] init];
while (streamB.EndOfStream != YES) {
    // Each call to ReadSb appends to the contents of sb.
    [streamB ReadSb: sb];
}

[sb WriteFile: @"qa_output/hamletB.xml" charset: @"utf-8" emitBom: NO];

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

// ----------------------------------------------------------------
// Case 2b: Uzip to a stream asynchronously and emit output while reading. 
CkoStream *streamC = [[CkoStream alloc] init];

unzipTask = [entry UnzipToStreamAsync: streamC];
if (entry.LastMethodSuccess != YES) {
    NSLog(@"%@",entry.LastErrorText);
    return;
}

[unzipTask Run];

while (streamC.EndOfStream != YES) {
    NSString *s = [streamC ReadString];
    NSLog(@"%@",s);
}

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