How can I compress data using Zlib, without directly using zlib.dylib? - objective-c

Question

Is there a class that allows compressing data using Zlib, or is using zlib.dylib directly the only possibility I have?

Answer 1

NSData+Compression is an easy to use NSData category implementation.
NSData+Compression.h
NSData+Compression.m
Usage:
NSData* compressed = [myData zlibDeflate];
NSData* originalData = [compressed zlibInflate];

Answer 2

Here is what worked for me:
1) ZLib based Objective-Zip new location: https://github.com/gianlucabertani/Objective-Zip
Podfile:
pod 'objective-zip', '~> 1.0'
Quick example:
#import "ViewController.h"
#import "Objective-Zip.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
NSString *docsDir;
NSArray *dirPaths;
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
NSString *path = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent:#"test.zip"]];
OZZipFile *zipFile= [[OZZipFile alloc] initWithFileName:path
mode:OZZipFileModeCreate];
NSString *str = #"Hello world";
OZZipWriteStream *stream= [zipFile writeFileInZipWithName:#"file.txt"
compressionLevel:OZZipCompressionLevelBest];
[stream writeData:[str dataUsingEncoding:NSUTF8StringEncoding]];
[stream finishedWriting];
[zipFile close];
}
2) Other zlib based library worked fine too. https://github.com/ZipArchive/ZipArchive
note: sometimes it's needed to add libz.tbd (new name of zlib.dylib) to "Link Binary With Libraries"
Quick example:
#import "SSZipArchive.h"
...
- (void)viewDidLoad {
[super viewDidLoad];
NSString *docsDir;
NSArray *dirPaths;
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
NSError *error;
NSString *str = #"Hello world";
NSString *fileName = [docsDir stringByAppendingPathComponent:#"test.txt"];
BOOL succeed = [str writeToFile:fileName atomically:YES encoding:NSUTF8StringEncoding error:&error];
if (succeed){
NSString *path = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent:#"test.zip"]];
[SSZipArchive createZipFileAtPath:path withFilesAtPaths:#[fileName]];
}
}

Answer 3

As alternative, there is also objective-zip, which is, "a small Cocoa/Objective-C library that wraps ZLib and MiniZip in an object-oriented friendly way."
Writing a file into a ".zip" archive is simple as executing the following code:
ZipWriteStream *stream = [zipFile writeFileInZipWithName:#"abc.txt" compressionLevel:ZipCompressionLevelBest];
[stream writeData:abcData];
[stream finishedWriting];
The library allows also to read the content of a ".zip" file, and to enumerate the files it contains.
Listing the content of a ".zip" file is done from code similar to the following one.
ZipFile *unzipFile = [[ZipFile alloc] initWithFileName:#"test.zip" mode:ZipFileModeUnzip];
NSArray *infos = [unzipFile listFileInZipInfos];
for (FileInZipInfo *info in infos) {
NSLog(#"- %# %# %d (%d)", info.name, info.date, info.size, info.level);
// Locate the file in the zip
[unzipFile locateFileInZip:info.name];
// Expand the file in memory
ZipReadStream *read = [unzipFile readCurrentFileInZip];
NSMutableData *data = [[NSMutableData alloc] initWithLength:256];
int bytesRead = [read readDataWithBuffer:data];
[read finishedReading];
}