ZipArchive memory problems on iPhone for large archive - iphone

Question

I am trying to compress multiple files into a single zip archive and I am running into low memory warning. Since the complete zip file is loaded into the memory I guess that's the problem. Is there a way by which I can manage the compression/decompression better using ZipArchive so that not all the data is in the memory at once?
Thanks!

Answer 1

After doing some investigation on alternatives to ZipArchive I found another project called Objective-zip that seems to be a little better than ZipArchive. Here is the link:
http://code.google.com/p/objective-zip/
The API is quite simple. One thing I ran into was that in the begging I was reading data and never releasing it so if you are adding a bunch of large files to the zip file remember to release the data. Here is a little code I used:
ZipFile *zipFile = [[ZipFile alloc] initWithFileName:archivePath mode:ZipFileModeCreate];
for(NSString *path in subpaths){
NSData *data= [[NSData alloc] initWithContentsOfFile:longPath];
ZipWriteStream *stream = [zipFile writeFileInZipWithName:path compressionLevel:ZipCompressionLevelNone];
[stream writeData:data];
[stream finishedWriting];
[data release];
}
[zipFile close];
[zipFile release];
I hope this is helpful for anyone who runs into the same issue.

Answer 2

An easier way to deal with this is to simply change ZipArchive's method of reading the file into the NSData. Just change the following code
data = [ NSData dataWithContentsOfFile:file ];
to
data = [ NSData dataWithContentsOfMappedFile:file ];
That will cause the OS to read the file in a memory mapped way. Basically it just uses way less memory as it reads from the file as it needs to rather than loading it all into memory at once.