memory leaks issue while saving images to directory - objective-c

Question

Please try to understand my question.
i am picking images from phone library and saving into Documents Directory. But When I pick large number of images the utilised memory increases gradually and reach above of 400 mb then my app crash. Please if anybody can solve my problem what should I do? I'm new comer to Objective C. Any response will be appreciated.
here is my code
when Picker finish picking
- (void)agImagePickerController:(AGImagePickerController *)picker didFinishPickingMediaWithInfo:(NSArray *)info {
[self ShowLoadingView:#"Files Are Loading...."];
[self performSelectorInBackground:#selector(saveAllSelectedImages:) withObject:info];}
and then I save images to Directory
-(void) saveAllSelectedImages:(NSArray*)imagesArray{
for (int i=0; i<imagesArray.count; i++) {
ALAsset *asset = [imagesArray objectAtIndex:i];
ALAssetRepresentation *alassetRep = [asset defaultRepresentation];
NSDate *currentDate = [NSDate date];
NSString* DucPath = [[AppDelegate GetDocumentDirectoryPath] stringByAppendingPathComponent:#"Media"];
if (![[NSFileManager defaultManager] fileExistsAtPath:DucPath])
[[NSFileManager defaultManager] createDirectoryAtPath:DucPath withIntermediateDirectories:NO attributes:nil error:nil];
if ([[asset valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypeVideo])
{
long long DataSize = [alassetRep size];
Byte *buffer = (Byte*)malloc(DataSize);
NSUInteger buffered = (NSUInteger)[alassetRep getBytes:buffer fromOffset:0.0 length:alassetRep.size error:nil];
NSData *videoData = [NSData dataWithBytesNoCopy:buffer length:buffered freeWhenDone:YES];
NSString* newVideoName = [NSString stringWithFormat:#"video_%d_%d.mov",(int)currentDate,i];
NSString* newVideoPath = [DucPath stringByAppendingPathComponent:newVideoName];
[videoData writeToFile:newVideoPath atomically:YES];
[pImageMediaArray addObject:newVideoName];
}
else
{
UIImage *image = [UIImage imageWithCGImage:[alassetRep fullResolutionImage]];
/************************************Full Resolution Images ******************************************/
NSData *imageData = UIImageJPEGRepresentation(image, 0.8);
image = nil;
NSString *originalPath = [NSString stringWithFormat:#"IMAGE_%d_%d.jpg",(int)currentDate,i];
NSString* pImagePath = [DucPath stringByAppendingPathComponent:originalPath];
[imageData writeToFile:pImagePath atomically:YES];
[pImageMediaArray addObject:originalPath];
}
/************************************Low Resolution Images ******************************************/
UIImage *image = [UIImage imageWithCGImage:[alassetRep fullResolutionImage]];
UIImage *thumbImage = [self imageWithImage:image scaledToSize:CGSizeMake(50, 50)];
NSData *thumbImageData = UIImageJPEGRepresentation(thumbImage, 0.8);
NSString *thumbOriginalPath = [NSString stringWithFormat:#"SMALL_IMAGE_%d_%d.jpg",(int)currentDate,i];
NSString* thumbImagePath = [DucPath stringByAppendingPathComponent:thumbOriginalPath];
NSLog(#"Image path At Save Time:%#",thumbImagePath);
[thumbImageData writeToFile:thumbImagePath atomically:YES];
[pMediaArray addObject:thumbOriginalPath];
}
[appDelegate setPMediaArray:pImageMediaArray];
[pGridView reloadData];
imagesArray = nil;
[imagesArray release];
[pImageMediaArray release];
[self performSelectorOnMainThread:#selector(closeLoadindView) withObject:nil waitUntilDone:YES];}

Answer 1

Byte *buffer = (Byte*)malloc(DataSize);
is not being freed?

Answer 2

I had the same exact same issue. What worked for me was to use an autorelease pool block when you save the image. This will free up the retain count and the garbage collection will release the memory appropriately instead of retaining those objects in memory until the containing loop is finished running.
Example: In the method that you are using to save the images add code that looks like this:
#autoreleasepool {
NSString *filePath = [[NSArray arrayWithObjects:self.imagePath, #"/", GUID, #".png", nil] componentsJoinedByString:#""];
NSData *imageData = [NSData dataWithData:UIImagePNGRepresentation(image)];
BOOL res = [imageData writeToFile:filePath atomically:YES];
imageData = nil;
}

Answer 3

You need to add the autoreleasepool for task that perform in the background. In the above code content of the saveAllSelectedImages should be written inside autoreleasepool, Otherwise memory won't be released.