Open Radar

 
Summary:
The imageData NSData returned by PHImageManager has appended garbage bytes full of zeros. 
The length of these bytes varies between assets (and perhaps, runs)

Steps to Reproduce:
- Open attached project.
- Compile & Run on device.

Expected Results:
Data returned by PHImageManager should be the same as the obtained from ALAssetRepresentation

Actual Results:
Data returned by PHImageManager contains garbage bytes, easily noted because are only zeros

Version:
8.0 (12A365)

Notes:


Configuration:
iPhone 5c (Model A1456, A1532)

Attachments:
'PhotosZeroBytesBugDemo.zip' was successfully uploaded.
Demo project: http://cl.ly/0o2n3g0Y3p40

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Current Workaround/Fix

#define BUFFER_LENGTH 16

NS_INLINE NSData *VDTrimmedZeroBytesData(NSData *data) {
    NSRange dataRange = NSMakeRange(0, data.length);
    unsigned char *buffer = malloc(BUFFER_LENGTH);
    BOOL stop = NO;
    
    while (!stop) {
        NSRange bufferRange = NSMakeRange(dataRange.length-BUFFER_LENGTH, BUFFER_LENGTH);
        [data getBytes:buffer range:bufferRange];
        for (int i = (BUFFER_LENGTH-1); i > 0; i--) {
            unsigned char byte = buffer[i];
            if (byte != 0) {
                stop = YES;
                break;
            }
            dataRange.length = dataRange.length-1;
        }
    }
    free(buffer);
    
    if (dataRange.length == data.length) {
        return data;
    } else {
        return [data subdataWithRange:dataRange];
    }
}

@implementation PHImageManager (compatibleImageData)

- (PHImageRequestID)vd_requestImageDataForAsset:(PHAsset *)asset options:(PHImageRequestOptions *)options resultHandler:(void (^)(NSData *, NSString *, UIImageOrientation, NSDictionary *))resultHandler
{
    return [self requestImageDataForAsset:asset options:options resultHandler:^(NSData *imageData, NSString *dataUTI, UIImageOrientation orientation, NSDictionary *info) {
        resultHandler(VDTrimmedZeroBytesData(imageData), dataUTI, orientation, info);
    }];
}

@end