Objective-c category for saving an `ALAssetRepresentation` to disk using a buffer (instead of reading the whole thing into memory).

ALAssetRepresentation+SaveToDisk.m

//
//  ALAssetRepresentation+SaveToDisk.m
//
//  Adapted from http://damir.me/import-video-from-alasset
//
//  Created by Joshua Wright<@BendyTree> on 12/17/13.
//  http://www.joshwright.com
//

#import "ALAssetRepresentation+SaveToDisk.h"

@implementation ALAssetRepresentation (SaveToDisk)

- (BOOL) saveTo:(NSString *)filePath
{
    // Create a file handle to write the file at your destination path
    [[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil];
    NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:filePath];
    if (!handle)
        return NO;
    
    // Create a buffer for the asset
    static const NSUInteger BufferSize = 1024*1024;
    uint8_t *buffer = calloc(BufferSize, sizeof(*buffer));
    NSUInteger offset = 0, bytesRead = 0;
    
    // Read the buffer and write the data to your destination path as you go
    do
    {
        @try
        {
            NSError* error = nil;
            bytesRead = [self getBytes:buffer fromOffset:offset length:BufferSize error:&error];
            [handle writeData:[NSData dataWithBytesNoCopy:buffer length:bytesRead freeWhenDone:NO]];
            offset += bytesRead;
            
            if(error) return NO;
        }
        @catch (NSException *exception)
        {
            free(buffer);
            return NO;
        }
    } while (bytesRead > 0);
    
    free(buffer);
    
    return YES;
}

@end