cog/Plugins/CueSheet/CueSheetDecoder.m

//
//  CueSheetDecoder.m
//  CueSheet
//
//  Created by Zaphod Beeblebrox on 10/8/07.
//  Copyright 2007 __MyCompanyName__. All rights reserved.
//

#import "CueSheetDecoder.h"

#import "CueSheet.h"
#import "CueSheetTrack.h"
#import "CueSheetContainer.h"

#import "Logging.h"

@implementation CueSheetDecoder

+ (NSArray *)fileTypes 
{	
	return [CueSheetContainer fileTypes];
}

+ (NSArray *)mimeTypes
{	
	return [CueSheetContainer mimeTypes];
}

+ (float)priority
{
    return 16.0f;
}

- (NSDictionary *)properties 
{
	NSMutableDictionary *properties = [[decoder properties] mutableCopy];

	//Need to alter length
	[properties setObject:[NSNumber numberWithLong:(trackEnd - trackStart)] forKey:@"totalFrames"];

	return properties;
}

- (BOOL)open:(id<CogSource>)s
{
	if (![[s url] isFileURL]) {
		return NO;
	}

	NSURL *url = [s url];

    embedded = NO;
    cuesheet = nil;
    NSDictionary * fileMetadata;

    noFragment = NO;

    NSString *ext = [url pathExtension];
    if ([ext caseInsensitiveCompare:@"cue"] != NSOrderedSame)
    {
        // Embedded cuesheet check
        fileMetadata = [NSClassFromString(@"AudioMetadataReader") metadataForURL:url skipCue:YES];
        NSString * sheet = [fileMetadata objectForKey:@"cuesheet"];
        if ([sheet length])
        {
            cuesheet = [CueSheet cueSheetWithString:sheet withFilename:[url path]];
            embedded = YES;
        }
        
        baseURL = url;
        
        NSString *fragment = [url fragment];
        if (!fragment || [fragment isEqualToString:@""])
            noFragment = YES;
    }
    else
        cuesheet = [CueSheet cueSheetWithFile:[url path]];
	
    if (!noFragment)
    {
        NSArray *tracks = [cuesheet tracks];
        int i;
        for (i = 0; i < [tracks count]; i++)
        {
            if ([[[tracks objectAtIndex:i] track] isEqualToString:[url fragment]]){
                track = [tracks objectAtIndex:i];

                NSURL *trackUrl = (embedded) ? baseURL : [track url];

                //Kind of a hackish way of accessing outside classes.
                source = [NSClassFromString(@"AudioSource") audioSourceForURL:trackUrl];

                if (![source open:url]) {
                    ALog(@"Could not open cuesheet source");
                    return NO;
                }

                decoder = [NSClassFromString(@"AudioDecoder") audioDecoderForSource:source skipCue:YES];

                if (![decoder open:source]) {
                    ALog(@"Could not open cuesheet decoder");
                    return NO;
                }

                CueSheetTrack *nextTrack = nil;
                if (i + 1 < [tracks count]) {
                    nextTrack = [tracks objectAtIndex:i + 1];
                }

                NSDictionary *properties = [decoder properties];
                int bitsPerSample = [[properties objectForKey:@"bitsPerSample"] intValue];
                int channels = [[properties objectForKey:@"channels"] intValue];
                float sampleRate = [[properties objectForKey:@"sampleRate"] floatValue];

                bytesPerFrame = (bitsPerSample/8) * channels;
			
                double _trackStart = [track time];
                if (![track timeInSamples]) _trackStart *= sampleRate;
                trackStart = _trackStart;

                if (nextTrack && (embedded || ([[[nextTrack url] absoluteString] isEqualToString:[[track url] absoluteString]]))) {
                    double _trackEnd = [nextTrack time];
                    if (![nextTrack timeInSamples]) _trackEnd *= sampleRate;
                    trackEnd = _trackEnd;
                }
                else {
                    trackEnd = [[properties objectForKey:@"totalFrames"] doubleValue];
                }
			
                [self seek: 0];

                //Note: Should register for observations of the decoder
                [self willChangeValueForKey:@"properties"];
                [self didChangeValueForKey:@"properties"];

                return YES;
            }
        }
    }
    else {
        NSURL *trackUrl = (embedded) ? baseURL : [track url];

        //Kind of a hackish way of accessing outside classes.
        source = [NSClassFromString(@"AudioSource") audioSourceForURL:trackUrl];

        if (![source open:url]) {
            ALog(@"Could not open cuesheet source");
            return NO;
        }

        decoder = [NSClassFromString(@"AudioDecoder") audioDecoderForSource:source skipCue:YES];

        if (![decoder open:source]) {
            ALog(@"Could not open cuesheet decoder");
            return NO;
        }

        NSDictionary *properties = [decoder properties];
        int bitsPerSample = [[properties objectForKey:@"bitsPerSample"] intValue];
        int channels = [[properties objectForKey:@"channels"] intValue];

        bytesPerFrame = (bitsPerSample/8) * channels;

        trackStart = 0;

        trackEnd = [[properties objectForKey:@"totalFrames"] doubleValue];
        
        [self seek: 0];
        
        return YES;
    }

	return NO;
}

- (void)close {
	if (decoder) {
		[decoder close];
		decoder = nil;
	}

    source = nil;
    cuesheet = nil;
    track = nil;
}

- (void)dealloc {
    [self close];
}

- (BOOL)setTrack:(NSURL *)url
{
    // handling the file directly
    if (noFragment)
        return NO;
    
	//Same file, just next track...this may be unnecessary since frame-based decoding is done now...
	if (embedded || ([[[track url] path] isEqualToString:[url path]] && [[[track url] host] isEqualToString:[url host]] && [[url fragment] intValue] == [[track track] intValue] + 1)) {
		NSArray *tracks = [cuesheet tracks];
		
		int i;
		for (i = 0; i < [tracks count]; i++) {
			if ([[[tracks objectAtIndex:i] track] isEqualToString:[url fragment]]){
				track = [tracks objectAtIndex:i];
				
				float sampleRate = [[[decoder properties] objectForKey:@"sampleRate"] floatValue];
				
				double _trackStart = [track time];
                if (![track timeInSamples]) _trackStart *= sampleRate;
                trackStart = _trackStart;
				
				CueSheetTrack *nextTrack = nil;
				if (i + 1 < [tracks count]) {
					nextTrack = [tracks objectAtIndex:i + 1];
				}

				if (nextTrack && (embedded || [[[nextTrack url] absoluteString] isEqualToString:[[track url] absoluteString]])) {
                    double _trackEnd = [nextTrack time];
                    if (![nextTrack timeInSamples]) _trackEnd *= sampleRate;
                    trackEnd = _trackEnd;
				}
				else {
					trackEnd = [[[decoder properties] objectForKey:@"totalFrames"] longValue];
				}
                
                if (embedded)
                    [self seek:0];
				
				DLog(@"CHANGING TRACK!");
				return YES;
			}
		}
	}
	
	return NO;
}

- (long)seek:(long)frame
{
	if (frame > trackEnd - trackStart) {
		//need a better way of returning fail.
		return -1;
	}
	
	frame += trackStart;
	
	framePosition = [decoder seek:frame];

	return framePosition;
}

- (int)readAudio:(void *)buf frames:(UInt32)frames
{
	if (framePosition + frames > trackEnd) {
		frames = (UInt32)(trackEnd - framePosition);
	}

	if (!frames)
	{
		DLog(@"Returning 0");
		return 0;
	}

	int n = [decoder readAudio:buf frames:frames];
	
	framePosition += n;
	
	return n;
}


@end