cog/Plugins/Shorten/ShortenDecoder.mm

//
//  ShnFile.mm
//  Cog
//
//  Created by Vincent Spader on 6/6/05.
//  Copyright 2005 Vincent Spader All rights reserved.
//

#import "ShortenDecoder.h"

@implementation ShortenDecoder

- (BOOL)open:(id<CogSource>)source
{
	NSURL *url = [source url];
	[source close];

	if (![[url scheme] isEqualToString:@"file"])
		return NO;
	
	decoder	= new shn_reader;
	
	if (!decoder)
	{
		return NO;
	}
	
	decoder->open([[url path] UTF8String], true);
	
	bufferSize = decoder->shn_get_buffer_block_size(NUM_DEFAULT_BUFFER_BLOCKS);
	
	bool seekTable;
	decoder->file_info(NULL, &channels, &frequency, NULL, &bitsPerSample, &seekTable);

	seekable = seekTable == true ? YES : NO;

	totalFrames = (decoder->shn_get_song_length() * frequency)/1000.0;
	
	decoder->go();

	[self willChangeValueForKey:@"properties"];
	[self didChangeValueForKey:@"properties"];
		
	return YES;
}

- (int)readAudio:(void *)buf frames:(UInt32)frames
{
	int bytesPerFrame = channels * (bitsPerSample/8);
	int amountRead;

	//For some reason a busy loop is causing pops when output is set to 48000. Probably CPU starvation, since the SHN decoder seems to use a multithreaded nonblocking approach.
	do
	{
		amountRead = decoder->read(buf, frames * bytesPerFrame);
	} while(amountRead == -1);
		

	return amountRead/bytesPerFrame;
}

- (long)seek:(long)sample
{
	unsigned int sec = sample/frequency;
		
	decoder->seek(sec);
	
	return sample;
}

- (void)close
{
	if(decoder)
	{
		decoder->exit();
		delete decoder;
		decoder	= NULL;
	}

	/*if (shn_cleanup_decoder(handle))
		shn_unload(handle);*/
}

- (NSDictionary *)properties
{
	return [NSDictionary dictionaryWithObjectsAndKeys:
		[NSNumber numberWithInt:channels],@"channels",
		[NSNumber numberWithInt:bitsPerSample],@"bitsPerSample",
		[NSNumber numberWithFloat:frequency],@"sampleRate",
		[NSNumber numberWithDouble:totalFrames],@"totalFrames",
		[NSNumber numberWithBool:seekable ],@"seekable",
		@"little",@"endian",
		nil];
}

+ (NSArray *)fileTypes
{
	return [NSArray arrayWithObject:@"shn"];
}

+ (NSArray *)mimeTypes
{
	return [NSArray arrayWithObjects:@"application/x-shorten", nil]; //This is basically useless, since we cant stream shorten yet
}


@end