Cog/Audio/Chain/Node.m

//
//  Node.m
//  CogNew
//
//  Created by Vincent Spader on 1/4/06.
//  Copyright 2006 Vincent Spader. All rights reserved.
//

#import "Node.h"

#import "Logging.h"
#import "BufferChain.h"

@implementation Node

- (id)initWithController:(id)c previous:(id)p
{
	self = [super init];
	if (self)
	{
        buffer = [[ChunkList alloc] initWithMaximumDuration:3.0];
        semaphore = [[Semaphore alloc] init];
        
        accessLock = [[NSRecursiveLock alloc] init];
		
		initialBufferFilled = NO;
		
		controller = c;
		endOfStream = NO;
		shouldContinue = YES;
        
        nodeLossless = NO;

		[self setPreviousNode:p];
	}
	
	return self;
}

- (AudioStreamBasicDescription)nodeFormat
{
    return nodeFormat;
}

- (BOOL)nodeLossless
{
    return nodeLossless;
}

- (void)writeData:(const void *)ptr amount:(size_t)amount
{
    [accessLock lock];
    
    AudioChunk * chunk = [[AudioChunk alloc] init];
    [chunk setFormat:nodeFormat];
    [chunk setLossless:nodeLossless];
    [chunk assignSamples:ptr frameCount:amount / nodeFormat.mBytesPerPacket];
    
    const double chunkDuration = [chunk duration];
    double durationLeft = [buffer maxDuration] - [buffer listDuration];
    
    while (shouldContinue == YES && chunkDuration > durationLeft)
    {
        if (durationLeft < chunkDuration) {
            if (initialBufferFilled == NO) {
                initialBufferFilled = YES;
                if ([controller respondsToSelector:@selector(initialBufferFilled:)])
                    [controller performSelector:@selector(initialBufferFilled:) withObject:self];
            }
        }
        
        if (durationLeft < chunkDuration || shouldReset) {
            [accessLock unlock];
            [semaphore wait];
            [accessLock lock];
        }
        
        durationLeft = [buffer maxDuration] - [buffer listDuration];
    }
    
    [buffer addChunk:chunk];
    
    [accessLock unlock];
}

//Should be overwriten by subclass.
- (void)process
{
}

- (void)threadEntry:(id)arg
{
    @autoreleasepool {
        [self process];
    }
}

- (AudioChunk *)readChunk:(size_t)maxFrames
{
    [accessLock lock];
    
    if ([[previousNode buffer] isEmpty] && [previousNode endOfStream] == YES)
    {
        endOfStream = YES;
        [accessLock unlock];
        return [[AudioChunk alloc] init];
    }
    
    if ([previousNode shouldReset] == YES) {
		[buffer reset];

		shouldReset = YES;
		[previousNode setShouldReset: NO];
        
        [[previousNode semaphore] signal];
	}

    AudioChunk * ret = [[previousNode buffer] removeSamples:maxFrames];

    [accessLock unlock];
    
    if ([ret frameCount])
    {
        [[previousNode semaphore] signal];
    }

    return ret;
}

- (void)launchThread
{
	[NSThread detachNewThreadSelector:@selector(threadEntry:) toTarget:self withObject:nil];
}

- (void)setPreviousNode:(id)p
{
	previousNode = p;
}

- (id)previousNode
{
	return previousNode;
}

- (BOOL)shouldContinue
{
	return shouldContinue;
}

- (void)setShouldContinue:(BOOL)s
{
	shouldContinue = s;
}

- (ChunkList *)buffer
{
	return buffer;
}

- (void)resetBuffer
{
	shouldReset = YES; //Will reset on next write.
	if (previousNode == nil) {
        [accessLock lock];
		[buffer reset];
        [accessLock unlock];
	}
}

- (Semaphore *)semaphore
{
	return semaphore;
}

- (BOOL)endOfStream
{
	return endOfStream;
}

- (void)setEndOfStream:(BOOL)e
{
	endOfStream = e;
}

- (void)setShouldReset:(BOOL)s
{
	shouldReset = s;
}
- (BOOL)shouldReset
{
	return shouldReset;
}

// Buffering nodes should implement this
- (double)secondsBuffered
{
    return 0.0;
}


@end