SWFParser.m

#import "SWFParser.h"
#import <XADMaster/CSFileHandle.h>
#import <XADMaster/CSZlibHandle.h>


NSString *SWFWrongMagicException=@"SWFWrongMagicException";
NSString *SWFNoMoreTagsException=@"SWFNoMoreTagsException";


@implementation SWFParser

+(SWFParser *)parserWithHandle:(CSHandle *)handle
{
	return [[[SWFParser alloc] initWithHandle:handle] autorelease];
}

+(SWFParser *)parserForPath:(NSString *)path
{
	CSFileHandle *handle=[CSFileHandle fileHandleForReadingAtPath:path];
	return [[[SWFParser alloc] initWithHandle:handle] autorelease];
}

-(id)initWithHandle:(CSHandle *)handle
{
	if(self=[super init])
	{
		fh=[handle retain];

		@try { [self parseHeader]; }
		@catch(id e) { [self release]; @throw; }
	}
	return self;
}

-(void)dealloc
{
	[fh release];
	[super dealloc];
}

-(void)parseHeader
{
	uint8_t magic[4];
	[fh readBytes:4 toBuffer:magic];

	version=magic[3];
	totallen=[fh readUInt32LE];

	if((magic[0]!='F'&&magic[0]!='C')||magic[1]!='W'||magic[2]!='S')
	[NSException raise:SWFWrongMagicException format:@"Not a Shockwave Flash file."];

	if(magic[0]=='C')
	{
		CSZlibHandle *zh=[CSZlibHandle zlibHandleWithHandle:fh];
		[fh release];
		fh=[zh retain];
	}

	rect=SWFParseRect(fh);
	fps=[fh readUInt16LE];
	frames=[fh readUInt16LE];

	nexttag=[fh offsetInFile];

	currtag=0;
	currlen=0;
	currframe=0;
}


-(int)version { return version; }
-(SWFRect)rect { return rect; }
-(int)frames { return frames; }
-(int)framesPerSecond { return fps; }

-(int)nextTag
{
	if(!nexttag) [NSException raise:SWFNoMoreTagsException format:@"No more tags available in the SWF file."];
	if(currtag==SWFShowFrameTag) currframe++;

	[fh seekToFileOffset:nexttag];

	int tagval=[fh readUInt16LE];

	currtag=tagval>>6;
	if(currtag==0)
	{
		nexttag=0;
		return 0;
	}

	currlen=tagval&0x3f;
	if(currlen==0x3f) currlen=[fh readUInt32LE];

	nexttag=[fh offsetInFile]+currlen;

	return currtag;
}

-(int)tag { return currtag; }
-(int)tagLength { return currlen; }
-(int)tagBytesLeft { return nexttag-[fh offsetInFile]; }
-(int)frame { return currframe; }
-(double)time { return (double)currframe/((double)fps/256.0); }

-(CSHandle *)handle { return fh; }

-(CSHandle *)tagHandle { return [fh subHandleOfLength:[self tagBytesLeft]]; }

-(NSData *)tagContents { return [fh readDataOfLength:[self tagBytesLeft]]; }

@end