/*

    File:  TestTrack.m

    Contains:  Simple class that illustrates how to implement a verifying track data producer.

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*/

#import "TestTrack.h"

@implementation TestTrack

- (id) initWithProducer:(id)producer

{

    if ((self = [super initWithProducer:producer]) != nil)

    {

        NSMutableDictionary*    properties = [[NSMutableDictionary alloc] init];

        [properties setObject:[(TestTrackProducer*)producer length] forKey:DRTrackLengthKey];

        [properties setObject:[NSNumber numberWithUnsignedShort:2048] forKey:DRBlockSizeKey];

        [properties setObject:[NSNumber numberWithInt:16] forKey:DRDataFormKey];

        [properties setObject:[NSNumber numberWithInt:8] forKey:DRBlockTypeKey];

        [properties setObject:[NSNumber numberWithInt:4] forKey:DRTrackModeKey];

        [properties setObject:[NSNumber numberWithInt:0] forKey:DRSessionFormatKey];

        [properties setObject:[producer verificationType] forKey:DRVerificationTypeKey];

        [self setProperties:properties];

        [properties release];

    }

    return self;

}

@end

@implementation TestTrackProducer

#define POLYNOMIAL 0x04c11db7L

static unsigned long crc_table[256];

/* generate the table of CRC remainders for all possible bytes */

static void GenerateCRCTable()

{

    register int i, j;  

    register unsigned long crc_accum;

    for (i = 0;  i < 256;  i++)

    {

        crc_accum = ((unsigned long) i << 24);

        for (j = 0;  j < 8;  j++)

        {

            if (crc_accum & 0x80000000L)

                crc_accum = (crc_accum << 1) ^ POLYNOMIAL;

            else

                crc_accum = (crc_accum << 1);

        }

        crc_table[i] = crc_accum;

    }

}

/* update the CRC on the data block one byte at a time */

static unsigned long UpdateCRC(unsigned long crc_accum, const char *data_blk_ptr, int data_blk_size)

{

    register int i, j;

    for (j = 0;  j < data_blk_size;  j++)

    {

        i = ((int) (crc_accum >> 24) ^ *data_blk_ptr++) & 0xff;

        crc_accum = (crc_accum << 8) ^ crc_table[i];

    }

    return crc_accum;

}

+ (void) initialize

{

    // see the random number generator for later use.

    srandom([NSDate timeIntervalSinceReferenceDate]);

    GenerateCRCTable();

}

// -------------------------------------------------------------------------

- (id) initWithLength:(DRMSF*)aLength verificationType:(NSString*)type

{

    if ((self = [super init]) != nil)

    {

        length = [aLength retain];

        verificationType = [type retain];

    }

    return self;

}

// -------------------------------------------------------------------------

- (void) dealloc

{

    [length release];

    [verificationType release];

    [super dealloc];

}

// -------------------------------------------------------------------------

- (DRMSF*) length

{

    return length;

}

// -------------------------------------------------------------------------

- (NSString*) verificationType

{

    return verificationType;

}

#pragma mark -

// -------------------------------------------------------------------------

/* This method is called before the burn is to begin. */

- (BOOL) prepareTrack:(DRTrack*)track forBurn:(DRBurn*)burn toMedia:(NSDictionary*)mediaInfo

{

    productionChecksum = 0xFFFFFFFF;

    return YES;

}

// -------------------------------------------------------------------------

/* The meat of the producer object. This method is called repeatedly during a burn.

    It's the producer's job to write data into the passed in buffer each time it's 

    called.  It's best if you can fill up the buffer completely. The buffer is

    a multiple of blockSize in length. */

- (uint32_t) produceDataForTrack:(DRTrack*)track intoBuffer:(char*)buffer length:(uint32_t)bufferLength atAddress:(uint64_t)address blockSize:(uint32_t)blockSize ioFlags:(uint32_t*)flags

{

    uint32_t        expectedFrames = (bufferLength / 4);

    if ([[self verificationType] isEqualToString:DRVerificationTypeReceiveData])

    {

        while (expectedFrames--)

        {

            ((unsigned long*)buffer)[expectedFrames] = (unsigned long)random();

        }

        productionChecksum = UpdateCRC(productionChecksum, buffer, bufferLength);

    }

    else

    {

        while (expectedFrames--)

        {

            ((long*)buffer)[expectedFrames] = expectedFrames;

        }

    }

    return bufferLength;

}

// -------------------------------------------------------------------------

/* This method is called after the data has been burned to the disc, but right before

    the data is verified. If no verification is asked for, this method won't

    be called. Rewind file pointers to 0, or do whatever is needed to get ready to

    start verifying. */

- (BOOL) prepareTrackForVerification:(DRTrack*)track

{

    verificationChecksum = 0xFFFFFFFF;

    return YES;

}

// -------------------------------------------------------------------------

/* OK, we're doing something to illustrate a point. The track producer has asked for

    DRTrackVerificationReceiveData. This means that every bit of data written to

    CD will be sent back to us through this method for us to verify. It's very similar

    to a production call, except that we need to do verification of the buffer passed in. 

    Don't think you have to do it this way. The more typical way of verifying a disc

    is to set the verification type of the track to DRTrackVerificationProduceAgain

    and let the engine do the checking for you. This method is here if you really need

    to do the checking yourself. */

- (BOOL) verifyDataForTrack:(DRTrack*)track inBuffer:(const char*)buffer length:(uint32_t)bufferLength atAddress:(uint64_t)address blockSize:(uint32_t)blockSize ioFlags:(uint32_t*)flags

{

    verificationChecksum = UpdateCRC(verificationChecksum, buffer, bufferLength);

    return YES; // we won't know for sure if it verified until the end.

}

// -------------------------------------------------------------------------

/* This method is sent when verification is all done and it verified correct.

    Last chance to say something is wrong!! */

- (BOOL) cleanupTrackAfterVerification:(DRTrack*)track

{

    // This works because in the non-checksumming case (DRTrackVerificationProduceAgain)

    // both checksum values are 0xFFFFFFFF. In the other case (DRTrackVerificationReceiveData)

    // they had better be the same or else something is wrong.

    return verificationChecksum == productionChecksum;

}

// -------------------------------------------------------------------------

/* This method is called after the burn is finished and all data has been written

    to disc and optionally verified. This producer, doesn't need to do anything in it, 

    but this would be where you would free up any resources allocated in preBurn. */

- (void) cleanupTrackAfterBurn:(DRTrack*)track

{

}

@end