sl@0: // Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: // All rights reserved.
sl@0: // This component and the accompanying materials are made available
sl@0: // under the terms of "Eclipse Public License v1.0"
sl@0: // which accompanies this distribution, and is available
sl@0: // at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: //
sl@0: // Initial Contributors:
sl@0: // Nokia Corporation - initial contribution.
sl@0: //
sl@0: // Contributors:
sl@0: //
sl@0: // Description:
sl@0: //
sl@0: 
sl@0: #include "constants.h"
sl@0: #include "parsers.h"
sl@0: 
sl@0: //
sl@0: // Matroska 'XML' tags.
sl@0: //
sl@0: static const TUint32 KEBML = 0x1A45DFA3;
sl@0: static const TUint32 KSegment = 0x18538067;
sl@0: static const TUint32 KTracks = 0x1654AE6B;
sl@0: static const TUint32 KTrackEntry = 0xAE;
sl@0: static const TUint32 KTrackType = 0x83;
sl@0: static const TUint32 KVoid = 0xEC;
sl@0: static const TUint32 KSeekHead = 0x114D9B74;
sl@0: static const TUint32 KSegmentInfo = 0x1549A966;
sl@0: static const TUint32 KCluster = 0x1F43B675;
sl@0: static const TUint32 KCues = 0x1C53BB6B;
sl@0: static const TUint32 KAttachments = 0x1941A469;
sl@0: static const TUint32 KChapters = 0x1043A770;
sl@0: static const TUint32 KTags = 0x1254C367;
sl@0: 
sl@0: //
sl@0: // Matroska Track Types.
sl@0: //
sl@0: static const TUint8 KTrackTypeVideo = 0x01;
sl@0: 
sl@0: #define KMatroskaConfidenceMask	0x07	// 00000111
sl@0: #define KMatroskaEBMLBit		KBit1
sl@0: #define KMatroskaSegmentBit		KBit2
sl@0: #define KMatroskaVideoBit		KBit3
sl@0: 
sl@0: 
sl@0: //
sl@0: // This truth table maps the following flags to confidence levels.
sl@0: //
sl@0: // A: Extension match.
sl@0: // B: EBML tag found.
sl@0: // C: Segment tag found.
sl@0: //
sl@0: // C B A -> Confidence
sl@0: // --------------------
sl@0: // 0 0 0 -> NotRecognised
sl@0: // 0 0 1 -> EPossible
sl@0: // 0 1 0 -> EPossible
sl@0: // 0 1 1 -> EProbable
sl@0: // 1 0 0 -> ENotRecognised (EBML should be present)
sl@0: // 1 0 1 -> ENotRecognised (EBML should be present)
sl@0: // 1 1 0 -> EProbable
sl@0: // 1 1 1 -> ECertain
sl@0: //
sl@0: static const TInt KMatroskaFlagsToConfidence[8] =
sl@0: 	{
sl@0: 	KConfNotRecognised,
sl@0: 	KConfPossible,
sl@0: 	KConfPossible,
sl@0: 	KConfProbable,
sl@0: 	KConfNotRecognised,
sl@0: 	KConfNotRecognised,
sl@0: 	KConfProbable,
sl@0: 	KConfCertain
sl@0: 	};
sl@0: 	
sl@0: static const TInt KMatExtensionOnlyIndex = 1; // See truth table.
sl@0: 
sl@0: 
sl@0: typedef struct
sl@0: 	{
sl@0: 	const TText* iExt;
sl@0: 	const TText8* iMime;
sl@0: 	}
sl@0: TMatroskaExt;
sl@0: 
sl@0: //
sl@0: // Known Matroska extensions and their corresponding MIME-types.
sl@0: //
sl@0: static const TMatroskaExt KMatroskaExt[] =
sl@0: 	{
sl@0: 		{KExtMAT_A, KMimeMAT_A },
sl@0: 		{KExtMAT_V, KMimeMAT_V }
sl@0: 	};
sl@0: 
sl@0: static const TInt KMatroskaExtCount = sizeof(KMatroskaExt) / sizeof(TMatroskaExt);
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: TMatroskaParser::TMatroskaParser(CReader& aReader, TFlags& aFlags)
sl@0:  :	iReader(aReader),
sl@0:  	iFlags(aFlags)
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: const TText8* TMatroskaParser::MatchExtension(const TDesC& aExt)
sl@0: 	{
sl@0: 	for (TInt i = 0; i < KMatroskaExtCount; i++)
sl@0: 		{
sl@0: 		if (aExt.MatchF(TPtrC(KMatroskaExt[i].iExt)) != KErrNotFound)
sl@0: 			{
sl@0: 			return KMatroskaExt[i].iMime;
sl@0: 			}
sl@0: 		}
sl@0: 	
sl@0: 	return NULL;
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // This function calls the parser and turns the results
sl@0: // into a MIME-type.
sl@0: //
sl@0: void TMatroskaParser::DoRecognise(const TDesC& aExt, CReader& aReader, TMatch& aMatch)
sl@0: 	{
sl@0: 	TFlags flags;
sl@0: 	TMatroskaParser parser(aReader, flags);
sl@0: 	
sl@0: 	// Try to match the extension.
sl@0: 	const TText8* extMime = parser.MatchExtension(aExt);
sl@0: 	if (extMime != NULL)
sl@0: 		{
sl@0: 		flags.SetExtensionFlag();
sl@0: 		}
sl@0: 
sl@0: 	// Try to parse the content.
sl@0: 	TRAP_IGNORE(parser.ParseL());
sl@0: 	TInt confIndex = flags.GetBitField(KMatroskaConfidenceMask);
sl@0: 	aMatch.iConfidence = KMatroskaFlagsToConfidence[confIndex];
sl@0: 	if (aMatch.iConfidence != KConfNotRecognised)
sl@0: 		{
sl@0: 		// If any header data has been recognised trust that,
sl@0: 		// otherwise go with the extension.
sl@0: 		if (confIndex == KMatExtensionOnlyIndex)
sl@0: 			{
sl@0: 			aMatch.iMime = extMime;
sl@0: 			}
sl@0: 		else
sl@0: 			{
sl@0: 			aMatch.iMime = (flags.GetBitField(KMatroskaVideoBit) ? KMimeMAT_V : KMimeMAT_A);
sl@0: 			}
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // This function does the parsing.
sl@0: //
sl@0: void TMatroskaParser::ParseL()
sl@0: 	{
sl@0: 	TUint64 id;
sl@0: 	TInt64 size;
sl@0: 	TBool haveElement = EFalse;
sl@0: 	
sl@0: 	// Assume there's video content if we only have buffer data.
sl@0: 	if (iReader.Type() == CReader::EBuffer)
sl@0: 		{
sl@0: 		iFlags.SetBit(KMatroskaVideoBit);
sl@0: 		}
sl@0: 		
sl@0: 	FOREVER
sl@0: 		{
sl@0: 		if (!haveElement)
sl@0: 			{
sl@0: 			ReadElementL(id, size);
sl@0: 			}
sl@0: 		
sl@0: 		switch (id)
sl@0: 			{
sl@0: 			case KEBML:
sl@0: 				iFlags.SetBit(KMatroskaEBMLBit);
sl@0: 				break;
sl@0: 				
sl@0: 			case KSegment:
sl@0: 				haveElement = ReadSegmentL(id, size);
sl@0: 				break;
sl@0: 				
sl@0: 			default:
sl@0: 				// Skip it.
sl@0: 				iReader.SeekL(size);
sl@0: 			}
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // This function returns ETrue if the aNextID and aNextSize parameters
sl@0: // contain valid values, EFalse otherwise.
sl@0: //
sl@0: TBool TMatroskaParser::ReadSegmentL(TUint64& aNextID, TInt64& aNextSize)
sl@0: 	{
sl@0: 	TUint64 id;
sl@0: 	TInt64 size;
sl@0: 	TBool videoContent = EFalse;
sl@0: 	
sl@0: 	aNextID = 0;
sl@0: 	aNextSize = 0;
sl@0: 	
sl@0: 	iFlags.SetBit(KMatroskaSegmentBit);
sl@0: 	
sl@0: 	while (!videoContent)
sl@0: 		{
sl@0: 		ReadElementL(id, size);
sl@0: 		
sl@0: 		switch (id)
sl@0: 			{
sl@0: 			case KTracks:
sl@0: 				videoContent = ReadTrackL(size);
sl@0: 				break;
sl@0: 			
sl@0: 			case KSeekHead:
sl@0: 			case KSegmentInfo:
sl@0: 			case KCluster:
sl@0: 			case KCues:
sl@0: 			case KAttachments: 
sl@0: 			case KChapters:
sl@0: 			case KTags:
sl@0: 				iReader.SeekL(size);
sl@0: 				break;
sl@0: 				
sl@0: 			default:
sl@0: 				// Unrecognised element id. Pass it back to the caller
sl@0: 				aNextID = id;
sl@0: 				aNextSize = size;
sl@0: 				return ETrue;
sl@0: 			}
sl@0: 		}
sl@0: 	
sl@0: 	// Tell the caller they must read the next element themselves.
sl@0: 	return EFalse;
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // The Track. This lets us know if there's video content present.
sl@0: //
sl@0: TBool TMatroskaParser::ReadTrackL(TInt64 aTrackSize)
sl@0: 	{
sl@0: 	TUint64 id;
sl@0: 	TInt64 size;
sl@0: 	TInt startPos = iReader.Position();
sl@0: 	
sl@0: 	while (iReader.Position() - startPos < aTrackSize)
sl@0: 		{
sl@0: 		ReadElementL(id, size);
sl@0: 
sl@0: 		switch (id)
sl@0: 			{
sl@0: 			case KTrackEntry:
sl@0: 				break;
sl@0: 				
sl@0: 			case KTrackType:
sl@0: 				TUint8 trackType;
sl@0: 				iReader.ReadByteL(trackType);
sl@0: 				if (trackType == KTrackTypeVideo)
sl@0: 					{
sl@0: 					// We found video content so we can stop parsing.
sl@0: 					iFlags.SetBit(KMatroskaVideoBit);
sl@0: 					return ETrue;
sl@0: 					}
sl@0: 				break;
sl@0: 				
sl@0: 			default:
sl@0: 				iReader.SeekL(size);
sl@0: 			}
sl@0: 		}
sl@0: 		
sl@0: 	return EFalse;
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: void TMatroskaParser::ReadElementL(TUint64& aElementID, TInt64& aSize)
sl@0: 	{
sl@0: 	do
sl@0: 		{
sl@0: 		aElementID = ReadDataL();
sl@0: 		aSize = ReadDataL(ETrue);
sl@0: 
sl@0: 		// Void elements are used for padding and
sl@0: 		// can be ignored.
sl@0: 		if (aElementID == KVoid)
sl@0: 			{
sl@0: 			iReader.SeekL(aSize);
sl@0: 			}
sl@0: 		}
sl@0: 	while (aElementID == KVoid);
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: TUint64 TMatroskaParser::ReadDataL(TBool aTurnOffHighestSetBit)
sl@0: 	{
sl@0: 	TUint64 retval;
sl@0: 	TUint8 byte;
sl@0: 	TUint8 mask = 0x80; // [1000 0000]. It will be shifted right 1 in each 'i' iteration.
sl@0: 	TUint8 size = 1;	// It will be incremented in each 'i' iteration.
sl@0: 	
sl@0: 	iReader.ReadByteL(byte);
sl@0: 	
sl@0: 	for (TInt i = 0; i < sizeof(TUint64); i++)
sl@0: 		{
sl@0: 		if (byte & mask)
sl@0: 			{
sl@0: 			retval = byte;
sl@0: 			if (aTurnOffHighestSetBit)
sl@0: 				{
sl@0: 				retval &= ~mask; // Turn off the highest set bit.
sl@0: 				}
sl@0: 			
sl@0: 			// Now read the real data.
sl@0: 			// Start from 1 because we've already read a byte.
sl@0: 			for (TInt j = 1; j < size; j++)
sl@0: 				{
sl@0: 				iReader.ReadByteL(byte);
sl@0: 				retval <<= 8;
sl@0: 				retval |= byte;
sl@0: 				}
sl@0: 				
sl@0: 			return retval;
sl@0: 			}
sl@0: 		else
sl@0: 			{
sl@0: 			mask >>= 1;
sl@0: 			size++;
sl@0: 			}
sl@0: 		}
sl@0: 
sl@0: 	User::Leave(KErrCorrupt);
sl@0: 	return 0; // Keep the compiler happy.
sl@0: 	}
sl@0: