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 "parsers.h"
sl@0: 
sl@0: static const TUint32 KRMFileHeaderId = MAKE_INT32('.', 'R', 'M', 'F');
sl@0: static const TUint32 KRMMediaPropertiesId = MAKE_INT32('M', 'D', 'P', 'R');
sl@0: static const TInt KRMMaxMimeTypeLen = 255;	// Specified by an 8-bit field
sl@0: 
sl@0: #define KRMExtensionBit			KBit0
sl@0: #define KRMFileHeaderBit		KBit1
sl@0: #define KRMMediaPropertiesBit	KBit2
sl@0: #define KRMVideoBit				KBit3
sl@0: 
sl@0: #define KRMVideoMask			0x08	// 0000 1000
sl@0: #define KRMConfidenceMask 		0x07	// 0000 0111
sl@0: 
sl@0: //
sl@0: // This truth table maps the following flags to a confidence level.
sl@0: // -----------------------------------------------------------------
sl@0: // A: MediaProperties chunk found
sl@0: // B: FileHeader signature found
sl@0: // C: Extension recognised.
sl@0: //
sl@0: // A B C -> Confidence
sl@0: // ===================
sl@0: // 0 0 0 -> ENotRecognized
sl@0: // 0 0 1 -> EPossible
sl@0: // 0 1 0 -> EPossible (EPossible beacuse the header is ASCII and may match plaintext)
sl@0: // 0 1 1 -> ECertain
sl@0: // 1 0 0 -> ENotRecognised (Can't have MediaProperties without FileHeader)
sl@0: // 1 0 1 -> ENotRecognised (Can't have MediaProperties without FileHeader)
sl@0: // 1 1 0 -> EProbable
sl@0: // 1 1 1 -> ECertain
sl@0: //
sl@0: static const TInt KRMFlagsToConfidence[] =
sl@0: 	{
sl@0: 	KConfNotRecognised,
sl@0: 	KConfPossible,
sl@0: 	KConfPossible,
sl@0: 	KConfCertain,
sl@0: 	KConfNotRecognised,
sl@0: 	KConfNotRecognised,
sl@0: 	KConfProbable,
sl@0: 	KConfCertain
sl@0: 	};
sl@0: 
sl@0: 
sl@0: //
sl@0: // Constructor.
sl@0: //
sl@0: TRMParser::TRMParser(CReader& aReader, TFlags& aFlags)
sl@0:  :	iReader(aReader),
sl@0: 	iFlags(aFlags)
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // The main RealMedia parsing function.
sl@0: //
sl@0: void TRMParser::DoRecognise(const TDesC& aFileExt, CReader& aReader, TMatch& aMatch)
sl@0: 	{
sl@0: 	TFlags flags;
sl@0: 	TRMParser parser(aReader, flags);
sl@0: 
sl@0: 	parser.MatchExtension(aFileExt);
sl@0: 
sl@0: 	TRAP_IGNORE(parser.ParseL());
sl@0: 
sl@0: 	TInt confIndex = flags.GetBitField(KRMConfidenceMask);
sl@0: 	aMatch.iConfidence = KRMFlagsToConfidence[confIndex];
sl@0: 
sl@0: 	if (aMatch.iConfidence != KConfNotRecognised)
sl@0: 		{
sl@0: 		aMatch.iMime = (flags.GetBitField(KRMVideoMask) ? KMimeRM_V : KMimeRM_A);
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // Match the file extension given by AppArc against known
sl@0: // extensions for this format.
sl@0: //
sl@0: void TRMParser::MatchExtension(const TDesC& aFileExt)
sl@0: 	{
sl@0: 	TBool match;
sl@0: 
sl@0: 	match = (aFileExt.MatchF(TPtrC(KExtRMF)) != KErrNotFound);
sl@0: 	match |= (aFileExt.MatchF(TPtrC(KExtRM)) != KErrNotFound);
sl@0: 
sl@0: 	if (match)
sl@0: 		{
sl@0: 		iFlags.SetExtensionFlag();
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: //
sl@0: // RealMedia files are divided into chunks. Chunks begins with a 32-bit identifier
sl@0: // which is followed by a 32-bit unsigned field that specifies the size of the chunk
sl@0: // in bytes. Since the size field is unsigned, it must be cast to a TInt64 in order
sl@0: // for SeekL() to work reliably. The size field also includes the length of the chunk
sl@0: // identifier and the length of the size field itself, so these must be subtracted
sl@0: // from any seek operation.
sl@0: //
sl@0: void TRMParser::ParseL()
sl@0: 	{
sl@0: 	TUint32 objectId;
sl@0: 	TUint32 size;
sl@0: 	const TInt KChunkHeaderSize = sizeof(TUint32) * 2; // sizeof objectId and size fields.
sl@0: 
sl@0: 	// The first chunk must be the FileHeader.
sl@0: 	ReadChunkHeaderL(objectId, size, ETrue);
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(KRMVideoBit);
sl@0: 		}
sl@0: 
sl@0: 	iReader.SeekL(TInt64(size - KChunkHeaderSize));
sl@0: 
sl@0: 	// The other chunks can occur in any order.
sl@0: 	TBool complete = EFalse;
sl@0: 	do
sl@0: 		{
sl@0: 		ReadChunkHeaderL(objectId, size);
sl@0: 
sl@0: 		if (objectId == KRMMediaPropertiesId)
sl@0: 			{
sl@0: 			iFlags.SetBit(KRMMediaPropertiesBit);
sl@0: 			if (ReadMediaPropertiesL())
sl@0: 				{
sl@0: 				// Exit early if the video flag has been set by ReadMediaPropertiesL.
sl@0: 				complete = ETrue;
sl@0: 				}
sl@0: 			}
sl@0: 		else
sl@0: 			{
sl@0: 			// Skip over the unneeded chunk.
sl@0: 			iReader.SeekL(TInt64(size - KChunkHeaderSize));
sl@0: 			}
sl@0: 		}
sl@0: 	while (!complete);
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // Reads the chunk identifier and size.
sl@0: //
sl@0: void TRMParser::ReadChunkHeaderL(TUint32& aObjectId, TUint32& aSize, TBool aFirstChunk)
sl@0: 	{
sl@0: 	iReader.Read32L(aObjectId);
sl@0: 
sl@0: 	if (aFirstChunk)
sl@0: 		{
sl@0: 		if (aObjectId == KRMFileHeaderId)
sl@0: 			{
sl@0: 			iFlags.SetBit(KRMFileHeaderBit);
sl@0: 			}
sl@0: 		else
sl@0: 			{
sl@0: 			User::Leave(KErrCorrupt);
sl@0: 			}
sl@0: 		}
sl@0: 
sl@0: 	iReader.Read32L(aSize);
sl@0: 	if (aSize == 0)
sl@0: 		{
sl@0: 		User::Leave(KErrCorrupt);
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // The MediaProperties chunk describes a stream in the RM file. There
sl@0: // may be several MediaProperties chunks in one file. In order to determine
sl@0: // if video content is present we must look at the MIME-type that may
sl@0: // be present in each MediaProperties chunk.
sl@0: // Return ETrue if this function set the video bit.
sl@0: //
sl@0: TBool TRMParser::ReadMediaPropertiesL()
sl@0: 	{
sl@0: 	const TInt KBytesToFieldSize = 30;
sl@0: 	
sl@0: 	// ObjectId and size fields have already been read.
sl@0: 	TBool setVideo = EFalse;
sl@0: 	TUint16 objectVersion;
sl@0: 
sl@0: 	iReader.Read16L(objectVersion);
sl@0: 
sl@0: 	if (objectVersion == 0)
sl@0: 		{
sl@0: 		TUint8 fieldSize;
sl@0: 		TBuf8<KRMMaxMimeTypeLen> mimeType;
sl@0: 		_LIT8(KVideoStar, "video/*");
sl@0: 
sl@0: 		// Skip unneeded information.
sl@0: 		iReader.SeekL(KBytesToFieldSize);
sl@0: 
sl@0: 		// Read stream_name_size so we can skip over it.
sl@0: 		iReader.ReadByteL(fieldSize);
sl@0: 		iReader.SeekL(fieldSize);
sl@0: 
sl@0: 		// Read the mime_type_size. Because it's 8-bit, it has a max length of 256 bytes.
sl@0: 		iReader.ReadByteL(fieldSize);
sl@0: 
sl@0: 		mimeType.SetLength(fieldSize);
sl@0: 		iReader.ReadBytesL(mimeType);
sl@0: 
sl@0: 		// Now check if the mime-type field indicates video content.
sl@0: 		if (mimeType.MatchF(KVideoStar) != KErrNotFound)
sl@0: 			{
sl@0: 			iFlags.SetBit(KRMVideoBit);
sl@0: 			setVideo = ETrue;
sl@0: 			}
sl@0: 
sl@0: 		// Read the type_specific_len so we can skip over it.
sl@0: 		TUint32 typeSpecificLen;
sl@0: 		iReader.Read32L(typeSpecificLen);
sl@0: 		iReader.SeekL(TInt64(typeSpecificLen));
sl@0: 		}
sl@0: 
sl@0: 	return setVideo;
sl@0: 	}
sl@0: