sl@0: // Copyright (c) 1998-2009 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 the License "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: // f32\sfile\sf_inflate.h
sl@0: // 
sl@0: //
sl@0: 
sl@0: #include "sf_deflate.h"
sl@0: #include "sf_ldr.h"
sl@0: 
sl@0: // Class RInflater
sl@0: //
sl@0: // The inflation algorithm, complete with huffman decoding
sl@0: 
sl@0: inline CInflater::CInflater(TBitInput& aInput)
sl@0: 	:iBits(&aInput),iEncoding(0),iOut(0)
sl@0: 	{}
sl@0: 
sl@0: void CInflater::ConstructL()
sl@0: 	{
sl@0: 	iEncoding=new(ELeave) TEncoding;
sl@0: 	InitL();
sl@0: 	iLen=0;
sl@0: 	iOut=new(ELeave) TUint8[KDeflateMaxDistance];
sl@0: 	iAvail=iLimit=iOut;
sl@0: 	}
sl@0: 
sl@0: CInflater* CInflater::NewLC(TBitInput& aInput)
sl@0: 	{
sl@0: 	CInflater* self=new(ELeave) CInflater(aInput);
sl@0: 	CleanupStack::PushL(self);
sl@0: 	self->ConstructL();
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: CInflater::~CInflater()
sl@0: 	{
sl@0: 	delete iEncoding;
sl@0: 	delete [] iOut;
sl@0: 	}
sl@0: 
sl@0: TInt CInflater::ReadL(TUint8* aBuffer,TInt aLength, TMemoryMoveFunction aMemMovefn)
sl@0: 	{
sl@0: 	TInt tfr=0;
sl@0: 	for (;;)
sl@0: 		{
sl@0: 		TInt len=Min(aLength,iLimit-iAvail);
sl@0: 		if (len && aBuffer)
sl@0: 			{
sl@0: 			aMemMovefn(aBuffer,iAvail,len);
sl@0: 			aBuffer+=len;
sl@0: 			}
sl@0: 		aLength-=len;
sl@0: 		iAvail+=len;
sl@0: 		tfr+=len;
sl@0: 		if (aLength==0)
sl@0: 			return tfr;
sl@0: 		len=InflateL();
sl@0: 		if (len==0)
sl@0: 			return tfr;
sl@0: 		iAvail=iOut;
sl@0: 		iLimit=iAvail+len;
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: TInt CInflater::SkipL(TInt aLength)
sl@0: 	{
sl@0: 	return ReadL(0,aLength,Mem::Move);
sl@0: 	}
sl@0: 
sl@0: void CInflater::InitL()
sl@0: 	{
sl@0: // read the encoding
sl@0: 	Huffman::InternalizeL(*iBits,iEncoding->iLitLen,KDeflationCodes);
sl@0: // validate the encoding
sl@0: 	if (!Huffman::IsValid(iEncoding->iLitLen,TEncoding::ELitLens) ||
sl@0: 		!Huffman::IsValid(iEncoding->iDistance,TEncoding::EDistances))
sl@0: 		LEAVE_FAILURE(KErrCorrupt);
sl@0: // convert the length tables into huffman decoding trees
sl@0: 	Huffman::Decoding(iEncoding->iLitLen,TEncoding::ELitLens,iEncoding->iLitLen);
sl@0: 	Huffman::Decoding(iEncoding->iDistance,TEncoding::EDistances,iEncoding->iDistance,KDeflateDistCodeBase);
sl@0: 	}
sl@0: 
sl@0: TInt CInflater::InflateL()
sl@0: //
sl@0: // consume all data lag in the history buffer, then decode to fill up the output buffer
sl@0: // return the number of available bytes in the output buffer. This is only ever less than
sl@0: // the buffer size if the end of stream marker has been read
sl@0: //
sl@0: 	{
sl@0: // empty the history buffer into the output
sl@0: 	TUint8* out=iOut;
sl@0: 	TUint8* const end=out+KDeflateMaxDistance;
sl@0: 	const TUint32* tree=iEncoding->iLitLen;
sl@0: 	if (iLen<0)	// EOF
sl@0: 		return 0;
sl@0: 	if (iLen>0)
sl@0: 		goto useHistory;
sl@0: //
sl@0: 	while (out<end)
sl@0: 		{
sl@0: 		// get a huffman code
sl@0: 		{
sl@0: 		TInt val=iBits->HuffmanL(tree)-TEncoding::ELiterals;
sl@0: 		if (val<0)
sl@0: 			{
sl@0: 			*out++=TUint8(val);
sl@0: 			continue;			// another literal/length combo
sl@0: 			}
sl@0: 		if (val==TEncoding::EEos-TEncoding::ELiterals)
sl@0: 			{	// eos marker. we're done
sl@0: 			iLen=-1;
sl@0: 			break;
sl@0: 			}
sl@0: 		// get the extra bits for the code
sl@0: 		TInt code=val&0xff;
sl@0: 		if (code>=8)
sl@0: 			{	// xtra bits
sl@0: 			TInt xtra=(code>>2)-1;
sl@0: 			code-=xtra<<2;
sl@0: 			code<<=xtra;
sl@0: 			code|=iBits->ReadL(xtra);
sl@0: 			}
sl@0: 		if (val<KDeflateDistCodeBase-TEncoding::ELiterals)
sl@0: 			{
sl@0: 			// length code... get the code
sl@0: 			if(TUint(code)>TUint(KDeflateMaxLength-KDeflateMinLength))
sl@0: 				{
sl@0: 				CHECK_FAILURE(KErrCorrupt);
sl@0: 				goto error;
sl@0: 				}
sl@0: 			iLen=code+KDeflateMinLength;
sl@0: 			tree=iEncoding->iDistance;
sl@0: 			continue;			// read the huffman code
sl@0: 			}
sl@0: 		// distance code
sl@0: 		if(TUint(code)>TUint(KDeflateMaxDistance-1))
sl@0: 			{
sl@0: 			CHECK_FAILURE(KErrCorrupt);
sl@0: 			goto error;
sl@0: 			}
sl@0: 		iRptr=out-(code+1);
sl@0: 		if (iRptr+KDeflateMaxDistance<end)
sl@0: 			iRptr+=KDeflateMaxDistance;
sl@0: 		if(!iLen)
sl@0: 			{
sl@0: 			CHECK_FAILURE(KErrCorrupt);
sl@0: 			goto error;
sl@0: 			}
sl@0: 		}
sl@0: useHistory:
sl@0: 		{
sl@0: 		TInt tfr=Min(end-out,iLen);
sl@0: 		iLen-=tfr;
sl@0: 		const TUint8* from=iRptr;
sl@0: 		do
sl@0: 			{
sl@0: 			*out++=*from++;
sl@0: 			if (from==end)
sl@0: 				from-=KDeflateMaxDistance;
sl@0: 			} while (--tfr!=0);
sl@0: 		iRptr=from;
sl@0: 		tree=iEncoding->iLitLen;
sl@0: 		}
sl@0: 
sl@0: 		};
sl@0: 	return out-iOut;
sl@0: 
sl@0: error:
sl@0: 	LEAVE_FAILURE(KErrCorrupt);
sl@0: 	return 0;
sl@0: 	}
sl@0: