os/persistentdata/persistentstorage/store/USTRM/US_FRAME.CPP
changeset 0 bde4ae8d615e
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/os/persistentdata/persistentstorage/store/USTRM/US_FRAME.CPP	Fri Jun 15 03:10:57 2012 +0200
     1.3 @@ -0,0 +1,560 @@
     1.4 +// Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).
     1.5 +// All rights reserved.
     1.6 +// This component and the accompanying materials are made available
     1.7 +// under the terms of "Eclipse Public License v1.0"
     1.8 +// which accompanies this distribution, and is available
     1.9 +// at the URL "http://www.eclipse.org/legal/epl-v10.html".
    1.10 +//
    1.11 +// Initial Contributors:
    1.12 +// Nokia Corporation - initial contribution.
    1.13 +//
    1.14 +// Contributors:
    1.15 +//
    1.16 +// Description:
    1.17 +//
    1.18 +
    1.19 +#include "US_STD.H"
    1.20 +
    1.21 +TInt RFrame16Buf::Offset(TStreamPos aBase,TStreamPos aPos)
    1.22 +	{
    1.23 +	TInt off=aPos-aBase;
    1.24 +	__ASSERT_DEBUG(off>=0,Panic(EStreamPosInvalid));
    1.25 +	TInt n=off/(KFrameFullLength16+KSizeFrameDes16);
    1.26 +		// number of full frames from base
    1.27 +	off-=n<<KShiftFrameDes16;
    1.28 +		// target offset in frame coordinates
    1.29 +	TInt over=off-(n<<KShiftFrameLength16)-KFrameFullLength16;
    1.30 +		// adjust for overshoot into the frame descriptor
    1.31 +	__ASSERT_DEBUG(over>=-KFrameFullLength16&&over<TInt(KSizeFrameDes16),User::Invariant());
    1.32 +	if (over>0)
    1.33 +		off-=over;
    1.34 +	return off;
    1.35 +	}
    1.36 +
    1.37 +TStreamPos RFrame16Buf::Position(TStreamPos aBase,TInt anOffset)
    1.38 +	{
    1.39 +	return aBase+(anOffset+(anOffset>>KShiftFrameLength16<<KShiftFrameDes16));
    1.40 +	}
    1.41 +
    1.42 +RFrame16Buf::RFrame16Buf(TStreamPos aBase)
    1.43 +	: iBase(aBase),iHost(NULL),iExt(KFrameNonexistent16)
    1.44 +	{
    1.45 +	__ASSERT_DEBUG(aBase>=KStreamBeginning+KSizeFrameDes16,Panic(EStreamPosInvalid));
    1.46 +	}
    1.47 +
    1.48 +TInt RFrame16Buf::ExtendL(TStreamExchange& aHost,TInt anExtent,TInt aMode)
    1.49 +	{
    1.50 +	__ASSERT_DEBUG(anExtent>=0,Panic(EStreamExtentNegative));
    1.51 +	__ASSERT_DEBUG((KMaskFrameType16&aMode)!=EFrameContinuation16,Panic(EStreamTypeInvalid));
    1.52 +	TFrameDes16 des[2]={0,TFrameDes16(KMaskFrameType16&aMode|KFrameOpen16)};
    1.53 +	TUint8* ptr=(TUint8*)&des[1];
    1.54 +	TInt len=KSizeFrameDes16;
    1.55 +	TStreamPos pos=Position(anExtent);
    1.56 +	TInt off=anExtent;
    1.57 +	anExtent&=KMaskFrameLength16;
    1.58 +	if (anExtent==0)
    1.59 +		pos-=KSizeFrameDes16;
    1.60 +	else
    1.61 +		{
    1.62 +		anExtent=KFrameFullLength16-anExtent;
    1.63 +		if (anExtent>KSizeFrameDes16)
    1.64 +			off+=KSizeFrameDes16;
    1.65 +		else
    1.66 +			{
    1.67 +			ptr-=anExtent;
    1.68 +			len+=anExtent;
    1.69 +			off+=anExtent;
    1.70 +			}
    1.71 +		}
    1.72 +//
    1.73 +	TStreamMark mark(pos);
    1.74 +	mark.WriteL(aHost,ptr,len); // platform dependency
    1.75 +	mark.Withdraw(aHost);
    1.76 +	Set(aHost,off,0,aMode);
    1.77 +	return off;
    1.78 +	}
    1.79 +
    1.80 +void RFrame16Buf::OpenL(TStreamExchange& aHost,TInt anOffset,TInt aMode)
    1.81 +	{
    1.82 +	__ASSERT_DEBUG(anOffset>=0,Panic(EStreamOffsetNegative));
    1.83 +	__ASSERT_DEBUG((KMaskFrameType16&aMode)!=EFrameContinuation16,Panic(EStreamTypeInvalid));
    1.84 +	TStreamMark mark(Position(anOffset)-KSizeFrameDes16);
    1.85 +	TFrameDes16 des;
    1.86 +	TInt frame=mark.ReadL(aHost,&des,KSizeFrameDes16);
    1.87 +		// platform dependency
    1.88 +	mark.Withdraw(aHost);
    1.89 +	__ASSERT_DEBUG(frame>=0&&frame<=KSizeFrameDes16,Panic(EStreamReadInBreach));
    1.90 +	if (frame<KSizeFrameDes16)
    1.91 +		__LEAVE(KErrEof);
    1.92 +//
    1.93 +	frame=des;
    1.94 +	if ((frame^aMode)&KMaskFrameType16)
    1.95 +		__LEAVE(KErrCorrupt);
    1.96 +//
    1.97 +	TInt in=anOffset&KMaskFrameLength16;
    1.98 +	frame&=KMaskFrameLength16;
    1.99 +	if (frame==KFrameOpen16)
   1.100 +		frame=KFrameFullLength16-in;
   1.101 +	if (in+frame>KFrameFullLength16)
   1.102 +		__LEAVE(KErrCorrupt);
   1.103 +//
   1.104 +	Set(aHost,anOffset,anOffset+frame,aMode);
   1.105 +	}
   1.106 +
   1.107 +void RFrame16Buf::Set(TStreamExchange& aHost,TInt anOffset,TInt anExtent,TInt aMode)
   1.108 +	{
   1.109 +	__ASSERT_DEBUG(anOffset>=0||anOffset==anExtent,Panic(EStreamOffsetNegative));
   1.110 +	__ASSERT_DEBUG(anExtent>=0||anOffset==anExtent,Panic(EStreamExtentNegative));
   1.111 +	iHost=&aHost;
   1.112 +	iOff=anOffset;
   1.113 +	iExt=anExtent;
   1.114 +	TInt lim;
   1.115 +	if (anOffset<0)
   1.116 +		lim=anExtent;
   1.117 +	else
   1.118 +		{
   1.119 +		TStreamPos start=Position(anOffset);
   1.120 +		if (aMode&ERead)
   1.121 +			iRMark=start;
   1.122 +		else
   1.123 +			iRMark.Clear();
   1.124 +		if (aMode&EWrite)
   1.125 +			iWMark=start;
   1.126 +		else
   1.127 +			iWMark.Clear();
   1.128 +		lim=(anOffset&~KMaskFrameLength16)+KFrameFullLength16;
   1.129 +		if (anExtent>0&&lim>anExtent)
   1.130 +			lim=anExtent;
   1.131 +		}
   1.132 +	iRAvail=iWAvail=lim-anOffset;
   1.133 +	iRLim=iWLim=lim;
   1.134 +	iMode=aMode;
   1.135 +	}
   1.136 +
   1.137 +void RFrame16Buf::CommitL()
   1.138 +	{
   1.139 +	__ASSERT_DEBUG(!IsCommitted(),Panic(EStreamCommitted));
   1.140 +	TInt ext=Host().SizeL()-Base().Offset();
   1.141 +	if (ext<0)
   1.142 +		__LEAVE(KErrCorrupt);
   1.143 +//
   1.144 +	TInt n=ext/(KFrameFullLength16+KSizeFrameDes16);
   1.145 +		// number of full frames from base
   1.146 +	ext-=n<<KShiftFrameDes16;
   1.147 +		// end in frame coordinates
   1.148 +	TInt off=Offset();
   1.149 +	if (ext==off)
   1.150 +		{ // committing an empty stream
   1.151 +		iOff=iExt=KFrameNonexistent16;
   1.152 +		return;
   1.153 +		}
   1.154 +//
   1.155 +	TInt frame=ext-(n<<KShiftFrameLength16);
   1.156 +		// size of final frame (remainder of the division above)
   1.157 +	__ASSERT_DEBUG(frame>=0&&frame<KFrameFullLength16+KSizeFrameDes16,User::Invariant());
   1.158 +	if (ext<off||frame==0||frame>KFrameFullLength16)
   1.159 +		__LEAVE(KErrCorrupt); // bad offset, empty frame or partial frame descriptor
   1.160 +//
   1.161 +	if (frame<KFrameFullLength16)
   1.162 +		{
   1.163 +		TFrameDes16 des;
   1.164 +		if ((off^ext)&~KMaskFrameLength16)
   1.165 +			{ // in a different frame from the one we started in
   1.166 +			off=ext&~KMaskFrameLength16;
   1.167 +			des=TFrameDes16(EFrameContinuation16|frame);
   1.168 +			}
   1.169 +		else
   1.170 +			{
   1.171 +			frame-=off&KMaskFrameLength16;
   1.172 +			__ASSERT_DEBUG(frame>0&&frame<KFrameFullLength16,User::Invariant());
   1.173 +			des=TFrameDes16(iMode&KMaskFrameType16|frame);
   1.174 +			}
   1.175 +		TStreamMark mark(Position(off)-KSizeFrameDes16);
   1.176 +		mark.WriteL(Host(),&des,KSizeFrameDes16);
   1.177 +		mark.Withdraw(Host());
   1.178 +		}
   1.179 +	iExt=ext;
   1.180 +	}
   1.181 +
   1.182 +void RFrame16Buf::DoRelease()
   1.183 +	{
   1.184 +	if (iHost!=NULL)
   1.185 +		{
   1.186 +		iRMark.Withdraw(*iHost);
   1.187 +		iWMark.Withdraw(*iHost);
   1.188 +		iHost=NULL;
   1.189 +		iExt=KFrameNonexistent16;
   1.190 +		}
   1.191 +	}
   1.192 +
   1.193 +void RFrame16Buf::DoSynchL()
   1.194 +	{
   1.195 +	if (IsCommitted())
   1.196 +		return;
   1.197 +//
   1.198 +	CommitL();
   1.199 +	}
   1.200 +
   1.201 +TInt RFrame16Buf::DoReadL(TAny* aPtr,TInt aMaxLength)
   1.202 +	{
   1.203 +	__ASSERT_DEBUG(aMaxLength>=0,Panic(EStreamReadLengthNegative));
   1.204 +	__ASSERT_DEBUG(aMaxLength>0,Panic(EStreamReadNoTransfer));
   1.205 +	TInt left=aMaxLength;
   1.206 +	TInt avail=iRAvail;
   1.207 +	if (avail==0)
   1.208 +		goto underflow; // we'd used up the whole frame
   1.209 +//
   1.210 +	do
   1.211 +		{
   1.212 +		__ASSERT_DEBUG(left>0&&avail>0,User::Invariant());
   1.213 +		{
   1.214 +		TInt len=iRMark.ReadL(Host(),aPtr,Min(left,avail));
   1.215 +		__ASSERT_DEBUG(len>=0&&len<=left&&len<=avail,Panic(EStreamReadInBreach));
   1.216 +		iRAvail=avail-=len;
   1.217 +		left-=len;
   1.218 +		if (left==0)
   1.219 +			return aMaxLength; // that's it
   1.220 +//
   1.221 +		aPtr=(TUint8*)aPtr+len;
   1.222 +		}
   1.223 +		if (avail>0)
   1.224 +			{ // we've run out of host 
   1.225 +			if ((Extent()&KMaskFrameLength16)==KFrameOpen16)
   1.226 +				break; // all's well, provided we're open-ended
   1.227 +//
   1.228 +			iRMark.Withdraw(Host());
   1.229 +			__LEAVE(KErrCorrupt);
   1.230 +			}
   1.231 +//
   1.232 +	underflow:
   1.233 +		avail=UnderflowL();
   1.234 +		} while (avail>0);
   1.235 +	return aMaxLength-left;
   1.236 +	}
   1.237 +
   1.238 +TInt RFrame16Buf::DoReadL(TDes8& aDes,TInt aMaxLength,TRequestStatus& aStatus)
   1.239 +//
   1.240 +// Read up to aMaxLength bytes asynchronously.
   1.241 +//
   1.242 +	{
   1.243 +//#pragma message( __FILE__ " : 'RFrame16Buf::DoReadL(TDes8&,TInt,TRequestStatus&)' not implemented" )
   1.244 +	__ASSERT_DEBUG(aMaxLength<=aDes.MaxLength(),Panic(EStreamReadBeyondEnd));
   1.245 +	aDes.SetLength(DoReadL((TUint8*)aDes.Ptr(),aMaxLength));
   1.246 +	TRequestStatus* stat=&aStatus;
   1.247 +	User::RequestComplete(stat,KErrNone);
   1.248 +	return aMaxLength;
   1.249 +	}
   1.250 +
   1.251 +TStreamTransfer RFrame16Buf::DoReadL(MStreamInput& anInput,TStreamTransfer aTransfer)
   1.252 +	{
   1.253 +	__ASSERT_DEBUG(aTransfer>0,Panic(EStreamReadNoTransfer));
   1.254 +	if (iRAvail>0)
   1.255 +		{
   1.256 +		TInt len=iRMark.ReadL(Host(),anInput,aTransfer[iRAvail]);
   1.257 +		aTransfer-=len;
   1.258 +		iRAvail-=len;
   1.259 +		}
   1.260 +	if (aTransfer>0)
   1.261 +		return anInput.ReadFromL(*this,aTransfer);
   1.262 +//
   1.263 +	return aTransfer;
   1.264 +	}
   1.265 +
   1.266 +void RFrame16Buf::DoWriteL(const TAny* aPtr,TInt aLength)
   1.267 +	{
   1.268 +	__ASSERT_DEBUG(aLength>=0,Panic(EStreamWriteLengthNegative));
   1.269 +	__ASSERT_DEBUG(aLength>0,Panic(EStreamWriteNoTransfer));
   1.270 +	TInt avail=iWAvail;
   1.271 +	if (avail==0)
   1.272 +		goto overflow; // we'd used up the whole frame
   1.273 +//
   1.274 +	for (;;)
   1.275 +		{
   1.276 +		__ASSERT_DEBUG(aLength>0&&avail>0,User::Invariant());
   1.277 +		{
   1.278 +		TInt len=Min(aLength,avail);
   1.279 +		iWMark.WriteL(Host(),aPtr,len);
   1.280 +		iWAvail=avail-len;
   1.281 +		aLength-=len;
   1.282 +		if (aLength==0)
   1.283 +			return; // won't worry about the next frame just yet
   1.284 +//
   1.285 +		aPtr=(TUint8*)aPtr+len;
   1.286 +		}
   1.287 +	overflow:
   1.288 +		OverflowL();
   1.289 +		avail=iWAvail;
   1.290 +		};
   1.291 +	}
   1.292 +
   1.293 +TInt RFrame16Buf::DoWriteL(const TDesC8& aDes,TInt aMaxLength,TRequestStatus& aStatus)
   1.294 +//
   1.295 +// Write up to aMaxLength bytes asynchronously.
   1.296 +//
   1.297 +	{
   1.298 +//#pragma message( __FILE__ " : 'RFrame16Buf::DoWriteL(const TDesC8&,TInt,TRequestStatus&)' not implemented" )
   1.299 +	__ASSERT_DEBUG(aMaxLength<=aDes.Length(),Panic(EStreamWriteBeyondEnd));
   1.300 +	DoWriteL(aDes.Ptr(),aMaxLength);
   1.301 +	TRequestStatus* stat=&aStatus;
   1.302 +	User::RequestComplete(stat,KErrNone);
   1.303 +	return aMaxLength;
   1.304 +	}
   1.305 +
   1.306 +TStreamTransfer RFrame16Buf::DoWriteL(MStreamOutput& anOutput,TStreamTransfer aTransfer)
   1.307 +	{
   1.308 +	__ASSERT_DEBUG(aTransfer>0,Panic(EStreamWriteNoTransfer));
   1.309 +	if (iWAvail>0)
   1.310 +		{
   1.311 +		TInt len=iWMark.WriteL(Host(),anOutput,aTransfer[iWAvail]);
   1.312 +		aTransfer-=len;
   1.313 +		iWAvail-=len;
   1.314 +		}
   1.315 +	if (aTransfer>0)
   1.316 +		return anOutput.WriteToL(*this,aTransfer);
   1.317 +//
   1.318 +	return aTransfer;
   1.319 +	}
   1.320 +
   1.321 +TStreamPos RFrame16Buf::DoSeekL(TMark aMark,TStreamLocation aLocation,TInt anOffset)
   1.322 +//
   1.323 +// Position the mark(s) indicated by aMark at anOffset from aLocation.
   1.324 +//
   1.325 +	{
   1.326 +	switch (aLocation)
   1.327 +		{
   1.328 +	case EStreamBeginning:
   1.329 +		anOffset+=Offset();
   1.330 +		break;
   1.331 +	case EStreamMark:
   1.332 +		if (aMark==ERead)
   1.333 +			anOffset+=iRLim-iRAvail;
   1.334 +		else
   1.335 +			{
   1.336 +			__ASSERT_ALWAYS(aMark==EWrite,Panic(EStreamMarkInvalid));
   1.337 +			anOffset+=iWLim-iWAvail;
   1.338 +			}
   1.339 +		break;
   1.340 +	case EStreamEnd:
   1.341 +		anOffset+=EndL();
   1.342 +		break;
   1.343 +	default:
   1.344 +		Panic(EStreamLocationInvalid);
   1.345 +		break;
   1.346 +		}
   1.347 +	TInt r=KErrNone;
   1.348 +	if (anOffset<Offset())
   1.349 +		{
   1.350 +		anOffset=Offset();
   1.351 +		r=KErrEof;
   1.352 +		}
   1.353 +	else if (anOffset>=0&&!ReachL(anOffset))
   1.354 +		{
   1.355 +		__ASSERT_DEBUG(Extent()!=0,User::Invariant());
   1.356 +		anOffset=Extent();
   1.357 +		r=KErrEof;
   1.358 +		}
   1.359 +//
   1.360 +	if (aMark&&anOffset>=0)
   1.361 +		{
   1.362 +		__ASSERT_ALWAYS(!(aMark&~(ERead|EWrite)),Panic(EStreamMarkInvalid));
   1.363 +		TInt in=anOffset&KMaskFrameLength16;
   1.364 +		TInt off=anOffset-in;
   1.365 +		__ASSERT_DEBUG(Extent()==0||anOffset<=Extent(),User::Invariant());
   1.366 +		if (in==0&&off>Offset()&&(Extent()==0||off==Extent()))
   1.367 +			{ // positioning at the start of a frame that may not exist
   1.368 +			in=KFrameFullLength16;
   1.369 +			off-=in;
   1.370 +			}
   1.371 +		TStreamPos pos=Base()+(off+(off>>KShiftFrameLength16<<KShiftFrameDes16))+in;
   1.372 +		TInt lim=off+KFrameFullLength16;
   1.373 +		if (Extent()>0&&lim>Extent())
   1.374 +			lim=Extent();
   1.375 +		TInt left=lim-anOffset;
   1.376 +		__ASSERT_DEBUG(left>=0&&left<=KFrameFullLength16,User::Invariant());
   1.377 +//
   1.378 +		if (aMark&ERead)
   1.379 +			{
   1.380 +			if (iMode&ERead)
   1.381 +				iRMark.SeekL(Host(),pos);
   1.382 +			iRAvail=left;
   1.383 +			iRLim=lim;
   1.384 +			}
   1.385 +		if (aMark&EWrite)
   1.386 +			{
   1.387 +			if (iMode&EWrite)
   1.388 +				iWMark.SeekL(Host(),pos);
   1.389 +			iWAvail=left;
   1.390 +			iWLim=lim;
   1.391 +			}
   1.392 +		}
   1.393 +	__LEAVE_IF_ERROR(r);
   1.394 +	return TStreamPos(anOffset-Offset());
   1.395 +	}
   1.396 +
   1.397 +TInt RFrame16Buf::UnderflowL()
   1.398 +	{
   1.399 +	__ASSERT_DEBUG(iRAvail==0,User::Invariant());
   1.400 +	if ((iRLim&KMaskFrameLength16)!=KFrameOpen16)
   1.401 +		{
   1.402 +		__ASSERT_DEBUG(iExt==iRLim,User::Invariant());
   1.403 +		return 0; // we've used up the closing, partial frame
   1.404 +		}
   1.405 +//
   1.406 +	__ASSERT_DEBUG(iRLim>0&&(iExt>0&&iRLim<=iExt||iExt==0),User::Invariant());
   1.407 +		// let's see if there's a continuation frame
   1.408 +	TFrameDes16 des;
   1.409 +	TInt frame=iRMark.ReadL(Host(),&des,KSizeFrameDes16);
   1.410 +		// platform dependency
   1.411 +	__ASSERT_DEBUG(frame>=0&&frame<=KSizeFrameDes16,Panic(EStreamReadInBreach));
   1.412 +	if (frame==KSizeFrameDes16)
   1.413 +		{
   1.414 +		frame=des;
   1.415 +		if ((frame&KMaskFrameType16)==EFrameContinuation16)
   1.416 +			{ // we have a continuation frame, prepare ourselves for it
   1.417 +			frame&=KMaskFrameLength16;
   1.418 +			if (frame==KFrameOpen16)
   1.419 +				frame=KFrameFullLength16;
   1.420 +			iRAvail=frame;
   1.421 +			TInt lim=iRLim;
   1.422 +			iRLim=lim+frame;
   1.423 +			if (iExt==lim)
   1.424 +				iExt=iRLim;
   1.425 +			return frame;
   1.426 +			}
   1.427 +		iRMark.SeekL(Host(),-KSizeFrameDes16);
   1.428 +		frame=0;
   1.429 +		}
   1.430 +//
   1.431 +	if (frame>0||iRLim<iExt)
   1.432 +		{ // we'd definitely seen a continuation frame here before
   1.433 +		iRMark.Withdraw(Host());
   1.434 +		__LEAVE(KErrCorrupt);
   1.435 +		}
   1.436 +	return 0;
   1.437 +	}
   1.438 +
   1.439 +void RFrame16Buf::OverflowL()
   1.440 +	{
   1.441 +	__ASSERT_DEBUG(iWAvail==0,User::Invariant());
   1.442 +	if ((iWLim&KMaskFrameLength16)!=KFrameOpen16)
   1.443 +		{ // filled the closing, partial frame
   1.444 +		__ASSERT_DEBUG(iExt==iWLim,User::Invariant());
   1.445 +	overflow:
   1.446 +		iWMark.Withdraw(Host());
   1.447 +		__LEAVE(KErrOverflow);
   1.448 +		}
   1.449 +//
   1.450 +	__ASSERT_DEBUG(iWLim>0&&(iExt>0&&iWLim<=iExt||iExt==0),User::Invariant());
   1.451 +	if (iWLim==iExt)
   1.452 +		{ // let's see if this carries on
   1.453 +		TFrameDes16 des;
   1.454 +		TInt frame=iWMark.ReadL(Host(),&des,KSizeFrameDes16);
   1.455 +			// platform dependency
   1.456 +		__ASSERT_DEBUG(frame>=0&&frame<=KSizeFrameDes16,Panic(EStreamReadInBreach));
   1.457 +		if (frame==0)
   1.458 +			iExt=0; // end-of-host, let's start extending
   1.459 +		else
   1.460 +			{
   1.461 +			if (frame==KSizeFrameDes16)
   1.462 +				{
   1.463 +				frame=des;
   1.464 +				if ((frame&KMaskFrameType16)==EFrameContinuation16)
   1.465 +					{ // there's more, set up for the next frame
   1.466 +					frame&=KMaskFrameLength16;
   1.467 +					if (frame==KFrameOpen16)
   1.468 +						frame=KFrameFullLength16;
   1.469 +					iWAvail=frame;
   1.470 +					iExt=iWLim+=frame;
   1.471 +					return;
   1.472 +					}
   1.473 +				goto overflow;
   1.474 +				}
   1.475 +//
   1.476 +			iWMark.Withdraw(Host());
   1.477 +			__LEAVE(KErrCorrupt);
   1.478 +			}
   1.479 +		}
   1.480 +//
   1.481 +	__ASSERT_DEBUG(iWLim<iExt||iExt==0,User::Invariant());
   1.482 +		// calculate the frame descriptor to be written
   1.483 +	TInt frame=iExt&KMaskFrameLength16;
   1.484 +	if (iWLim<iExt-frame)
   1.485 +		frame=KFrameOpen16;
   1.486 +	TFrameDes16 des=TFrameDes16(EFrameContinuation16|frame);
   1.487 +	if (frame==KFrameOpen16)
   1.488 +		frame=KFrameFullLength16;
   1.489 +	iWMark.WriteL(Host(),&des,KSizeFrameDes16);
   1.490 +		// platform dependency
   1.491 +	iWAvail=frame;
   1.492 +	iWLim+=frame;
   1.493 +	}
   1.494 +
   1.495 +TBool RFrame16Buf::ReachL(TInt anOffset)
   1.496 +	{
   1.497 +	if (iExt<=0)
   1.498 +		return iExt==0;
   1.499 +//
   1.500 +	TStreamMark mark(Base());
   1.501 +	TInt frame=(iExt+(iExt>>KShiftFrameLength16<<KShiftFrameDes16))-KSizeFrameDes16;
   1.502 +	while (iExt<anOffset)
   1.503 +		{
   1.504 +		if ((iExt&KMaskFrameLength16)!=KFrameOpen16)
   1.505 +			{
   1.506 +			mark.Withdraw(Host());
   1.507 +			return EFalse;
   1.508 +			}
   1.509 +//
   1.510 +		TFrameDes16 des;
   1.511 +		mark.SeekL(Host(),EStreamMark,frame);
   1.512 +		frame=mark.ReadL(Host(),&des,KSizeFrameDes16);
   1.513 +			// platform dependency
   1.514 +		__ASSERT_DEBUG(frame>=0&&frame<=KSizeFrameDes16,Panic(EStreamReadInBreach));
   1.515 +		if (frame==KSizeFrameDes16)
   1.516 +			{
   1.517 +			frame=des;
   1.518 +			if ((frame&KMaskFrameType16)==EFrameContinuation16)
   1.519 +				{ // we have a continuation frame, boost upper
   1.520 +				frame&=KMaskFrameLength16;
   1.521 +				if (frame==KFrameOpen16)
   1.522 +					frame=KFrameFullLength16;
   1.523 +				iExt+=frame;
   1.524 +				continue;
   1.525 +				}
   1.526 +			frame=0;
   1.527 +			}
   1.528 +//
   1.529 +		mark.Withdraw(Host());
   1.530 +		if (frame>0)
   1.531 +			__LEAVE(KErrCorrupt);
   1.532 +//
   1.533 +		return EFalse;
   1.534 +		}
   1.535 +	mark.Withdraw(Host());
   1.536 +	return ETrue;
   1.537 +	}
   1.538 +
   1.539 +TInt RFrame16Buf::EndL()
   1.540 +	{
   1.541 +	TInt ext=Host().SizeL()-Base().Offset();
   1.542 +	if (ext<0)
   1.543 +		__LEAVE(KErrCorrupt);
   1.544 +//
   1.545 +	TInt n=ext/(KFrameFullLength16+KSizeFrameDes16);
   1.546 +		// number of full frames from base
   1.547 +	ext-=n<<KShiftFrameDes16;
   1.548 +		// end in frame coordinates
   1.549 +	TInt frame=ext-(n<<KShiftFrameLength16);
   1.550 +		// size of final frame (remainder of the division above)
   1.551 +	__ASSERT_DEBUG(frame>=0&&frame<KFrameFullLength16+KSizeFrameDes16,User::Invariant());
   1.552 +	if (ext<Offset()||frame>KFrameFullLength16)
   1.553 +		__LEAVE(KErrCorrupt); // bad offset or partial frame descriptor
   1.554 +//
   1.555 +	if (!ReachL(ext))
   1.556 +		{
   1.557 +		__ASSERT_DEBUG(Extent()!=0,User::Invariant());
   1.558 +		return Extent();
   1.559 +		}
   1.560 +//
   1.561 +	return ext;
   1.562 +	}
   1.563 +