// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

//

#include "US_STD.H"

/** Synchronises the stream buffer with the stream, returning any error.

In effect, this ensures that buffered data is delivered to the stream.

This function calls SynchL() inside a TRAPD harness and returns the leave 

code if a leave occurs.

@return KErrNone, if successful; otherwise one of the other system wide error 

codes.

@see MStreamBuf::SynchL()

@see MStreamBuf::DoSynchL() */

	{

	TRAPD(r,SynchL());

	return r;

	}

/** Closes the stream buffer.

This function attempts to synchronise buffered data with the stream before 

freeing any resources. All errors are ignored.

@see MStreamBuf::Synch()

@see MStreamBuf::Release() */

	{

	Synch();

	Release();

	}

/** Puts a cleanup item for this object onto the cleanup stack.

This allows allocated resources to be cleaned up if a subsequent leave occurs. */

	{

	CleanupReleasePushL(*this);

	}

/** Reads data, asynchronously, from the stream buffer into the specified descriptor; 

request completion is guaranteed, even if request initiation fails.

The function calls the virtual function DoReadL(TDes8&,TInt,TRequestStatus&) 

to implement this behaviour. The maximum number of bytes to be read is the 

value of the maximum length of the descriptor.

@param aDes The target descriptor for the data read from the stream buffer.

@param aStatus The request status that indicates the completion status of this 

asynchronous request.

@return The maximum number of bytes to be read, as used in this request. This 

value can be different to the maximum length of the descriptor; this is dependent 

on the implementation.

@see MStreamBuf::DoReadL() */

	{

	return Read(aDes,aDes.MaxLength(),aStatus);

	}

/** Reads data, asynchronously, from the stream buffer into the specified descriptor; 

request completion is guaranteed, even if request initiation fails.

The function calls the virtual function DoReadL(TDes8&,TInt,TRequestStatus&) 

to implement this behaviour.

@param aDes The target descriptor for the data read from the stream buffer.

@param aMaxLength The maximum number of bytes to be read.

@param aStatus The request status that indicates the completion status of this 

asynchronous request.

@return The maximum number of bytes to be read, as used in this request. This 

can be different to the value supplied in aMaxLength; this is dependent on 

the implementation.

@see MStreamBuf::DoReadL() */

	{

	TInt len=0;

	TRAPD(r,len=DoReadL(aDes,aMaxLength,aStatus));

	if (r!=KErrNone)

		{

		TRequestStatus* stat=&aStatus;

		User::RequestComplete(stat,r);

		}

	return len;

	}

/** Reads data, asynchronously, from the stream buffer into the specified descriptor.

The function calls the virtual function DoReadL(TDes8&,TInt,TRequestStatus&) 

to implement this behaviour. The maximum number of bytes to be read is the 

maximum length of the descriptor.

If the function leaves, then no read request will have been initiated.

@param aDes The target descriptor for the data read from the stream buffer.

@param aStatus The request status that indicates the completion status of this 

asynchronous request.

@return The maximum number of bytes to be read, as used in this request. This 

value can be different to the maximum length of the descriptor; this is dependent 

on the implementation.

@see MStreamBuf::DoReadL() */

	{

	return DoReadL(aDes,aDes.MaxLength(),aStatus);

	}

/** Reads data from the stream buffer into the specified data sink.

The function uses the virtual function DoReadL(MStreamInput&,TStreamTransfer) 

to implement this behaviour.

@param anInput The data sink which is the target for the read operation.

@param aMaxLength The maximum amount of data available to be read.

@return The amount of data that was not consumed. */

	{

	return aMaxLength-DoReadL(anInput,TStreamTransfer(aMaxLength)).Left();

	}

/** Writes data, asynchronously, from the specified descriptor into the stream buffer; 

request completion is guaranteed, even if request initiation fails.

The function calls the virtual function DoWriteL(const TDesC8&,TInt,TRequestStatus&) 

to implement this behaviour. The maximum number of bytes to be written is 

the value of the maximum length of the descriptor.

@param aDes The source descriptor for the data to be written into the stream 

buffer.

@param aStatus The request status that indicates the completion status of this 

asynchronous request.

@return The maximum number of bytes to be written, as used in this request. 

This can be different to the value supplied in aMaxLength; this is dependent 

on the implementation.

@see MStreamBuf::DoWriteL() */

	{

	return Write(aDes,aDes.Length(),aStatus);

	}

//

// Write up to aMaxLength bytes with guaranteed completion.

//

	{

	TInt len=0;

	TRAPD(r,len=DoWriteL(aDes,aMaxLength,aStatus));

	if (r!=KErrNone)

		{

		TRequestStatus* stat=&aStatus;

		User::RequestComplete(stat,r);

		}

	return len;

	}

/** Writes data, asynchronously, from the specified descriptor into the stream buffer.

The function calls the virtual function DoWriteL(const TDesC8&,TInt,TRequestStatus&) 

to implement this behaviour. The maximum number of bytes to be written is 

the value of the maximum length of the descriptor.

If the function leaves, then no write request will have been initiated.

@param aDes The source descriptor for the data to be written into the stream 

buffer.

@param aStatus The request status that indicates the completion status of this 

asynchronous request.

@return The maximum number of bytes to be written, as used in this request. 

This can be different to the maximum length of the descriptor; this is dependent 

on the implementation.

@see MStreamBuf::DoWriteL() */

	{

	return DoWriteL(aDes,aDes.Length(),aStatus);

	}

/** Writes data into the stream buffer from the specified data source.

The function calls the virtual function DoWriteL(MStreamOutput&,TStreamTransfer) 

to implement this behaviour.

@param anOutput The data source for the write operation.

@param aMaxLength The maximum amount of data available to be written.

@return The amount of data that was not consumed. */

	{

	return aMaxLength-DoWriteL(anOutput,TStreamTransfer(aMaxLength)).Left();

	}

/** Frees resources before abandoning the stream buffer.

It is called by Release().

This implementation is empty, but classes derived from MStreamBuf can provide 

their own implementation, if necessary.

@see MStreamBuf::Release() */

/** Synchronises the stream buffer with the stream, leaving if any error occurs.

In effect, this ensures that buffered data is delivered to the stream.

It is called by SynchL().

This implementation is empty, but classes derived from MStreamBuf can provide 

their own implementation, if necessary.

@see MStreamBuf::SynchL() */

//

// Cannot read from this stream buffer.

//

	{

	Panic(EStreamCannotRead);

	return TInt();

	}

/** Reads data from the stream buffer into the specified descriptor.

This function is called by ReadL(TDes8&,TInt,TRequestStatus&).

This implementation deals with the request synchronously, and completes the 

request with KErrNone. Other implementations may choose to deal with this 

in a true asynchronous manner.

In addition, the read operation itself uses the DoReadL(TAny*,TInt) variant.

@param aDes The target descriptor for the data read from the stream buffer. 

On return, the length of the descriptor is set to the number of bytes read 

from the stream buffer.

@param aMaxLength The maximum number of bytes to be read. This value must not 

be greater than the maximum length of the descriptor, otherwise the function 

raises a STORE-Stream 2 panic.

@param aStatus The request status that indicates the completion status of this 

asynchronous request.

@return The maximum number of bytes to be read, as used in this request. This 

implementation uses, and returns, the value supplied in aMaxLength. Other 

implementations may choose to use a different value.

@see MStreamBuf::ReadL() */

	{

	__ASSERT_DEBUG(aMaxLength<=aDes.MaxLength(),Panic(EStreamReadBeyondEnd));

	aDes.SetLength(DoReadL((TUint8*)aDes.Ptr(),aMaxLength));

	TRequestStatus* stat=&aStatus;

	User::RequestComplete(stat,KErrNone);

	return aMaxLength;

	}

/** Reads data from the stream into the specified data sink.

It is called by ReadL(MStreamInput&,TStreamTransfer).

This implementation calls the sink's ReadFromL() function, which performs 

the read (transfer) operation.

This implementation of DoReadL() is called for streams that do not have buffering 

capabilities, and that are derived directly from this class.

@param anInput The target data sink.

@param aTransfer A stream transfer object defining the amount of data available 

to be read.

@return A stream transfer object defining the amount of data that was not consumed.

@see MStreamInput::ReadFromL() */

	{

	return anInput.ReadFromL(*this,aTransfer);

	}

/** Writes data from the specified descriptor into this stream buffer.

This function is called by WriteL(const TDesC8&,TInt,TRequestStatus&).

This implementation deals with the request synchronously, and completes the 

request with KErrNone. Other implementations may choose to deal with this 

in a true asynchronous manner.

In addition, the write operation itself uses the DoWriteL(TAny*,TInt) variant.

@param aDes The source descriptor for the data to be written into the stream 

buffer.

@param aMaxLength The number of bytes to be written. This value must not be 

greater than the maximum length of the descriptor, otherwise the function 

raises a STORE-Stream 6 panic.

@param aStatus The request status that indicates the completion status of this 

asynchronous request.

@return The maximum number of bytes to be written, as used in this request. 

This implementation uses, and returns, the value supplied in aMaxLength. Other 

implementations may choose to use a different value.

@see MStreamBuf::WriteL() */

	{

	__ASSERT_DEBUG(aMaxLength<=aDes.Length(),Panic(EStreamWriteBeyondEnd));

	DoWriteL(aDes.Ptr(),aMaxLength);

	TRequestStatus* stat=&aStatus;

	User::RequestComplete(stat,KErrNone);

	return aMaxLength;

	}

//

// Default implementation turning around to anOutput.

//

	{

	return anOutput.WriteToL(*this,aTransfer);

	}

	{

	}

/** Sets the start and end points of the read and/or the write area within the intermediate 

buffer.

A start point is always within an area; an end point is always the first byte 

beyond the end of an area.

@param anArea The areas within the intermediate buffer for which the start 

and end points are to be set. These can be the read area and/or the write 

area, as indicated by the ERead and EWrite bits. Only these bits can be set, 

otherwise the function raises a STORE-Stream 17 panic.

@param aPtr The start point.

@param anEnd The end point.

@see MStreamBuf::TRead

@see MStreamBuf::TWrite */

	{

	__ASSERT_ALWAYS(!(anArea&~(ERead|EWrite)),Panic(EStreamAreaInvalid));

	if (anArea&ERead)

		SetBuf(ERead,aPtr,anEnd);

	if (anArea&EWrite)

		SetBuf(EWrite,aPtr,anEnd);

	}

/** Sets the start point of the read and/or the write area within the intermediate 

buffer.

A start point is always within an area.

@param anArea The areas within the intermediate buffer for which the start 

point is to be set. These can be the read area and/or the write area, as indicated 

by the ERead and EWrite bits. Only these bits can be set, otherwise the function 

raises a STORE-Stream 17 panic.

@param aPtr The start point.

@see MStreamBuf::TRead

@see MStreamBuf::TWrite */

	{

	__ASSERT_ALWAYS(!(anArea&~(ERead|EWrite)),Panic(EStreamAreaInvalid));

	if (anArea&ERead)

		SetPtr(ERead,aPtr);

	if (anArea&EWrite)

		SetPtr(EWrite,aPtr);

	}

//

// Set the end pointer for the buffer area(s) indicated by anArea.

//

	{

	__ASSERT_ALWAYS(!(anArea&~(ERead|EWrite)),Panic(EStreamAreaInvalid));

	if (anArea&ERead)

		SetEnd(ERead,anEnd);

	if (anArea&EWrite)

		SetEnd(EWrite,anEnd);

	}

/** Gets the current start point of the read or write area within the intermediate 

buffer.

@param anArea The area within the intermediate buffer for which the start 

point is to be fetched. This can be either the read area or the write area, 

as indicated by the ERead and EWrite bits. Only one of these can be set, otherwise 

the function raises a STORE-Stream 17 panic.

@return The start point.

@see MStreamBuf::TRead

@see MStreamBuf::TWrite */

	{

	if (anArea==ERead)

		return Ptr(ERead);

//

	__ASSERT_ALWAYS(anArea==EWrite,Panic(EStreamAreaInvalid));

	return Ptr(EWrite);

	}

/** Gets the current end point of the read or write area within the intermediate 

buffer.

An end point is always the first byte beyond the end of an area.

@param anArea The area within the intermediate buffer for which the end point 

is to be fetched. This can be either the read area or the write area, as indicated 

by the ERead and EWrite bits. Only one of these can be set, otherwise the 

function raises a STORE-Stream 17 panic.

@return The end point. */

	{

	if (anArea==ERead)

		return End(ERead);

//

	__ASSERT_ALWAYS(anArea==EWrite,Panic(EStreamAreaInvalid));

	return End(EWrite);

	}

/** Gets the number of bytes available in the read or write area within the intermediate 

buffer.

@param anArea The area within the intermediate buffer for which the number 

of available bytes is to be fetched. This can be either the read area or the 

write area, as indicated by the ERead and EWrite bits. Only one of these can 

be set, otherwise the function raises a STORE-Stream 17 panic.

@return The number of bytes available. */

	{

	if (anArea==ERead)

		return Avail(ERead);

//

	__ASSERT_ALWAYS(anArea==EWrite,Panic(EStreamAreaInvalid));

	return Avail(EWrite);

	}

/** Reads data from the intermediate buffer into the specified memory location.

The function calls the virtual function UnderfLowL() to give concrete implementations 

the chance to refill the intermediate buffer, and satisfy the caller's requirements.

This implementation overrides the one supplied by the base class MStreamBuf, 

and is called by, MStreamBuf::ReadL(TAny*,TInt).

@param aPtr A pointer to the target memory location for the data read from 

the intermediate buffer.

@param aMaxLength The maximum number of bytes to be read.

@return The number of bytes read. This may be less than the amount requested.

@see MStreamBuf::ReadL()

@see MStreamBuf::DoReadL() */

	{

	__ASSERT_DEBUG(aMaxLength>=0,Panic(EStreamReadLengthNegative));

	__ASSERT_DEBUG(aMaxLength>0,Panic(EStreamReadNoTransfer));

	__ASSERT_DEBUG(Ptr(ERead)!=NULL||End(ERead)==NULL,Panic(EStreamCannotRead));

	TInt left=aMaxLength;

	TInt avail=Avail(ERead);

	__ASSERT_DEBUG(avail>=0,User::Invariant());

	if (avail==0)

		goto underflow;

//

	do

		{

		__ASSERT_DEBUG(avail==Avail(ERead),Panic(EStreamUnderflowInBreach));

		__ASSERT_DEBUG(left>0&&avail>0,User::Invariant());

		{

		TInt len=Min(left,avail);

		TUint8* ptr=Ptr(ERead);

		aPtr=Mem::Copy(aPtr,ptr,len);

		SetPtr(ERead,ptr+len);

		left-=len;

		if (left==0)

			return aMaxLength; // that's it

		}

//

	underflow:

		avail=UnderflowL(left);

		} while (avail>0);

	__ASSERT_DEBUG(avail==0&&Avail(ERead)==0,Panic(EStreamUnderflowInBreach));

	return aMaxLength-left;

	}

/** Reads data from the intermediate buffer and, if necessary, any remaining data 

from the stream to the specified target stream input object.

It is called by ReadL(MStreamInput&,TStreamTransfer).

The intermediate buffer is emptied first by calling the target stream input's 

PushL() function, which performs the read from intermediate buffer operation. 

Any remaining data is then read from the stream by calling the target stream 

object's ReadFromL() function, which performs the read from stream operation.