// Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).

// 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 <zipfile.h>

#include <zipfilememberinputstream.h>

#include "libzcore.h"

RZipFileMemberReaderStream::RZipFileMemberReaderStream(

    CZipFile& aZipFile,

    TUint32   aDataOffset,

    TUint32   aCompressedSize,

    TUint32   aUncompressedSize,

    TUint32   aCompressionMethod):

    iZipFile(aZipFile),

	iCompressionMethod(aCompressionMethod),

    iCompressedSize(aCompressedSize),

    iUncompressedSize(aUncompressedSize),

	iFileOffset(aDataOffset)

    {    

    }

RZipFileMemberReaderStream* RZipFileMemberReaderStream::NewL(

	CZipFile& aZipFile,

    TUint32   aDataOffset,

    TUint32   aCompressedSize,

    TUint32   aUncompressedSize,

    TUint32   aCompressionMethod)

    {    

	RZipFileMemberReaderStream* me = new(ELeave) RZipFileMemberReaderStream(aZipFile, aDataOffset, aCompressedSize,aUncompressedSize, aCompressionMethod);

	CleanupStack::PushL(me);

	me->ConstructL();

	CleanupStack::Pop(me);

	return me;		

    }

/**

Creates input stream to be used for reading the contents of the compressed file.

*/

void RZipFileMemberReaderStream::ConstructL()

	{

	TInt err = inflateInit2_r(&iStream, -MAX_WBITS);

	if (err == Z_MEM_ERROR)

		{

		User::Leave(KErrNoMemory);

		}

	}

/**

Destructor. All dynamically allocated data structures for this stream are freed.

*/

EXPORT_C RZipFileMemberReaderStream::~RZipFileMemberReaderStream()

{

	inflateEnd_r(&iStream);

}

/**

Reads data from the stream buffer into the specified descriptor.

On return, contains the data read from the stream buffer

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

@param aLength The maximum number of bytes to be read

@return KErrNone If all bytes read successfully.

@return	KErrCorrupt If reading fails.

@return KErrEof If end of file is reached.

@return ... Any one of the system-wide error codes for other errors.

*/

EXPORT_C TInt RZipFileMemberReaderStream::Read(TDes16& aDes, TInt aLength)

{

	TUint32 numBytesRead = 0;

	TInt err = Read(CONST_CAST(TByte*,(const TByte*)aDes.Ptr()), 2*aLength, &numBytesRead);

	if (err != KErrNone)

	{

		aDes.SetLength( (err==KErrEof) ? numBytesRead>>2 : 0 );

		return err;

	}

	aDes.SetLength(numBytesRead>>2);

	return KErrNone;

}

TInt RZipFileMemberReaderStream::Read(void)

	{

	TByte b;

	TUint32 numRead = 0;

	if (Read(&b, 1, &numRead) == 1)

		{

		return b;

		}

	else

		{

		return -1;

		}

	}

TInt RZipFileMemberReaderStream::Read(TDes8& aDes, TInt aLength)

	{

	TUint32 numBytesRead = 0;

	TInt err = Read(CONST_CAST(TByte*,aDes.Ptr()), aLength, &numBytesRead);

	if (err != KErrNone)

	{

		aDes.SetLength( (err==KErrEof) ? numBytesRead : 0 );

		return err;

	}

	aDes.SetLength(numBytesRead);

	return KErrNone;

	}

void RZipFileMemberReaderStream::ReadL(TDes16& aDes, TInt aLength)

	{

	User::LeaveIfError(Read(aDes, aLength));

	}

void RZipFileMemberReaderStream::Release()

{}

void RZipFileMemberReaderStream::Close()

{}

TInt RZipFileMemberReaderStream::Read(TByte* aBytes, TUint32 aLength, TUint32* aRetLength)

	{

	if (iCompressionMethod == CZipArchive::EDeflated)

		{

		return GetBytes(aBytes, aLength, aRetLength);

		}

	else

		{

		return GetStoredBytes(aBytes, aLength, aRetLength);

		}

	}

TInt RZipFileMemberReaderStream::GetBytes(TByte* aBytes, TUint32 aLength, TUint32* aRetLength)

	{

	TUint32 bytesLeftToRead;

	TInt	status;

	iBytesLength = 0;

	// Be careful not to confuse compressed bytes and uncompressed bytes.

	// The length passed in is in uncompressed bytes, compressed bytes

	// are mainly used in the GetCompressedBytes() function called.

	// iBytesLength refers to the number of bytes already read.

	// If the request is to read past the end of the file

	// we should return KErrNone on the first instance, i.e. return all bytes

	// read successfully. On the second instance return KErrEof, i.e. we have 

	// already read all the bytes when another request comes in, so return KErrEof.

	// This follows the rules for reading an uncompressed file within this component

	// and this is also the way that RFile::ReadL() does it.

	if (aLength > iUncompressedSize)

		{

		aLength = iUncompressedSize; // no point trying to read more than we have

		}

	bytesLeftToRead = aLength;

	while (bytesLeftToRead > 0) 

		{

		if (iStream.avail_in == 0)

			{

			if (GetCompressedBytes() != KErrNone)

				{

				return KErrCorrupt;

				}

			}

		// The decompression will be done in the user provided memory.

		iStream.next_out = &aBytes[iBytesLength];

		iStream.avail_out = aLength - iBytesLength;

		status = inflate_r(&iStream, Z_SYNC_FLUSH);

		switch (status)

			{

			case Z_OK:

				iBytesLength = aLength - iStream.avail_out;

				break;

			case Z_STREAM_END:	//EOF

				if (iBytesLength == aLength - iStream.avail_out)

					{

					*aRetLength = iBytesLength;

					return KErrEof;

					}

				else

					{

					iBytesLength = aLength - iStream.avail_out;

					break;

					}

			case Z_MEM_ERROR:

				return KErrNoMemory;

			default:

				return KErrCorrupt;

			}

		bytesLeftToRead = aLength - iBytesLength;

		}

	*aRetLength = iBytesLength;

	return KErrNone;

	}

TInt RZipFileMemberReaderStream::GetCompressedBytes(void)

	{

	if (iOffset < iCompressedSize)

		{

		TUint32	nBytesLeft;

		TUint32 nBytesToRead;

		nBytesLeft = iCompressedSize - iOffset;

		nBytesToRead = (nBytesLeft > sizeof(iCompressedBytes)) ? sizeof(iCompressedBytes) : nBytesLeft;

		if (iZipFile.Seek(iFileOffset) != KErrNone)

			{

			return KErrCorrupt; 

			}

		else

		if (iZipFile.Read(iCompressedBytes, nBytesToRead) != KErrNone)

			{

			return KErrCorrupt; 

			}

		iFileOffset += nBytesToRead;

		iOffset += nBytesToRead;

		iStream.next_in = iCompressedBytes;

		iStream.avail_in = nBytesToRead;

		return KErrNone;

		}

	else

	if (iDone == EFalse)

		{

		iCompressedBytes[0] = 0;

		iStream.avail_in = 1;

		iStream.next_in = iCompressedBytes;

		iDone = ETrue;

		return KErrNone;

		}

	else

		{

		return KErrCorrupt; 

		}

	}

TInt RZipFileMemberReaderStream::GetStoredBytes(TByte* aBytes, TUint32 aLength, TUint32* aRetLength)

	{

	TInt status;

	if (aLength > iUncompressedSize)

		{

		aLength = iUncompressedSize; // no point trying to read more than we have

		}

	if (aLength == 0) // empty file like a directory

		{

		return KErrNone;

		}

	if (iOffset == iCompressedSize) // end of zip item.

		{

		return KErrEof; 

		}

	if ((iOffset + aLength) > iCompressedSize)

		{

		aLength = iCompressedSize - iOffset; // adjust read to what is left

		if ( aLength <= 0 )

			{

			return KErrCorrupt; 

			}

		}

	if (iZipFile.Seek(iFileOffset) != KErrNone)

		{

		return KErrCorrupt; 

		}

	status = iZipFile.Read(aBytes, aLength);

	if (status == KErrNone)

		{

		iFileOffset += aLength;

		iOffset += aLength;

		*aRetLength = aLength;

		}

	return status;

	}