/**************************************************************
 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
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// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_tools.hxx"
#include <tools/stream.hxx>
#ifndef _ZLIB_H
#ifdef SYSTEM_ZLIB
#include "zlib.h"
#else
#include "zlib/zlib.h"
#endif
#endif 
#include <tools/zcodec.hxx>
#include <rtl/crc.h>
#include <osl/endian.h>

// -----------
// - Defines -
// -----------

#define PZSTREAM ((z_stream*) mpsC_Stream)

/* gzip flag byte */
#define GZ_ASCII_FLAG   0x01 /* bit 0 set: file probably ascii text */
#define GZ_HEAD_CRC     0x02 /* bit 1 set: header CRC present */
#define GZ_EXTRA_FIELD  0x04 /* bit 2 set: extra field present */
#define GZ_ORIG_NAME    0x08 /* bit 3 set: original file name present */
#define GZ_COMMENT      0x10 /* bit 4 set: file comment present */
#define GZ_RESERVED     0xE0 /* bits 5..7: reserved */

static int gz_magic[2] = { 0x1f, 0x8b }; /* gzip magic header */


// ----------
// - ZCodec -
// ----------

ZCodec::ZCodec( sal_uIntPtr nInBufSize, sal_uIntPtr nOutBufSize, sal_uIntPtr nMemUsage )
    : mnCRC(0)
{
	mnMemUsage = nMemUsage;
	mnInBufSize = nInBufSize;
	mnOutBufSize = nOutBufSize;
	mpsC_Stream = new z_stream;
}

ZCodec::ZCodec( void )
    : mnCRC(0)
{
	mnMemUsage = MAX_MEM_USAGE;
	mnInBufSize = DEFAULT_IN_BUFSIZE;
	mnOutBufSize = DEFAULT_OUT_BUFSIZE;
	mpsC_Stream = new z_stream;
}

// ------------------------------------------------------------------------
														
ZCodec::~ZCodec()
{
	delete (z_stream*) mpsC_Stream;
}

// ------------------------------------------------------------------------

void ZCodec::BeginCompression( sal_uIntPtr nCompressMethod )
{
	mbInit = 0;
	mbStatus = sal_True;
	mbFinish = sal_False;
	mpIStm = mpOStm = NULL;
	mnInToRead = 0xffffffff;
	mpInBuf = mpOutBuf = NULL;
	PZSTREAM->total_out = PZSTREAM->total_in = 0;
	mnCompressMethod = nCompressMethod;
	PZSTREAM->zalloc = ( alloc_func )0;
    PZSTREAM->zfree = ( free_func )0;
    PZSTREAM->opaque = ( voidpf )0;
	PZSTREAM->avail_out = PZSTREAM->avail_in = 0;
}

// ------------------------------------------------------------------------

long ZCodec::EndCompression()
{
	long retvalue = 0;

	if ( mbInit != 0 )
	{
		if ( mbInit & 2 )	// 1->decompress, 3->compress
		{
			do
			{		
				ImplWriteBack();
			}
			while ( deflate( PZSTREAM, Z_FINISH ) != Z_STREAM_END );

			ImplWriteBack();

			retvalue = PZSTREAM->total_in;
			deflateEnd( PZSTREAM );
		}
		else 
		{
			retvalue = PZSTREAM->total_out;
			inflateEnd( PZSTREAM );
		}
		delete[] mpOutBuf;
		delete[] mpInBuf;
	}
	return ( mbStatus ) ? retvalue : -1;
}


// ------------------------------------------------------------------------

long ZCodec::Compress( SvStream& rIStm, SvStream& rOStm )
{	
	long nOldTotal_In = PZSTREAM->total_in;
	
	if ( mbInit == 0 )
	{
		mpIStm = &rIStm;
		mpOStm = &rOStm;
		ImplInitBuf( sal_False );
		mpInBuf = new sal_uInt8[ mnInBufSize ];
	}
	while (( PZSTREAM->avail_in = mpIStm->Read( PZSTREAM->next_in = mpInBuf, mnInBufSize )) != 0 )
	{
		if ( PZSTREAM->avail_out == 0 ) 
			ImplWriteBack();
		if ( deflate( PZSTREAM, Z_NO_FLUSH ) < 0 ) 
		{
			mbStatus = sal_False;
			break;
		}
	};
	return ( mbStatus ) ? (long)(PZSTREAM->total_in - nOldTotal_In) : -1;
}

// ------------------------------------------------------------------------

long ZCodec::Decompress( SvStream& rIStm, SvStream& rOStm )
{
	int err;
	sal_uIntPtr	nInToRead;
	long	nOldTotal_Out = PZSTREAM->total_out;

	if ( mbFinish )	
		return PZSTREAM->total_out - nOldTotal_Out;

	if ( mbInit == 0 )
	{
		mpIStm = &rIStm;
		mpOStm = &rOStm;
		ImplInitBuf( sal_True );
		PZSTREAM->next_out = mpOutBuf = new sal_uInt8[ PZSTREAM->avail_out = mnOutBufSize ];
	}
	do
	{
		if ( PZSTREAM->avail_out == 0 ) ImplWriteBack();
		if ( PZSTREAM->avail_in == 0 && mnInToRead )
		{		
			nInToRead = ( mnInBufSize > mnInToRead ) ? mnInToRead : mnInBufSize;
			PZSTREAM->avail_in = mpIStm->Read( PZSTREAM->next_in = mpInBuf, nInToRead );
			mnInToRead -= nInToRead;

			if ( mnCompressMethod & ZCODEC_UPDATE_CRC )
				mnCRC = UpdateCRC( mnCRC, mpInBuf, nInToRead );

		}
		err = inflate( PZSTREAM, Z_NO_FLUSH );
		if ( err < 0 )
		{
			mbStatus = sal_False;
			break;
		}
		
	}		
	while ( ( err != Z_STREAM_END)  && ( PZSTREAM->avail_in || mnInToRead ) );
	ImplWriteBack();
	
	if ( err == Z_STREAM_END ) 
		mbFinish = sal_True;	
	return ( mbStatus ) ? (long)(PZSTREAM->total_out - nOldTotal_Out) : -1;
}

// ------------------------------------------------------------------------

long ZCodec::Write( SvStream& rOStm, const sal_uInt8* pData, sal_uIntPtr nSize )
{		
	if ( mbInit == 0 )
	{
		mpOStm = &rOStm;
		ImplInitBuf( sal_False );
	}
		
	PZSTREAM->avail_in = nSize;
	PZSTREAM->next_in = (unsigned char*)pData;
	
    while ( PZSTREAM->avail_in || ( PZSTREAM->avail_out == 0 ) )
    {
        if ( PZSTREAM->avail_out == 0 )
			ImplWriteBack();

		if ( deflate( PZSTREAM, Z_NO_FLUSH ) < 0 )
		{	
			mbStatus = sal_False;
			break;
		}
    }
	return ( mbStatus ) ? (long)nSize : -1;
}

// ------------------------------------------------------------------------

long ZCodec::Read( SvStream& rIStm, sal_uInt8* pData, sal_uIntPtr nSize )
{
	int err;
	sal_uIntPtr	nInToRead;

	if ( mbFinish )	
		return 0;			// PZSTREAM->total_out;

	mpIStm = &rIStm;
	if ( mbInit == 0 )
	{
		ImplInitBuf( sal_True );
	}
	PZSTREAM->avail_out = nSize;
	PZSTREAM->next_out = pData;
	do
	{
		if ( PZSTREAM->avail_in == 0 && mnInToRead )
		{
			nInToRead = (mnInBufSize > mnInToRead) ? mnInToRead : mnInBufSize;
			PZSTREAM->avail_in = mpIStm->Read (
				PZSTREAM->next_in = mpInBuf, nInToRead);
			mnInToRead -= nInToRead;

			if ( mnCompressMethod & ZCODEC_UPDATE_CRC )
				mnCRC = UpdateCRC( mnCRC, mpInBuf, nInToRead );

		}
		err = inflate( PZSTREAM, Z_NO_FLUSH );
		if ( err < 0 )
		{
			// Accept Z_BUF_ERROR as EAGAIN or EWOULDBLOCK.
			mbStatus = (err == Z_BUF_ERROR);
			break;
		}
	}
	while ( (err != Z_STREAM_END) &&
			(PZSTREAM->avail_out != 0) &&
			(PZSTREAM->avail_in || mnInToRead) );
	if ( err == Z_STREAM_END ) 
		mbFinish = sal_True;

	return (mbStatus ? (long)(nSize - PZSTREAM->avail_out) : -1);
}

// ------------------------------------------------------------------------

long ZCodec::ReadAsynchron( SvStream& rIStm, sal_uInt8* pData, sal_uIntPtr nSize )
{
	int err = 0;
	sal_uIntPtr	nInToRead;

	if ( mbFinish )	
		return 0;			// PZSTREAM->total_out;

	if ( mbInit == 0 )
	{
		mpIStm = &rIStm;
		ImplInitBuf( sal_True );
	}
	PZSTREAM->avail_out = nSize;
	PZSTREAM->next_out = pData;
	do
	{
		if ( PZSTREAM->avail_in == 0 && mnInToRead )
		{
			nInToRead = (mnInBufSize > mnInToRead) ? mnInToRead : mnInBufSize;

			sal_uIntPtr nStreamPos = rIStm.Tell();
			rIStm.Seek( STREAM_SEEK_TO_END );
			sal_uIntPtr nMaxPos = rIStm.Tell();
			rIStm.Seek( nStreamPos );
			if ( ( nMaxPos - nStreamPos ) < nInToRead )
			{
				rIStm.SetError( ERRCODE_IO_PENDING );
				err= ! Z_STREAM_END; // TODO What is appropriate code for this?
				break;
			}

			PZSTREAM->avail_in = mpIStm->Read (
				PZSTREAM->next_in = mpInBuf, nInToRead);
			mnInToRead -= nInToRead;

			if ( mnCompressMethod & ZCODEC_UPDATE_CRC )
				mnCRC = UpdateCRC( mnCRC, mpInBuf, nInToRead );

		}
		err = inflate( PZSTREAM, Z_NO_FLUSH );
		if ( err < 0 )
		{
			// Accept Z_BUF_ERROR as EAGAIN or EWOULDBLOCK.
			mbStatus = (err == Z_BUF_ERROR);
			break;
		}
	}
	while ( (err != Z_STREAM_END) &&
			(PZSTREAM->avail_out != 0) &&
			(PZSTREAM->avail_in || mnInToRead) );
	if ( err == Z_STREAM_END ) 
		mbFinish = sal_True;

	return (mbStatus ? (long)(nSize - PZSTREAM->avail_out) : -1);
}

// ------------------------------------------------------------------------

void ZCodec::ImplWriteBack()
{
	sal_uIntPtr nAvail = mnOutBufSize - PZSTREAM->avail_out;
	
	if ( nAvail )
	{
		if ( mbInit & 2 && ( mnCompressMethod & ZCODEC_UPDATE_CRC ) )
			mnCRC = UpdateCRC( mnCRC, mpOutBuf, nAvail );
		mpOStm->Write( PZSTREAM->next_out = mpOutBuf, nAvail );
		PZSTREAM->avail_out = mnOutBufSize;
	}
}

// ------------------------------------------------------------------------

void ZCodec::SetBreak( sal_uIntPtr nInToRead )
{
	mnInToRead = nInToRead;
}

// ------------------------------------------------------------------------

sal_uIntPtr ZCodec::GetBreak( void )
{
	return ( mnInToRead + PZSTREAM->avail_in );
}

// ------------------------------------------------------------------------

void ZCodec::SetCRC( sal_uIntPtr nCRC )
{
	mnCRC = nCRC;
}

// ------------------------------------------------------------------------

sal_uIntPtr ZCodec::GetCRC()
{
	return mnCRC;
}

// ------------------------------------------------------------------------

void ZCodec::ImplInitBuf ( sal_Bool nIOFlag )
{
	if ( mbInit == 0 )
	{
		if ( nIOFlag )
		{	
			mbInit = 1;
			if ( mbStatus && ( mnCompressMethod & ZCODEC_GZ_LIB ) )
			{
				sal_uInt8 n1, n2, j, nMethod, nFlags;
				for ( int i = 0; i < 2; i++ )	// gz - magic number
				{
					*mpIStm >> j;
					if ( j != gz_magic[ i ] )
						mbStatus = sal_False;
				}
				*mpIStm >> nMethod;
				*mpIStm >> nFlags;
				if ( nMethod != Z_DEFLATED )
					mbStatus = sal_False;
				if ( ( nFlags & GZ_RESERVED ) != 0 )
					mbStatus = sal_False;
				/* Discard time, xflags and OS code: */
				mpIStm->SeekRel( 6 );
			    /* skip the extra field */
				if ( nFlags & GZ_EXTRA_FIELD )
				{
					*mpIStm >> n1 >> n2;
					mpIStm->SeekRel( n1 + ( n2 << 8 ) );
				}
				/* skip the original file name */
			    if ( nFlags & GZ_ORIG_NAME)
				{
					do
					{
						*mpIStm >> j;
					}									
					while ( j && !mpIStm->IsEof() );
				}
				/* skip the .gz file comment */
				if ( nFlags & GZ_COMMENT )
				{
					do
					{
						*mpIStm >> j;
					}
					while ( j && !mpIStm->IsEof() );
				}
				/* skip the header crc */
				if ( nFlags & GZ_HEAD_CRC ) 
					mpIStm->SeekRel( 2 );
				if ( mbStatus )
				    mbStatus = ( inflateInit2( PZSTREAM, -MAX_WBITS) != Z_OK ) ? sal_False : sal_True;
			}
			else
			{
				mbStatus = ( inflateInit( PZSTREAM ) >= 0 );
			}
			mpInBuf = new sal_uInt8[ mnInBufSize ];
		}
		else
		{	
			mbInit = 3;

			mbStatus = ( deflateInit2_( PZSTREAM, mnCompressMethod & 0xff, Z_DEFLATED, 
				MAX_WBITS, mnMemUsage, ( mnCompressMethod >> 8 ) & 0xff, 
					ZLIB_VERSION, sizeof( z_stream ) ) >= 0 );

			PZSTREAM->next_out = mpOutBuf = new sal_uInt8[ PZSTREAM->avail_out = mnOutBufSize ];
		}
	}
}

// ------------------------------------------------------------------------

sal_uIntPtr ZCodec::UpdateCRC ( sal_uIntPtr nLatestCRC, sal_uIntPtr nNumber )
{

#ifdef OSL_LITENDIAN
	nNumber = SWAPLONG( nNumber );
#endif
	return rtl_crc32( nLatestCRC, &nNumber, 4 );
}

// ------------------------------------------------------------------------

sal_uIntPtr ZCodec::UpdateCRC ( sal_uIntPtr nLatestCRC, sal_uInt8* pSource, long nDatSize)
{
	return rtl_crc32( nLatestCRC, pSource, nDatSize );
}

// ------------------------------------------------------------------------

void GZCodec::BeginCompression( sal_uIntPtr nCompressMethod )
{
	ZCodec::BeginCompression( nCompressMethod | ZCODEC_GZ_LIB );
};