/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   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 .
 */

#include <tools/stream.hxx>

#include <zlib.h>

#include <tools/zcodec.hxx>
#include <rtl/crc.h>
#include <osl/endian.h>

#define PZSTREAM ((z_stream*) mpsC_Stream)

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

ZCodec::ZCodec( sal_uIntPtr nInBufSize, sal_uIntPtr nOutBufSize, sal_uIntPtr nMemUsage )
    : mbInit(0)
    , mbStatus(false)
    , mbFinish(false)
    , mnMemUsage(nMemUsage)
    , mpIStm(NULL)
    , mpInBuf(NULL)
    , mnInBufSize(nInBufSize)
    , mnInToRead(0)
    , mpOStm(NULL)
    , mpOutBuf(NULL)
    , mnOutBufSize(nOutBufSize)
    , mnCRC(0)
    , mnCompressMethod(0)
{
    mpsC_Stream = new z_stream;
}

ZCodec::ZCodec()
    : mbInit(0)
    , mbStatus(false)
    , mbFinish(false)
    , mnMemUsage(MAX_MEM_USAGE)
    , mpIStm(NULL)
    , mpInBuf(NULL)
    , mnInBufSize(DEFAULT_IN_BUFSIZE)
    , mnInToRead(0)
    , mpOStm(NULL)
    , mpOutBuf(NULL)
    , mnOutBufSize(DEFAULT_OUT_BUFSIZE)
    , mnCRC(0)
    , mnCompressMethod(0)
{
    mpsC_Stream = new z_stream;
}

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

void ZCodec::BeginCompression( sal_uIntPtr nCompressMethod )
{
    mbInit = 0;
    mbStatus = true;
    mbFinish = 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( 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 = 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( 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 = false;
            break;
        }

    }
    while ( ( err != Z_STREAM_END)  && ( PZSTREAM->avail_in || mnInToRead ) );
    ImplWriteBack();

    if ( err == Z_STREAM_END )
        mbFinish = 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( 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 = 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( 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 = 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( true );
    }
    PZSTREAM->avail_out = nSize;
    PZSTREAM->next_out = pData;
    do
    {
        if ( PZSTREAM->avail_in == 0 && mnInToRead )
        {
            nInToRead = (mnInBufSize > mnInToRead) ? mnInToRead : mnInBufSize;

            sal_uInt64 const nRemaining = rIStm.remainingSize();
            if (nRemaining < nInToRead)
            {
                rIStm.SetError( ERRCODE_IO_PENDING );
                err= int(!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 = 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()
{
    return ( mnInToRead + PZSTREAM->avail_in );
}

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

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

void ZCodec::ImplInitBuf ( 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->ReadUChar( j );
                    if ( j != gz_magic[ i ] )
                        mbStatus = false;
                }
                mpIStm->ReadUChar( nMethod );
                mpIStm->ReadUChar( nFlags );
                if ( nMethod != Z_DEFLATED )
                    mbStatus = false;
                if ( ( nFlags & GZ_RESERVED ) != 0 )
                    mbStatus = false;
                /* Discard time, xflags and OS code: */
                mpIStm->SeekRel( 6 );
                /* skip the extra field */
                if ( nFlags & GZ_EXTRA_FIELD )
                {
                    mpIStm->ReadUChar( n1 ).ReadUChar( n2 );
                    mpIStm->SeekRel( n1 + ( n2 << 8 ) );
                }
                /* skip the original file name */
                if ( nFlags & GZ_ORIG_NAME)
                {
                    do
                    {
                        mpIStm->ReadUChar( j );
                    }
                    while ( j && !mpIStm->IsEof() );
                }
                /* skip the .gz file comment */
                if ( nFlags & GZ_COMMENT )
                {
                    do
                    {
                        mpIStm->ReadUChar( 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 ) ? false : 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_uInt8* pSource, long nDatSize)
{
    return rtl_crc32( nLatestCRC, pSource, nDatSize );
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */