// this code is copied from TQt, with fixes for not finishing decoding
// prematurely

/* The actual patch is:
=====
--- /opt/_q/src/kernel/qmngio.cpp	2004-05-04 18:28:15.000000000 +0200
+++ gvmngformattype.cpp	2005-04-13 16:11:50.000000000 +0200
@@ -411,8 +417,11 @@ int TQMNGFormat::decode( TQImage& img, TQIm
     }
 
     losttime += losingtimer.elapsed();
-    if ( ndata || !length )
-	mng_display_resume(handle);
+    bool needmore = false;
+    if ( ndata ) {
+	mng_retcode r = mng_display_resume(handle);
+	needmore = ( r == MNG_NEEDMOREDATA );
+    }
     losingtimer.start();
 
     image = 0;
@@ -422,6 +431,13 @@ int TQMNGFormat::decode( TQImage& img, TQIm
 	// Move back unused tail
 	memcpy(buffer,buffer+ubuffer,nbuffer);
     }
+    // "The function should return without processing all the data if it reaches the end of a frame in the input."
+    if( ndata && !needmore ) {
+	length -= ndata;
+	ndata = 0;
+	if( length == 0 ) // 0 means done, process at least one byte
+	    length = ndata = 1;
+    }
     if ( ndata ) {
 	// Not all used.
 	enlargeBuffer(nbuffer+ndata);
=====
*/

/****************************************************************************
** 
**
** Implementation of MNG TQImage IOHandler
**
** Created : 970521
**
** Copyright (C) 1997-2004 Trolltech AS.  All rights reserved.
**
** This file is part of the kernel module of the TQt GUI Toolkit.
**
** This file may be distributed under the terms of the Q Public License
** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.TQPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** Licensees holding valid TQt Enterprise Edition or TQt Professional Edition
** licenses may use this file in accordance with the TQt Commercial License
** Agreement provided with the Software.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
**   information about TQt Commercial License Agreements.
** See http://www.trolltech.com/qpl/ for TQPL licensing information.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/

#include <config.h>

#include "tqdatetime.h"
#include "mngformattype.h"

//#ifndef TQT_NO_IMAGEIO_MNG
#ifdef HAVE_LIBMNG

#include "tqimage.h"
#include "tqasyncimageio.h"
#include "tqiodevice.h"

#include <libmng.h>
#include <stdlib.h>


#ifndef TQT_NO_ASYNC_IMAGE_IO
namespace Gwenview {

class MNGFormat : public TQImageFormat {
public:
    MNGFormat();
    virtual ~MNGFormat();

    int decode(TQImage& img, TQImageConsumer* consumer,
	    const uchar* buffer, int length);

    bool openstream()
    {
	// ### We should figure out how many loops an MNG has, but for now always assume infinite.
	if (consumer)
	    consumer->setLooping(0);
	return true;
    }
    bool closestream( )
    {
	if (consumer)
	    consumer->end();
	return true;
    }
    bool readdata( mng_ptr pBuf, mng_uint32 iBuflen, mng_uint32p pRead )
    {
	uint m = ndata + nbuffer - ubuffer;
	if ( iBuflen > m ) {
	    iBuflen = m;
	}
	*pRead = iBuflen;
	uint n = nbuffer-ubuffer;
	if ( iBuflen < n ) {
	    // enough in buffer
	    memcpy(pBuf, buffer+ubuffer, iBuflen);
	    ubuffer += iBuflen;
	    return true;
	}
	if ( n ) {
	    // consume buffer
	    memcpy(pBuf, buffer+ubuffer, n );
	    pBuf = (mng_ptr)((char*)pBuf + n);
	    iBuflen -= n;
	    ubuffer = nbuffer;
	}
	if ( iBuflen ) {
	    // fill from incoming data
	    memcpy(pBuf, data, iBuflen);
	    data += iBuflen;
	    ndata -= iBuflen;
	}
	return true;
    }
    bool errorproc( mng_int32   iErrorcode,
		   mng_int8    /*iSeverity*/,
		   mng_chunkid iChunkname,
		   mng_uint32  /*iChunkseq*/,
		   mng_int32   iExtra1,
		   mng_int32   iExtra2,
		   mng_pchar   zErrortext )
    {
	tqWarning("MNG error %d: %s; chunk %c%c%c%c; subcode %d:%d",
	    iErrorcode,zErrortext,
	    (iChunkname>>24)&0xff,
	    (iChunkname>>16)&0xff,
	    (iChunkname>>8)&0xff,
	    (iChunkname>>0)&0xff,
	    iExtra1,iExtra2);
	return true;
    }
    bool processheader( mng_uint32 iWidth, mng_uint32 iHeight )
    {
	image->create(iWidth,iHeight,32);
	image->setAlphaBuffer(true);
	memset(image->bits(),0,iWidth*iHeight*4);
	consumer->setSize(iWidth,iHeight);
	mng_set_canvasstyle(handle,
	    TQImage::systemByteOrder() == TQImage::LittleEndian
		? MNG_CANVAS_BGRA8 : MNG_CANVAS_ARGB8 );
	return true;
    }
    mng_ptr getcanvasline( mng_uint32 iLinenr )
    {
	return image->scanLine(iLinenr);
    }
    mng_bool refresh( mng_uint32 x, mng_uint32 y, mng_uint32 w, mng_uint32 h )
    {
	TQRect r(x,y,w,h);
	consumer->changed(r);
	consumer->setFramePeriod(0);
	consumer->frameDone();
	return TRUE;
    }
    mng_uint32 gettickcount( )
    {
	return timer.elapsed() - losttime;
    }
    bool settimer( mng_uint32 iMsecs )
    {
	consumer->setFramePeriod(iMsecs);
	consumer->frameDone();
	state = Time;
	losingtimer.start();
	losttime -= iMsecs;
	return true;
    }

private:
    // Animation-level information
    enum { MovieStart, Time, Data, Data2 } state;

    // Image-level information
    mng_handle handle;

    // For storing unused data
    uchar *buffer;
    uint maxbuffer;
    uint nbuffer;

    // Timing
    TQTime timer;
    TQTime losingtimer;
    int losttime;

    void enlargeBuffer(uint n)
    {
	if ( n > maxbuffer ) {
	    maxbuffer = n;
	    buffer = (uchar*)realloc(buffer,n);
	}
    }

    // Temporary locals during single data-chunk processing
    const uchar* data;
    uint ndata;
    uint ubuffer;
    TQImageConsumer* consumer;
    TQImage* image;
};

class MNGFormatType : public TQImageFormatType
{
    TQImageFormat* decoderFor(const uchar* buffer, int length);
    const char* formatName() const;
};


/*
  \class TQMNGFormat qmngio.h
  \brief Incremental image decoder for MNG image format.

  \ingroup images
  \ingroup graphics

  This subclass of TQImageFormat decodes MNG format images,
  including animated MNGs.

  Animated MNG images are standard MNG images.  The MNG standard
  defines two extension chunks that are useful for animations:

  <dl>
   <dt>gIFg - GIF-like Graphic Control Extension
    <dd>Includes frame disposal, user input flag (we ignore this),
	    and inter-frame delay.
   <dt>gIFx - GIF-like Application Extension
    <dd>Multi-purpose, but we just use the Netscape extension
	    which specifies looping.
  </dl>

  The subimages usually contain a offset chunk (oFFs) but need not.

  The first image defines the "screen" size.  Any subsequent image that
  doesn't fit is clipped.

TODO: decide on this point.  gIFg gives disposal types, so it can be done.
  All images paste (\e not composite, just place all-channel copying)
  over the previous image to produce a subsequent frame.
*/

/*
  \class TQMNGFormatType qasyncimageio.h
  \brief Incremental image decoder for MNG image format.

  \ingroup images
  \ingroup graphics
  \ingroup io

  This subclass of TQImageFormatType recognizes MNG
  format images, creating a TQMNGFormat when required.  An instance
  of this class is created automatically before any other factories,
  so you should have no need for such objects.
*/

TQImageFormat* MNGFormatType::decoderFor( const uchar* buffer, int length )
{
    if (length < 8) return 0;

    if (  (   buffer[0]==138 // MNG signature
           && buffer[1]=='M'
           && buffer[2]=='N'
           && buffer[3]=='G'
           && buffer[4]==13
           && buffer[5]==10
           && buffer[6]==26
           && buffer[7]==10 )
       || (   buffer[0]==139 // JNG signature
           && buffer[1]=='J'
           && buffer[2]=='N'
           && buffer[3]=='G'
           && buffer[4]==13
           && buffer[5]==10
           && buffer[6]==26
           && buffer[7]==10 )
#ifdef TQT_NO_IMAGEIO_PNG // if we don't have native PNG support use libmng
       || (   buffer[0]==137 // PNG signature
           && buffer[1]=='P'
           && buffer[2]=='N'
           && buffer[3]=='G'
           && buffer[4]==13
           && buffer[5]==10
           && buffer[6]==26
           && buffer[7]==10 )
#endif
    ) {
        return new MNGFormat;
    }
    return 0;
}

const char* MNGFormatType::formatName() const
{
    return "MNG";
}


/*!
  Constructs a TQMNGFormat.
*/
MNGFormat::MNGFormat()
{
    state = MovieStart;
    handle = 0;
    nbuffer = 0;
    maxbuffer = 0;
    buffer = 0;
    losttime = 0;
}

/*
  Destroys a TQMNGFormat.
*/
MNGFormat::~MNGFormat()
{
    // We're setting the consumer to 0 since it may have been
    // deleted by read_async_image in qimage.cpp
    consumer = 0;
    if (handle) mng_cleanup(&handle);
}


// C-callback to C++-member-function conversion
//
static mng_bool openstream( mng_handle handle )
{
    return ((MNGFormat*)mng_get_userdata(handle))->openstream();
}
static mng_bool closestream( mng_handle handle )
{
    return ((MNGFormat*)mng_get_userdata(handle))->closestream();
}
static mng_bool readdata( mng_handle handle, mng_ptr pBuf, mng_uint32 iBuflen, mng_uint32p pRead )
{
    return ((MNGFormat*)mng_get_userdata(handle))->readdata(pBuf,iBuflen,pRead);
}
static mng_bool errorproc( mng_handle handle,
		       mng_int32   iErrorcode,
		       mng_int8    iSeverity,
		       mng_chunkid iChunkname,
		       mng_uint32  iChunkseq,
		       mng_int32   iExtra1,
		       mng_int32   iExtra2,
		       mng_pchar   zErrortext )
{
    return ((MNGFormat*)mng_get_userdata(handle))->errorproc(iErrorcode,
	iSeverity,iChunkname,iChunkseq,iExtra1,iExtra2,zErrortext);
}
static mng_bool processheader( mng_handle handle,
			   mng_uint32 iWidth, mng_uint32 iHeight )
{
    return ((MNGFormat*)mng_get_userdata(handle))->processheader(iWidth,iHeight);
}
static mng_ptr getcanvasline( mng_handle handle, mng_uint32 iLinenr )
{
    return ((MNGFormat*)mng_get_userdata(handle))->getcanvasline(iLinenr);
}
static mng_bool refresh( mng_handle handle,
		      mng_uint32  iTop,
		      mng_uint32  iLeft,
		      mng_uint32  iBottom,
		      mng_uint32  iRight	)
{
    return ((MNGFormat*)mng_get_userdata(handle))->refresh(iTop,iLeft,iBottom,iRight);
}
static mng_uint32 gettickcount( mng_handle handle )
{
    return ((MNGFormat*)mng_get_userdata(handle))->gettickcount();
}
static mng_bool settimer( mng_handle handle, mng_uint32  iMsecs )
{
    return ((MNGFormat*)mng_get_userdata(handle))->settimer(iMsecs);
}

static mng_ptr memalloc( mng_size_t iLen )
{
    return calloc(1,iLen);
}
static void memfree( mng_ptr iPtr, mng_size_t /*iLen*/ )
{
    free(iPtr);
}

/*!
  This function decodes some data into image changes.

  Returns the number of bytes consumed.
*/
int MNGFormat::decode( TQImage& img, TQImageConsumer* cons,
			const uchar* buf, int length )
{
    consumer = cons;
    image = &img;

    data = buf;
    ndata = length;
    ubuffer = 0;

    if ( state == MovieStart ) {
        handle = mng_initialize( (mng_ptr)this, Gwenview::memalloc, Gwenview::memfree, 0 );
	mng_set_suspensionmode( handle, MNG_TRUE );
	mng_setcb_openstream( handle, Gwenview::openstream );
	mng_setcb_closestream( handle, Gwenview::closestream );
	mng_setcb_readdata( handle, Gwenview::readdata );
	mng_setcb_errorproc( handle, Gwenview::errorproc );
	mng_setcb_processheader( handle, Gwenview::processheader );
	mng_setcb_getcanvasline( handle, Gwenview::getcanvasline );
	mng_setcb_refresh( handle, Gwenview::refresh );
	mng_setcb_gettickcount( handle, Gwenview::gettickcount );
	mng_setcb_settimer( handle, Gwenview::settimer );
	state = Data;
	mng_readdisplay(handle);
	losingtimer.start();
    }

    losttime += losingtimer.elapsed();
    bool needmore = false;
    if ( ndata ) {
	mng_retcode r = mng_display_resume(handle);
	needmore = ( r == MNG_NEEDMOREDATA );
    }
    losingtimer.start();

    image = 0;

    nbuffer -= ubuffer;
    if ( nbuffer ) {
	// Move back unused tail
	memcpy(buffer,buffer+ubuffer,nbuffer);
    }
    // "The function should return without processing all the data if it reaches the end of a frame in the input."
    if( ndata && !needmore ) {
	length -= ndata;
	ndata = 0;
	if( length == 0 ) // 0 means done, process at least one byte
	    length = ndata = 1;
    }
    if ( ndata ) {
	// Not all used.
	enlargeBuffer(nbuffer+ndata);
	memcpy(buffer+nbuffer,data,ndata);
	nbuffer += ndata;
    }

    return length;
}

static MNGFormatType* globalMngFormatTypeObject = 0;

#endif // TQT_NO_ASYNC_IMAGE_IO

#ifndef TQT_NO_ASYNC_IMAGE_IO
void gvCleanupMngIO()
{
    if ( globalMngFormatTypeObject ) {
	delete globalMngFormatTypeObject;
	globalMngFormatTypeObject = 0;
    }
}
#endif

void gvInitMngIO()
{
    static bool done = false;
    if ( !done ) {
	done = true;
#ifndef TQT_NO_ASYNC_IMAGE_IO
	globalMngFormatTypeObject = new MNGFormatType;
	tqAddPostRoutine( gvCleanupMngIO );
#endif
    }
}

#else
void gvInitMngIO() {}

namespace Gwenview {
#endif

MNG::MNG() { gvInitMngIO(); }
} // namespace
