imfpizcompressor.cpp

对gif

///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2004, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
// 
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// *       Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// *       Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// *       Neither the name of Industrial Light & Magic nor the names of
// its contributors may be used to endorse or promote products derived
// from this software without specific prior written permission. 
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
///////////////////////////////////////////////////////////////////////////


//-----------------------------------------------------------------------------
//
//	class PizCompressor
//
//-----------------------------------------------------------------------------

#include <ImfPizCompressor.h>
#include <ImfHeader.h>
#include <ImfChannelList.h>
#include <ImfHuf.h>
#include <ImfWav.h>
#include <ImfMisc.h>
#include <ImathFun.h>
#include <ImathBox.h>
#include <Iex.h>
#include <ImfIO.h>
#include <ImfXdr.h>
#include <ImfAutoArray.h>
#include <string.h>
#include <assert.h>

namespace Imf {

using Imath::divp;
using Imath::modp;
using Imath::Box2i;
using Imath::V2i;
using Iex::InputExc;

namespace {

//
// Functions to compress the range of values in the pixel data
//

const int USHORT_RANGE = (1 << 16);
const int BITMAP_SIZE  = (USHORT_RANGE >> 3);

void
bitmapFromData (const unsigned short data[/*nData*/],
		int nData,
		unsigned char bitmap[BITMAP_SIZE],
		unsigned short &minNonZero,
		unsigned short &maxNonZero)
{
    for (int i = 0; i < BITMAP_SIZE; ++i)
	bitmap[i] = 0;

    for (int i = 0; i < nData; ++i)
	bitmap[data[i] >> 3] |= (1 << (data[i] & 7));

    bitmap[0] &= ~1;			// zero is not explicitly stored in
					// the bitmap; we assume that the
					// data always contain zeroes
    minNonZero = BITMAP_SIZE - 1;
    maxNonZero = 0;

    for (int i = 0; i < BITMAP_SIZE; ++i)
    {
	if (bitmap[i])
	{
	    if (minNonZero > i)
		minNonZero = i;
	    if (maxNonZero < i)
		maxNonZero = i;
	}
    }
}


unsigned short
forwardLutFromBitmap (const unsigned char bitmap[BITMAP_SIZE],
		      unsigned short lut[USHORT_RANGE])
{
    int k = 0;

    for (int i = 0; i < USHORT_RANGE; ++i)
    {
	if ((i == 0) || (bitmap[i >> 3] & (1 << (i & 7))))
	    lut[i] = k++;
	else
	    lut[i] = 0;
    }

    return k - 1;	// maximum value stored in lut[],
}			// i.e. number of ones in bitmap minus 1


unsigned short
reverseLutFromBitmap (const unsigned char bitmap[BITMAP_SIZE],
		      unsigned short lut[USHORT_RANGE])
{
    int k = 0;

    for (int i = 0; i < USHORT_RANGE; ++i)
    {
	if ((i == 0) || (bitmap[i >> 3] & (1 << (i & 7))))
	    lut[k++] = i;
    }

    int n = k - 1;

    while (k < USHORT_RANGE)
	lut[k++] = 0;

    return n;		// maximum k where lut[k] is non-zero,
}			// i.e. number of ones in bitmap minus 1


void
applyLut (const unsigned short lut[USHORT_RANGE],
	  unsigned short data[/*nData*/],
	  int nData)
{
    for (int i = 0; i < nData; ++i)
	data[i] = lut[data[i]];
}


} // namespace


struct PizCompressor::ChannelData
{
    unsigned short *	start;
    unsigned short *	end;
    int			nx;
    int			ny;
    int			ys;
    int			size;
};


PizCompressor::PizCompressor
    (const Header &hdr,
     int maxScanLineSize,
     int numScanLines)
:
    Compressor (hdr),
    _maxScanLineSize (maxScanLineSize),
    _format (XDR),
    _numScanLines (numScanLines),
    _tmpBuffer (0),
    _outBuffer (0),
    _numChans (0),
    _channels (hdr.channels()),
    _channelData (0)
{
    _tmpBuffer = new unsigned short [maxScanLineSize * numScanLines / 2];
    _outBuffer = new char [maxScanLineSize * numScanLines + 65536 + 8192];

    const ChannelList &channels = header().channels();
    bool onlyHalfChannels = true;

    for (ChannelList::ConstIterator c = channels.begin();
	 c != channels.end();
	 ++c)
    {
	_numChans++;

	assert (pixelTypeSize (c.channel().type) % pixelTypeSize (HALF) == 0);

	if (c.channel().type != HALF)
	    onlyHalfChannels = false;
    }

    _channelData = new ChannelData[_numChans];

    const Box2i &dataWindow = hdr.dataWindow();

    _minX = dataWindow.min.x;
    _maxX = dataWindow.max.x;
    _maxY = dataWindow.max.y;

    //
    // We can support uncompressed data in the machine's native format
    // if all image channels are of type HALF, and if the Xdr and the
    // native represenations of a half have the same size.
    //

    if (onlyHalfChannels && (sizeof (half) == pixelTypeSize (HALF)))
	_format = NATIVE;
}


PizCompressor::~PizCompressor ()
{
    delete [] _tmpBuffer;
    delete [] _outBuffer;
    delete [] _channelData;
}


int
PizCompressor::numScanLines () const
{
    return _numScanLines;
}


Compressor::Format
PizCompressor::format () const
{
    return _format;
}


int
PizCompressor::compress (const char *inPtr,
			 int inSize,
			 int minY,
			 const char *&outPtr)
{
    return compress (inPtr,
		     inSize,
		     Box2i (V2i (_minX, minY),
			    V2i (_maxX, minY + numScanLines() - 1)),
		     outPtr);
}


int
PizCompressor::compressTile (const char *inPtr,
			     int inSize,
			     Imath::Box2i range,
			     const char *&outPtr)
{
    return compress (inPtr, inSize, range, outPtr);
}


int
PizCompressor::uncompress (const char *inPtr,
			   int inSize,
			   int minY,
			   const char *&outPtr)
{
    return uncompress (inPtr,
		       inSize,
		       Box2i (V2i (_minX, minY),
			      V2i (_maxX, minY + numScanLines() - 1)),
		       outPtr);
}


int
PizCompressor::uncompressTile (const char *inPtr,
			       int inSize,
			       Imath::Box2i range,
			       const char *&outPtr)
{
    return uncompress (inPtr, inSize, range, outPtr);
}


int
PizCompressor::compress (const char *inPtr,
			 int inSize,
			 Imath::Box2i range,
			 const char *&outPtr)
{
    //
    // This is the compress function which is used by both the tiled and
    // scanline compression routines.
    //

    //
    // Special case