imfscanlineinputfile.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 ScanLineInputFile
//
//-----------------------------------------------------------------------------

#include <ImfScanLineInputFile.h>
#include <ImfChannelList.h>
#include <ImfMisc.h>
#include <ImfStdIO.h>
#include <ImfCompressor.h>
#include "ImathBox.h"
#include "ImathFun.h"
#include <ImfXdr.h>
#include <ImfConvert.h>
#include <ImfThreading.h>
#include "IlmThreadPool.h"
#include "IlmThreadSemaphore.h"
#include "IlmThreadMutex.h"
#include "Iex.h"
#include <string>
#include <vector>
#include <assert.h>


namespace Imf {

using Imath::Box2i;
using Imath::divp;
using Imath::modp;
using std::string;
using std::vector;
using std::ifstream;
using std::min;
using std::max;
using IlmThread::Mutex;
using IlmThread::Lock;
using IlmThread::Semaphore;
using IlmThread::Task;
using IlmThread::TaskGroup;
using IlmThread::ThreadPool;

namespace {

struct InSliceInfo
{
    PixelType	typeInFrameBuffer;
    PixelType	typeInFile;
    char *	base;
    size_t	xStride;
    size_t	yStride;
    int		xSampling;
    int		ySampling;
    bool	fill;
    bool	skip;
    double	fillValue;

    InSliceInfo (PixelType typeInFrameBuffer = HALF,
		 PixelType typeInFile = HALF,
	         char *base = 0,
	         size_t xStride = 0,
	         size_t yStride = 0,
	         int xSampling = 1,
	         int ySampling = 1,
	         bool fill = false,
	         bool skip = false,
	         double fillValue = 0.0);
};


InSliceInfo::InSliceInfo (PixelType tifb,
			  PixelType tifl,
			  char *b,
			  size_t xs, size_t ys,
			  int xsm, int ysm,
			  bool f, bool s,
			  double fv)
:
    typeInFrameBuffer (tifb),
    typeInFile (tifl),
    base (b),
    xStride (xs),
    yStride (ys),
    xSampling (xsm),
    ySampling (ysm),
    fill (f),
    skip (s),
    fillValue (fv)
{
    // empty
}


struct LineBuffer
{
    const char *	uncompressedData;
    char *		buffer;
    int			dataSize;
    int			minY;
    int			maxY;
    Compressor *	compressor;
    Compressor::Format	format;
    int			number;
    bool		hasException;
    string		exception;

    LineBuffer (Compressor * const comp);
    ~LineBuffer ();

    inline void		wait () {_sem.wait();}
    inline void		post () {_sem.post();}

  private:

    Semaphore		_sem;
};


LineBuffer::LineBuffer (Compressor *comp):
    uncompressedData (0),
    buffer (0),
    dataSize (0),
    compressor (comp),
    format (defaultFormat(compressor)),
    number (-1),
    hasException (false),
    exception (),
    _sem (1)
{
    // empty
}


LineBuffer::~LineBuffer ()
{
    delete compressor;
}

} // namespace


struct ScanLineInputFile::Data: public Mutex
{
    Header		header;		    // the image header
    int			version;            // file's version
    FrameBuffer		frameBuffer;	    // framebuffer to write into
    LineOrder		lineOrder;          // order of the scanlines in file
    int			minX;		    // data window's min x coord
    int			maxX;		    // data window's max x coord
    int			minY;		    // data window's min y coord
    int			maxY;		    // data window's max x coord
    vector<Int64>	lineOffsets;	    // stores offsets in file for
					    // each line
    bool		fileIsComplete;	    // True if no scanlines are missing
    					    // in the file
    int			nextLineBufferMinY; // minimum y of the next linebuffer
    vector<size_t>	bytesPerLine;       // combined size of a line over all
                                            // channels
    vector<size_t>	offsetInLineBuffer; // offset for each scanline in its
                                            // linebuffer
    vector<InSliceInfo>	slices;             // info about channels in file
    IStream *		is;                 // file stream to read from
    
    vector<LineBuffer*> lineBuffers;        // each holds one line buffer
    int			linesInBuffer;      // number of scanlines each buffer
                                            // holds
    size_t		lineBufferSize;     // size of the line buffer

     Data (IStream *is, int numThreads);
    ~Data ();
    
    inline LineBuffer * getLineBuffer (int number); // hash function from line
    						    // buffer indices into our
						    // vector of line buffers
};


ScanLineInputFile::Data::Data (IStream *is, int numThreads):
    is (is)
{
    //
    // We need at least one lineBuffer, but if threading is used,
    // to keep n threads busy we need 2*n lineBuffers
    //

    lineBuffers.resize (max (1, 2 * numThreads));
}


ScanLineInputFile::Data::~Data ()
{
    for (size_t i = 0; i < lineBuffers.size(); i++)
        delete lineBuffers[i];
}


inline LineBuffer *
ScanLineInputFile::Data::getLineBuffer (int lineBufferNumber)
{
    return lineBuffers[lineBufferNumber % lineBuffers.size()];
}


namespace {


void
reconstructLineOffsets (IStream &is,
			LineOrder lineOrder,
			vector<Int64> &lineOffsets)
{
    Int64 position = is.tellg();

    try
    {
	for (unsigned int i = 0; i < lineOffsets.size(); i++)
	{
	    Int64 lineOffset = is.tellg();

	    int y;
	    Xdr::read <StreamIO> (is, y);

	    int dataSize;
	    Xdr::read <StreamIO> (is, dataSize);

	    Xdr::skip <StreamIO> (is, dataSize);

	    if (lineOrder == INCREASING_Y)
		lineOffsets[i] = lineOffset;
	    else
		lineOffsets[lineOffsets.size() - i - 1] = lineOffset;
	}
    }
    catch (...)
    {
	//
	// Suppress all exceptions.  This functions is
	// called only to reconstruct the line offset
	// table for incomplete files, and exceptions
	// are likely.
	//
    }

    is.clear();
    is.seekg (position);
}


void
readLineOffsets (IStream &is,
		 LineOrder lineOrder,
		 vector<Int64> &lineOffsets,
		 bool &complete)
{
    for (unsigned int i = 0; i < lineOffsets.size(); i++)
    {
	Xdr::read <StreamIO> (is, lineOffsets[i]);
    }

    complete = true;

    for (unsigned int i = 0; i < lineOffsets.size(); i++)
    {
	if (lineOffsets[i] <= 0)
	{
	    //
	    // Invalid data in the line offset table mean that
	    // the file is probably incomplete (the table is
	    // the last thing written to the file).  Either
	    // some process is still busy writing the file,
	    // or writing the file was aborted.
	    //
	    // We should still be able to read the existing
	    // parts of the file.  In order to do this, we
	    // have to make a sequential scan over the scan
	    // line data to reconstruct the line offset table.
	    //

	    complete = false;
	    reconstructLineOffsets (is, lineOrder, lineOffsets);
	    break;
	}
    }
}


void
readPixelData (ScanLineInputFile::Data *ifd,
	       int minY,
	       char *&buffer,
	       int &dataSize)
{
    //
    // Read a single line buffer from the input file.
    //
    // If the input file is not memory-mapped, we copy the pixel data into
    // into the array pointed to by buffer.  If the file is memory-mapped,
    // then we change where buffer points to instead of writing into the
    // array (hence buffer needs to be a reference to a char *).
    //

    Int64 lineOffset =
	ifd->lineOffsets[(minY - ifd->minY) / ifd->linesInBuffer];

    if (lineOffset == 0)
	THROW (Iex::InputExc, "Scan line " << minY << " is missing.");

    //
    // Seek to the start of the scan line in the file,
    // if necessary.
    //

    if (ifd->nextLineBufferMinY != minY)
	ifd->is->seekg (lineOffset);

    //
    // Read the data block's header.
    //

    int yInFile;

    Xdr::read <StreamIO> (*ifd->is, yInFile);
    Xdr::read <StreamIO> (*ifd->is, dataSize);
    
    if (yInFile != minY)
        throw Iex::InputExc ("Unexpected data block y coordinate.");

    if (dataSize > (int) ifd->lineBufferSize)
	throw Iex::InputExc ("Unexpected data block length.");

    //
    // Read the pixel data.
    //

    if (ifd->is->isMemoryMapped ())
        buffer = ifd->is->readMemoryMapped (dataSize);
    else
        ifd->is->read (buffer, dataSize);

    //
    // Keep track of which scan line is the next one in
    // the file, so that we can avoid redundant seekg()
    // operations (seekg() can be fairly expensive).
    //

    if (ifd->lineOrder == INCREASING_Y)
	ifd->nextLineBufferMinY = minY + ifd->linesInBuffer;
    else
	ifd->nextLineBufferMinY = minY - ifd->linesInBuffer;
}


//
// A LineBufferTask encapsulates the task uncompressing a set of
// scanlines (line buffer) and copying them into the frame buffer.
//

class LineBufferTask : public Task
{
  public:

    LineBufferTask (TaskGroup *group,
                    ScanLineInputFile::Data *ifd,
		    LineBuffer *lineBuffer,
                    int scanLineMin,
		    int scanLineMax);

    virtual ~LineBufferTask ();

    virtual void		execute ();

  private:

    ScanLineInputFile::Data *	_ifd;
    LineBuffer *		_lineBuffer;
    int				_scanLineMin;
    int				_scanLineMax;
};


LineBufferTask::LineBufferTask
    (TaskGroup *group,
     ScanLineInputFile::Data *ifd,
     LineBuffer *lineBuffer,
     int scanLineMin,
     int scanLineMax)
:
    Task (group),
    _ifd (ifd),
    _lineBuffer (lineBuffer),
    _scanLineMin (scanLineMin),
    _scanLineMax (scanLineMax)
{
    // empty
}


LineBufferTask::~LineBufferTask ()
{
    //
    // Signal that the line buffer is now free
    //

    _lineBuffer->post ();
}


void
LineBufferTask::execute ()
{
    try
    {
        //
        // Uncompress the data, if necessary
        //
    
        if (_lineBuffer->uncompressedData == 0)
        {
            int uncompressedSize = 0;
            int maxY = min (_lineBuffer->maxY, _ifd->maxY);
    
            for (int i = _lineBuffer->minY - _ifd->minY;
                 i <= maxY - _ifd->minY;
		 ++i)
	    {
                uncompressedSize += (int) _ifd->bytesPerLine[i];
	    }
    
            if (_lineBuffer->compressor &&
                _lineBuffer->dataSize < uncompressedSize)
            {
                _lineBuffer->format = _lineBuffer->compressor->format();

                _lineBuffer->dataSize = _lineBuffer->compressor->uncompress
                    (_lineBuffer->buffer, _lineBuffer->dataSize,
		     _lineBuffer->minY, _lineBuffer->uncompressedData);
            }
            else
            {
                //
                // If the line is uncompressed, it's in XDR format,
                // regardless of the compressor's output format.
                //
    
                _lineBuffer->format = Compressor::XDR;
                _lineBuffer->uncompressedData = _lineBuffer->buffer;
            }
        }
        
        int yStart, yStop, dy;

        if (_ifd->lineOrder == INCREASING_Y)
        {
            yStart = _scanLineMin;
            yStop = _scanLineMax + 1;
            dy = 1;
        }
        else
        {
            yStart = _scanLineMax;
            yStop = _scanLineMin - 1;
            dy = -1;
        }
    
        for (int y = yStart; y != yStop; y += dy)
        {
            //
            // Convert one scan line's worth of pixel data back
            // from the machine-independent representation, and
            // store the result in the frame buffer.