///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2002, 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 RleCompressor
//
//-----------------------------------------------------------------------------
#include <ImfRleCompressor.h>
#include <ImfCheckedArithmetic.h>
#include "Iex.h"
namespace Imf {
namespace {
const int MIN_RUN_LENGTH = 3;
const int MAX_RUN_LENGTH = 127;
//
// Compress an array of bytes, using run-length encoding,
// and return the length of the compressed data.
//
int
rleCompress (int inLength, const char in[], signed char out[])
{
const char *inEnd = in + inLength;
const char *runStart = in;
const char *runEnd = in + 1;
signed char *outWrite = out;
while (runStart < inEnd)
{
while (runEnd < inEnd &&
*runStart == *runEnd &&
runEnd - runStart - 1 < MAX_RUN_LENGTH)
{
++runEnd;
}
if (runEnd - runStart >= MIN_RUN_LENGTH)
{
//
// Compressable run
//
*outWrite++ = (runEnd - runStart) - 1;
*outWrite++ = *(signed char *) runStart;
runStart = runEnd;
}
else
{
//
// Uncompressable run
//
while (runEnd < inEnd &&
((runEnd + 1 >= inEnd ||
*runEnd != *(runEnd + 1)) ||
(runEnd + 2 >= inEnd ||
*(runEnd + 1) != *(runEnd + 2))) &&
runEnd - runStart < MAX_RUN_LENGTH)
{
++runEnd;
}
*outWrite++ = runStart - runEnd;
while (runStart < runEnd)
{
*outWrite++ = *(signed char *) (runStart++);
}
}
++runEnd;
}
return outWrite - out;
}
//
// Uncompress an array of bytes compressed with rleCompress().
// Returns the length of the oncompressed data, or 0 if the
// length of the uncompressed data would be more than maxLength.
//
int
rleUncompress (int inLength, int maxLength, const signed char in[], char out[])
{
char *outStart = out;
while (inLength > 0)
{
if (*in < 0)
{
int count = -((int)*in++);
inLength -= count + 1;
if (0 > (maxLength -= count))
return 0;
while (count-- > 0)
*out++ = *(char *) (in++);
}
else
{
int count = *in++;
inLength -= 2;
if (0 > (maxLength -= count + 1))
return 0;
while (count-- >= 0)
*out++ = *(char *) in;
in++;
}
}
return out - outStart;
}
} // namespace
RleCompressor::RleCompressor (const Header &hdr, size_t maxScanLineSize):
Compressor (hdr),
_maxScanLineSize (maxScanLineSize),
_tmpBuffer (0),
_outBuffer (0)
{
_tmpBuffer = new char [maxScanLineSize];
_outBuffer = new char [uiMult (maxScanLineSize, size_t (3)) / 2];
}
RleCompressor::~RleCompressor ()
{
delete [] _tmpBuffer;
delete [] _outBuffer;
}
int
RleCompressor::numScanLines () const
{
//
// This compressor compresses individual scan lines.
//
return 1;
}
int
RleCompressor::compress (const char *inPtr,
int inSize,
int /*minY*/,
const char *&outPtr)
{
//
// Special case - empty input buffer
//
if (inSize == 0)
{
outPtr = _outBuffer;
return 0;
}
//
// Reorder the pixel data.
//
{
char *t1 = _tmpBuffer;
char *t2 = _tmpBuffer + (inSize + 1) / 2;
const char *stop = inPtr + inSize;
while (true)
{
if (inPtr < stop)
*(t1++) = *(inPtr++);
else
break;
if (inPtr < stop)
*(t2++) = *(inPtr++);
else
break;
}
}
//
// Predictor.
//
{
unsigned char *t = (unsigned char *) _tmpBuffer + 1;
unsigned char *stop = (unsigned char *) _tmpBuffer + inSize;
int p = t[-1];
while (t < stop)
{
int d = int (t[0]) - p + (128 + 256);
p = t[0];
t[0] = d;
++t;
}
}
//
// Run-length encode the data.
//
outPtr = _outBuffer;
return rleCompress (inSize, _tmpBuffer, (signed char *) _outBuffer);
}
int
RleCompressor::uncompress (const char *inPtr,
int inSize,
int /*minY*/,
const char *&outPtr)
{
//
// Special case - empty input buffer
//
if (inSize == 0)
{
outPtr = _outBuffer;
return 0;
}
//
// Decode the run-length encoded data
//
int outSize;
if (0 == (outSize = rleUncompress (inSize, _maxScanLineSize,
(const signed char *) inPtr,
_tmpBuffer)))
{
throw Iex::InputExc ("Data decoding (rle) failed.");
}
//
// Predictor.
//
{
unsigned char *t = (unsigned char *) _tmpBuffer + 1;
unsigned char *stop = (unsigned char *) _tmpBuffer + outSize;
while (t < stop)
{
int d = int (t[-1]) + int (t[0]) - 128;
t[0] = d;
++t;
}
}
//
// Reorder the pixel data.
//
{
const char *t1 = _tmpBuffer;
const char *t2 = _tmpBuffer + (outSize + 1) / 2;
char *s = _outBuffer;
char *stop = s + outSize;
while (true)
{
if (s < stop)
*(s++) = *(t1++);
else
break;
if (s < stop)
*(s++) = *(t2++);
else
break;
}
}
outPtr = _outBuffer;
return outSize;
}
} // namespace Imf