///////////////////////////////////////////////////////////////////////////

//

// 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.

//

///////////////////////////////////////////////////////////////////////////

#include <string.h>

#include "ImfRle.h"

#include "ImfNamespace.h"

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER

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;

        memcpy(out, in, count);

        out += count;

        in  += count;

	}

	else

	{

	    int count = *in++;

	    inLength -= 2;

	    if (0 > (maxLength -= count + 1))

		return 0;

        memset(out, *(char*)in, count+1);

        out += count+1;

	    in++;

	}

    }

    return out - outStart;

}

OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT