#include "runsmap.h"

//---------------------------------------------------------------------------------------------

void RunsMap::setRunLength(TPixelGR8 *pix, TUINT32 length)
{
	TPixelGR8 *origPix = pix;
	pix = origPix;

	TPixelGR8 *pixRev = pix + length - 1;

	--length;
	if (length < 3)
		pix->value = pixRev->value = (length << 6);
	else {
		pix->value = pixRev->value = (3 << 6);
		++pix, --pixRev;
		if (length < 255)
			pix->value = pixRev->value = length;
		else {
			pix->value = pixRev->value = 255;
			++pix, pixRev -= 4;
			TUINT32 *l = (TUINT32 *)pix;
			*l = length;
		}
	}

	assert(runLength(origPix) == (length + 1));
}

//---------------------------------------------------------------------------------------------

TUINT32 RunsMap::runLength(const TPixelGR8 *pix, bool reversed) const
{
	int length = pix->value >> 6;
	if (length >= 3) {
		pix += (reversed) ? -1 : 1, length = pix->value;
		if (length >= 255) {
			pix += (reversed) ? -4 : 1;
			length = *(TUINT32 *)pix;
		}
	}

	return length + 1;
}