#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;
}