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  package sun.java2d.pisces;
  
  import java.util.Arrays;
  
  /**
   * An object used to cache pre-rendered complex paths.
   *
   * @see PiscesRenderer#render
   */
  final class PiscesCache {
  
      final int bboxX0, bboxY0, bboxX1, bboxY1;
  
      // rowAARLE[i] holds the encoding of the pixel row with y = bboxY0+i.
      // The format of each of the inner arrays is: rowAARLE[i][0,1] = (x0, n)
      // where x0 is the first x in row i with nonzero alpha, and n is the
      // number of RLE entries in this row. rowAARLE[i][j,j+1] for j>1 is
      // (val,runlen)
      final int[][] rowAARLE;
  
      // RLE encodings are added in increasing y rows and then in increasing
      // x inside those rows. Therefore, at any one time there is a well
      // defined position (x,y) where a run length is about to be added (or
      // the row terminated). x0,y0 is this (x,y)-(bboxX0,bboxY0). They
      // are used to get indices into the current tile.
      private int x0 = Integer.MIN_VALUE, y0 = Integer.MIN_VALUE;
  
      // touchedTile[i][j] is the sum of all the alphas in the tile with
      // y=i*TILE_SIZE+bboxY0 and x=j*TILE_SIZE+bboxX0.
      private final int[][] touchedTile;
  
      static final int TILE_SIZE_LG = 5;
      static final int TILE_SIZE = 1 << TILE_SIZE_LG; // 32
      private static final int INIT_ROW_SIZE = 8; // enough for 3 run lengths
  
      PiscesCache(int minx, int miny, int maxx, int maxy) {
          assert maxy >= miny && maxx >= minx;
          bboxX0 = minx;
          bboxY0 = miny;
          bboxX1 = maxx + 1;
          bboxY1 = maxy + 1;
          // we could just leave the inner arrays as null and allocate them
          // lazily (which would be beneficial for shapes with gaps), but we
          // assume there won't be too many of those so we allocate everything
          // up front (which is better for other cases)
          rowAARLE = new int[bboxY1 - bboxY0 + 1][INIT_ROW_SIZE];
          x0 = 0;
          y0 = -1; // -1 makes the first assert in startRow succeed
          // the ceiling of (maxy - miny + 1) / TILE_SIZE;
          int nyTiles = (maxy - miny + TILE_SIZE) >> TILE_SIZE_LG;
          int nxTiles = (maxx - minx + TILE_SIZE) >> TILE_SIZE_LG;
  
          touchedTile = new int[nyTiles][nxTiles];
      }
  
      void addRLERun(int val, int runLen) {
          if (runLen > 0) {
              addTupleToRow(y0, val, runLen);
              if (val != 0) {
                  // the x and y of the current row, minus bboxX0, bboxY0
                  int tx = x0 >> TILE_SIZE_LG;
                  int ty = y0 >> TILE_SIZE_LG;
                  int tx1 = (x0 + runLen - 1) >> TILE_SIZE_LG;
                  // while we forbid rows from starting before bboxx0, our users
                  // can still store rows that go beyond bboxx1 (although this
                  // shouldn't happen), so it's a good idea to check that i
                  // is not going out of bounds in touchedTile[ty]
                  if (tx1 >= touchedTile[ty].length) {
                      tx1 = touchedTile[ty].length - 1;
                  }
                  if (tx <= tx1) {
                      int nextTileXCoord = (tx + 1) << TILE_SIZE_LG;
                      if (nextTileXCoord > x0+runLen) {
                          touchedTile[ty][tx] += val * runLen;
                     } else {
                         touchedTile[ty][tx] += val * (nextTileXCoord - x0);
                     }
                     tx++;
                 }
                 // don't go all the way to tx1 - we need to handle the last
                 // tile as a special case (just like we did with the first
                 for (; tx < tx1; tx++) {
 //                    try {
                     touchedTile[ty][tx] += (val << TILE_SIZE_LG);
 //                    } catch (RuntimeException e) {
 //                        System.out.println("x0, y0: " + x0 + ", " + y0);
 //                        System.out.printf("tx, ty, tx1: %d, %d, %d %n", tx, ty, tx1);
 //                        System.out.printf("bboxX/Y0/1: %d, %d, %d, %d %n",
 //                                bboxX0, bboxY0, bboxX1, bboxY1);
 //                        throw e;
 //                    }
                 }
                 // they will be equal unless x0>>TILE_SIZE_LG == tx1
                 if (tx == tx1) {
                     int lastXCoord = Math.min(x0 + runLen, (tx + 1) << TILE_SIZE_LG);
                     int txXCoord = tx << TILE_SIZE_LG;
                     touchedTile[ty][tx] += val * (lastXCoord - txXCoord);
                 }
             }
             x0 += runLen;
         }
     }
 
     void startRow(int y, int x) {
         // rows are supposed to be added by increasing y.
         assert y - bboxY0 > y0;
         assert y <= bboxY1; // perhaps this should be < instead of <=
 
         y0 = y - bboxY0;
         // this should be a new, uninitialized row.
         assert rowAARLE[y0][1] == 0;
 
         x0 = x - bboxX0;
         assert x0 >= 0 : "Input must not be to the left of bbox bounds";
 
         // the way addTupleToRow is implemented it would work for this but it's
         // not a good idea to use it because it is meant for adding
         // RLE tuples, not the first tuple (which is special).
         rowAARLE[y0][0] = x;
         rowAARLE[y0][1] = 2;
     }
 
     int alphaSumInTile(int x, int y) {
         x -= bboxX0;
         y -= bboxY0;
         return touchedTile[y>>TILE_SIZE_LG][x>>TILE_SIZE_LG];
     }
 
     int minTouched(int rowidx) {
         return rowAARLE[rowidx][0];
     }
 
     int rowLength(int rowidx) {
         return rowAARLE[rowidx][1];
     }
 
     private void addTupleToRow(int row, int a, int b) {
         int end = rowAARLE[row][1];
         rowAARLE[row] = Helpers.widenArray(rowAARLE[row], end, 2);
         rowAARLE[row][end++] = a;
         rowAARLE[row][end++] = b;
         rowAARLE[row][1] = end;
     }
 
     @Override
     public String toString() {
         String ret = "bbox = ["+
                       bboxX0+", "+bboxY0+" => "+
                       bboxX1+", "+bboxY1+"]\n";
         for (int[] row : rowAARLE) {
             if (row != null) {
                 ret += ("minTouchedX=" + row[0] +
                         "\tRLE Entries: " + Arrays.toString(
                                 Arrays.copyOfRange(row, 2, row[1])) + "\n");
             } else {
                 ret += "[]\n";
             }
         }
         return ret;
     }
 }