/*

 * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.java2d.pisces;

import java.util.Arrays;

/**

 * An object used to cache pre-rendered complex paths.

 */

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;

    }

    void getBBox(int bbox[]) {

        // Since we add +1 to bboxX1,bboxY1 so when PTG asks for bbox,

        // we will give after -1

        bbox[0] = bboxX0;

        bbox[1] = bboxY0;

        bbox[2] = bboxX1 - 1;

        bbox[3] = bboxY1 - 1;

    }

    @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;

    }

}