content: /*
   * Copyright 2008 ZXing authors
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.ailiwean.core.zxing.core.qrcode.encoder;
  
  
  /**
   * @author Satoru Takabayashi
   * @author Daniel Switkin
   * @author Sean Owen
   */
  final class MaskUtil {
  
    // Penalty weights from section 6.8.2.1
    private static final int N1 = 3;
    private static final int N2 = 3;
    private static final int N3 = 40;
    private static final int N4 = 10;
  
    private MaskUtil() {
      // do nothing
    }
  
    /**
     * Apply mask penalty rule 1 and return the penalty. Find repetitive cells with the same color and
     * give penalty to them. Example: 00000 or 11111.
     */
    static int applyMaskPenaltyRule1(ByteMatrix matrix) {
      return applyMaskPenaltyRule1Internal(matrix, true) + applyMaskPenaltyRule1Internal(matrix, false);
    }
  
    /**
     * Apply mask penalty rule 2 and return the penalty. Find 2x2 blocks with the same color and give
     * penalty to them. This is actually equivalent to the spec's rule, which is to find MxN blocks and give a
     * penalty proportional to (M-1)x(N-1), because this is the number of 2x2 blocks inside such a block.
     */
    static int applyMaskPenaltyRule2(ByteMatrix matrix) {
      int penalty = 0;
      byte[][] array = matrix.getArray();
      int width = matrix.getWidth();
      int height = matrix.getHeight();
      for (int y = 0; y < height - 1; y++) {
        byte[] arrayY = array[y];
        for (int x = 0; x < width - 1; x++) {
          int value = arrayY[x];
          if (value == arrayY[x + 1] && value == array[y + 1][x] && value == array[y + 1][x + 1]) {
            penalty++;
          }
        }
      }
      return N2 * penalty;
    }
  
    /**
     * Apply mask penalty rule 3 and return the penalty. Find consecutive runs of 1:1:3:1:1:4
     * starting with black, or 4:1:1:3:1:1 starting with white, and give penalty to them.  If we
     * find patterns like 000010111010000, we give penalty once.
     */
    static int applyMaskPenaltyRule3(ByteMatrix matrix) {
      int numPenalties = 0;
      byte[][] array = matrix.getArray();
      int width = matrix.getWidth();
      int height = matrix.getHeight();
      for (int y = 0; y < height; y++) {
        for (int x = 0; x < width; x++) {
          byte[] arrayY = array[y];  // We can at least optimize this access
          if (x + 6 < width &&
              arrayY[x] == 1 &&
              arrayY[x + 1] == 0 &&
              arrayY[x + 2] == 1 &&
              arrayY[x + 3] == 1 &&
              arrayY[x + 4] == 1 &&
              arrayY[x + 5] == 0 &&
              arrayY[x + 6] == 1 &&
              (isWhiteHorizontal(arrayY, x - 4, x) || isWhiteHorizontal(arrayY, x + 7, x + 11))) {
            numPenalties++;
          }
          if (y + 6 < height &&
              array[y][x] == 1 &&
              array[y + 1][x] == 0 &&
              array[y + 2][x] == 1 &&
              array[y + 3][x] == 1 &&
              array[y + 4][x] == 1 &&
              array[y + 5][x] == 0 &&
              array[y + 6][x] == 1 &&
              (isWhiteVertical(array, x, y - 4, y) || isWhiteVertical(array, x, y + 7, y + 11))) {
            numPenalties++;
          }
        }
      }
      return numPenalties * N3;
    }
  
    private static boolean isWhiteHorizontal(byte[] rowArray, int from, int to) {
      from = Math.max(from, 0);
      to = Math.min(to, rowArray.length);
      for (int i = from; i < to; i++) {
        if (rowArray[i] == 1) {
          return false;
        }
      }
      return true;
    }
  
    private static boolean isWhiteVertical(byte[][] array, int col, int from, int to) {
      from = Math.max(from, 0);
      to = Math.min(to, array.length);
      for (int i = from; i < to; i++) {
        if (array[i][col] == 1) {
          return false;
        }
      }
      return true;
    }
  
    /**
     * Apply mask penalty rule 4 and return the penalty. Calculate the ratio of dark cells and give
     * penalty if the ratio is far from 50%. It gives 10 penalty for 5% distance.
     */
    static int applyMaskPenaltyRule4(ByteMatrix matrix) {
      int numDarkCells = 0;
      byte[][] array = matrix.getArray();
      int width = matrix.getWidth();
      int height = matrix.getHeight();
      for (int y = 0; y < height; y++) {
        byte[] arrayY = array[y];
        for (int x = 0; x < width; x++) {
          if (arrayY[x] == 1) {
            numDarkCells++;
          }
        }
      }
      int numTotalCells = matrix.getHeight() * matrix.getWidth();
      int fivePercentVariances = Math.abs(numDarkCells * 2 - numTotalCells) * 10 / numTotalCells;
      return fivePercentVariances * N4;
    }
  
    /**
     * Return the mask bit for "getMaskPattern" at "x" and "y". See 8.8 of JISX0510:2004 for mask
     * pattern conditions.
     */
    static boolean getDataMaskBit(int maskPattern, int x, int y) {
      int intermediate;
      int temp;
      switch (maskPattern) {
        case 0:
          intermediate = (y + x) & 0x1;
          break;
        case 1:
          intermediate = y & 0x1;
          break;
        case 2:
          intermediate = x % 3;
          break;
        case 3:
          intermediate = (y + x) % 3;
          break;
        case 4:
          intermediate = ((y / 2) + (x / 3)) & 0x1;
          break;
        case 5:
          temp = y * x;
          intermediate = (temp & 0x1) + (temp % 3);
          break;
        case 6:
          temp = y * x;
          intermediate = ((temp & 0x1) + (temp % 3)) & 0x1;
          break;
        case 7:
          temp = y * x;
          intermediate = ((temp % 3) + ((y + x) & 0x1)) & 0x1;
          break;
        default:
          throw new IllegalArgumentException("Invalid mask pattern: " + maskPattern);
      }
      return intermediate == 0;
    }
  
    /**
     * Helper function for applyMaskPenaltyRule1. We need this for doing this calculation in both
     * vertical and horizontal orders respectively.
     */
    private static int applyMaskPenaltyRule1Internal(ByteMatrix matrix, boolean isHorizontal) {
      int penalty = 0;
      int iLimit = isHorizontal ? matrix.getHeight() : matrix.getWidth();
      int jLimit = isHorizontal ? matrix.getWidth() : matrix.getHeight();
      byte[][] array = matrix.getArray();
      for (int i = 0; i < iLimit; i++) {
        int numSameBitCells = 0;
        int prevBit = -1;
        for (int j = 0; j < jLimit; j++) {
          int bit = isHorizontal ? array[i][j] : array[j][i];
          if (bit == prevBit) {
            numSameBitCells++;
          } else {
            if (numSameBitCells >= 5) {
              penalty += N1 + (numSameBitCells - 5);
            }
            numSameBitCells = 1;  // Include the cell itself.
            prevBit = bit;
          }
        }
        if (numSameBitCells >= 5) {
          penalty += N1 + (numSameBitCells - 5);
        }
      }
      return penalty;
    }
  
  }
  