mirror of
https://github.com/zxing/zxing.git
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7854d30103
git-svn-id: https://zxing.googlecode.com/svn/trunk@817 59b500cc-1b3d-0410-9834-0bbf25fbcc57
282 lines
11 KiB
C#
Executable file
282 lines
11 KiB
C#
Executable file
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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using System;
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namespace com.google.zxing.qrcode.decoder
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{
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/// <summary> <p>Encapsulates data masks for the data bits in a QR code, per ISO 18004:2006 6.8. Implementations
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/// of this class can un-mask a raw BitMatrix. For simplicity, they will unmask the entire BitMatrix,
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/// including areas used for finder patterns, timing patterns, etc. These areas should be unused
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/// after the point they are unmasked anyway.</p>
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///
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/// <p>Note that the diagram in section 6.8.1 is misleading since it indicates that i is column position
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/// and j is row position. In fact, as the text says, i is row position and j is column position.</p>
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///
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/// </summary>
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/// <author> srowen@google.com (Sean Owen)
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/// </author>
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abstract class DataMask
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{
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/// <summary> See ISO 18004:2006 6.8.1</summary>
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//UPGRADE_NOTE: Final was removed from the declaration of 'DATA_MASKS '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
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private static readonly DataMask[] DATA_MASKS = new DataMask[] { new DataMask000(), new DataMask001(), new DataMask010(), new DataMask011(), new DataMask100(), new DataMask101(), new DataMask110(), new DataMask111() };
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private DataMask()
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{
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}
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/// <summary> <p>Implementations of this method reverse the data masking process applied to a QR Code and
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/// make its bits ready to read.</p>
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///
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/// </summary>
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/// <param name="bits">representation of QR Code bits from {@link com.google.zxing.common.BitMatrix#getBits()}
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/// </param>
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/// <param name="dimension">dimension of QR Code, represented by bits, being unmasked
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/// </param>
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internal abstract void unmaskBitMatrix(int[] bits, int dimension);
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/// <param name="reference">a value between 0 and 7 indicating one of the eight possible
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/// data mask patterns a QR Code may use
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/// </param>
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/// <returns> {@link DataMask} encapsulating the data mask pattern
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/// </returns>
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internal static DataMask forReference(int reference)
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{
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if (reference < 0 || reference > 7)
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{
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throw new System.ArgumentException();
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}
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return DATA_MASKS[reference];
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}
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/// <summary> 000: mask bits for which (i + j) mod 2 == 0</summary>
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private class DataMask000 : DataMask
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{
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private const int BITMASK = 0x55555555; // = 010101...
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internal override void unmaskBitMatrix(int[] bits, int dimension)
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{
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// This one's easy. Because the dimension of BitMatrix is always odd,
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// we can merely flip every other bit
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int max = bits.Length;
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for (int i = 0; i < max; i++)
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{
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bits[i] ^= BITMASK;
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}
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}
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}
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/// <summary> 001: mask bits for which i mod 2 == 0</summary>
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private class DataMask001 : DataMask
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{
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internal override void unmaskBitMatrix(int[] bits, int dimension)
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{
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int bitMask = 0;
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int count = 0;
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int offset = 0;
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for (int j = 0; j < dimension; j++)
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{
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for (int i = 0; i < dimension; i++)
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{
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if ((i & 0x01) == 0)
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{
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bitMask |= 1 << count;
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}
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if (++count == 32)
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{
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bits[offset++] ^= bitMask;
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count = 0;
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bitMask = 0;
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}
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}
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}
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bits[offset] ^= bitMask;
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}
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}
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/// <summary> 010: mask bits for which j mod 3 == 0</summary>
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private class DataMask010 : DataMask
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{
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internal override void unmaskBitMatrix(int[] bits, int dimension)
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{
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int bitMask = 0;
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int count = 0;
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int offset = 0;
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for (int j = 0; j < dimension; j++)
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{
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bool columnMasked = j % 3 == 0;
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for (int i = 0; i < dimension; i++)
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{
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if (columnMasked)
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{
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bitMask |= 1 << count;
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}
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if (++count == 32)
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{
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bits[offset++] ^= bitMask;
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count = 0;
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bitMask = 0;
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}
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}
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}
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bits[offset] ^= bitMask;
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}
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}
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/// <summary> 011: mask bits for which (i + j) mod 3 == 0</summary>
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private class DataMask011 : DataMask
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{
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internal override void unmaskBitMatrix(int[] bits, int dimension)
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{
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int bitMask = 0;
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int count = 0;
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int offset = 0;
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for (int j = 0; j < dimension; j++)
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{
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for (int i = 0; i < dimension; i++)
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{
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if ((i + j) % 3 == 0)
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{
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bitMask |= 1 << count;
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}
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if (++count == 32)
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{
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bits[offset++] ^= bitMask;
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count = 0;
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bitMask = 0;
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}
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}
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}
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bits[offset] ^= bitMask;
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}
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}
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/// <summary> 100: mask bits for which (i/2 + j/3) mod 2 == 0</summary>
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private class DataMask100 : DataMask
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{
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internal override void unmaskBitMatrix(int[] bits, int dimension)
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{
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int bitMask = 0;
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int count = 0;
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int offset = 0;
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for (int j = 0; j < dimension; j++)
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{
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int jComponentParity = (j / 3) & 0x01;
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for (int i = 0; i < dimension; i++)
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{
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if (((i >> 1) & 0x01) == jComponentParity)
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{
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bitMask |= 1 << count;
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}
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if (++count == 32)
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{
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bits[offset++] ^= bitMask;
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count = 0;
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bitMask = 0;
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}
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}
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}
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bits[offset] ^= bitMask;
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}
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}
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/// <summary> 101: mask bits for which ij mod 2 + ij mod 3 == 0</summary>
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private class DataMask101 : DataMask
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{
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internal override void unmaskBitMatrix(int[] bits, int dimension)
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{
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int bitMask = 0;
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int count = 0;
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int offset = 0;
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for (int j = 0; j < dimension; j++)
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{
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for (int i = 0; i < dimension; i++)
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{
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int product = i * j;
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if (((product & 0x01) == 0) && product % 3 == 0)
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{
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bitMask |= 1 << count;
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}
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if (++count == 32)
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{
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bits[offset++] ^= bitMask;
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count = 0;
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bitMask = 0;
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}
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}
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}
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bits[offset] ^= bitMask;
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}
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}
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/// <summary> 110: mask bits for which (ij mod 2 + ij mod 3) mod 2 == 0</summary>
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private class DataMask110 : DataMask
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{
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internal override void unmaskBitMatrix(int[] bits, int dimension)
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{
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int bitMask = 0;
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int count = 0;
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int offset = 0;
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for (int j = 0; j < dimension; j++)
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{
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for (int i = 0; i < dimension; i++)
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{
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int product = i * j;
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if ((((product & 0x01) + product % 3) & 0x01) == 0)
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{
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bitMask |= 1 << count;
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}
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if (++count == 32)
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{
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bits[offset++] ^= bitMask;
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count = 0;
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bitMask = 0;
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}
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}
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}
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bits[offset] ^= bitMask;
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}
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}
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/// <summary> 111: mask bits for which ((i+j)mod 2 + ij mod 3) mod 2 == 0</summary>
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private class DataMask111 : DataMask
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{
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internal override void unmaskBitMatrix(int[] bits, int dimension)
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{
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int bitMask = 0;
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int count = 0;
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int offset = 0;
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for (int j = 0; j < dimension; j++)
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{
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for (int i = 0; i < dimension; i++)
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{
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if (((((i + j) & 0x01) + (i * j) % 3) & 0x01) == 0)
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{
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bitMask |= 1 << count;
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}
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if (++count == 32)
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{
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bits[offset++] ^= bitMask;
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count = 0;
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bitMask = 0;
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}
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}
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}
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bits[offset] ^= bitMask;
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}
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}
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}
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} |