mirror of
https://github.com/zxing/zxing.git
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d4efd44fb0
git-svn-id: https://zxing.googlecode.com/svn/trunk@1202 59b500cc-1b3d-0410-9834-0bbf25fbcc57
392 lines
13 KiB
C#
Executable file
392 lines
13 KiB
C#
Executable file
/*
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* Copyright 2008 ZXing authors
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*
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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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using BarcodeFormat = com.google.zxing.BarcodeFormat;
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using ReaderException = com.google.zxing.ReaderException;
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using Result = com.google.zxing.Result;
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using ResultPoint = com.google.zxing.ResultPoint;
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using BitArray = com.google.zxing.common.BitArray;
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namespace com.google.zxing.oned
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{
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/// <summary> <p>Decodes Code 39 barcodes. This does not support "Full ASCII Code 39" yet.</p>
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///
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/// </summary>
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/// <author> Sean Owen
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/// </author>
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/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source
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/// </author>
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public sealed class Code39Reader:OneDReader
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{
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private const System.String ALPHABET_STRING = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. *$/+%";
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//UPGRADE_NOTE: Final was removed from the declaration of 'ALPHABET '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
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private static readonly char[] ALPHABET = ALPHABET_STRING.ToCharArray();
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/// <summary> These represent the encodings of characters, as patterns of wide and narrow bars.
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/// The 9 least-significant bits of each int correspond to the pattern of wide and narrow,
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/// with 1s representing "wide" and 0s representing narrow.
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/// </summary>
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//UPGRADE_NOTE: Final was removed from the declaration of 'CHARACTER_ENCODINGS'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
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private static readonly int[] CHARACTER_ENCODINGS = new int[]{0x034, 0x121, 0x061, 0x160, 0x031, 0x130, 0x070, 0x025, 0x124, 0x064, 0x109, 0x049, 0x148, 0x019, 0x118, 0x058, 0x00D, 0x10C, 0x04C, 0x01C, 0x103, 0x043, 0x142, 0x013, 0x112, 0x052, 0x007, 0x106, 0x046, 0x016, 0x181, 0x0C1, 0x1C0, 0x091, 0x190, 0x0D0, 0x085, 0x184, 0x0C4, 0x094, 0x0A8, 0x0A2, 0x08A, 0x02A};
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//UPGRADE_NOTE: Final was removed from the declaration of 'ASTERISK_ENCODING '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
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private static readonly int ASTERISK_ENCODING = CHARACTER_ENCODINGS[39];
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//UPGRADE_NOTE: Final was removed from the declaration of 'usingCheckDigit '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
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private bool usingCheckDigit;
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//UPGRADE_NOTE: Final was removed from the declaration of 'extendedMode '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
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private bool extendedMode;
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/// <summary> Creates a reader that assumes all encoded data is data, and does not treat the final
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/// character as a check digit. It will not decoded "extended Code 39" sequences.
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/// </summary>
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public Code39Reader()
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{
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usingCheckDigit = false;
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extendedMode = false;
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}
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/// <summary> Creates a reader that can be configured to check the last character as a check digit.
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/// It will not decoded "extended Code 39" sequences.
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///
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/// </summary>
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/// <param name="usingCheckDigit">if true, treat the last data character as a check digit, not
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/// data, and verify that the checksum passes.
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/// </param>
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public Code39Reader(bool usingCheckDigit)
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{
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this.usingCheckDigit = usingCheckDigit;
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this.extendedMode = false;
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}
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/// <summary> Creates a reader that can be configured to check the last character as a check digit,
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/// or optionally attempt to decode "extended Code 39" sequences that are used to encode
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/// the full ASCII character set.
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///
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/// </summary>
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/// <param name="usingCheckDigit">if true, treat the last data character as a check digit, not
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/// data, and verify that the checksum passes.
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/// </param>
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/// <param name="extendedMode">if true, will attempt to decode extended Code 39 sequences in the
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/// text.
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/// </param>
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public Code39Reader(bool usingCheckDigit, bool extendedMode)
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{
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this.usingCheckDigit = usingCheckDigit;
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this.extendedMode = extendedMode;
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}
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public override Result decodeRow(int rowNumber, BitArray row, System.Collections.Hashtable hints)
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{
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int[] start = findAsteriskPattern(row);
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int nextStart = start[1];
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int end = row.Size;
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// Read off white space
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while (nextStart < end && !row.get_Renamed(nextStart))
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{
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nextStart++;
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}
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System.Text.StringBuilder result = new System.Text.StringBuilder(20);
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int[] counters = new int[9];
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char decodedChar;
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int lastStart;
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do
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{
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recordPattern(row, nextStart, counters);
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int pattern = toNarrowWidePattern(counters);
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if (pattern < 0)
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{
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throw ReaderException.Instance;
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}
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decodedChar = patternToChar(pattern);
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result.Append(decodedChar);
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lastStart = nextStart;
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for (int i = 0; i < counters.Length; i++)
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{
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nextStart += counters[i];
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}
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// Read off white space
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while (nextStart < end && !row.get_Renamed(nextStart))
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{
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nextStart++;
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}
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}
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while (decodedChar != '*');
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result.Remove(result.Length - 1, 1); // remove asterisk
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// Look for whitespace after pattern:
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int lastPatternSize = 0;
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for (int i = 0; i < counters.Length; i++)
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{
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lastPatternSize += counters[i];
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}
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int whiteSpaceAfterEnd = nextStart - lastStart - lastPatternSize;
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// If 50% of last pattern size, following last pattern, is not whitespace, fail
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// (but if it's whitespace to the very end of the image, that's OK)
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if (nextStart != end && whiteSpaceAfterEnd / 2 < lastPatternSize)
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{
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throw ReaderException.Instance;
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}
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if (usingCheckDigit)
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{
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int max = result.Length - 1;
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int total = 0;
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for (int i = 0; i < max; i++)
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{
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total += ALPHABET_STRING.IndexOf((System.Char) result[i]);
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}
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if (total % 43 != ALPHABET_STRING.IndexOf((System.Char) result[max]))
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{
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throw ReaderException.Instance;
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}
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result.Remove(max, 1);
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}
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System.String resultString = result.ToString();
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if (extendedMode)
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{
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resultString = decodeExtended(resultString);
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}
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if (resultString.Length == 0)
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{
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// Almost surely a false positive
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throw ReaderException.Instance;
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}
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//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
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float left = (float) (start[1] + start[0]) / 2.0f;
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//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
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float right = (float) (nextStart + lastStart) / 2.0f;
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//UPGRADE_WARNING: Data types in Visual C# might be different. Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
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return new Result(resultString, null, new ResultPoint[]{new ResultPoint(left, (float) rowNumber), new ResultPoint(right, (float) rowNumber)}, BarcodeFormat.CODE_39);
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}
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private static int[] findAsteriskPattern(BitArray row)
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{
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int width = row.Size;
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int rowOffset = 0;
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while (rowOffset < width)
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{
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if (row.get_Renamed(rowOffset))
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{
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break;
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}
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rowOffset++;
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}
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int counterPosition = 0;
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int[] counters = new int[9];
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int patternStart = rowOffset;
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bool isWhite = false;
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int patternLength = counters.Length;
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for (int i = rowOffset; i < width; i++)
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{
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bool pixel = row.get_Renamed(i);
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if (pixel ^ isWhite)
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{
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counters[counterPosition]++;
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}
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else
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{
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if (counterPosition == patternLength - 1)
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{
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if (toNarrowWidePattern(counters) == ASTERISK_ENCODING)
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{
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// Look for whitespace before start pattern, >= 50% of width of start pattern
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if (row.isRange(System.Math.Max(0, patternStart - (i - patternStart) / 2), patternStart, false))
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{
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return new int[]{patternStart, i};
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}
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}
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patternStart += counters[0] + counters[1];
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for (int y = 2; y < patternLength; y++)
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{
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counters[y - 2] = counters[y];
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}
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counters[patternLength - 2] = 0;
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counters[patternLength - 1] = 0;
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counterPosition--;
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}
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else
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{
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counterPosition++;
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}
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counters[counterPosition] = 1;
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isWhite = !isWhite;
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}
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}
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throw ReaderException.Instance;
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}
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// For efficiency, returns -1 on failure. Not throwing here saved as many as 700 exceptions
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// per image when using some of our blackbox images.
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private static int toNarrowWidePattern(int[] counters)
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{
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int numCounters = counters.Length;
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int maxNarrowCounter = 0;
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int wideCounters;
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do
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{
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int minCounter = System.Int32.MaxValue;
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for (int i = 0; i < numCounters; i++)
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{
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int counter = counters[i];
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if (counter < minCounter && counter > maxNarrowCounter)
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{
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minCounter = counter;
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}
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}
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maxNarrowCounter = minCounter;
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wideCounters = 0;
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int totalWideCountersWidth = 0;
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int pattern = 0;
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for (int i = 0; i < numCounters; i++)
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{
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int counter = counters[i];
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if (counters[i] > maxNarrowCounter)
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{
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pattern |= 1 << (numCounters - 1 - i);
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wideCounters++;
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totalWideCountersWidth += counter;
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}
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}
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if (wideCounters == 3)
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{
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// Found 3 wide counters, but are they close enough in width?
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// We can perform a cheap, conservative check to see if any individual
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// counter is more than 1.5 times the average:
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for (int i = 0; i < numCounters && wideCounters > 0; i++)
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{
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int counter = counters[i];
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if (counters[i] > maxNarrowCounter)
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{
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wideCounters--;
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// totalWideCountersWidth = 3 * average, so this checks if counter >= 3/2 * average
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if ((counter << 1) >= totalWideCountersWidth)
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{
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return - 1;
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}
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}
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}
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return pattern;
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}
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}
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while (wideCounters > 3);
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return - 1;
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}
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private static char patternToChar(int pattern)
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{
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for (int i = 0; i < CHARACTER_ENCODINGS.Length; i++)
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{
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if (CHARACTER_ENCODINGS[i] == pattern)
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{
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return ALPHABET[i];
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}
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}
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throw ReaderException.Instance;
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}
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private static System.String decodeExtended(System.String encoded)
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{
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int length = encoded.Length;
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System.Text.StringBuilder decoded = new System.Text.StringBuilder(length);
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for (int i = 0; i < length; i++)
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{
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char c = encoded[i];
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if (c == '+' || c == '$' || c == '%' || c == '/')
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{
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char next = encoded[i + 1];
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char decodedChar = '\x0000';
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switch (c)
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{
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case '+':
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// +A to +Z map to a to z
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if (next >= 'A' && next <= 'Z')
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{
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decodedChar = (char) (next + 32);
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}
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else
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{
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throw ReaderException.Instance;
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}
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break;
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case '$':
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// $A to $Z map to control codes SH to SB
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if (next >= 'A' && next <= 'Z')
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{
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decodedChar = (char) (next - 64);
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}
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else
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{
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throw ReaderException.Instance;
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}
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break;
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case '%':
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// %A to %E map to control codes ESC to US
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if (next >= 'A' && next <= 'E')
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{
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decodedChar = (char) (next - 38);
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}
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else if (next >= 'F' && next <= 'W')
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{
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decodedChar = (char) (next - 11);
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}
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else
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{
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throw ReaderException.Instance;
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}
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break;
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case '/':
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// /A to /O map to ! to , and /Z maps to :
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if (next >= 'A' && next <= 'O')
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{
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decodedChar = (char) (next - 32);
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}
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else if (next == 'Z')
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{
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decodedChar = ':';
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}
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else
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{
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throw ReaderException.Instance;
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}
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break;
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}
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decoded.Append(decodedChar);
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// bump up i again since we read two characters
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i++;
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}
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else
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{
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decoded.Append(c);
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}
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}
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return decoded.ToString();
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}
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}
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} |