zxing/csharp/oned/UPCEANReader.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

/*
 * 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.
 */

namespace com.google.zxing.oned
{

	using BarcodeFormat = com.google.zxing.BarcodeFormat;
	using ChecksumException = com.google.zxing.ChecksumException;
	using DecodeHintType = com.google.zxing.DecodeHintType;
	using FormatException = com.google.zxing.FormatException;
	using NotFoundException = com.google.zxing.NotFoundException;
	using ReaderException = com.google.zxing.ReaderException;
	using Result = com.google.zxing.Result;
	using ResultMetadataType = com.google.zxing.ResultMetadataType;
	using ResultPoint = com.google.zxing.ResultPoint;
	using ResultPointCallback = com.google.zxing.ResultPointCallback;
	using BitArray = com.google.zxing.common.BitArray;
    using com.google.zxing.common;

    public static class ArrayExtensions
    {
        public static void Fill(this int[] arr,int value)
        {
            for (int i = 0; i < arr.Length;i++ )
            {
                arr.SetValue(value,i);
            }
        }
    }


	/// <summary>
	/// <p>Encapsulates functionality and implementation that is common to UPC and EAN families
	/// of one-dimensional barcodes.</p>
	/// 
	/// @author dswitkin@google.com (Daniel Switkin)
	/// @author Sean Owen
	/// @author alasdair@google.com (Alasdair Mackintosh)
	/// </summary>
	public abstract class UPCEANReader : OneDReader
	{

	  // These two values are critical for determining how permissive the decoding will be.
	  // We've arrived at these values through a lot of trial and error. Setting them any higher
	  // lets false positives creep in quickly.
	  private static readonly int MAX_AVG_VARIANCE = (int)(PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.48f);
	  private static readonly int MAX_INDIVIDUAL_VARIANCE = (int)(PATTERN_MATCH_RESULT_SCALE_FACTOR * 0.7f);

	  /// <summary>
	  /// Start/end guard pattern.
	  /// </summary>
	  internal static readonly int[] START_END_PATTERN = {1, 1, 1};

	  /// <summary>
	  /// Pattern marking the middle of a UPC/EAN pattern, separating the two halves.
	  /// </summary>
	  internal static readonly int[] MIDDLE_PATTERN = {1, 1, 1, 1, 1};

	  /// <summary>
	  /// "Odd", or "L" patterns used to encode UPC/EAN digits.
	  /// </summary>
	  internal static readonly int[][] L_PATTERNS = {new int[] {3, 2, 1, 1}, new int[] {2, 2, 2, 1}, new int[] {2, 1, 2, 2}, new int[] {1, 4, 1, 1}, new int[] {1, 1, 3, 2}, new int[] {1, 2, 3, 1}, new int[] {1, 1, 1, 4}, new int[] {1, 3, 1, 2}, new int[] {1, 2, 1, 3}, new int[] {3, 1, 1, 2}};

	  /// <summary>
	  /// As above but also including the "even", or "G" patterns used to encode UPC/EAN digits.
	  /// </summary>
	  internal static readonly int[][] L_AND_G_PATTERNS;

	  static UPCEANReader()
	  {
		L_AND_G_PATTERNS = new int[20][];
		Array.Copy(L_PATTERNS, 0, L_AND_G_PATTERNS, 0, 10);
		for (int i = 10; i < 20; i++)
		{
		  int[] widths = L_PATTERNS[i - 10];
		  int[] reversedWidths = new int[widths.Length];
		  for (int j = 0; j < widths.Length; j++)
		  {
			reversedWidths[j] = widths[widths.Length - j - 1];
		  }
		  L_AND_G_PATTERNS[i] = reversedWidths;
		}
	  }

	  private readonly StringBuilder decodeRowStringBuffer;
	  private readonly UPCEANExtensionSupport extensionReader;
	  private readonly EANManufacturerOrgSupport eanManSupport;

	  protected internal UPCEANReader()
	  {
		decodeRowStringBuffer = new StringBuilder(20);
		extensionReader = new UPCEANExtensionSupport();
		eanManSupport = new EANManufacturerOrgSupport();
	  }

//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: static int[] findStartGuardPattern(com.google.zxing.common.BitArray row) throws com.google.zxing.NotFoundException
	  internal static int[] findStartGuardPattern(BitArray row)
	  {
		bool foundStart = false;
		int[] startRange = null;
		int nextStart = 0;
		int[] counters = new int[START_END_PATTERN.Length];
		while (!foundStart)
		{
          //Arrays.fill(counters, 0, START_END_PATTERN.Length, 0);
		  counters.Fill(0);
		  startRange = findGuardPattern(row, nextStart, false, START_END_PATTERN, counters);
		  int start = startRange[0];
		  nextStart = startRange[1];
		  // Make sure there is a quiet zone at least as big as the start pattern before the barcode.
		  // If this check would run off the left edge of the image, do not accept this barcode,
		  // as it is very likely to be a false positive.
		  int quietStart = start - (nextStart - start);
		  if (quietStart >= 0)
		  {
			foundStart = row.isRange(quietStart, start, false);
		  }
		}
		return startRange;
	  }

//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: public com.google.zxing.Result decodeRow(int rowNumber, com.google.zxing.common.BitArray row, java.util.Map<com.google.zxing.DecodeHintType,?> hints) throws com.google.zxing.NotFoundException, com.google.zxing.ChecksumException, com.google.zxing.FormatException
      public override Result decodeRow(int rowNumber, BitArray row, IDictionary<DecodeHintType, object> hints)
	  {
		return decodeRow(rowNumber, row, findStartGuardPattern(row), hints);
	  }

	  /// <summary>
	  /// <p>Like <seealso cref="#decodeRow(int, BitArray, java.util.Map)"/>, but
	  /// allows caller to inform method about where the UPC/EAN start pattern is
	  /// found. This allows this to be computed once and reused across many implementations.</p>
	  /// </summary>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: public com.google.zxing.Result decodeRow(int rowNumber, com.google.zxing.common.BitArray row, int[] startGuardRange, java.util.Map<com.google.zxing.DecodeHintType,?> hints) throws com.google.zxing.NotFoundException, com.google.zxing.ChecksumException, com.google.zxing.FormatException
      public virtual Result decodeRow(int rowNumber, BitArray row, int[] startGuardRange, IDictionary<DecodeHintType, object> hints)
	  {

        //ResultPointCallback resultPointCallback = hints == null ? null : (ResultPointCallback) hints[DecodeHintType.NEED_RESULT_POINT_CALLBACK];
        ResultPointCallback resultPointCallback = null;
        if (hints != null && hints.ContainsKey(DecodeHintType.NEED_RESULT_POINT_CALLBACK))
        {
            resultPointCallback = (ResultPointCallback)hints[DecodeHintType.NEED_RESULT_POINT_CALLBACK];
        }

		if (resultPointCallback != null)
		{
		  resultPointCallback.foundPossibleResultPoint(new ResultPoint((startGuardRange[0] + startGuardRange[1]) / 2.0f, rowNumber));
		}

		StringBuilder result = decodeRowStringBuffer;
		result.Length = 0;
		int endStart = decodeMiddle(row, startGuardRange, result);

		if (resultPointCallback != null)
		{
		  resultPointCallback.foundPossibleResultPoint(new ResultPoint(endStart, rowNumber));
		}

		int[] endRange = decodeEnd(row, endStart);

		if (resultPointCallback != null)
		{
		  resultPointCallback.foundPossibleResultPoint(new ResultPoint((endRange[0] + endRange[1]) / 2.0f, rowNumber));
		}


		// Make sure there is a quiet zone at least as big as the end pattern after the barcode. The
		// spec might want more whitespace, but in practice this is the maximum we can count on.
		int end = endRange[1];
		int quietEnd = end + (end - endRange[0]);
		if (quietEnd >= row.Size || !row.isRange(end, quietEnd, false))
		{
		  throw NotFoundException.NotFoundInstance;
		}

		string resultString = result.ToString();
		if (!checkChecksum(resultString))
		{
		  throw ChecksumException.ChecksumInstance;
		}

		float left = (float)(startGuardRange[1] + startGuardRange[0]) / 2.0f;
		float right = (float)(endRange[1] + endRange[0]) / 2.0f;
		BarcodeFormat format = BarcodeFormat;
		Result decodeResult = new Result(resultString, null, new ResultPoint[]{new ResultPoint(left, (float) rowNumber), new ResultPoint(right, (float) rowNumber)}, format); // no natural byte representation for these barcodes

		try
		{
		  Result extensionResult = extensionReader.decodeRow(rowNumber, row, endRange[1]);
		  decodeResult.putMetadata(ResultMetadataType.UPC_EAN_EXTENSION, extensionResult.Text);
		  decodeResult.putAllMetadata(extensionResult.ResultMetadata);
		  decodeResult.addResultPoints(extensionResult.ResultPoints);
		}
		catch (ReaderException re)
		{
		  // continue
		}

		if (format == BarcodeFormat.EAN_13 || format == BarcodeFormat.UPC_A)
		{
		  string countryID = eanManSupport.lookupCountryIdentifier(resultString);
		  if (countryID != null)
		  {
			decodeResult.putMetadata(ResultMetadataType.POSSIBLE_COUNTRY, countryID);
		  }
		}

		return decodeResult;
	  }

	  /// <returns> <seealso cref="#checkStandardUPCEANChecksum(string)"/> </returns>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: boolean checkChecksum(String s) throws com.google.zxing.ChecksumException, com.google.zxing.FormatException
	  protected internal virtual bool checkChecksum(string s)
	  {
		return checkStandardUPCEANChecksum(s);
	  }

	  /// <summary>
	  /// Computes the UPC/EAN checksum on a string of digits, and reports
	  /// whether the checksum is correct or not.
	  /// </summary>
	  /// <param name="s"> string of digits to check </param>
	  /// <returns> true iff string of digits passes the UPC/EAN checksum algorithm </returns>
	  /// <exception cref="FormatException"> if the string does not contain only digits </exception>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: static boolean checkStandardUPCEANChecksum(CharSequence s) throws com.google.zxing.FormatException
	  internal static bool checkStandardUPCEANChecksum(string s)
	  {
		int length = s.Length;
		if (length == 0)
		{
		  return false;
		}

		int sum = 0;
		for (int i = length - 2; i >= 0; i -= 2)
		{
		  int digit = (int) s[i] - (int) '0';
		  if (digit < 0 || digit > 9)
		  {
			throw FormatException.FormatInstance;
		  }
		  sum += digit;
		}
		sum *= 3;
		for (int i = length - 1; i >= 0; i -= 2)
		{
		  int digit = (int) s[i] - (int) '0';
		  if (digit < 0 || digit > 9)
		  {
			throw FormatException.FormatInstance;
		  }
		  sum += digit;
		}
		return sum % 10 == 0;
	  }

//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: int[] decodeEnd(com.google.zxing.common.BitArray row, int endStart) throws com.google.zxing.NotFoundException
	    protected internal virtual int[] decodeEnd(BitArray row, int endStart)
	  {
		return findGuardPattern(row, endStart, false, START_END_PATTERN);
	  }

//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: static int[] findGuardPattern(com.google.zxing.common.BitArray row, int rowOffset, boolean whiteFirst, int[] pattern) throws com.google.zxing.NotFoundException
	  internal static int[] findGuardPattern(BitArray row, int rowOffset, bool whiteFirst, int[] pattern)
	  {
		return findGuardPattern(row, rowOffset, whiteFirst, pattern, new int[pattern.Length]);
	  }

	  /// <param name="row"> row of black/white values to search </param>
	  /// <param name="rowOffset"> position to start search </param>
	  /// <param name="whiteFirst"> if true, indicates that the pattern specifies white/black/white/...
	  /// pixel counts, otherwise, it is interpreted as black/white/black/... </param>
	  /// <param name="pattern"> pattern of counts of number of black and white pixels that are being
	  /// searched for as a pattern </param>
	  /// <param name="counters"> array of counters, as long as pattern, to re-use </param>
	  /// <returns> start/end horizontal offset of guard pattern, as an array of two ints </returns>
	  /// <exception cref="NotFoundException"> if pattern is not found </exception>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: private static int[] findGuardPattern(com.google.zxing.common.BitArray row, int rowOffset, boolean whiteFirst, int[] pattern, int[] counters) throws com.google.zxing.NotFoundException
	  private static int[] findGuardPattern(BitArray row, int rowOffset, bool whiteFirst, int[] pattern, int[] counters)
	  {
		int patternLength = pattern.Length;
		int width = row.Size;
		bool isWhite = whiteFirst;
		rowOffset = whiteFirst ? row.getNextUnset(rowOffset) : row.getNextSet(rowOffset);
		int counterPosition = 0;
		int patternStart = rowOffset;
		for (int x = rowOffset; x < width; x++)
		{
		  if (row.get(x) ^ isWhite)
		  {
			counters[counterPosition]++;
		  }
		  else
		  {
			if (counterPosition == patternLength - 1)
			{
			  if (patternMatchVariance(counters, pattern, MAX_INDIVIDUAL_VARIANCE) < MAX_AVG_VARIANCE)
			  {
				return new int[]{patternStart, x};
			  }
			  patternStart += counters[0] + counters[1];
			  Array.Copy(counters, 2, counters, 0, patternLength - 2);
			  counters[patternLength - 2] = 0;
			  counters[patternLength - 1] = 0;
			  counterPosition--;
			}
			else
			{
			  counterPosition++;
			}
			counters[counterPosition] = 1;
			isWhite = !isWhite;
		  }
		}
		throw NotFoundException.NotFoundInstance;
	  }

	  /// <summary>
	  /// Attempts to decode a single UPC/EAN-encoded digit.
	  /// </summary>
	  /// <param name="row"> row of black/white values to decode </param>
	  /// <param name="counters"> the counts of runs of observed black/white/black/... values </param>
	  /// <param name="rowOffset"> horizontal offset to start decoding from </param>
	  /// <param name="patterns"> the set of patterns to use to decode -- sometimes different encodings
	  /// for the digits 0-9 are used, and this indicates the encodings for 0 to 9 that should
	  /// be used </param>
	  /// <returns> horizontal offset of first pixel beyond the decoded digit </returns>
	  /// <exception cref="NotFoundException"> if digit cannot be decoded </exception>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: static int decodeDigit(com.google.zxing.common.BitArray row, int[] counters, int rowOffset, int[][] patterns) throws com.google.zxing.NotFoundException
	  internal static int decodeDigit(BitArray row, int[] counters, int rowOffset, int[][] patterns)
	  {
		recordPattern(row, rowOffset, counters);
		int bestVariance = MAX_AVG_VARIANCE; // worst variance we'll accept
		int bestMatch = -1;
		int max = patterns.Length;
		for (int i = 0; i < max; i++)
		{
		  int[] pattern = patterns[i];
		  int variance = patternMatchVariance(counters, pattern, MAX_INDIVIDUAL_VARIANCE);
		  if (variance < bestVariance)
		  {
			bestVariance = variance;
			bestMatch = i;
		  }
		}
		if (bestMatch >= 0)
		{
		  return bestMatch;
		}
		else
		{
		  throw NotFoundException.NotFoundInstance;
		}
	  }

	  /// <summary>
	  /// Get the format of this decoder.
	  /// </summary>
	  /// <returns> The 1D format. </returns>
	  internal abstract BarcodeFormat BarcodeFormat {get;}

	  /// <summary>
	  /// Subclasses override this to decode the portion of a barcode between the start
	  /// and end guard patterns.
	  /// </summary>
	  /// <param name="row"> row of black/white values to search </param>
	  /// <param name="startRange"> start/end offset of start guard pattern </param>
	  /// <param name="resultString"> <seealso cref="StringBuilder"/> to append decoded chars to </param>
	  /// <returns> horizontal offset of first pixel after the "middle" that was decoded </returns>
	  /// <exception cref="NotFoundException"> if decoding could not complete successfully </exception>
//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in .NET:
//ORIGINAL LINE: protected abstract int decodeMiddle(com.google.zxing.common.BitArray row, int[] startRange, StringBuilder resultString) throws com.google.zxing.NotFoundException;
	  protected internal abstract int decodeMiddle(BitArray row, int[] startRange, StringBuilder resultString);

	}

}