zxing/csharp/oned/UPCEANReader.cs
2013-01-18 20:14:03 +00:00

403 lines
16 KiB
C#
Executable file

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);
}
}