zxing/csharp/oned/MultiFormatUPCEANReader.cs
2011-10-08 10:38:07 +00:00

110 lines
4 KiB
C#
Executable file

/*
* 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.
*/
using System;
using BarcodeFormat = com.google.zxing.BarcodeFormat;
using DecodeHintType = com.google.zxing.DecodeHintType;
using ReaderException = com.google.zxing.ReaderException;
using Result = com.google.zxing.Result;
using BitArray = com.google.zxing.common.BitArray;
namespace com.google.zxing.oned
{
/// <summary> <p>A reader that can read all available UPC/EAN formats. If a caller wants to try to
/// read all such formats, it is most efficient to use this implementation rather than invoke
/// individual readers.</p>
///
/// </summary>
/// <author> Sean Owen
/// </author>
/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source
/// </author>
public sealed class MultiFormatUPCEANReader:OneDReader
{
//UPGRADE_NOTE: Final was removed from the declaration of 'readers '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
private System.Collections.ArrayList readers;
public MultiFormatUPCEANReader(System.Collections.Hashtable hints)
{
System.Collections.ArrayList possibleFormats = hints == null?null:(System.Collections.ArrayList) hints[DecodeHintType.POSSIBLE_FORMATS];
readers = System.Collections.ArrayList.Synchronized(new System.Collections.ArrayList(10));
if (possibleFormats != null)
{
if (possibleFormats.Contains(BarcodeFormat.EAN_13))
{
readers.Add(new EAN13Reader());
}
else if (possibleFormats.Contains(BarcodeFormat.UPC_A))
{
readers.Add(new UPCAReader());
}
if (possibleFormats.Contains(BarcodeFormat.EAN_8))
{
readers.Add(new EAN8Reader());
}
if (possibleFormats.Contains(BarcodeFormat.UPC_E))
{
readers.Add(new UPCEReader());
}
}
if ((readers.Count == 0))
{
readers.Add(new EAN13Reader());
// UPC-A is covered by EAN-13
readers.Add(new EAN8Reader());
readers.Add(new UPCEReader());
}
}
public override Result decodeRow(int rowNumber, BitArray row, System.Collections.Hashtable hints)
{
// Compute this location once and reuse it on multiple implementations
int[] startGuardPattern = UPCEANReader.findStartGuardPattern(row);
int size = readers.Count;
for (int i = 0; i < size; i++)
{
UPCEANReader reader = (UPCEANReader) readers[i];
Result result;
try
{
result = reader.decodeRow(rowNumber, row, startGuardPattern, hints);
}
catch (ReaderException)
{
continue;
}
// Special case: a 12-digit code encoded in UPC-A is identical to a "0"
// followed by those 12 digits encoded as EAN-13. Each will recognize such a code,
// UPC-A as a 12-digit string and EAN-13 as a 13-digit string starting with "0".
// Individually these are correct and their readers will both read such a code
// and correctly call it EAN-13, or UPC-A, respectively.
//
// In this case, if we've been looking for both types, we'd like to call it
// a UPC-A code. But for efficiency we only run the EAN-13 decoder to also read
// UPC-A. So we special case it here, and convert an EAN-13 result to a UPC-A
// result if appropriate.
if (result.BarcodeFormat.Equals(BarcodeFormat.EAN_13) && result.Text[0] == '0')
{
return new Result(result.Text.Substring(1), null, result.ResultPoints, BarcodeFormat.UPC_A);
}
return result;
}
throw ReaderException.Instance;
}
}
}