csharp/oned/MultiFormatUPCEANReader.cs

   1 /*\r
   2 * Copyright 2008 ZXing authors\r
   3 *\r
   4 * Licensed under the Apache License, Version 2.0 (the "License");\r
   5 * you may not use this file except in compliance with the License.\r
   6 * You may obtain a copy of the License at\r
   7 *\r
   8 *      http://www.apache.org/licenses/LICENSE-2.0\r
   9 *\r
  10 * Unless required by applicable law or agreed to in writing, software\r
  11 * distributed under the License is distributed on an "AS IS" BASIS,\r
  12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
  13 * See the License for the specific language governing permissions and\r
  14 * limitations under the License.\r
  15 */\r
  16 using System;\r
  17 using BarcodeFormat = com.google.zxing.BarcodeFormat;\r
  18 using DecodeHintType = com.google.zxing.DecodeHintType;\r
  19 using ReaderException = com.google.zxing.ReaderException;\r
  20 using Result = com.google.zxing.Result;\r
  21 using BitArray = com.google.zxing.common.BitArray;\r
  22 namespace com.google.zxing.oned\r
  23 {\r
  24         \r
  25         /// <summary> <p>A reader that can read all available UPC/EAN formats. If a caller wants to try to\r
  26         /// read all such formats, it is most efficient to use this implementation rather than invoke\r
  27         /// individual readers.</p>\r
  28         /// \r
  29         /// </summary>\r
  30         /// <author>  Sean Owen\r
  31         /// </author>\r
  32         /// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source \r
  33         /// </author>\r
  34         public sealed class MultiFormatUPCEANReader:OneDReader\r
  35         {\r
  36                 \r
  37                 //UPGRADE_NOTE: Final was removed from the declaration of 'readers '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"\r
  38                 private System.Collections.ArrayList readers;\r
  39                 \r
  40                 public MultiFormatUPCEANReader(System.Collections.Hashtable hints)\r
  41                 {\r
  42                         System.Collections.ArrayList possibleFormats = hints == null?null:(System.Collections.ArrayList) hints[DecodeHintType.POSSIBLE_FORMATS];\r
  43                         readers = System.Collections.ArrayList.Synchronized(new System.Collections.ArrayList(10));\r
  44                         if (possibleFormats != null)\r
  45                         {\r
  46                                 if (possibleFormats.Contains(BarcodeFormat.EAN_13))\r
  47                                 {\r
  48                                         readers.Add(new EAN13Reader());\r
  49                                 }\r
  50                                 else if (possibleFormats.Contains(BarcodeFormat.UPC_A))\r
  51                                 {\r
  52                                         readers.Add(new UPCAReader());\r
  53                                 }\r
  54                                 if (possibleFormats.Contains(BarcodeFormat.EAN_8))\r
  55                                 {\r
  56                                         readers.Add(new EAN8Reader());\r
  57                                 }\r
  58                                 if (possibleFormats.Contains(BarcodeFormat.UPC_E))\r
  59                                 {\r
  60                                         readers.Add(new UPCEReader());\r
  61                                 }\r
  62                         }\r
  63                         if ((readers.Count == 0))\r
  64                         {\r
  65                                 readers.Add(new EAN13Reader());\r
  66                                 // UPC-A is covered by EAN-13\r
  67                                 readers.Add(new EAN8Reader());\r
  68                                 readers.Add(new UPCEReader());\r
  69                         }\r
  70                 }\r
  71                 \r
  72                 public override Result decodeRow(int rowNumber, BitArray row, System.Collections.Hashtable hints)\r
  73                 {\r
  74                         // Compute this location once and reuse it on multiple implementations\r
  75                         int[] startGuardPattern = UPCEANReader.findStartGuardPattern(row);\r
  76                         int size = readers.Count;\r
  77                         for (int i = 0; i < size; i++)\r
  78                         {\r
  79                                 UPCEANReader reader = (UPCEANReader) readers[i];\r
  80                                 Result result;\r
  81                                 try\r
  82                                 {\r
  83                                         result = reader.decodeRow(rowNumber, row, startGuardPattern, hints);\r
  84                                 }\r
  85                                 catch (ReaderException re)\r
  86                                 {\r
  87                                         continue;\r
  88                                 }\r
  89                                 // Special case: a 12-digit code encoded in UPC-A is identical to a "0"\r
  90                                 // followed by those 12 digits encoded as EAN-13. Each will recognize such a code,\r
  91                                 // UPC-A as a 12-digit string and EAN-13 as a 13-digit string starting with "0".\r
  92                                 // Individually these are correct and their readers will both read such a code\r
  93                                 // and correctly call it EAN-13, or UPC-A, respectively.\r
  94                                 //\r
  95                                 // In this case, if we've been looking for both types, we'd like to call it\r
  96                                 // a UPC-A code. But for efficiency we only run the EAN-13 decoder to also read\r
  97                                 // UPC-A. So we special case it here, and convert an EAN-13 result to a UPC-A\r
  98                                 // result if appropriate.\r
  99                                 if (result.BarcodeFormat.Equals(BarcodeFormat.EAN_13) && result.Text[0] == '0')\r
 100                                 {\r
 101                                         return new Result(result.Text.Substring(1), null, result.ResultPoints, BarcodeFormat.UPC_A);\r
 102                                 }\r
 103                                 return result;\r
 104                         }\r
 105                         \r
 106                         throw ReaderException.Instance;\r
 107                 }\r
 108         }\r
 109 }