X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=csharp%2FReaderException.cs;h=1db04364bfb240b4412e59300b5545c82b1516db;hb=73bf85ccc1e4b58fac273ecf043104f3fb9fb28e;hp=c84928a4feb9aeb16e0dfceeff8c031a1ef76e7b;hpb=e35d358134873c3f640672da7cd0c01f02253151;p=zxing.git

diff --git a/csharp/ReaderException.cs b/csharp/ReaderException.cs
index c84928a4..1db04364 100755
--- a/csharp/ReaderException.cs
+++ b/csharp/ReaderException.cs
@@ -1,4 +1,6 @@
-/*
+/*
+* Copyright 2007 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
@@ -11,30 +13,101 @@
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
-
 using System;
 namespace com.google.zxing
 {
+	
+	/// <summary> The general exception class throw when something goes wrong during decoding of a barcode.
+	/// This includes, but is not limited to, failing checksums / error correction algorithms, being
+	/// unable to locate finder timing patterns, and so on.
+	/// 
+	/// </summary>
+	/// <author>  Sean Owen
+	/// </author>
+	/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source 
+	/// </author>
 
-    /// <summary> The general exception class throw when something goes wrong during decoding of a barcode.
-    /// This includes, but is not limited to, failing checksums / error correction algorithms, being
-    /// unable to locate finder timing patterns, and so on.
-    /// 
-    /// </summary>
-    /// <author>  srowen@google.com (Sean Owen)
-    /// </author>
-    //[Serializable]
-    public sealed class ReaderException : System.Exception
-    {
-
-          private static ReaderException instance = new ReaderException();
-
-          public ReaderException() {
-            // do nothing
-          }
-
-          public ReaderException(System.String message): base(message)
-          {
-          }
-    }
+	[Serializable]
+	public sealed class ReaderException:System.Exception
+	{
+		public static ReaderException Instance
+		{
+			get
+			{
+				//    Exception e = new Exception();
+				//    // Take the stack frame before this one.
+				//    StackTraceElement stack = e.getStackTrace()[1];
+				//    String key = stack.getClassName() + "." + stack.getMethodName() + "(), line " +
+				//        stack.getLineNumber();
+				//    if (throwers.containsKey(key)) {
+				//      Integer value = throwers.get(key);
+				//      value++;
+				//      throwers.put(key, value);
+				//    } else {
+				//      throwers.put(key, 1);
+				//    }
+				//    exceptionCount++;
+				
+				return instance;
+			}
+			
+		}
+		
+		// TODO: Currently we throw up to 400 ReaderExceptions while scanning a single 240x240 image before
+		// rejecting it. This involves a lot of overhead and memory allocation, and affects both performance
+		// and latency on continuous scan clients. In the future, we should change all the decoders not to
+		// throw exceptions for routine events, like not finding a barcode on a given row. Instead, we
+		// should return error codes back to the callers, and simply delete this class. In the mean time, I
+		// have altered this class to be as lightweight as possible, by ignoring the exception string, and
+		// by disabling the generation of stack traces, which is especially time consuming. These are just
+		// temporary measures, pending the big cleanup.
+		
+		//UPGRADE_NOTE: Final was removed from the declaration of 'instance '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
+		private static readonly ReaderException instance = new ReaderException();
+		
+		// EXCEPTION TRACKING SUPPORT
+		// Identifies who is throwing exceptions and how often. To use:
+		//
+		// 1. Uncomment these lines and the code below which uses them.
+		// 2. Uncomment the two corresponding lines in j2se/CommandLineRunner.decode()
+		// 3. Change core to build as Java 1.5 temporarily
+		//  private static int exceptionCount = 0;
+		//  private static Map<String,Integer> throwers = new HashMap<String,Integer>(32);
+		
+		private ReaderException()
+		{
+			// do nothing
+		}
+		
+		//  public static int getExceptionCountAndReset() {
+		//    int temp = exceptionCount;
+		//    exceptionCount = 0;
+		//    return temp;
+		//  }
+		//
+		//  public static String getThrowersAndReset() {
+		//    StringBuilder builder = new StringBuilder(1024);
+		//    Object[] keys = throwers.keySet().toArray();
+		//    for (int x = 0; x < keys.length; x++) {
+		//      String key = (String) keys[x];
+		//      Integer value = throwers.get(key);
+		//      builder.append(key);
+		//      builder.append(": ");
+		//      builder.append(value);
+		//      builder.append("\n");
+		//    }
+		//    throwers.clear();
+		//    return builder.toString();
+		//  }
+		
+		// Prevent stack traces from being taken
+		// srowen says: huh, my IDE is saying this is not an override. native methods can't be overridden?
+		// This, at least, does not hurt. Because we use a singleton pattern here, it doesn't matter anyhow.
+		//UPGRADE_NOTE: Exception 'java.lang.Throwable' was converted to 'System.Exception' which has different behavior. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1100'"
+		//UPGRADE_NOTE: The equivalent of method 'java.lang.Throwable.fillInStackTrace' is not an override method. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1143'"
+		public System.Exception fillInStackTrace()
+		{
+			return null;
+		}
+	}
 }
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