[Mono-bugs] [Bug 77195][Maj] New - BitArray.CopyTo throws ArgumentException when 0-length BitArray is copied

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Changed by monobugzilla at bakta.org.

http://bugzilla.ximian.com/show_bug.cgi?id=77195

--- shadow/77195	2006-01-10 10:41:41.000000000 -0500
+++ shadow/77195.tmp.5190	2006-01-10 10:41:41.000000000 -0500
@@ -0,0 +1,123 @@
+Bug#: 77195
+Product: Mono: Class Libraries
+Version: unspecified
+OS: All
+OS Details: 
+Status: NEW   
+Resolution: 
+Severity: 
+Priority: Major
+Component: CORLIB
+AssignedTo: mono-bugs at ximian.com                            
+ReportedBy: monobugzilla at bakta.org               
+QAContact: mono-bugs at ximian.com
+TargetMilestone: ---
+URL: 
+Summary: BitArray.CopyTo throws ArgumentException when 0-length BitArray is copied
+
+Please fill in this template when reporting a bug, unless you know what you
+are doing.
+Description of Problem:
+
+
+Steps to reproduce the problem:
+1. Use any System.Collection.BitArray of Length=0
+2. Allocate also Length=0 byte Array
+3. Try to use BitArray.CopyTo(byteArray, 0)
+Example:
+using System;
+using System.Collections;
+
+namespace BitArrTest
+{
+	class Class1
+	{
+		[STAThread]
+		static void Main(string[] args)
+		{
+			ArrayList al = new ArrayList();
+			//al.Add(1);
+			//al.Add(0);
+			BitArray ba = new BitArray(al.Count);
+			for(int i = 0; i < al.Count; i++)
+				if((int)al[i] != 0)
+					ba[i] = true;
+				else
+					ba[i] = false;
+			byte[] bya = new byte[(al.Count+7)/8];
+			ba.CopyTo(bya, 0); // When al empty then ArgumentException here.
+			Console.WriteLine("Done");
+		}
+	}
+}
+
+std compile and run
+
+
+Actual Results:
+fik:~/mono/vt# mono BitArrTest.exe
+
+Unhandled Exception: System.ArgumentException: index
+Parameter name: index is greater than array.Length
+in <0x003d4> System.Collections.BitArray:CopyTo (System.Array array, Int32
+index)
+in <0x00100> BitArrTest.Class1:Main (System.String[] args)
+fik:~/mono/vt#
+
+
+Expected Results:
+Print: Done. (byte array created with length=0, no actual data copy)
+
+How often does this happen? 
+allways when destination array is length=0 (
+
+Additional Information:
+
+Possible part:
+
+		public void CopyTo (Array array, int index)
+		{
+			if (array == null)
+				throw new ArgumentNullException ("array");
+			if (index < 0)
+				throw new ArgumentOutOfRangeException ("index");
+			
+			if (array.Rank != 1)
+				throw new ArgumentException ("array", "Array rank must be 1");
+			
+			if (index >= array.Length) // Possible error here! add || index == 0 ->
+which provides success for 0len to 0len array copy
+				throw new ArgumentException ("index", "index is greater than
+array.Length");
+			
+			// in each case, check to make sure enough space in array
+			
+			if (array is bool []) {
+				if (array.Length - index < _length)
+					 throw new ArgumentException ();
+				
+				bool [] barray = (bool []) array;
+				
+				// Copy the bits into the array
+				for (int i = 0; i < _length; i++)
+					barray[index + i] = this [i];
+				
+			} else if (array is byte []) {
+				int numbytes = (_length + 7) / 8;
+				
+				if ((array.Length - index) < numbytes)
+					 throw new ArgumentException ();
+				
+				byte [] barray = (byte []) array;
+				// Copy the bytes into the array
+				for (int i = 0; i < numbytes; i++)
+					barray [index + i] = getByte (i);
+				
+			} else if (array is int []) {
+				
+				Array.Copy (_array, 0, array, index, (_length + 31) / 32);
+				
+			} else {
+				throw new ArgumentException ("array", "Unsupported type");
+			}
+		}