Implemented more efficient Insert() method for the deque; split RemoveAt() into left-shifting and right-shifting specializations (right-shifting still is a copy of the left-shifting one, will fix it soon); improved unit tests to catch any and all border cases; made the IndexOf() method workable; wrote unit tests for the IndexOf() method; moved removal and insertion functions into the own sub-files to avoid having huge source files

git-svn-id: file:///srv/devel/repo-conversion/nusu@160 d2e56fa2-650e-0410-a79f-9358c0239efd

Nuclex.Support (Xbox 360).csproj

@@ -70,6 +70,12 @@
       <DependentUpon>AssertHelper.cs</DependentUpon>
     </Compile>
     <Compile Include="Source\Collections\Deque.cs" />
+    <Compile Include="Source\Collections\Deque.Insertion.cs">
+      <DependentUpon>Deque.cs</DependentUpon>
+    </Compile>
+    <Compile Include="Source\Collections\Deque.Removal.cs">
+      <DependentUpon>Deque.cs</DependentUpon>
+    </Compile>
     <Compile Include="Source\Collections\Deque.Test.cs">
       <DependentUpon>Deque.cs</DependentUpon>
     </Compile>

Nuclex.Support.csproj

@@ -52,6 +52,12 @@
       <DependentUpon>AssertHelper.cs</DependentUpon>
     </Compile>
     <Compile Include="Source\Collections\Deque.cs" />
+    <Compile Include="Source\Collections\Deque.Insertion.cs">
+      <DependentUpon>Deque.cs</DependentUpon>
+    </Compile>
+    <Compile Include="Source\Collections\Deque.Removal.cs">
+      <DependentUpon>Deque.cs</DependentUpon>
+    </Compile>
     <Compile Include="Source\Collections\Deque.Test.cs">
       <DependentUpon>Deque.cs</DependentUpon>
     </Compile>

Source/Collections/Deque.Insertion.cs

@@ -0,0 +1,184 @@
+using System;
+using System.Collections.Generic;
+using System.Collections;
+
+namespace Nuclex.Support.Collections {
+
+  partial class Deque<ItemType> {
+
+    /// <summary>Inserts an item at the beginning of the double-ended queue</summary>
+    /// <param name="item">Item that will be inserted into the queue</param>
+    public void AddFirst(ItemType item) {
+      if(this.firstBlockStartIndex > 0) {
+        --this.firstBlockStartIndex;
+      } else { // Need to allocate a new block
+        this.blocks.Insert(0, new ItemType[this.blockSize]);
+        this.firstBlockStartIndex = this.blockSize - 1;
+      }
+
+      this.blocks[0][this.firstBlockStartIndex] = item;
+      ++this.count;
+    }
+
+    /// <summary>Appends an item to the end of the double-ended queue</summary>
+    /// <param name="item">Item that will be appended to the queue</param>
+    public void AddLast(ItemType item) {
+      if(this.lastBlockEndIndex < this.blockSize) {
+        ++this.lastBlockEndIndex;
+      } else { // Need to allocate a new block
+        this.blocks.Add(new ItemType[this.blockSize]);
+        this.lastBlockEndIndex = 1;
+      }
+
+      this.blocks[this.blocks.Count - 1][this.lastBlockEndIndex - 1] = item;
+      ++this.count;
+    }
+
+    /// <summary>Inserts the item at the specified index</summary>
+    /// <param name="index">Index the item will be inserted at</param>
+    /// <param name="item">Item that will be inserted</param>
+    public void Insert(int index, ItemType item) {
+      int distanceToRightEnd = this.count - index;
+      if(index < distanceToRightEnd) { // Are we closer to the left end?
+        shiftLeftAndInsert(index, item);
+      } else { // Nope, we're closer to the right end
+        shiftRightAndInsert(index, item);
+      }
+    }
+
+    /// <summary>
+    ///   Shifts all items before the insertion point to the left and inserts
+    ///   the item at the specified index
+    /// </summary>
+    /// <param name="index">Index the item will be inserted at</param>
+    /// <param name="item">Item that will be inserted</param>
+    private void shiftLeftAndInsert(int index, ItemType item) {
+      if(index == 0) {
+        AddFirst(item);
+      } else {
+        int blockIndex, subIndex;
+        findIndex(index, out blockIndex, out subIndex);
+
+        int firstBlock = 0;
+        int blockStart;
+
+        // If the first block is full, we need to add another block
+        if(this.firstBlockStartIndex == 0) {
+          this.blocks.Insert(0, new ItemType[this.blockSize]);
+          this.blocks[0][this.blockSize - 1] = this.blocks[1][0];
+          this.firstBlockStartIndex = this.blockSize - 1;
+
+          blockStart = 1;
+          --subIndex;
+          if(subIndex < 0) {
+            subIndex = this.blockSize - 1;
+          } else {
+            ++blockIndex;
+          }
+          ++firstBlock;
+        } else {
+          blockStart = this.firstBlockStartIndex;
+          --this.firstBlockStartIndex;
+
+          --subIndex;
+          if(subIndex < 0) {
+            subIndex = this.blockSize - 1;
+            --blockIndex;
+          }
+        }
+
+        // If the insertion point is not in the first block
+        if(blockIndex != firstBlock) {
+          Array.Copy(
+            this.blocks[firstBlock], blockStart,
+            this.blocks[firstBlock], blockStart - 1,
+            this.blockSize - blockStart
+          );
+          this.blocks[firstBlock][this.blockSize - 1] = this.blocks[firstBlock + 1][0];
+
+          // Move all the blocks following the insertion point to the right by one item.
+          // If there are no blocks inbetween, this for loop will not run.
+          for(int tempIndex = firstBlock + 1; tempIndex < blockIndex; ++tempIndex) {
+            Array.Copy(
+              this.blocks[tempIndex], 1, this.blocks[tempIndex], 0, this.blockSize - 1
+            );
+            this.blocks[tempIndex][this.blockSize - 1] = this.blocks[tempIndex + 1][0];
+          }
+
+          blockStart = 1;
+        }
+
+        // Finally, move the items in the block the insertion takes place in
+        Array.Copy(
+          this.blocks[blockIndex], blockStart,
+          this.blocks[blockIndex], blockStart - 1,
+          subIndex - blockStart + 1
+        );
+
+        this.blocks[blockIndex][subIndex] = item;
+        ++this.count;
+      }
+    }
+
+    /// <summary>
+    ///   Shifts all items after the insertion point to the right and inserts
+    ///   the item at the specified index
+    /// </summary>
+    /// <param name="index">Index the item will be inserted at</param>
+    /// <param name="item">Item that will be inserted</param>
+    private void shiftRightAndInsert(int index, ItemType item) {
+      if(index == this.count) {
+        AddLast(item);
+      } else {
+        int blockIndex, subIndex;
+        findIndex(index, out blockIndex, out subIndex);
+
+        int lastBlock = this.blocks.Count - 1;
+        int blockLength;
+
+        // If the lastmost block is full, we need to add another block
+        if(this.lastBlockEndIndex == this.blockSize) {
+          this.blocks.Add(new ItemType[this.blockSize]);
+          this.blocks[lastBlock + 1][0] = this.blocks[lastBlock][this.blockSize - 1];
+          this.lastBlockEndIndex = 1;
+
+          blockLength = this.blockSize - 1;
+        } else {
+          blockLength = this.lastBlockEndIndex;
+          ++this.lastBlockEndIndex;
+        }
+
+        // If the insertion point is not in the lastmost block
+        if(blockIndex != lastBlock) {
+          Array.Copy(
+            this.blocks[lastBlock], 0, this.blocks[lastBlock], 1, blockLength
+          );
+          this.blocks[lastBlock][0] = this.blocks[lastBlock - 1][this.blockSize - 1];
+
+          // Move all the blocks following the insertion point to the right by one item.
+          // If there are no blocks inbetween, this for loop will not run.
+          for(int tempIndex = lastBlock - 1; tempIndex > blockIndex; --tempIndex) {
+            Array.Copy(
+              this.blocks[tempIndex], 0, this.blocks[tempIndex], 1, this.blockSize - 1
+            );
+            this.blocks[tempIndex][0] = this.blocks[tempIndex - 1][this.blockSize - 1];
+          }
+
+          blockLength = this.blockSize - 1;
+        }
+
+        // Finally, move the items in the block the insertion takes place in
+        Array.Copy(
+          this.blocks[blockIndex], subIndex,
+          this.blocks[blockIndex], subIndex + 1,
+          blockLength - subIndex
+        );
+
+        this.blocks[blockIndex][subIndex] = item;
+        ++this.count;
+      }
+    }
+
+  }
+
+} // namespace Nuclex.Support.Collections

Source/Collections/Deque.Removal.cs

@@ -0,0 +1,174 @@
+using System;
+using System.Collections.Generic;
+using System.Collections;
+
+namespace Nuclex.Support.Collections {
+
+  partial class Deque<ItemType> {
+
+    /// <summary>Removes the first item in the double-ended queue</summary>
+    public void RemoveFirst() {
+      if(this.count == 0) {
+        throw new InvalidOperationException("Cannot remove items from empty deque");
+      }
+
+      // TODO: Zero removed array entry if array is kept
+
+      ++this.firstBlockStartIndex;
+      if(this.firstBlockStartIndex >= this.blockSize) { // Block became empty
+        if(this.count > 1) { // Still more blocks in queue, remove block
+          this.blocks.RemoveAt(0);
+          this.firstBlockStartIndex = 0;
+        } else { // Last block - do not remove
+          this.firstBlockStartIndex = 0;
+          this.lastBlockEndIndex = 0;
+        }
+      }
+      --this.count;
+    }
+
+    /// <summary>Removes the last item in the double-ended queue</summary>
+    public void RemoveLast() {
+      if(this.count == 0) {
+        throw new InvalidOperationException("Cannot remove items from empty deque");
+      }
+
+      // TODO: Zero removed array entry if array is kept
+
+      --this.lastBlockEndIndex;
+      if(this.lastBlockEndIndex == 0) { // Block became empty
+        if(this.count > 1) {
+          this.blocks.RemoveAt(this.blocks.Count - 1);
+          this.lastBlockEndIndex = this.blockSize;
+        } else { // Last block - do not remove
+          this.firstBlockStartIndex = 0;
+          this.lastBlockEndIndex = 0;
+        }
+      }
+      --this.count;
+    }
+
+    /// <summary>Removes the item at the specified index</summary>
+    /// <param name="index">Index of the item that will be removed</param>
+    public void RemoveAt(int index) {
+      int distanceToRightEnd = this.count - index;
+      if(index < distanceToRightEnd) { // Are we closer to the left end?
+        removeFromLeft(index);
+      } else { // Nope, we're closer to the right end
+        removeFromRight(index);
+      }
+    }
+
+    /// <summary>
+    ///   Removes an item from the left side of the queue by shifting all items that
+    ///   come before it to the right by one
+    /// </summary>
+    /// <param name="index">Index of the item that will be removed</param>
+    private void removeFromLeft(int index) {
+      if(index == this.count - 1) {
+        RemoveLast();
+      } else {
+        int blockIndex, subIndex;
+        findIndex(index, out blockIndex, out subIndex);
+
+        int lastBlock = this.blocks.Count - 1;
+        int startIndex;
+
+        if(blockIndex < lastBlock) {
+          Array.Copy(
+            this.blocks[blockIndex], subIndex + 1,
+            this.blocks[blockIndex], subIndex,
+            this.blockSize - subIndex - 1
+          );
+          this.blocks[blockIndex][this.blockSize - 1] = this.blocks[blockIndex + 1][0];
+
+          for(int tempIndex = blockIndex + 1; tempIndex < lastBlock; ++tempIndex) {
+            Array.Copy(
+              this.blocks[tempIndex], 1,
+              this.blocks[tempIndex], 0,
+              this.blockSize - 1
+            );
+            this.blocks[tempIndex][this.blockSize - 1] = this.blocks[tempIndex + 1][0];
+          }
+
+          startIndex = 0;
+        } else {
+          startIndex = subIndex;
+        }
+
+        Array.Copy(
+          this.blocks[lastBlock], startIndex + 1,
+          this.blocks[lastBlock], startIndex,
+          this.lastBlockEndIndex - startIndex - 1
+        );
+
+        if(this.lastBlockEndIndex == 1) {
+          this.blocks.RemoveAt(lastBlock);
+          this.lastBlockEndIndex = this.blockSize;
+        } else {
+          this.blocks[lastBlock][this.lastBlockEndIndex - 1] = default(ItemType);
+          --this.lastBlockEndIndex;
+        }
+
+        --this.count;
+      }
+    }
+
+    /// <summary>
+    ///   Removes an item from the right side of the queue by shifting all items that
+    ///   come after it to the left by one
+    /// </summary>
+    /// <param name="index">Index of the item that will be removed</param>
+    private void removeFromRight(int index) {
+      if(index == this.count - 1) {
+        RemoveLast();
+      } else {
+        int blockIndex, subIndex;
+        findIndex(index, out blockIndex, out subIndex);
+
+        int lastBlock = this.blocks.Count - 1;
+        int startIndex;
+
+        if(blockIndex < lastBlock) {
+          Array.Copy(
+            this.blocks[blockIndex], subIndex + 1,
+            this.blocks[blockIndex], subIndex,
+            this.blockSize - subIndex - 1
+          );
+          this.blocks[blockIndex][this.blockSize - 1] = this.blocks[blockIndex + 1][0];
+
+          for(int tempIndex = blockIndex + 1; tempIndex < lastBlock; ++tempIndex) {
+            Array.Copy(
+              this.blocks[tempIndex], 1,
+              this.blocks[tempIndex], 0,
+              this.blockSize - 1
+            );
+            this.blocks[tempIndex][this.blockSize - 1] = this.blocks[tempIndex + 1][0];
+          }
+
+          startIndex = 0;
+        } else {
+          startIndex = subIndex;
+        }
+
+        Array.Copy(
+          this.blocks[lastBlock], startIndex + 1,
+          this.blocks[lastBlock], startIndex,
+          this.lastBlockEndIndex - startIndex - 1
+        );
+
+        if(this.lastBlockEndIndex == 1) {
+          this.blocks.RemoveAt(lastBlock);
+          this.lastBlockEndIndex = this.blockSize;
+        } else {
+          this.blocks[lastBlock][this.lastBlockEndIndex - 1] = default(ItemType);
+          --this.lastBlockEndIndex;
+        }
+
+        --this.count;
+      }
+    }
+
+  }
+
+} // namespace Nuclex.Support.Collections

Source/Collections/Deque.Test.cs

@@ -28,8 +28,6 @@ using NMock2;
 
 namespace Nuclex.Support.Collections {
 
-#if true
-
   /// <summary>Unit Test for the double ended queue</summary>
   [TestFixture]
   public class DequeTest {
@@ -94,6 +92,111 @@ namespace Nuclex.Support.Collections {
       }
     }
 
+
+    /// <summary>Verifies that the Insert() method works in all cases</summary>
+    /// <remarks>
+    ///   We have several different cases here that will be tested. The deque can
+    ///   shift items to the left or right (depending on which end is closer to
+    ///   the insertion point) and the insertion point may fall in an only partially
+    ///   occupied block, requiring elaborate index calculations
+    /// </remarks>
+    [Test]
+    public void TestInsert() {
+      for(int testedIndex = 0; testedIndex <= 96; ++testedIndex) {
+        Deque<int> intDeque = new Deque<int>(16);
+        for(int item = 0; item < 96; ++item) {
+          intDeque.AddLast(item);
+        }
+
+        intDeque.Insert(testedIndex, 12345);
+
+        Assert.AreEqual(97, intDeque.Count);
+
+        for(int index = 0; index < testedIndex; ++index) {
+          Assert.AreEqual(index, intDeque[index]);
+        }
+        Assert.AreEqual(12345, intDeque[testedIndex]);
+        for(int index = testedIndex + 1; index < 97; ++index) {
+          Assert.AreEqual(index - 1, intDeque[index]);
+        }
+      }
+    }
+
+    /// <summary>Verifies that the Insert() method works in all cases</summary>
+    [Test]
+    public void TestInsertNonNormalized() {
+      for(int testedIndex = 0; testedIndex <= 96; ++testedIndex) {
+        Deque<int> intDeque = new Deque<int>(16);
+        for(int item = 4; item < 96; ++item) {
+          intDeque.AddLast(item);
+        }
+        intDeque.AddFirst(3);
+        intDeque.AddFirst(2);
+        intDeque.AddFirst(1);
+        intDeque.AddFirst(0);
+
+        intDeque.Insert(testedIndex, 12345);
+
+        Assert.AreEqual(97, intDeque.Count);
+
+        for(int index = 0; index < testedIndex; ++index) {
+          Assert.AreEqual(index, intDeque[index]);
+        }
+        Assert.AreEqual(12345, intDeque[testedIndex]);
+        for(int index = testedIndex + 1; index < 97; ++index) {
+          Assert.AreEqual(index - 1, intDeque[index]);
+        }
+      }
+    }
+
+    /// <summary>Verifies the the RemoveAt() method works in all cases</summary>
+    [Test]
+    public void TestRemoveAt() {
+      for(int testedIndex = 0; testedIndex < 96; ++testedIndex) {
+        Deque<int> intDeque = new Deque<int>(16);
+        for(int item = 0; item < 96; ++item) {
+          intDeque.AddLast(item);
+        }
+
+        intDeque.RemoveAt(testedIndex);
+
+        Assert.AreEqual(95, intDeque.Count);
+
+        for(int index = 0; index < testedIndex; ++index) {
+          Assert.AreEqual(index, intDeque[index]);
+        }
+        for(int index = testedIndex; index < 95; ++index) {
+          Assert.AreEqual(index + 1, intDeque[index]);
+        }
+      }
+    }
+
+    /// <summary>Verifies the the RemoveAt() method works in all cases</summary>
+    [Test]
+    public void TestRemoveAtNonNormalized() {
+      for(int testedIndex = 0; testedIndex < 96; ++testedIndex) {
+        Deque<int> intDeque = new Deque<int>(16);
+        for(int item = 4; item < 96; ++item) {
+          intDeque.AddLast(item);
+        }
+        intDeque.AddFirst(3);
+        intDeque.AddFirst(2);
+        intDeque.AddFirst(1);
+        intDeque.AddFirst(0);
+
+        intDeque.RemoveAt(testedIndex);
+
+        Assert.AreEqual(95, intDeque.Count);
+
+        for(int index = 0; index < testedIndex; ++index) {
+          Assert.AreEqual(index, intDeque[index]);
+        }
+        for(int index = testedIndex; index < 95; ++index) {
+          Assert.AreEqual(index + 1, intDeque[index]);
+        }
+      }
+    }
+
     /// <summary>
     ///   Validates that an exception is thrown if the 'First' property is accessed
     ///   in an empty deque
@@ -142,177 +245,6 @@ namespace Nuclex.Support.Collections {
       );
     }
 
-    /// <summary>
-    ///   Tests whether the Insert() method of the deque can insert an item at
-    ///   the end of the deque
-    /// </summary>
-    [Test]
-    public void TestInsertAtEnd() {
-      Deque<int> intDeque = new Deque<int>(16);
-      for(int item = 0; item < 48; ++item) {
-        intDeque.AddLast(item);
-      }
-      
-      intDeque.Insert(intDeque.Count, 12345);
-
-      Assert.AreEqual(12345, intDeque.Last);
-    }
-
-    /// <summary>
-    ///   Tests whether the Insert() method of the deque can insert an item into
-    ///   the last block of the deque when that last block is already full
-    /// </summary>
-    [Test]
-    public void TestInsertInLastBlock() {
-      Deque<int> intDeque = new Deque<int>(16);
-      for(int item = 0; item < 48; ++item) {
-        intDeque.AddLast(item);
-      }
-
-      intDeque.Insert(45, 12345);
-
-      Assert.AreEqual(49, intDeque.Count);
-      for(int index = 0; index < 44; ++index) {
-        Assert.AreEqual(index, intDeque[index]);
-      }
-      Assert.AreEqual(12345, intDeque[45]);
-      for(int index = 46; index < 49; ++index) {
-        Assert.AreEqual(index - 1, intDeque[index]);
-      }
-    }
-
-    /// <summary>
-    ///   Tests whether the Insert() method of the deque can insert an item into
-    ///   the second-to-last block of the deque
-    /// </summary>
-    [Test]
-    public void TestInsertInSecondToLastBlock() {
-      Deque<int> intDeque = new Deque<int>(16);
-      for(int item = 0; item < 40; ++item) {
-        intDeque.AddLast(item);
-      }
-      
-      intDeque.Insert(24, 12345);
-
-      Assert.AreEqual(41, intDeque.Count);
-      for(int index = 0; index < 24; ++index) {
-        Assert.AreEqual(index, intDeque[index]);
-      }
-      Assert.AreEqual(12345, intDeque[24]);
-      for(int index = 25; index < 41; ++index) {
-        Assert.AreEqual(index - 1, intDeque[index]);
-      }
-    }
-
-    /// <summary>
-    ///   Tests whether the Insert() method of the deque can insert an item into
-    ///   the third-to-last block of the deque
-    /// </summary>
-    [Test]
-    public void TestInsertInThirdToLastBlock() {
-      Deque<int> intDeque = new Deque<int>(16);
-      for(int item = 0; item < 40; ++item) {
-        intDeque.AddLast(item);
-      }
-
-      intDeque.Insert(8, 12345);
-
-      Assert.AreEqual(41, intDeque.Count);
-
-      for(int index = 0; index < 8; ++index) {
-        Assert.AreEqual(index, intDeque[index]);
-      }
-      Assert.AreEqual(12345, intDeque[8]);
-      for(int index = 9; index < 41; ++index) {
-        Assert.AreEqual(index - 1, intDeque[index]);
-      }
-    }
-
-    /// <summary>
-    ///   Tests whether the RemoveAt() method of the deque can remove an item from
-    ///   the end of the deque
-    /// </summary>
-    [Test]
-    public void TestRemoveAtEnd() {
-      Deque<int> intDeque = new Deque<int>(16);
-      for(int item = 0; item < 48; ++item) {
-        intDeque.AddLast(item);
-      }
-
-      intDeque.RemoveAt(intDeque.Count - 1);
-
-      Assert.AreEqual(46, intDeque.Last);
-    }
-
-    /// <summary>
-    ///   Tests whether the RemoveAt() method of the deque can remove an item
-    ///   from the last block of the deque
-    /// </summary>
-    [Test]
-    public void TestRemoveFromLastBlock() {
-      Deque<int> intDeque = new Deque<int>(16);
-      for(int item = 0; item < 48; ++item) {
-        intDeque.AddLast(item);
-      }
-
-      intDeque.RemoveAt(45);
-
-      Assert.AreEqual(47, intDeque.Count);
-
-      for(int index = 0; index < 45; ++index) {
-        Assert.AreEqual(index, intDeque[index]);
-      }
-      for(int index = 45; index < 47; ++index) {
-        Assert.AreEqual(index + 1, intDeque[index]);
-      }
-    }
-
-    /// <summary>
-    ///   Tests whether the RemoveAt() method of the deque can remove an item from
-    ///   the second-to-last block of the deque
-    /// </summary>
-    [Test]
-    public void TestRemoveFromSecondToLastBlock() {
-      Deque<int> intDeque = new Deque<int>(16);
-      for(int item = 0; item < 40; ++item) {
-        intDeque.AddLast(item);
-      }
-
-      intDeque.RemoveAt(24);
-
-      Assert.AreEqual(39, intDeque.Count);
-
-      for(int index = 0; index < 24; ++index) {
-        Assert.AreEqual(index, intDeque[index]);
-      }
-      for(int index = 24; index < 39; ++index) {
-        Assert.AreEqual(index + 1, intDeque[index]);
-      }
-    }
-
-    /// <summary>
-    ///   Tests whether the RemoveAt() method of the deque can remove an item from
-    ///   the third-to-last block of the deque
-    /// </summary>
-    [Test]
-    public void TestRemoveFromThirdToLastBlock() {
-      Deque<int> intDeque = new Deque<int>(16);
-      for(int item = 0; item < 33; ++item) {
-        intDeque.AddLast(item);
-      }
-
-      intDeque.RemoveAt(8);
-
-      Assert.AreEqual(32, intDeque.Count);
-
-      for(int index = 0; index < 8; ++index) {
-        Assert.AreEqual(index, intDeque[index]);
-      }
-      for(int index = 8; index < 32; ++index) {
-        Assert.AreEqual(index + 1, intDeque[index]);
-      }
-    }
-    
     /// <summary>
     ///   Verifies that items can be assigned by their index
     /// </summary>
@@ -349,9 +281,23 @@ namespace Nuclex.Support.Collections {
       );
     }
 
+    /// <summary>Tests the IndexOf() method</summary>
+    [Test, TestCase(0), TestCase(16), TestCase(32), TestCase(48)]
+    public void TestIndexOf(int count) {
+      Deque<int> intDeque = new Deque<int>(16);
+      for(int item = 4; item < count; ++item) {
+        intDeque.AddLast(item);
+      }
+      if(count > 3) { intDeque.AddFirst(3); }
+      if(count > 2) { intDeque.AddFirst(2); }
+      if(count > 1) { intDeque.AddFirst(1); }
+      if(count > 0) { intDeque.AddFirst(0); }
+
+      Assert.AreEqual(count - 1, intDeque.IndexOf(count - 1));
+      Assert.AreEqual(-1, intDeque.IndexOf(count));
     }
 
-#endif
+  }
 
 } // namespace Nuclex.Support.Collections
 

Source/Collections/Deque.cs

@@ -4,8 +4,6 @@ using System.Collections;
 
 namespace Nuclex.Support.Collections {
 
-#if true
-
   /// <summary>A double-ended queue that allocates memory in blocks</summary>
   /// <typeparam name="ItemType">Type of the items being stored in the queue</typeparam>
   /// <remarks>
@@ -20,7 +18,7 @@ namespace Nuclex.Support.Collections {
   ///     require items to be copied around and still can be accessed by index.
   ///   </para>
   /// </remarks>
-  public class Deque<ItemType> /*: IList<ItemType>, IList*/ {
+  public partial class Deque<ItemType> /*: IList<ItemType>, IList*/ {
 
     /// <summary>Initializes a new deque</summary>
     public Deque() : this(512) { }
@@ -77,202 +75,16 @@ namespace Nuclex.Support.Collections {
       }
     }
 
-    /// <summary>Removes the first item in the double-ended queue</summary>
+    /// <summary>
-    public void RemoveFirst() {
+    ///   Determines the index of the first occurence of the specified item in the deque
-      if(this.count == 0) {
+    /// </summary>
-        throw new InvalidOperationException("Cannot remove items from empty deque");
+    /// <param name="item">Item that will be located in the deque</param>
-      }
+    /// <returns>The index of the item or -1 if it wasn't found</returns>
-      
-      // TODO: Zero removed array entry if array is kept
-
-      ++this.firstBlockStartIndex;
-      if(this.firstBlockStartIndex >= this.blockSize) { // Block became empty
-        if(this.count > 1) { // Still more blocks in queue, remove block
-          this.blocks.RemoveAt(0);
-          this.firstBlockStartIndex = 0;
-        } else { // Last block - do not remove
-          this.firstBlockStartIndex = 0;
-          this.lastBlockEndIndex = 0;
-        }
-      }
-      --this.count;
-    }
-
-    /// <summary>Removes the last item in the double-ended queue</summary>
-    public void RemoveLast() {
-      if(this.count == 0) {
-        throw new InvalidOperationException("Cannot remove items from empty deque");
-      }
-
-      // TODO: Zero removed array entry if array is kept
-
-      --this.lastBlockEndIndex;
-      if(this.lastBlockEndIndex == 0) { // Block became empty
-        if(this.count > 1) {
-          this.blocks.RemoveAt(this.blocks.Count - 1);
-          this.lastBlockEndIndex = this.blockSize;
-        } else { // Last block - do not remove
-          this.firstBlockStartIndex = 0;
-          this.lastBlockEndIndex = 0;
-        }
-      }
-      --this.count;
-    }
-
-    /// <summary>Inserts an item at the beginning of the double-ended queue</summary>
-    /// <param name="item">Item that will be inserted into the queue</param>
-    public void AddFirst(ItemType item) {
-      if(this.firstBlockStartIndex > 0) {
-        --this.firstBlockStartIndex;
-      } else { // Need to allocate a new block
-        this.blocks.Insert(0, new ItemType[this.blockSize]);
-        this.firstBlockStartIndex = this.blockSize - 1;
-      }
-
-      this.blocks[0][this.firstBlockStartIndex] = item;
-      ++this.count;
-    }
-
-    /// <summary>Appends an item to the end of the double-ended queue</summary>
-    /// <param name="item">Item that will be appended to the queue</param>
-    public void AddLast(ItemType item) {
-      if(this.lastBlockEndIndex < this.blockSize) {
-        ++this.lastBlockEndIndex;
-      } else { // Need to allocate a new block
-        this.blocks.Add(new ItemType[this.blockSize]);
-        this.lastBlockEndIndex = 1;
-      }
-
-      this.blocks[this.blocks.Count - 1][this.lastBlockEndIndex - 1] = item;
-      ++this.count;
-    }
-
-    /// <summary>Inserts the item at the specified index</summary>
-    /// <param name="index">Index the item will be inserted at</param>
-    /// <param name="item">Item that will be inserted</param>
-    public void Insert(int index, ItemType item) {
-      // TODO: Not perfect. Can shift to left or to right in a deque.
-      //       Rewrite!
-      if(index == this.count) {
-        AddLast(item);
-      } else {
-        int blockIndex, subIndex;
-        findIndex(index, out blockIndex, out subIndex);
-
-        int lastBlock = this.blocks.Count - 1;
-        int blockLength;
-
-        // If the lastmost block is full, we need to add another block
-        if(this.lastBlockEndIndex == this.blockSize) {
-          this.blocks.Add(new ItemType[this.blockSize]);
-          this.blocks[lastBlock + 1][0] = this.blocks[lastBlock][this.blockSize - 1];
-          this.lastBlockEndIndex = 1;
-
-          blockLength = this.blockSize - 1;
-        } else {
-          blockLength = this.lastBlockEndIndex;
-          ++this.lastBlockEndIndex;
-        }
-
-        // If the insertion point is not in the lastmost block
-        if(blockIndex != lastBlock) {
-          Array.Copy(
-            this.blocks[lastBlock], 0, this.blocks[lastBlock], 1, blockLength
-          );
-          this.blocks[lastBlock][0] = this.blocks[lastBlock - 1][this.blockSize - 1];
-
-          // Move all the blocks following the insertion point to the right by one item.
-          // If there are no blocks inbetween, this for loop will not run.
-          for(int tempIndex = lastBlock - 1; tempIndex > blockIndex; --tempIndex) {
-            Array.Copy(
-              this.blocks[tempIndex], 0, this.blocks[tempIndex], 1, this.blockSize - 1
-            );
-            this.blocks[tempIndex][0] = this.blocks[tempIndex - 1][this.blockSize - 1];
-          }
-
-          blockLength = this.blockSize - 1;
-        }
-
-        // Finally, move the items in the block the insertion takes place in
-        Array.Copy(
-          this.blocks[blockIndex], subIndex,
-          this.blocks[blockIndex], subIndex + 1,
-          blockLength - subIndex
-        );
-
-        this.blocks[blockIndex][subIndex] = item;
-        ++this.count;
-      }
-    }
-
-    /// <summary>Removes the item at the specified index</summary>
-    /// <param name="index">Index of the item that will be removed</param>
-    public void RemoveAt(int index) {
-      // TODO: Not perfect. Can shift to left or to right in a deque.
-      //       Rewrite!
-      if(index == this.count - 1) {
-        RemoveLast();
-      } else {
-        int blockIndex, subIndex;
-        findIndex(index, out blockIndex, out subIndex);
-
-        int lastBlock = this.blocks.Count - 1;
-        int startIndex;
-
-        if(blockIndex < lastBlock) {
-          Array.Copy(
-            this.blocks[blockIndex], subIndex + 1,
-            this.blocks[blockIndex], subIndex,
-            this.blockSize - subIndex - 1
-          );
-          this.blocks[blockIndex][this.blockSize - 1] = this.blocks[blockIndex + 1][0];
-
-          for(int tempIndex = blockIndex + 1; tempIndex < lastBlock; ++tempIndex) {
-            Array.Copy(
-              this.blocks[tempIndex], 1,
-              this.blocks[tempIndex], 0,
-              this.blockSize - 1
-            );
-            this.blocks[tempIndex][this.blockSize - 1] = this.blocks[tempIndex + 1][0];
-          }
-          
-          startIndex = 0;
-        } else {
-          startIndex = subIndex;
-        }
-
-        Array.Copy(
-          this.blocks[lastBlock], startIndex + 1,
-          this.blocks[lastBlock], startIndex,
-          this.lastBlockEndIndex - startIndex - 1
-        );
-
-        if(this.lastBlockEndIndex == 1) {
-          this.blocks.RemoveAt(lastBlock);
-          this.lastBlockEndIndex = this.blockSize;
-        } else {
-          this.blocks[lastBlock][this.lastBlockEndIndex - 1] = default(ItemType);
-          --this.lastBlockEndIndex;
-        }
-
-        --this.count;
-      }
-    }
-
-    /*
     public int IndexOf(ItemType item) {
-          switch(this.blocks.Count) {
+      if(this.blocks.Count == 1) { // Only one block to scan?
-
+        int length = this.lastBlockEndIndex - this.firstBlockStartIndex;
-            // No block exist, so the item cannot be found
-            case 0: {
-              return -1;
-            }
-
-            // Only one block exists, start index and end index apply to the same block
-            case 1: {
-              int count = this.lastBlockEndIndex - this.firstBlockStartIndex;
         int index = Array.IndexOf<ItemType>(
-                this.blocks[0], item, this.firstBlockStartIndex, count
+          this.blocks[0], item, this.firstBlockStartIndex, length
         );
 
         // If we found something, we need to adjust its index so the first item in
@@ -282,15 +94,12 @@ namespace Nuclex.Support.Collections {
         } else {
           return -1;
         }
-            }
+      } else { // At least two blocks exist
-
-            // Two blocks exist, start index is in first block, end index in second block
-            case 2: {
 
         // Scan the first block for the item and if found, return the index
-              int count = this.blockSize - this.firstBlockStartIndex;
+        int length = this.blockSize - this.firstBlockStartIndex;
         int index = Array.IndexOf<ItemType>(
-                this.blocks[0], item, this.firstBlockStartIndex, this.blockSize
+          this.blocks[0], item, this.firstBlockStartIndex, length
         );
 
         // If we found something, we need to adjust its index
@@ -298,28 +107,28 @@ namespace Nuclex.Support.Collections {
           return (index - this.firstBlockStartIndex);
         }
 
+        int lastBlock = this.blocks.Count - 1;
+        for(int tempIndex = 1; tempIndex < lastBlock; ++tempIndex) {
+          index = Array.IndexOf<ItemType>(
+            this.blocks[1], item, 0, this.blockSize
+          );
+          if(index != -1) {
+            return (index - this.firstBlockStartIndex + tempIndex * this.blockSize);
+          }
+        }
+
         // Nothing found, continue the search in the 
         index = Array.IndexOf<ItemType>(
-                this.blocks[1], item, 0, this.lastBlockEndIndex
+          this.blocks[lastBlock], item, 0, this.lastBlockEndIndex
         );
         if(index == -1) {
           return -1;
         } else {
-                return (index - this.firstBlockStartIndex + this.blockSize);
+          return (index - this.firstBlockStartIndex + lastBlock * this.blockSize);
+        }
       }
     }
 
-            default: {
-              int count = this.blockSize - this.firstBlockStartIndex;
-              int index = Array.IndexOf<ItemType>(
-                this.blocks[0], item, this.firstBlockStartIndex, this.blockSize
-              );
-              return -1;
-            }
-
-          }
-        }
-    */
     /// <summary>Calculates the block index and local sub index of an entry</summary>
     /// <param name="index">Index of the entry that will be located</param>
     /// <param name="blockIndex">Index of the block the entry is contained in</param>
@@ -346,6 +155,4 @@ namespace Nuclex.Support.Collections {
 
   }
 
-#endif
-
 } // namespace Nuclex.Support.Collections