Improve memory reuse while iterating over QTable, QDictionary and QKe…

…yedTable

CHANGELOG.txt

@@ -5,6 +5,8 @@
   - API convenience extensions
   - QTable, QDictionary and QKeyedTable now implements generic version of
     IEnumerable interface
+  - Improved memory reuse while iterating over QTable, QDictionary 
+    and QKeyedTable
   - Fix: QDictionary enumerator failing to retrieve values
 
 ------------------------------------------------------------------------------

qSharp/src/QDictionary.cs

@@ -185,23 +185,23 @@ public override string ToString()
         public struct KeyValuePair
         {
             private readonly QDictionary _dictionary;
-            private readonly int _index;
+            public int Index { get; internal set; }
 
             /// <summary>
             ///     Initializes a new instance of the KeyValuePair.
             /// </summary>
-            public KeyValuePair(QDictionary dictionary, int index)
+            public KeyValuePair(QDictionary dictionary, int index) : this()
             {
                 _dictionary = dictionary;
-                _index = index;
+                Index = index;
             }
 
             /// <summary>
             ///     Gets the key in the key/value pair.
             /// </summary>
             public object Key
             {
-                get { return _dictionary._keys.GetValue(_index); }
+                get { return _dictionary._keys.GetValue(Index); }
             }
 
             /// <summary>
@@ -214,14 +214,13 @@ public object Value
                     if (!_dictionary._areValuesArray)
                     {
                         var qTable = _dictionary._values as QTable;
-                        if (qTable != null) return qTable[_index];
+
+                        return qTable[Index];
                     }
                     else
                     {
-                        return (_dictionary._values as Array).GetValue(_index);
+                        return (_dictionary._values as Array).GetValue(Index);
                     }
-
-                    throw new NotFiniteNumberException(string.Format("Type {0} is unsupported.", _dictionary._values != null ? _dictionary._values.GetType().Name : "null"));
                 }
             }
         }
@@ -233,15 +232,17 @@ private sealed class QDictionaryEnumerator : IEnumerator<QDictionary.KeyValuePai
         {
             private readonly QDictionary _dictionary;
             private int _index = -1;
+            private QDictionary.KeyValuePair _current;
 
             public QDictionaryEnumerator(QDictionary dictionary)
             {
                 _dictionary = dictionary;
+                _current = new QDictionary.KeyValuePair(_dictionary, _index);
             }
 
             public QDictionary.KeyValuePair Current
             {
-                get { return new KeyValuePair(_dictionary, _index); }
+                get { return _current; }
             }
 
             object IEnumerator.Current
@@ -252,6 +253,7 @@ object IEnumerator.Current
             public bool MoveNext()
             {
                 _index++;
+                _current.Index = _index;
                 return _index < _dictionary._keys.Length;
             }
 

qSharp/src/QKeyedTable.cs

@@ -207,32 +207,32 @@ public override string ToString()
         /// </summary>
         public struct KeyValuePair
         {
-            private readonly int _index;
             private readonly QKeyedTable _kt;
+            public int Index { get; internal set; }
 
             /// <summary>
             ///     Initializes a new instance of the KeyValuePair.
             /// </summary>
-            public KeyValuePair(QKeyedTable table, int index)
+            public KeyValuePair(QKeyedTable table, int index) : this()
             {
                 _kt = table;
-                _index = index;
+                Index = index;
             }
 
             /// <summary>
             ///     Gets the key in the key/value pair.
             /// </summary>
             public object Key
             {
-                get { return _kt._keys[_index]; }
+                get { return _kt._keys[Index]; }
             }
 
             /// <summary>
             ///     Gets the value in the key/value pair.
             /// </summary>
             public object Value
             {
-                get { return _kt._values[_index]; }
+                get { return _kt._values[Index]; }
             }
         }
 
@@ -242,16 +242,18 @@ public object Value
         private sealed class QKeyedTableEnumerator : IEnumerator<QKeyedTable.KeyValuePair>
         {
             private readonly QKeyedTable _kt;
-            private int _index = -1;
+            private int _index = 0;
+            private QKeyedTable.KeyValuePair _current;
 
             public QKeyedTableEnumerator(QKeyedTable table)
             {
                 _kt = table;
+                _current = new KeyValuePair(_kt, _index);
             }
 
             public QKeyedTable.KeyValuePair Current
             {
-                get { return new KeyValuePair(_kt, _index); }
+                get { return _current; }
             }
 
             object IEnumerator.Current
@@ -261,8 +263,8 @@ object IEnumerator.Current
 
             public bool MoveNext()
             {
-                _index++;
-                return _index < _kt._keys.RowsCount;
+                _current.Index = _index; 
+                return _index++ < _kt._keys.RowsCount;
             }
 
             public void Reset()

qSharp/src/QTable.cs

@@ -181,16 +181,18 @@ public override string ToString()
         private sealed class QTableEnumerator : IEnumerator<QTable.Row>
         {
             private readonly QTable _table;
-            private int _index = -1;
+            private int _index = 0;
+            private QTable.Row _current;
 
             public QTableEnumerator(QTable table)
             {
                 _table = table;
+                _current = new Row(_table, _index);
             }
 
             public QTable.Row Current
             {
-                get { return new Row(_table, _index); }
+                get { return _current; }
             }
 
             object IEnumerator.Current
@@ -200,8 +202,8 @@ object IEnumerator.Current
 
             public bool MoveNext()
             {
-                _index++;
-                return _index < _table.RowsCount;
+                _current.Index = _index;
+                return _index++ < _table.RowsCount;
             }
 
             public void Reset()
@@ -220,20 +222,20 @@ public void Dispose()
         /// </summary>
         public struct Row : IEnumerable
         {
-            private readonly int _rowIndex;
             private readonly QTable _table;
+            public int Index { get; internal set; }
 
             /// <summary>
             ///     Initializes a new instance of the Row.
             /// </summary>
-            public Row(QTable table, int rowIndex)
+            public Row(QTable table, int rowIndex) : this()
             {
                 if (rowIndex < 0 || rowIndex > table.RowsCount)
                 {
                     throw new ArgumentOutOfRangeException();
                 }
                 _table = table;
-                _rowIndex = rowIndex;
+                Index = rowIndex;
             }
 
             /// <summary>
@@ -251,8 +253,8 @@ public int Length
             /// <returns>object</returns>
             public object this[int index]
             {
-                get { return ((Array) _table.Data.GetValue(index)).GetValue(_rowIndex); }
-                set { ((Array) _table.Data.GetValue(index)).SetValue(value, _rowIndex); }
+                get { return ((Array)_table.Data.GetValue(index)).GetValue(Index); }
+                set { ((Array)_table.Data.GetValue(index)).SetValue(value, Index); }
             }
 
             /// <summary>