Optimised a lot of the List methods to increase performance.

svn path=/trunk/mcs/; revision=75021

diff --git a/mcs/class/corlib/System.Collections.Generic/ChangeLog b/mcs/class/corlib/System.Collections.Generic/ChangeLog
index 34cd7d12976c1a487ee9be03370fa17baa2b1fc2..478923401efdd72c3485b069be4d2ad84736ce9c 100644 (file)
--- a/mcs/class/corlib/System.Collections.Generic/ChangeLog
+++ b/mcs/class/corlib/System.Collections.Generic/ChangeLog
@@ -1,3 +1,7 @@
+2007-03-27  Alan McGovern <alan.mcgovern@gmail.com>
+
+       * List.cs: Optimized several methods to increase performance
+
 2007-03-21  Juraj Skripsky <js@hotfeet.ch>
 
        * List.cs (FindAllStackBits): Small optimization to the new code.

diff --git a/mcs/class/corlib/System.Collections.Generic/List.cs b/mcs/class/corlib/System.Collections.Generic/List.cs
index bd1522e38b46b272860ee014e65fb10e9707cede..1d0d8ecb6112f9d858313f3b1cecb49c90d7d95d 100644 (file)
--- a/mcs/class/corlib/System.Collections.Generic/List.cs
+++ b/mcs/class/corlib/System.Collections.Generic/List.cs
@@ -82,7 +82,10 @@ namespace System.Collections.Generic {
                }
                public void Add (T item)
                {
-                       GrowIfNeeded (1);
+                       // If we check to see if we need to grow before trying to grow
+                       // we can speed things up by 25%
+                       if (_size == _items.Length)
+                               GrowIfNeeded (1);
                        _items [_size ++] = item;
                        _version++;
                }
@@ -163,11 +166,7 @@ namespace System.Collections.Generic {
                
                public bool Contains (T item)
                {
-                       EqualityComparer<T> equalityComparer = EqualityComparer<T>.Default;
-                       for (int i = 0; i < _size; i++)
-                               if (equalityComparer.Equals (_items[i], item))
-                                       return true;
-                       return false;
+                       return Array.IndexOf<T>(_items, item) != -1;
                }
                
                public List <TOutput> ConvertAll <TOutput> (Converter <T, TOutput> converter)
@@ -175,8 +174,10 @@ namespace System.Collections.Generic {
                        if (converter == null)
                                throw new ArgumentNullException ("converter");
                        List <TOutput> u = new List <TOutput> (_size);
-                       foreach (T t in this)
-                               u.Add (converter (t));
+                       for (int i = 0; i < _size; i++)
+                               u._items[i] = converter(_items[i]);
+
+                       u._size = _size;
                        return u;
                }
                
@@ -198,12 +199,14 @@ namespace System.Collections.Generic {
 
                public bool Exists (Predicate <T> match)
                {
-                       return FindIndex (match) != -1;
+                       CheckMatch(match);
+                       return GetIndex(0, _size, match) != -1;
                }
                
                public T Find (Predicate <T> match)
                {
-                       int i = FindIndex (match);
+                       CheckMatch(match);
+                       int i = GetIndex(0, _size, match);
                        return (i != -1) ? _items [i] : default (T);
                }
                void CheckMatch (Predicate <T> match)
@@ -297,7 +300,8 @@ namespace System.Collections.Generic {
                }
                int GetIndex (int startIndex, int count, Predicate <T> match)
                {
-                       for (int i = startIndex; i < startIndex + count; i ++)
+                       int end = startIndex + count;
+                       for (int i = startIndex; i < end; i ++)
                                if (match (_items [i]))
                                        return i;
                                
@@ -345,8 +349,8 @@ namespace System.Collections.Generic {
                {
                        if (action == null)
                                throw new ArgumentNullException ("action");
-                       foreach (T t in this)
-                               action (t);
+                       for(int i=0; i < _size; i++)
+                               action(_items[i]);
                }
                
                public Enumerator GetEnumerator ()
@@ -392,7 +396,8 @@ namespace System.Collections.Generic {
                        if (delta < 0)
                                start -= delta;
                        
-                       Array.Copy (_items, start, _items, start + delta, _size - start);
+                       if (start < _size)
+                               Array.Copy (_items, start, _items, start + delta, _size - start);
                        
                        _size += delta;
                }
@@ -406,9 +411,10 @@ namespace System.Collections.Generic {
                public void Insert (int index, T item)
                {
                        CheckIndex (index);                     
-                       GrowIfNeeded (1);
+                       if (_size == _items.Length)
+                               GrowIfNeeded (1);
                        Shift (index, 1);
-                       this [index] = item;
+                       _items[index] = item;
                        _version++;
                }
 
@@ -486,27 +492,38 @@ namespace System.Collections.Generic {
                        return loc != -1;
                }
                
-               // FIXME: this could probably be made faster.
                public int RemoveAll (Predicate <T> match)
                {
-                       CheckMatch (match);
+                       CheckMatch(match);
+                       int i = 0;
+                       int j = 0;
 
-                       int index = 0;
-                       int c = 0;
-                       while ((index = GetIndex (index, _size - index, match)) != -1) {
-                               RemoveAt (index);
-                               c ++;
+                       // Find the first item to remove
+                       for (i = 0; i < _size; i++)
+                               if (match(_items[i]))
+                                       break;
+
+                       if (i == _size)
+                               return 0;
+
+                       _version++;
+
+                       // Remove any additional items
+                       for (j = i + 1; j < _size; j++)
+                       {
+                               if (!match(_items[j]))
+                                       _items[i++] = _items[j];
                        }
-                       
-                       Array.Clear (_items, _size, c);
-                       return c;
+
+                       _size = i;
+                       return (j - i);
                }
                
                public void RemoveAt (int index)
                {
-                       CheckIndex (index);
+                       if (index < 0 || (uint)index >= (uint)_size)
+                               throw new ArgumentOutOfRangeException("index");
                        Shift (index, -1);
-                       Array.Clear (_items, _size, 0);
                        _version++;
                }
                
@@ -573,8 +590,8 @@ namespace System.Collections.Generic {
                {
                        CheckMatch (match);
 
-                       foreach (T t in this)
-                               if (!match (t))
+                       for (int i = 0; i < _size; i++)
+                               if (!match(_items[i]))
                                        return false;
                                
                        return true;