tree updates:

*) when CHILDREN_PER_NODE is large, use binary search
*) add a iterator implementation
*) some code cleanup

git-svn-id: https://svn.musicpd.org/mpd/trunk@4492 09075e82-0dd4-0310-85a5-a0d7c8717e4f

1 files changed, 203 insertions, 50 deletions

diff --git a/src/tree.c b/src/tree.c
index 0696f4b13..58e8a221f 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -5,6 +5,36 @@
 #include <string.h>
 #include <stdio.h>
 
+#ifndef CHILDREN_PER_NODE
+#define CHILDREN_PER_NODE 3
+#endif
+
+#define DATA_PER_NODE (CHILDREN_PER_NODE-1)
+
+#if CHILDREN_PER_NODE > 11
+#define USE_BINARY_SEARCH 1
+#endif
+
+
+/************************* DATA STRUCTURES **********************************/
+
+struct _TreeNode
+{
+	void * data[DATA_PER_NODE];
+	struct _TreeNode * parent;
+	struct _TreeNode * children[CHILDREN_PER_NODE];
+	int dataCount;
+};
+
+struct _Tree
+{
+	TreeCompareDataFunction compareData;
+	TreeFreeDataFunction freeData;
+	TreeNode * rootNode;
+};
+
+/************************* STATIC METHODS ***********************************/
+
 static
 TreeNode *
 _MakeNode()
@@ -16,31 +46,63 @@ _MakeNode()
 
 static
 int
+_FindPositionInNode(Tree * tree, TreeNode * node, void * data, int * pos)
+{
+#ifdef USE_BINARY_SEARCH
+	int low = 0;
+	int high = node->dataCount;
+	int cmp = -1;
+
+	while (high > low)
+	{
+		int cur = (high + low) >> 1;
+		cmp = tree->compareData(data, node->data[cur]);
+		if (cmp > 0)
+		{
+			low = cur+1;
+		}
+		else if (cmp < 0)
+		{
+			high = cur;
+		}
+		else
+		{
+			low = cur;
+			break;
+		}
+	}
+
+	*pos = low;
+	return (cmp == 0);
+#else
+	int i = 0;
+	int cmp = -1;
+	for (; 
+	     i < node->dataCount &&
+	     (cmp = tree->compareData(data, node->data[i])) > 0;
+	     i++);
+	*pos = i;
+	return (cmp == 0);
+#endif
+}
+
+static
+int
 _Find(TreeIterator * iter, void * data)
 {
 	while (1)
 	{
-		for (; iter->which < iter->node->dataCount; iter->which++)
+		if (_FindPositionInNode(iter->tree,
+					iter->node, 
+					data, 
+					&iter->which))
 		{
-			int comp = iter->tree->
-				compareData(data,iter->node->data[iter->which]);
-
-			if (comp == 0)
-			{
-				return 1;
-			}
-			else if (comp < 0)
-			{
-				break;
-			}
+			return 1;
 		}
 
-		assert(iter->which < CHILDREN_PER_NODE);
-
 		if (iter->node->children[iter->which])
 		{
 			iter->node = iter->node->children[iter->which];
-			iter->which = 0;
 		}
 		else
 		{
@@ -49,16 +111,6 @@ _Find(TreeIterator * iter, void * data)
 	}
 }
 
-Tree *
-MakeTree(TreeCompareDataFunction compareData, TreeFreeDataFunction freeData)
-{
-	Tree * ret = malloc(sizeof(Tree));
-	ret->compareData = compareData;
-	ret->freeData = freeData;
-	ret->rootNode = _MakeNode();
-	return ret;
-}
-
 static
 TreeNode *
 _SplitNode(TreeNode * node)
@@ -67,21 +119,38 @@ _SplitNode(TreeNode * node)
 
 	TreeNode * newNode = _MakeNode();
 
-	unsigned i = DATA_PER_NODE/2;
-	unsigned j = 0;
+#ifdef USE_MEM_FUNC
+	memcpy(&(newNode->data[0]),
+	       &(node->data[DATA_PER_NODE/2]),
+	       (DATA_PER_NODE-DATA_PER_NODE/2)*sizeof(void *));
+	memset(&(node->data[DATA_PER_NODE/2]),
+	       0,
+	       (DATA_PER_NODE-DATA_PER_NODE/2)*sizeof(void *));
+	memcpy(&(newNode->children[1]),
+	       &(node->children[DATA_PER_NODE/2+1]),
+	       (DATA_PER_NODE-DATA_PER_NODE/2)*sizeof(TreeNode *));
+	memset(&(node->children[DATA_PER_NODE/2+1]),
+	       0,
+	       (DATA_PER_NODE-DATA_PER_NODE/2)*sizeof(TreeNode *));
+#endif
+	
+	int i = DATA_PER_NODE/2;
+	int j = 0;
 	for (; i < DATA_PER_NODE; i++, j++)
 	{
+#ifndef USE_MEM_FUNC
 		newNode->data[j] = node->data[i];
 		newNode->children[j+1] = node->children[i+1];
+		node->data[i] = NULL;
+		node->children[i+1] = NULL;
+#endif
 		if (newNode->children[j+1])
 		{
 			newNode->children[j+1]->parent = newNode;
 		}
-		node->data[i] = NULL;
-		node->children[i+1] = NULL;
 	}
-	newNode->dataCount = j;
-	node->dataCount -= j;
+	newNode->dataCount = (DATA_PER_NODE-DATA_PER_NODE/2);
+	node->dataCount -= (DATA_PER_NODE-DATA_PER_NODE/2);
 
 	return newNode;
 }
@@ -102,23 +171,29 @@ _InsertNodeAndData(Tree * tree,
 	}
 
 	int i = 0;
-	for (; 
-	     i < node->dataCount &&
-	     tree->compareData(data, node->data[i]) > 0;
-	     i++);
-
+	_FindPositionInNode(tree, node, data, &i);
+
+#ifdef USE_MEM_FUNC
+	memmove(&(node->data[i+1]), 
+		&(node->data[i]),
+		(node->dataCount-i)*sizeof(void *));
+	memmove(&(node->children[i+2]), 
+		&(node->children[i+1]),
+		(node->dataCount-i)*sizeof(TreeNode *));
+#else
 	int j = node->dataCount;
 	for (; j > i; j--)
 	{
 		node->data[j] = node->data[j-1];
 		node->children[j+1] = node->children[j];
 	}
+#endif
 
-	assert(!node->children[j] ||
-	       tree->compareData(data, node->children[j]->data[0]) > 0);
+	assert(!node->children[i] ||
+	       tree->compareData(data, node->children[i]->data[0]) > 0);
 
-	node->data[j] = data;
-	node->children[j+1] = newNode;
+	node->data[i] = data;
+	node->children[i+1] = newNode;
 	node->dataCount++;
 }
 
@@ -150,10 +225,7 @@ _AddDataToSplitNodes(Tree * tree,
 		}
 
 		int i = 0;
-		for (; 
-		     i < moreNode->dataCount &&
-		     tree->compareData(data, moreNode->data[i]) > 0;
-		     i++);
+		_FindPositionInNode(tree, moreNode, data, &i);
 
 		if (i == 0)
 		{
@@ -165,19 +237,28 @@ _AddDataToSplitNodes(Tree * tree,
 			retData = moreNode->data[0];
 		}
 
+#ifdef USE_MEM_FUNC
+		memmove(&(moreNode->data[0]), 
+			&(moreNode->data[1]), 
+			i*sizeof(void *));
+		memmove(&(moreNode->children[0]),
+			&(moreNode->children[1]),
+			i*sizeof(TreeNode *));
+#else
 		int j = 0;
 		for (; j < i; j++)
 		{
 			moreNode->data[j] = moreNode->data[j+1];
 			moreNode->children[j] = moreNode->children[j+1];
 		}
+#endif
 
-		assert(!moreNode->children[j-1] ||
+		assert(!moreNode->children[i-1] ||
 		       tree->compareData(data,
-			       		 moreNode->children[j]->data[0]) > 0);
+			       		 moreNode->children[i]->data[0]) > 0);
 
-		moreNode->data[j-1] = data;
-		moreNode->children[j] = newNode;
+		moreNode->data[i-1] = data;
+		moreNode->children[i] = newNode;
 	}
 
 	return retData;
@@ -236,18 +317,90 @@ _InsertAt(TreeIterator * iter, void * data)
 	return;
 }
 
-void SetIteratorToBegin(TreeIterator * iter, Tree * tree)
+static void _SetTreeIteratorToRoot(TreeIterator * iter, Tree * tree)
 {
 	iter->tree = tree;
 	iter->node = tree->rootNode;
 	iter->which = 0;
 }
 
+/************************* PUBLIC METHODS ***********************************/
+
+Tree *
+MakeTree(TreeCompareDataFunction compareData, TreeFreeDataFunction freeData)
+{
+	Tree * ret = malloc(sizeof(Tree));
+	ret->compareData = compareData;
+	ret->freeData = freeData;
+	ret->rootNode = _MakeNode();
+	return ret;
+}
+
+void SetTreeIteratorToBegin(TreeIterator * iter, Tree * tree)
+{
+	_SetTreeIteratorToRoot(iter, tree);
+	IncrementTreeIterator(iter);
+}
+
+int IsTreeIteratorAtEnd(const TreeIterator * iter)
+{
+	return (iter->node == NULL);
+}
+
+void IncrementTreeIterator(TreeIterator * iter)
+{
+	while(iter->node)
+	{
+		if (iter->node->children[iter->which])
+		{
+			iter->node = iter->node->children[iter->which];
+			iter->which = 0;
+		}
+		else
+		{
+			iter->which++;
+		}
+
+		while (iter->node && iter->which > iter->node->dataCount)
+		{
+			TreeNode * childNode = iter->node;
+			iter->node = childNode->parent;
+			if (iter->node)
+			{
+				for (iter->which = 0;
+				     childNode != 
+				     iter->node->children[iter->which];
+				     iter->which++)
+				{
+					assert(iter->which <= 
+					       iter->node->dataCount);
+				}
+				iter->which++;
+			}
+		}
+
+		if (iter->node &&
+		    iter->which > 0 && iter->which <= iter->node->dataCount)
+		{
+			return;
+		}
+	}
+}
+
+void *
+GetDataFromTreeIterator(TreeIterator * iter)
+{
+	assert(iter->node && 
+	       iter->which > 0 && 
+	       iter->which <= iter->node->dataCount);
+	return iter->node->data[iter->which-1];
+}
+
 int
 InsertIntoTree(Tree * tree, void * data)
 {
 	TreeIterator iter;
-	SetIteratorToBegin(&iter, tree);
+	_SetTreeIteratorToRoot(&iter, tree);
 
 	if (_Find(&iter, data))
 	{