I do not use trees anymore within the optimized memory management. I realized th…

…at I can calculate the index of an array by the size and use stacks of memory segments under each array element. This should be much faster.

@@ -27,6 +27,48 @@
 
 #include <sys/types.h>
 
+/**
+ * I found this at stanford.edu: 
+ * https://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup
+ *
+ * Really cool way of dealing with this. The oneat stanford.edu is slightly
+ * different as ist deals only with 32bit values. I need a 64bit version 
+ * because on a 64bit system size_t is also 64bit and thus it is possible
+ * to allocate that much amount of memory theoretically.
+ */
+static
+inline
+int
+bitwidth(size_t value)
+{
+	static const char LogTable256[256] = {
+		-1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
+#define LT(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
+		LT(4), LT(5), LT(5), LT(6), LT(6), LT(6), LT(6),
+		LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7)
+	};
+#undef LT
+
+	int             r;          // r will be lg(v)
+	register size_t t1, t2, t3; // temporaries
+
+	if ((t3 = value >> 32)) {
+		if ((t2 = t3 >> 16)) {
+			r = (t1 = t2 >> 8) ? 56 + LogTable256[t1] : 48 + LogTable256[t2];
+		} else {
+			r = (t1 = t3 >> 8) ? 40 + LogTable256[t1] : 32 + LogTable256[t3];
+		}
+	} else {
+		if ((t2 = value >> 16)) {
+			r = (t1 = t2 >> 8) ? 24 + LogTable256[t1] : 16 + LogTable256[t2];
+		} else {
+			r = (t1 = value >> 8) ? 8 + LogTable256[t1] : LogTable256[value];
+		}
+	}
+
+	return r;
+}
+
 void   * TR_malloc(size_t);
 void   * TR_calloc(size_t, size_t);
 void   * TR_reference(void *);

@@ -53,310 +53,73 @@
 #include <string.h>
 #include <search.h>
 #include <unistd.h>
+#include <stdint.h>
 
 #include "tr/memory.h"
-#include "tr/tree_macros.h"
 
 
 struct memSegment
 {
 	size_t   ref_count;
     size_t   size;
+	int      idx;
     void   * ptr;
 
-    TR_rbColor color;
-
-	struct memSegment * data;
-
     struct memSegment * next;
-    struct memSegment * last;
-
-    struct memSegment * parent;
-    struct memSegment * left;
-    struct memSegment * right;
 };
 
 static
 struct memSegment *
-newElement(size_t size)
+newElement(size_t size, int idx)
 {
     struct memSegment * element = malloc(size);
 
 	element->ref_count = 1;
     element->size      = size;
+    element->idx       = idx;
     element->ptr       = (void*)element + sizeof(struct memSegment);
 
-	element->data      = element;
-
     element->next      = NULL;
-    element->last      = NULL;
-
-    element->color     = rbRed;
-    element->parent    = NULL;
-    element->left      = NULL;
-    element->right     = NULL;
 
     return element;
 }
 
 #ifdef MEM_OPT
-static
-int
-_memSegmentFindCompare(const void * a, const void * b)
-{
-    struct memSegment * _a = (struct memSegment *)a;
-    size_t              _b = *(size_t *)b;
-
-    /*
-     * find the smallest bigger or equal size segment
-     */
-    return _a->size < _b ? -1
-        : _a->size > _b && _a->left && _a->left->size >= _b ? 1 : 0;
-}
-
-static
-int
-_memSegmentCompare(const void * a, const void * b)
-{
-    size_t _a = ((struct memSegment *)a)->size;
-    size_t _b = ((struct memSegment *)b)->size;
-
-    return _a < _b ? -1 : _a > _b ? 1 : 0;
-}
-
 /**
  * insert element in tree
  */
 static
+inline
 struct memSegment *
-insertElement(struct memSegment ** tree, struct memSegment * element)
+insertElement(struct memSegment ** stack, struct memSegment * element)
 {
-    struct memSegment * node     = *tree;
-    struct memSegment * new_node = NULL;
-	int                 found;
-
-    element->next   = NULL;
-    element->last   = NULL;
-
-    element->color  = rbRed;
-    element->parent = NULL;
-    element->left   = NULL;
-    element->right  = NULL;
-
-	TR_TREE_FIND(node, element, found, _memSegmentCompare);
-
-    // if tree is empty it's simple... :)
-    if (NULL == node) {
-        *tree = node = new_node = element;
-	} else {
-		// normal binary tree add....
-		if (found == 0) {
-			if (NULL == node->next) {
-				node->next = element;
-				node->last = element;
-			} else {
-                node->last->next = element;
-                node->last       = element;
-			}
-			return node;
-		} else {
-			if (0 < found) {
-				node->left         = element;
-				node->left->parent = node;
-				new_node = node = node->left;
-			} else {
-				node->right         = element;
-				node->right->parent = node;
-				new_node = node = node->right;
+	element->next = *stack;
+	*stack        = element;
 
-			}
-		}
-	}
-
-	/* 
-	 * handle reballancing rb style
-	 */
-	TR_TREE_BALANCE_INSERT(tree, node);
-
-    return new_node;
+	return element;
 }
 
 static
+inline
 struct memSegment *
-deleteElement(struct memSegment ** tree, size_t size)
+deleteElement(struct memSegment ** stack)
 {
-    struct memSegment * node = *tree;
-    struct memSegment * del_node;
-    struct memSegment * child;
-    struct memSegment * s;
-	int                 found;
-
-    // find the relevant node and it's parent
-	TR_TREE_FIND(node, &size, found, _memSegmentFindCompare);
+	struct memSegment * del_node = *stack;
 
-	//while (node) {
-    if (found != 0) {
-		return NULL;
-	} else {
-		if (NULL != node->next) {
-			if (NULL != node->parent) {
-				if (node == node->parent->left) {
-					node->parent->left = node->next;
-				} else {
-					node->parent->right = node->next;
-				}
-			} else {
-				*tree = node->next;
-			}
-
-			if (NULL != node->left) {
-				node->left->parent = node->next;
-			}
-
-			if (NULL != node->right) {
-				node->right->parent = node->next;
-			}
-			
-			node->next->last   = node->last;
-			node->next->color  = node->color;
-			node->next->parent = node->parent;
-			node->next->left   = node->left;
-			node->next->right  = node->right;
-
-			return node;
-		}
+	if (*stack) {
+		*stack = (*stack)->next;
 	}
 
-    del_node = node;
-
-    // now our cases follows...the first one is the same as with
-    // simple binary search trees. Two non null children.
-
-    // case 1: two children
-    if (NULL != node->left && NULL != node->right) {
-        struct memSegment * successor;
-        struct memSegment * tmpparent;
-        struct memSegment * tmpleft;
-        struct memSegment * tmpright;
-        TR_rbColor tmpcolor;
-
-        TR_TREE_INORDER_SUCC(node, successor);
-        tmpparent = successor->parent;
-        tmpleft   = successor->left;
-        tmpright  = successor->right;
-        tmpcolor  = successor->color;
-
-        TR_TREE_REPLACE_NODE(tree, node, successor);
-
-        successor->color        = node->color;
-        successor->left         = node->left;
-        successor->left->parent = successor;
-        // the right one might be successor...
-        if (node->right == successor) {
-            successor->right = node;
-            node->parent     = successor;
-        } else {
-            successor->right    = node->right;
-            node->right->parent = successor;
-            node->parent        = tmpparent;
-            tmpparent->left     = node;
-        }
-
-        node->color  = tmpcolor;
-        node->left   = tmpleft;
-        node->right  = tmpright;
-    }
-
-    // Precondition: n has at most one non-null child.
-    child = (NULL == node->right) ? node->left : node->right;
-    TR_TREE_REPLACE_NODE(tree, node, child);
-
-    // delete one child case
-    // TODO this is overly complex as simply derived from the function...
-    // maybe this can be simplified. Maybe not...check.
-    if (node->color == rbBlack) {
-        if (NULL != child && child->color == rbRed) {
-            child->color = rbBlack;
-            // done despite modifying tree itself if neccessary..
-            return del_node;
-        } else {
-            if (NULL != child) {
-                node = child;
-            } else {
-                node->color = rbBlack;
-                node->left  = NULL;
-                node->right = NULL;
-            }
-        }
-    } else {
-        return del_node;
-    }
-
-	TR_TREE_BALANCE_DELETE(tree, node, s);
- 
-    return del_node;
+	return del_node;
 }
 
-static
-void
-post(struct memSegment * tree, void (*cb)(struct memSegment *, int))
-{
-    struct memSegment * previous = tree;
-    struct memSegment * node     = tree;
-    int                 depth    = 1;
-
-    /*
-     * I think this has something like O(n+log(n)) on a ballanced
-     * tree because I have to traverse back the rightmost leaf to
-     * the root to get a break condition.
-     */
-    while (node) {
-        /*
-         * If we come from the right so nothing and go to our
-         * next parent.
-         */
-        if (((NULL == node->left || previous == node->left)
-					&& NULL == node->right)
-                || previous == node->right) {
-
-            struct memSegment * parent = node->parent;
-
-            cb(node, depth);
-
-            previous = node;
-            node     = parent;
-            depth--;
-            continue;
-        }
+#define TR_MAX_MEM_IDX  1024
 
-        if ((NULL == node->left || previous == node->left)) {
-            /*
-             * If there are no more elements to the left or we
-             * came from the left, process data.
-             */
-            previous = node;
-
-            if (NULL != node->right) {
-                node = node->right;
-                depth++;
-            } else {
-                node = node->parent;
-                depth--;
-            }
-        } else {
-            /*
-             * if there are more elements to the left go there.
-             */
-            previous = node;
-            node     = node->left;
-            depth++;
-        }
-    }
-}
-
-struct memSegment * segments = NULL;
+struct memSegment * segments[TR_MAX_MEM_IDX] = {};
+pthread_mutex_t TR_memop_lock = PTHREAD_MUTEX_INITIALIZER;
 
 static
+inline
 void
 segmentFree(struct memSegment * segment, int depth)
 {
@@ -378,8 +141,6 @@ TR_reference(void * mem)
 	return mem;
 }
 
-pthread_mutex_t TR_memop_lock = PTHREAD_MUTEX_INITIALIZER;
-
 /*
  * This tries to reflect the memory management behaviour of the
  * GNU version of malloc. For other versions this might need
@@ -410,41 +171,60 @@ pthread_mutex_t TR_memop_lock = PTHREAD_MUTEX_INITIALIZER;
 void *
 TR_malloc(size_t size)
 {
-	struct memSegment * seg   = NULL;
-	long                psize = sysconf(_SC_PAGESIZE);
+	struct memSegment * seg         = NULL;
+	long                psize       = sysconf(_SC_PAGESIZE);
+	static int          psize_width = 0;
+	int                 idx;
+
+	if (psize_width == 0) psize_width = bitwidth(psize);
 
 	size += sizeof(struct memSegment);
 
-	if (size > psize) {
-		if (0 != (size % psize)) {
-			// size if not a multiple of pagesize so bring it to one.
-			size = ((size / psize) + 1) * psize;
-		}
-	} else {
-		if (size < 8) {
-			size = 8;
-		} else {
-			size_t check = size >> 4;
-			size_t mask  = 0x1F;
+#define MIN_BITS   8
 
-			while (check >>= 1) {
-				mask = (mask << 1) | 1;
-			}
+    if (size >= psize) {
+        idx = size / psize;
 
-			if (size != (size & ~(mask >> 1))) {
-				size = (size << 1) & ~mask;
-			}
-		}
-	}
+        if (0 != (size % psize)) {
+            // size if not a multiple of pagesize so bring it to one.
+            size = (idx + 1) * psize;
+            idx++;
+        } 
+
+        idx += psize_width - MIN_BITS;
+    } else {
+        if (size <= 1 << (MIN_BITS - 1)) {
+            size = 1 << (MIN_BITS - 1);
+            idx = 0;
+        } else {
+            size_t mask;
+
+            idx   = bitwidth(size);
+            mask  = (1 << (idx + 1)) - 1;
+            idx  -= (MIN_BITS - 1);
+
+            if (size != (size & ~(mask >> 1))) {
+                size = (size << 1) & ~mask;
+                idx++;
+            }
+        }
+    }
+
+#undef MIN_BITS
 
 #ifdef MEM_OPT
-	pthread_mutex_lock(&TR_memop_lock);
-	seg = deleteElement(&segments, size);
-	pthread_mutex_unlock(&TR_memop_lock);
+	if (idx < TR_MAX_MEM_IDX) {
+		pthread_mutex_lock(&TR_memop_lock);
+		seg = deleteElement(&(segments[idx]));
+		pthread_mutex_unlock(&TR_memop_lock);
+	} else
 #endif
+	{
+		idx = -1;
+	}
 
 	if (NULL == seg) {
-		seg = newElement(size);
+		seg = newElement(size, idx);
 	}
 
 	return seg->ptr;
@@ -479,12 +259,15 @@ TR_free(void ** mem)
 			seg->ref_count--;
 		} else {
 #ifdef MEM_OPT
-			pthread_mutex_lock(&TR_memop_lock);
-			insertElement(&segments, seg);
-			pthread_mutex_unlock(&TR_memop_lock);
-#else
-			free(seg);
+			if (-1 != seg->idx) {
+				pthread_mutex_lock(&TR_memop_lock);
+				insertElement(&(segments[seg->idx]), seg);
+				pthread_mutex_unlock(&TR_memop_lock);
+			} else
 #endif
+			{
+				free(seg);
+			}
 		}
 
 		*mem = NULL;
@@ -508,7 +291,15 @@ void
 TR_cleanup()
 {
 #ifdef MEM_OPT
-	post(segments, segmentFree);
+	int i;
+
+	for (i=0; i<TR_MAX_MEM_IDX; i++) {
+		while(segments[i]) {
+			struct memSegment * next = segments[i]->next;
+			free(segments[i]);
+			segments[i] = next;
+		}
+	}
 #endif
 }