* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/gin/ginbulk.c,v 1.19 2010/02/26 02:00:33 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/access/gin/ginbulk.c,v 1.20 2010/08/01 02:12:42 tgl Exp $
*-------------------------------------------------------------------------
*/
#include "utils/memutils.h"
-#define DEF_NENTRY 2048
-#define DEF_NPTR 4
+#define DEF_NENTRY 2048 /* EntryAccumulator allocation quantum */
+#define DEF_NPTR 5 /* ItemPointer initial allocation quantum */
-static void *
-ginAppendData(void *old, void *new, void *arg)
-{
- EntryAccumulator *eo = (EntryAccumulator *) old,
- *en = (EntryAccumulator *) new;
+/* Combiner function for rbtree.c */
+static void
+ginCombineData(RBNode *existing, const RBNode *newdata, void *arg)
+{
+ EntryAccumulator *eo = (EntryAccumulator *) existing;
+ const EntryAccumulator *en = (const EntryAccumulator *) newdata;
BuildAccumulator *accum = (BuildAccumulator *) arg;
+ /*
+ * Note this code assumes that newdata contains only one itempointer.
+ */
if (eo->number >= eo->length)
{
accum->allocatedMemory -= GetMemoryChunkSpace(eo->list);
eo->list[eo->number] = en->list[0];
eo->number++;
-
- return old;
}
+/* Comparator function for rbtree.c */
static int
-cmpEntryAccumulator(const void *a, const void *b, void *arg)
+cmpEntryAccumulator(const RBNode *a, const RBNode *b, void *arg)
{
- EntryAccumulator *ea = (EntryAccumulator *) a;
- EntryAccumulator *eb = (EntryAccumulator *) b;
+ const EntryAccumulator *ea = (const EntryAccumulator *) a;
+ const EntryAccumulator *eb = (const EntryAccumulator *) b;
BuildAccumulator *accum = (BuildAccumulator *) arg;
return compareAttEntries(accum->ginstate, ea->attnum, ea->value,
eb->attnum, eb->value);
}
+/* Allocator function for rbtree.c */
+static RBNode *
+ginAllocEntryAccumulator(void *arg)
+{
+ BuildAccumulator *accum = (BuildAccumulator *) arg;
+ EntryAccumulator *ea;
+
+ /*
+ * Allocate memory by rather big chunks to decrease overhead. We have
+ * no need to reclaim RBNodes individually, so this costs nothing.
+ */
+ if (accum->entryallocator == NULL || accum->length >= DEF_NENTRY)
+ {
+ accum->entryallocator = palloc(sizeof(EntryAccumulator) * DEF_NENTRY);
+ accum->allocatedMemory += GetMemoryChunkSpace(accum->entryallocator);
+ accum->length = 0;
+ }
+
+ /* Allocate new RBNode from current chunk */
+ ea = accum->entryallocator + accum->length;
+ accum->length++;
+
+ return (RBNode *) ea;
+}
+
void
ginInitBA(BuildAccumulator *accum)
{
accum->allocatedMemory = 0;
+ accum->length = 0;
accum->entryallocator = NULL;
- accum->tree = rb_create(cmpEntryAccumulator, ginAppendData, NULL, accum);
- accum->iterator = NULL;
- accum->tmpList = NULL;
+ accum->tree = rb_create(sizeof(EntryAccumulator),
+ cmpEntryAccumulator,
+ ginCombineData,
+ ginAllocEntryAccumulator,
+ NULL, /* no freefunc needed */
+ (void *) accum);
}
/*
static void
ginInsertEntry(BuildAccumulator *accum, ItemPointer heapptr, OffsetNumber attnum, Datum entry)
{
- EntryAccumulator *key,
- *ea;
+ EntryAccumulator key;
+ EntryAccumulator *ea;
+ bool isNew;
/*
- * Allocate memory by rather big chunk to decrease overhead, we don't keep
- * pointer to previously allocated chunks because they will free by
- * MemoryContextReset() call.
+ * For the moment, fill only the fields of key that will be looked at
+ * by cmpEntryAccumulator or ginCombineData.
*/
- if (accum->entryallocator == NULL || accum->length >= DEF_NENTRY)
- {
- accum->entryallocator = palloc(sizeof(EntryAccumulator) * DEF_NENTRY);
- accum->allocatedMemory += GetMemoryChunkSpace(accum->entryallocator);
- accum->length = 0;
- }
+ key.attnum = attnum;
+ key.value = entry;
+ /* temporarily set up single-entry itempointer list */
+ key.list = heapptr;
- /* "Allocate" new key in chunk */
- key = accum->entryallocator + accum->length;
- accum->length++;
+ ea = (EntryAccumulator *) rb_insert(accum->tree, (RBNode *) &key, &isNew);
- key->attnum = attnum;
- key->value = entry;
- /* To prevent multiple palloc/pfree cycles, we reuse array */
- if (accum->tmpList == NULL)
- accum->tmpList =
- (ItemPointerData *) palloc(sizeof(ItemPointerData) * DEF_NPTR);
- key->list = accum->tmpList;
- key->list[0] = *heapptr;
-
- ea = rb_insert(accum->tree, key);
-
- if (ea == NULL)
+ if (isNew)
{
/*
- * The key has been inserted, so continue initialization.
+ * Finish initializing new tree entry, including making permanent
+ * copies of the datum and itempointer.
*/
- key->value = getDatumCopy(accum, attnum, entry);
- key->length = DEF_NPTR;
- key->number = 1;
- key->shouldSort = FALSE;
- accum->allocatedMemory += GetMemoryChunkSpace(key->list);
- accum->tmpList = NULL;
+ ea->value = getDatumCopy(accum, attnum, entry);
+ ea->length = DEF_NPTR;
+ ea->number = 1;
+ ea->shouldSort = FALSE;
+ ea->list =
+ (ItemPointerData *) palloc(sizeof(ItemPointerData) * DEF_NPTR);
+ ea->list[0] = *heapptr;
+ accum->allocatedMemory += GetMemoryChunkSpace(ea->list);
}
else
{
/*
- * The key has been appended, so "free" allocated key by decrementing
- * chunk's counter.
+ * ginCombineData did everything needed.
*/
- accum->length--;
}
}
return res;
}
+/* Prepare to read out the rbtree contents using ginGetEntry */
+void
+ginBeginBAScan(BuildAccumulator *accum)
+{
+ rb_begin_iterate(accum->tree, LeftRightWalk);
+}
+
ItemPointerData *
ginGetEntry(BuildAccumulator *accum, OffsetNumber *attnum, Datum *value, uint32 *n)
{
EntryAccumulator *entry;
ItemPointerData *list;
- if (accum->iterator == NULL)
- accum->iterator = rb_begin_iterate(accum->tree, LeftRightWalk);
-
- entry = rb_iterate(accum->iterator);
+ entry = (EntryAccumulator *) rb_iterate(accum->tree);
if (entry == NULL)
return NULL;
* longest path from root to leaf is only about twice as long as the shortest,
* so lookups are guaranteed to run in O(lg n) time.
*
- * Copyright (c) 1996-2009, PostgreSQL Global Development Group
+ * Copyright (c) 2009-2010, PostgreSQL Global Development Group
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/misc/rbtree.c,v 1.3 2010/02/26 02:01:14 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/rbtree.c,v 1.4 2010/08/01 02:12:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "utils/rbtree.h"
-/**********************************************************************
- * Declarations *
- **********************************************************************/
/*
- * Values for RBNode->iteratorState
+ * Values of RBNode.iteratorState
+ *
+ * Note that iteratorState has an undefined value except in nodes that are
+ * currently being visited by an active iteration.
*/
#define InitialState (0)
#define FirstStepDone (1)
#define ThirdStepDone (3)
/*
- * Colors of node
+ * Colors of nodes (values of RBNode.color)
*/
#define RBBLACK (0)
#define RBRED (1)
-typedef struct RBNode
-{
- uint32 iteratorState:2,
- color: 1,
- unused:29;
- struct RBNode *left;
- struct RBNode *right;
- struct RBNode *parent;
- void *data;
-} RBNode;
-
+/*
+ * RBTree control structure
+ */
struct RBTree
{
- RBNode *root;
+ RBNode *root; /* root node, or RBNIL if tree is empty */
+
+ /* Iteration state */
+ RBNode *cur; /* current iteration node */
+ RBNode *(*iterate) (RBTree *rb);
+
+ /* Remaining fields are constant after rb_create */
+
+ Size node_size; /* actual size of tree nodes */
+ /* The caller-supplied manipulation functions */
rb_comparator comparator;
- rb_appendator appendator;
+ rb_combiner combiner;
+ rb_allocfunc allocfunc;
rb_freefunc freefunc;
+ /* Passthrough arg passed to all manipulation functions */
void *arg;
};
-struct RBTreeIterator
-{
- RBNode *node;
- void *(*iterate) (RBTreeIterator *iterator);
-};
-
/*
* all leafs are sentinels, use customized NIL name to prevent
- * collision with sytem-wide NIL which is actually NULL
+ * collision with system-wide constant NIL which is actually NULL
*/
-#define RBNIL &sentinel
+#define RBNIL (&sentinel)
-RBNode sentinel = {InitialState, RBBLACK, 0, RBNIL, RBNIL, NULL, NULL};
+static RBNode sentinel = {InitialState, RBBLACK, RBNIL, RBNIL, NULL};
-/**********************************************************************
- * Create *
- **********************************************************************/
+/*
+ * rb_create: create an empty RBTree
+ *
+ * Arguments are:
+ * node_size: actual size of tree nodes (> sizeof(RBNode))
+ * The manipulation functions:
+ * comparator: compare two RBNodes for less/equal/greater
+ * combiner: merge an existing tree entry with a new one
+ * allocfunc: allocate a new RBNode
+ * freefunc: free an old RBNode
+ * arg: passthrough pointer that will be passed to the manipulation functions
+ *
+ * Note that the combiner's righthand argument will be a "proposed" tree node,
+ * ie the input to rb_insert, in which the RBNode fields themselves aren't
+ * valid. Similarly, either input to the comparator may be a "proposed" node.
+ * This shouldn't matter since the functions aren't supposed to look at the
+ * RBNode fields, only the extra fields of the struct the RBNode is embedded
+ * in.
+ *
+ * The freefunc should just be pfree or equivalent; it should NOT attempt
+ * to free any subsidiary data, because the node passed to it may not contain
+ * valid data! freefunc can be NULL if caller doesn't require retail
+ * space reclamation.
+ *
+ * The RBTree node is palloc'd in the caller's memory context. Note that
+ * all contents of the tree are actually allocated by the caller, not here.
+ *
+ * Since tree contents are managed by the caller, there is currently not
+ * an explicit "destroy" operation; typically a tree would be freed by
+ * resetting or deleting the memory context it's stored in. You can pfree
+ * the RBTree node if you feel the urge.
+ */
RBTree *
-rb_create(rb_comparator comparator, rb_appendator appendator,
- rb_freefunc freefunc, void *arg)
+rb_create(Size node_size,
+ rb_comparator comparator,
+ rb_combiner combiner,
+ rb_allocfunc allocfunc,
+ rb_freefunc freefunc,
+ void *arg)
{
- RBTree *tree = palloc(sizeof(RBTree));
+ RBTree *tree = (RBTree *) palloc(sizeof(RBTree));
+
+ Assert(node_size > sizeof(RBNode));
tree->root = RBNIL;
+ tree->cur = RBNIL;
+ tree->iterate = NULL;
+ tree->node_size = node_size;
tree->comparator = comparator;
- tree->appendator = appendator;
+ tree->combiner = combiner;
+ tree->allocfunc = allocfunc;
tree->freefunc = freefunc;
-
tree->arg = arg;
return tree;
}
+/* Copy the additional data fields from one RBNode to another */
+static inline void
+rb_copy_data(RBTree *rb, RBNode *dest, const RBNode *src)
+{
+ memcpy(dest + 1, src + 1, rb->node_size - sizeof(RBNode));
+}
+
/**********************************************************************
* Search *
**********************************************************************/
-void *
-rb_find(RBTree *rb, void *data)
+/*
+ * rb_find: search for a value in an RBTree
+ *
+ * data represents the value to try to find. Its RBNode fields need not
+ * be valid, it's the extra data in the larger struct that is of interest.
+ *
+ * Returns the matching tree entry, or NULL if no match is found.
+ */
+RBNode *
+rb_find(RBTree *rb, const RBNode *data)
{
RBNode *node = rb->root;
- int cmp;
while (node != RBNIL)
{
- cmp = rb->comparator(data, node->data, rb->arg);
+ int cmp = rb->comparator(data, node, rb->arg);
if (cmp == 0)
- return node->data;
+ return node;
else if (cmp < 0)
node = node->left;
else
return NULL;
}
+/*
+ * rb_leftmost: fetch the leftmost (smallest-valued) tree node.
+ * Returns NULL if tree is empty.
+ *
+ * Note: in the original implementation this included an unlink step, but
+ * that's a bit awkward. Just call rb_delete on the result if that's what
+ * you want.
+ */
+RBNode *
+rb_leftmost(RBTree *rb)
+{
+ RBNode *node = rb->root;
+ RBNode *leftmost = rb->root;
+
+ while (node != RBNIL)
+ {
+ leftmost = node;
+ node = node->left;
+ }
+
+ if (leftmost != RBNIL)
+ return leftmost;
+
+ return NULL;
+}
+
/**********************************************************************
* Insertion *
**********************************************************************/
}
/*
- * Allocate node for data and insert in tree.
+ * rb_insert: insert a new value into the tree.
*
- * Return old data (or result of appendator method) if it exists and NULL
- * otherwise.
+ * data represents the value to insert. Its RBNode fields need not
+ * be valid, it's the extra data in the larger struct that is of interest.
+ *
+ * If the value represented by "data" is not present in the tree, then
+ * we copy "data" into a new tree entry and return that node, setting *isNew
+ * to true.
+ *
+ * If the value represented by "data" is already present, then we call the
+ * combiner function to merge data into the existing node, and return the
+ * existing node, setting *isNew to false.
+ *
+ * "data" is unmodified in either case; it's typically just a local
+ * variable in the caller.
*/
-void *
-rb_insert(RBTree *rb, void *data)
+RBNode *
+rb_insert(RBTree *rb, const RBNode *data, bool *isNew)
{
RBNode *current,
*parent,
/* find where node belongs */
current = rb->root;
parent = NULL;
- cmp = 0;
+ cmp = 0; /* just to prevent compiler warning */
+
while (current != RBNIL)
{
- cmp = rb->comparator(data, current->data, rb->arg);
+ cmp = rb->comparator(data, current, rb->arg);
if (cmp == 0)
{
/*
- * Found node with given key. If appendator method is provided,
- * call it to join old and new data; else, new data replaces old
- * data.
+ * Found node with given key. Apply combiner.
*/
- if (rb->appendator)
- {
- current->data = rb->appendator(current->data, data, rb->arg);
- return current->data;
- }
- else
- {
- void *old = current->data;
-
- current->data = data;
- return old;
- }
+ rb->combiner(current, data, rb->arg);
+ *isNew = false;
+ return current;
}
parent = current;
current = (cmp < 0) ? current->left : current->right;
}
- /* setup new node in tree */
- x = palloc(sizeof(RBNode));
- x->data = data;
- x->parent = parent;
- x->left = RBNIL;
- x->right = RBNIL;
- x->color = RBRED;
+ /*
+ * Value is not present, so create a new node containing data.
+ */
+ *isNew = true;
+
+ x = rb->allocfunc(rb->arg);
x->iteratorState = InitialState;
+ x->color = RBRED;
+ x->left = RBNIL;
+ x->right = RBNIL;
+ x->parent = parent;
+ rb_copy_data(rb, x, data);
/* insert node in tree */
if (parent)
}
rb_insert_fixup(rb, x);
- return NULL;
+
+ return x;
}
/**********************************************************************
}
/*
- * If we removed the tree successor of z rather than z itself, then attach
+ * If we removed the tree successor of z rather than z itself, then move
* the data for the removed node to the one we were supposed to remove.
*/
if (y != z)
- z->data = y->data;
+ rb_copy_data(rb, z, y);
/*
* Removing a black node might make some paths from root to leaf contain
if (y->color == RBBLACK)
rb_delete_fixup(rb, x);
- pfree(y);
-}
-
-extern void
-rb_delete(RBTree *rb, void *data)
-{
- RBNode *node = rb->root;
- int cmp;
-
- while (node != RBNIL)
- {
- cmp = rb->comparator(data, node->data, rb->arg);
-
- if (cmp == 0)
- {
- /* found node to delete */
- if (rb->freefunc)
- rb->freefunc (node->data);
-
- node->data = NULL;
- rb_delete_node(rb, node);
- return;
- }
- else if (cmp < 0)
- node = node->left;
- else
- node = node->right;
- }
+ /* Now we can recycle the y node */
+ if (rb->freefunc)
+ rb->freefunc(y, rb->arg);
}
/*
- * Return data on left most node and delete
- * that node
+ * rb_delete: remove the given tree entry
+ *
+ * "node" must have previously been found via rb_find or rb_leftmost.
+ * It is caller's responsibility to free any subsidiary data attached
+ * to the node before calling rb_delete. (Do *not* try to push that
+ * responsibility off to the freefunc, as some other physical node
+ * may be the one actually freed!)
*/
-extern void *
-rb_leftmost(RBTree *rb)
+void
+rb_delete(RBTree *rb, RBNode *node)
{
- RBNode *node = rb->root;
- RBNode *leftmost = rb->root;
- void *res = NULL;
-
- while (node != RBNIL)
- {
- leftmost = node;
- node = node->left;
- }
-
- if (leftmost != RBNIL)
- {
- res = leftmost->data;
- leftmost->data = NULL;
- rb_delete_node(rb, leftmost);
- }
-
- return res;
+ rb_delete_node(rb, node);
}
/**********************************************************************
* Traverse *
**********************************************************************/
-static void *
-rb_next_node(RBTreeIterator *iterator, RBNode *node)
-{
- node->iteratorState = InitialState;
- iterator->node = node;
- return iterator->iterate(iterator);
-}
-
-static void *
-rb_left_right_iterator(RBTreeIterator *iterator)
+/*
+ * The iterator routines were originally coded in tail-recursion style,
+ * which is nice to look at, but is trouble if your compiler isn't smart
+ * enough to optimize it. Now we just use looping.
+ */
+#define descend(next_node) \
+ do { \
+ (next_node)->iteratorState = InitialState; \
+ node = rb->cur = (next_node); \
+ goto restart; \
+ } while (0)
+
+#define ascend(next_node) \
+ do { \
+ node = rb->cur = (next_node); \
+ goto restart; \
+ } while (0)
+
+
+static RBNode *
+rb_left_right_iterator(RBTree *rb)
{
- RBNode *node = iterator->node;
+ RBNode *node = rb->cur;
+restart:
switch (node->iteratorState)
{
case InitialState:
if (node->left != RBNIL)
{
node->iteratorState = FirstStepDone;
- return rb_next_node(iterator, node->left);
+ descend(node->left);
}
+ /* FALL THROUGH */
case FirstStepDone:
node->iteratorState = SecondStepDone;
- return node->data;
+ return node;
case SecondStepDone:
if (node->right != RBNIL)
{
node->iteratorState = ThirdStepDone;
- return rb_next_node(iterator, node->right);
+ descend(node->right);
}
+ /* FALL THROUGH */
case ThirdStepDone:
if (node->parent)
- {
- iterator->node = node->parent;
- return iterator->iterate(iterator);
- }
+ ascend(node->parent);
break;
default:
- elog(ERROR, "Unknow node state: %d", node->iteratorState);
+ elog(ERROR, "unrecognized rbtree node state: %d",
+ node->iteratorState);
}
return NULL;
}
-static void *
-rb_right_left_iterator(RBTreeIterator *iterator)
+static RBNode *
+rb_right_left_iterator(RBTree *rb)
{
- RBNode *node = iterator->node;
+ RBNode *node = rb->cur;
+restart:
switch (node->iteratorState)
{
case InitialState:
if (node->right != RBNIL)
{
node->iteratorState = FirstStepDone;
- return rb_next_node(iterator, node->right);
+ descend(node->right);
}
+ /* FALL THROUGH */
case FirstStepDone:
node->iteratorState = SecondStepDone;
- return node->data;
+ return node;
case SecondStepDone:
if (node->left != RBNIL)
{
node->iteratorState = ThirdStepDone;
- return rb_next_node(iterator, node->left);
+ descend(node->left);
}
+ /* FALL THROUGH */
case ThirdStepDone:
if (node->parent)
- {
- iterator->node = node->parent;
- return iterator->iterate(iterator);
- }
+ ascend(node->parent);
break;
default:
- elog(ERROR, "Unknow node state: %d", node->iteratorState);
+ elog(ERROR, "unrecognized rbtree node state: %d",
+ node->iteratorState);
}
return NULL;
}
-static void *
-rb_direct_iterator(RBTreeIterator *iterator)
+static RBNode *
+rb_direct_iterator(RBTree *rb)
{
- RBNode *node = iterator->node;
+ RBNode *node = rb->cur;
+restart:
switch (node->iteratorState)
{
case InitialState:
node->iteratorState = FirstStepDone;
- return node->data;
+ return node;
case FirstStepDone:
if (node->left != RBNIL)
{
node->iteratorState = SecondStepDone;
- return rb_next_node(iterator, node->left);
+ descend(node->left);
}
+ /* FALL THROUGH */
case SecondStepDone:
if (node->right != RBNIL)
{
node->iteratorState = ThirdStepDone;
- return rb_next_node(iterator, node->right);
+ descend(node->right);
}
+ /* FALL THROUGH */
case ThirdStepDone:
if (node->parent)
- {
- iterator->node = node->parent;
- return iterator->iterate(iterator);
- }
+ ascend(node->parent);
break;
default:
- elog(ERROR, "Unknow node state: %d", node->iteratorState);
+ elog(ERROR, "unrecognized rbtree node state: %d",
+ node->iteratorState);
}
return NULL;
}
-static void *
-rb_inverted_iterator(RBTreeIterator *iterator)
+static RBNode *
+rb_inverted_iterator(RBTree *rb)
{
- RBNode *node = iterator->node;
+ RBNode *node = rb->cur;
+restart:
switch (node->iteratorState)
{
case InitialState:
if (node->left != RBNIL)
{
node->iteratorState = FirstStepDone;
- return rb_next_node(iterator, node->left);
+ descend(node->left);
}
+ /* FALL THROUGH */
case FirstStepDone:
if (node->right != RBNIL)
{
node->iteratorState = SecondStepDone;
- return rb_next_node(iterator, node->right);
+ descend(node->right);
}
+ /* FALL THROUGH */
case SecondStepDone:
node->iteratorState = ThirdStepDone;
- return node->data;
+ return node;
case ThirdStepDone:
if (node->parent)
- {
- iterator->node = node->parent;
- return iterator->iterate(iterator);
- }
+ ascend(node->parent);
break;
default:
- elog(ERROR, "Unknow node state: %d", node->iteratorState);
+ elog(ERROR, "unrecognized rbtree node state: %d",
+ node->iteratorState);
}
return NULL;
}
-RBTreeIterator *
+/*
+ * rb_begin_iterate: prepare to traverse the tree in any of several orders
+ *
+ * After calling rb_begin_iterate, call rb_iterate repeatedly until it
+ * returns NULL or the traversal stops being of interest.
+ *
+ * If the tree is changed during traversal, results of further calls to
+ * rb_iterate are unspecified.
+ *
+ * Note: this used to return a separately palloc'd iterator control struct,
+ * but that's a bit pointless since the data structure is incapable of
+ * supporting multiple concurrent traversals. Now we just keep the state
+ * in RBTree.
+ */
+void
rb_begin_iterate(RBTree *rb, RBOrderControl ctrl)
{
- RBTreeIterator *iterator = palloc(sizeof(RBTreeIterator));
-
- iterator->node = rb->root;
- if (iterator->node != RBNIL)
- iterator->node->iteratorState = InitialState;
+ rb->cur = rb->root;
+ if (rb->cur != RBNIL)
+ rb->cur->iteratorState = InitialState;
switch (ctrl)
{
case LeftRightWalk: /* visit left, then self, then right */
- iterator->iterate = rb_left_right_iterator;
+ rb->iterate = rb_left_right_iterator;
break;
case RightLeftWalk: /* visit right, then self, then left */
- iterator->iterate = rb_right_left_iterator;
+ rb->iterate = rb_right_left_iterator;
break;
case DirectWalk: /* visit self, then left, then right */
- iterator->iterate = rb_direct_iterator;
+ rb->iterate = rb_direct_iterator;
break;
case InvertedWalk: /* visit left, then right, then self */
- iterator->iterate = rb_inverted_iterator;
+ rb->iterate = rb_inverted_iterator;
break;
default:
- elog(ERROR, "Unknown iterator order: %d", ctrl);
+ elog(ERROR, "unrecognized rbtree iteration order: %d", ctrl);
}
-
- return iterator;
}
-void *
-rb_iterate(RBTreeIterator *iterator)
+/*
+ * rb_iterate: return the next node in traversal order, or NULL if no more
+ */
+RBNode *
+rb_iterate(RBTree *rb)
{
- if (iterator->node == RBNIL)
+ if (rb->cur == RBNIL)
return NULL;
- return iterator->iterate(iterator);
-}
-
-void
-rb_free_iterator(RBTreeIterator *iterator)
-{
- pfree(iterator);
+ return rb->iterate(rb);
}
* rbtree.h
* interface for PostgreSQL generic Red-Black binary tree package
*
- * Copyright (c) 1996-2009, PostgreSQL Global Development Group
+ * Copyright (c) 2009-2010, PostgreSQL Global Development Group
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/include/utils/rbtree.h,v 1.3 2010/05/11 18:14:01 rhaas Exp $
+ * $PostgreSQL: pgsql/src/include/utils/rbtree.h,v 1.4 2010/08/01 02:12:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
-
#ifndef RBTREE_H
#define RBTREE_H
+/*
+ * RBNode is intended to be used as the first field of a larger struct,
+ * whose additional fields carry whatever payload data the caller needs
+ * for a tree entry. (The total size of that larger struct is passed to
+ * rb_create.) RBNode is declared here to support this usage, but
+ * callers must treat it as an opaque struct.
+ */
+typedef struct RBNode
+{
+ char iteratorState; /* workspace for iterating through tree */
+ char color; /* node's current color, red or black */
+ struct RBNode *left; /* left child, or RBNIL if none */
+ struct RBNode *right; /* right child, or RBNIL if none */
+ struct RBNode *parent; /* parent, or NULL (not RBNIL!) if none */
+} RBNode;
+
+/* Opaque struct representing a whole tree */
typedef struct RBTree RBTree;
-typedef struct RBTreeIterator RBTreeIterator;
-typedef int (*rb_comparator) (const void *a, const void *b, void *arg);
-typedef void *(*rb_appendator) (void *currentdata, void *newval, void *arg);
-typedef void (*rb_freefunc) (void *a);
+/* Available tree iteration orderings */
+typedef enum RBOrderControl
+{
+ LeftRightWalk, /* inorder: left child, node, right child */
+ RightLeftWalk, /* reverse inorder: right, node, left */
+ DirectWalk, /* preorder: node, left child, right child */
+ InvertedWalk /* postorder: left child, right child, node */
+} RBOrderControl;
+
+/* Support functions to be provided by caller */
+typedef int (*rb_comparator) (const RBNode *a, const RBNode *b, void *arg);
+typedef void (*rb_combiner) (RBNode *existing, const RBNode *newdata, void *arg);
+typedef RBNode *(*rb_allocfunc) (void *arg);
+typedef void (*rb_freefunc) (RBNode *x, void *arg);
-extern RBTree *rb_create(rb_comparator comparator,
- rb_appendator appendator,
+extern RBTree *rb_create(Size node_size,
+ rb_comparator comparator,
+ rb_combiner combiner,
+ rb_allocfunc allocfunc,
rb_freefunc freefunc,
void *arg);
-extern void *rb_find(RBTree *rb, void *data);
-extern void *rb_insert(RBTree *rb, void *data);
-extern void rb_delete(RBTree *rb, void *data);
-extern void *rb_leftmost(RBTree *rb);
+extern RBNode *rb_find(RBTree *rb, const RBNode *data);
+extern RBNode *rb_leftmost(RBTree *rb);
-typedef enum RBOrderControl
-{
- LeftRightWalk,
- RightLeftWalk,
- DirectWalk,
- InvertedWalk
-} RBOrderControl;
+extern RBNode *rb_insert(RBTree *rb, const RBNode *data, bool *isNew);
+extern void rb_delete(RBTree *rb, RBNode *node);
-extern RBTreeIterator *rb_begin_iterate(RBTree *rb, RBOrderControl ctrl);
-extern void *rb_iterate(RBTreeIterator *iterator);
-extern void rb_free_iterator(RBTreeIterator *iterator);
+extern void rb_begin_iterate(RBTree *rb, RBOrderControl ctrl);
+extern RBNode *rb_iterate(RBTree *rb);
-#endif
+#endif /* RBTREE_H */
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