82 lines
2.7 KiB
C
82 lines
2.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* rbtree.h
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* interface for PostgreSQL generic Red-Black binary tree package
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*
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* Copyright (c) 2009-2024, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* src/include/lib/rbtree.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef RBTREE_H
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#define RBTREE_H
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/*
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* RBTNode is intended to be used as the first field of a larger struct,
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* whose additional fields carry whatever payload data the caller needs
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* for a tree entry. (The total size of that larger struct is passed to
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* rbt_create.) RBTNode is declared here to support this usage, but
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* callers must treat it as an opaque struct.
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*/
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typedef struct RBTNode
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{
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char color; /* node's current color, red or black */
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struct RBTNode *left; /* left child, or RBTNIL if none */
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struct RBTNode *right; /* right child, or RBTNIL if none */
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struct RBTNode *parent; /* parent, or NULL (not RBTNIL!) if none */
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} RBTNode;
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/* Opaque struct representing a whole tree */
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typedef struct RBTree RBTree;
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/* Available tree iteration orderings */
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typedef enum RBTOrderControl
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{
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LeftRightWalk, /* inorder: left child, node, right child */
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RightLeftWalk /* reverse inorder: right, node, left */
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} RBTOrderControl;
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/*
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* RBTreeIterator holds state while traversing a tree. This is declared
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* here so that callers can stack-allocate this, but must otherwise be
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* treated as an opaque struct.
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*/
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typedef struct RBTreeIterator RBTreeIterator;
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struct RBTreeIterator
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{
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RBTree *rbt;
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RBTNode *(*iterate) (RBTreeIterator *iter);
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RBTNode *last_visited;
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bool is_over;
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};
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/* Support functions to be provided by caller */
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typedef int (*rbt_comparator) (const RBTNode *a, const RBTNode *b, void *arg);
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typedef void (*rbt_combiner) (RBTNode *existing, const RBTNode *newdata, void *arg);
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typedef RBTNode *(*rbt_allocfunc) (void *arg);
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typedef void (*rbt_freefunc) (RBTNode *x, void *arg);
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extern RBTree *rbt_create(Size node_size,
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rbt_comparator comparator,
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rbt_combiner combiner,
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rbt_allocfunc allocfunc,
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rbt_freefunc freefunc,
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void *arg);
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extern RBTNode *rbt_find(RBTree *rbt, const RBTNode *data);
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extern RBTNode *rbt_find_great(RBTree *rbt, const RBTNode *data, bool equal_match);
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extern RBTNode *rbt_find_less(RBTree *rbt, const RBTNode *data, bool equal_match);
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extern RBTNode *rbt_leftmost(RBTree *rbt);
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extern RBTNode *rbt_insert(RBTree *rbt, const RBTNode *data, bool *isNew);
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extern void rbt_delete(RBTree *rbt, RBTNode *node);
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extern void rbt_begin_iterate(RBTree *rbt, RBTOrderControl ctrl,
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RBTreeIterator *iter);
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extern RBTNode *rbt_iterate(RBTreeIterator *iter);
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#endif /* RBTREE_H */
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