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Diffstat (limited to 'src/include/lib/rbtree.h')
-rw-r--r-- | src/include/lib/rbtree.h | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/src/include/lib/rbtree.h b/src/include/lib/rbtree.h new file mode 100644 index 0000000..48c60f7 --- /dev/null +++ b/src/include/lib/rbtree.h @@ -0,0 +1,79 @@ +/*------------------------------------------------------------------------- + * + * rbtree.h + * interface for PostgreSQL generic Red-Black binary tree package + * + * Copyright (c) 2009-2021, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/include/lib/rbtree.h + * + *------------------------------------------------------------------------- + */ +#ifndef RBTREE_H +#define RBTREE_H + +/* + * RBTNode 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 + * rbt_create.) RBTNode is declared here to support this usage, but + * callers must treat it as an opaque struct. + */ +typedef struct RBTNode +{ + char color; /* node's current color, red or black */ + struct RBTNode *left; /* left child, or RBTNIL if none */ + struct RBTNode *right; /* right child, or RBTNIL if none */ + struct RBTNode *parent; /* parent, or NULL (not RBTNIL!) if none */ +} RBTNode; + +/* Opaque struct representing a whole tree */ +typedef struct RBTree RBTree; + +/* Available tree iteration orderings */ +typedef enum RBTOrderControl +{ + LeftRightWalk, /* inorder: left child, node, right child */ + RightLeftWalk /* reverse inorder: right, node, left */ +} RBTOrderControl; + +/* + * RBTreeIterator holds state while traversing a tree. This is declared + * here so that callers can stack-allocate this, but must otherwise be + * treated as an opaque struct. + */ +typedef struct RBTreeIterator RBTreeIterator; + +struct RBTreeIterator +{ + RBTree *rbt; + RBTNode *(*iterate) (RBTreeIterator *iter); + RBTNode *last_visited; + bool is_over; +}; + +/* Support functions to be provided by caller */ +typedef int (*rbt_comparator) (const RBTNode *a, const RBTNode *b, void *arg); +typedef void (*rbt_combiner) (RBTNode *existing, const RBTNode *newdata, void *arg); +typedef RBTNode *(*rbt_allocfunc) (void *arg); +typedef void (*rbt_freefunc) (RBTNode *x, void *arg); + +extern RBTree *rbt_create(Size node_size, + rbt_comparator comparator, + rbt_combiner combiner, + rbt_allocfunc allocfunc, + rbt_freefunc freefunc, + void *arg); + +extern RBTNode *rbt_find(RBTree *rbt, const RBTNode *data); +extern RBTNode *rbt_leftmost(RBTree *rbt); + +extern RBTNode *rbt_insert(RBTree *rbt, const RBTNode *data, bool *isNew); +extern void rbt_delete(RBTree *rbt, RBTNode *node); + +extern void rbt_begin_iterate(RBTree *rbt, RBTOrderControl ctrl, + RBTreeIterator *iter); +extern RBTNode *rbt_iterate(RBTreeIterator *iter); + +#endif /* RBTREE_H */ |