132 lines
3.9 KiB
C
132 lines
3.9 KiB
C
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/** <plaintext>
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*
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* avl.h -- public types and external declarations for avl trees
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*
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* Created 03/01/89 by Brad Appleton
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*
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* ^{Mods:* }
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*
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* Fri Jul 14 13:54:12 1989, Rev 1.0, brad(0165)
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*
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**/
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#ifndef AVL_H_INCLUDED
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#define AVL_H_INCLUDED
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/* definition of traversal type */
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typedef enum { PREORDER, INORDER, POSTORDER } VISIT;
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/* definition of sibling order type */
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typedef enum { LEFT_TO_RIGHT, RIGHT_TO_LEFT } SIBLING_ORDER;
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/* definition of node type */
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typedef enum { IS_TREE, IS_LBRANCH, IS_RBRANCH, IS_LEAF, IS_NULL } NODE;
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/* definition of a NULL action and a NULL tree */
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#define NULL_ACTION ((void(*)()) NULL)
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#define NULL_TREE ((AVLtree) NULL)
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/* BEGIN Internal definitions */
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/* Directional Definitions */
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typedef short DIRECTION;
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#define LEFT 0
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#define RIGHT 1
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#define OPPOSITE(x) (1 - (x))
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/* return codes used by avl_insert(), avl_delete(), and balance() */
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#define HEIGHT_UNCHANGED 0
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#define HEIGHT_CHANGED 1
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/* Balance Definitions */
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#define LEFT_HEAVY -1
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#define BALANCED 0
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#define RIGHT_HEAVY 1
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#define LEFT_IMBALANCE(nd) ((nd)->bal < LEFT_HEAVY)
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#define RIGHT_IMBALANCE(nd) ((nd)->bal > RIGHT_HEAVY)
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/* structure for a node in an AVL tree */
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typedef struct avl_node
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{ struct avl_node *subtree[2]; /* LEFT and RIGHT subtrees */
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short bal; /* balance factor */
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void * data[1]; /* data on my back */
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} AVLnode, *AVLtree;
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/* End Internal definitions */
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/* structure which holds information about an AVL tree */
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typedef struct avl_tree
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{ AVLtree root; /* pointer to the root node of the tree */
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long count; /* number of nodes in the tree */
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/* function used to compare keys */
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void *client_data; /* arbitrary client data */
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int (*compar)(void *l, void*r, NODE type);
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void (*destroy)(void *data);
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void* (*alloc)(void *cdata, size_t size);
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void (*free)(void *cdata, void* data, size_t size);
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int isize; /* item data size */
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} avl_tree, *AVL_TREE;
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#define AVL_ENUM_MAX 32 /* balanced tree, allows for 2**32 */
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/* nodes */
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typedef struct avl_enum
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{ AVL_TREE tree;
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int current;
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AVLtree parents[AVL_ENUM_MAX];
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} avl_enum;
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void *avlfindfirst(AVL_TREE tree, void *key, avl_enum *e);
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void *avlfindnext(avl_enum *e);
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void avlfinddestroy(avl_enum *e);
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/* Constructor and Destructor functions for AVL trees:
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* avlfree is a macro for avldispose in the fashion
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* of free(). It assumes certain default values
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* (shown below) for the deallocation function and
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* for the order in which children are traversed.
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*/
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extern AVL_TREE avlinit(AVL_TREE tree,
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void *cdata, size_t isize,
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int (*compare)(void *l, void*r, NODE type),
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void (*destroy)(void *d),
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void* (*alloc)(void *cdata, size_t bytes),
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void (*free)(void *cdata, void *ptr, size_t size));
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extern void avlfree(AVL_TREE tree);
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/* Routine for manipulating/accessing each data item in a tree */
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extern void avlwalk(AVL_TREE,
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void (*action)(void *data,
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SIBLING_ORDER order,
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NODE type,
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int level,
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int balance),
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SIBLING_ORDER);
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/* Routine for obtaining the size of an AVL tree */
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extern int avlcount(AVL_TREE);
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/* Routines to search for a given item */
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extern void *avlins(AVL_TREE tree, void *data);
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extern int avldel(AVL_TREE tree, void *data);
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extern void *avlfind(AVL_TREE tree, void *data);
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/* Routines to search for the minimal item of a tree */
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extern int avldelmin(AVL_TREE tree, void *data);
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extern void *avlfindmin(AVL_TREE tree);
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/* Routines to search for the maximal item of a tree */
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extern int avldelmax(AVL_TREE tree, void *data);
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extern void *avlfindmax(AVL_TREE tree);
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#endif /* AVL_H_INCLUDED */
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