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	tree.h (7303B)
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	1 /* $OpenBSD: tree.h,v 1.31 2023/03/08 04:43:09 guenther Exp $ …
	2 /*
	3 * Copyright 2002 Niels Provos <[email protected]>
	4 * All rights reserved.
	5 *
	6 * Redistribution and use in source and binary forms, with or without
	7 * modification, are permitted provided that the following conditions
	8 * are met:
	9 * 1. Redistributions of source code must retain the above copyright
	10 * notice, this list of conditions and the following disclaimer.
	11 * 2. Redistributions in binary form must reproduce the above copyright
	12 * notice, this list of conditions and the following disclaimer in the
	13 * documentation and/or other materials provided with the distributio…
	14 *
	15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRAN…
	17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIME…
	18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, …
	20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF …
	21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE…
	24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	25 */
	26
	27 #ifndef TREE_H
	28 #define TREE_H
	29
	30 /*
	31 * This file defines a red-black tree structure.
	32 *
	33 * A red-black tree is a binary search tree with the node color as an
	34 * extra attribute. It fulfills a set of conditions:
	35 * - every search path from the root to a leaf consists of the
	36 * same number of black nodes,
	37 * - each red node (except for the root) has a black parent,
	38 * - each leaf node is black.
	39 *
	40 * Every operation on a red-black tree is bounded as O(lg n).
	41 * The maximum height of a red-black tree is 2lg (n+1).
	42 */
	43
	44 /* Macros that define a red-black tree */
	45 #define RB_HEAD(name, type) …
	46 struct name { …
	47 struct type rbh_root; / root of the tree */ …
	48 }
	49
	50 #define RB_INITIALIZER(root) …
	51 { NULL }
	52
	53 #define RB_INIT(root) do { …
	54 (root)->rbh_root = NULL; \
	55 } while (0)
	56
	57 #define RB_BLACK 0
	58 #define RB_RED 1
	59 #define RB_ENTRY(type) …
	60 struct { \
	61 struct type rbe_left; / left element */ …
	62 struct type rbe_right; / right element */ …
	63 struct type rbe_parent; / parent element */ …
	64 int rbe_color; /* node color */ …
	65 }
	66
	67 #define RB_LEFT(elm, field) (elm)->field.rbe_left
	68 #define RB_RIGHT(elm, field) (elm)->field.rbe_right
	69 #define RB_PARENT(elm, field) (elm)->field.rbe_parent
	70 #define RB_COLOR(elm, field) (elm)->field.rbe_color
	71 #define RB_ROOT(head) (head)->rbh_root
	72 #define RB_EMPTY(head) (RB_ROOT(head) == NULL)
	73
	74 #define RB_SET(elm, parent, field) do { …
	75 RB_PARENT(elm, field) = parent; …
	76 RB_LEFT(elm, field) = RB_RIGHT(elm, field) = NULL; …
	77 RB_COLOR(elm, field) = RB_RED; …
	78 } while (0)
	79
	80 #define RB_SET_BLACKRED(black, red, field) do { …
	81 RB_COLOR(black, field) = RB_BLACK; …
	82 RB_COLOR(red, field) = RB_RED; …
	83 } while (0)
	84
	85 #define RB_ROTATE_LEFT(head, elm, tmp, field) do { …
	86 (tmp) = RB_RIGHT(elm, field); …
	87 if ((RB_RIGHT(elm, field) = RB_LEFT(tmp, field))) { …
	88 RB_PARENT(RB_LEFT(tmp, field), field) = (elm); …
	89 } …
	90 if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field))) { …
	91 if ((elm) == RB_LEFT(RB_PARENT(elm, field), field)) …
	92 RB_LEFT(RB_PARENT(elm, field), field) = (tmp); …
	93 else …
	94 RB_RIGHT(RB_PARENT(elm, field), field) = (tmp); …
	95 } else …
	96 (head)->rbh_root = (tmp); …
	97 RB_LEFT(tmp, field) = (elm); …
	98 RB_PARENT(elm, field) = (tmp); …
	99 } while (0)
	100
	101 #define RB_ROTATE_RIGHT(head, elm, tmp, field) do { …
	102 (tmp) = RB_LEFT(elm, field); …
	103 if ((RB_LEFT(elm, field) = RB_RIGHT(tmp, field))) { …
	104 RB_PARENT(RB_RIGHT(tmp, field), field) = (elm); …
	105 } …
	106 if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field))) { …
	107 if ((elm) == RB_LEFT(RB_PARENT(elm, field), field)) …
	108 RB_LEFT(RB_PARENT(elm, field), field) = (tmp); …
	109 else …
	110 RB_RIGHT(RB_PARENT(elm, field), field) = (tmp); …
	111 } else …
	112 (head)->rbh_root = (tmp); …
	113 RB_RIGHT(tmp, field) = (elm); …
	114 RB_PARENT(elm, field) = (tmp); …
	115 } while (0)
	116
	117 /* Moves node close to the key of elm to top
	118 */
	119 #define RB_GENERATE(name, type, field, cmp) …
	120 RB_GENERATE_INTERNAL(name, type, field, cmp,)
	121 #define RB_GENERATE_INTERNAL(name, type, field, cmp, attr) …
	122 attr void …
	123 name##_RB_INSERT_COLOR(struct name head, struct type elm) …
	124 { …
	125 struct type parent, gparent, *tmp; …
	126 while ((parent = RB_PARENT(elm, field)) && …
	127 RB_COLOR(parent, field) == RB_RED) { \
	128 gparent = RB_PARENT(parent, field); …
	129 if (parent == RB_LEFT(gparent, field)) { \
	130 tmp = RB_RIGHT(gparent, field); …
	131 if (tmp && RB_COLOR(tmp, field) == RB_RED) { …
	132 RB_COLOR(tmp, field) = RB_BLACK; \
	133 RB_SET_BLACKRED(parent, gparent, field);\
	134 elm = gparent; …
	135 continue; …
	136 } …
	137 if (RB_RIGHT(parent, field) == elm) { …
	138 RB_ROTATE_LEFT(head, parent, tmp, field)…
	139 tmp = parent; …
	140 parent = elm; …
	141 elm = tmp; …
	142 } …
	143 RB_SET_BLACKRED(parent, gparent, field); \
	144 RB_ROTATE_RIGHT(head, gparent, tmp, field); …
	145 } else { \
	146 tmp = RB_LEFT(gparent, field); …
	147 if (tmp && RB_COLOR(tmp, field) == RB_RED) { …
	148 RB_COLOR(tmp, field) = RB_BLACK; \
	149 RB_SET_BLACKRED(parent, gparent, field);\
	150 elm = gparent; …
	151 continue; …
	152 } …
	153 if (RB_LEFT(parent, field) == elm) { …
	154 RB_ROTATE_RIGHT(head, parent, tmp, field…
	155 tmp = parent; …
	156 parent = elm; …
	157 elm = tmp; …
	158 } …
	159 RB_SET_BLACKRED(parent, gparent, field); \
	160 RB_ROTATE_LEFT(head, gparent, tmp, field); …
	161 } …
	162 } …
	163 RB_COLOR(head->rbh_root, field) = RB_BLACK; …
	164 } …
	165 \
	166 /* Inserts a node into the RB tree */ …
	167 attr struct type * …
	168 name##_RB_INSERT(struct name head, struct type elm) …
	169 { …
	170 struct type *tmp; …
	171 struct type *parent = NULL; …
	172 int comp = 0; …
	173 tmp = RB_ROOT(head); …
	174 while (tmp) { …
	175 parent = tmp; …
	176 comp = (cmp)(elm, parent); …
	177 if (comp < 0) …
	178 tmp = RB_LEFT(tmp, field); …
	179 else if (comp > 0) …
	180 tmp = RB_RIGHT(tmp, field); …
	181 else …
	182 return (tmp); …
	183 } …
	184 RB_SET(elm, parent, field); …
	185 if (parent != NULL) { …
	186 if (comp < 0) …
	187 RB_LEFT(parent, field) = elm; …
	188 else …
	189 RB_RIGHT(parent, field) = elm; …
	190 } else …
	191 RB_ROOT(head) = elm; …
	192 name##_RB_INSERT_COLOR(head, elm); …
	193 return (NULL); …
	194 } …
	195 \
	196 /* Finds the node with the same key as elm */ …
	197 attr struct type * …
	198 name##_RB_FIND(struct name head, struct type elm) …
	199 { …
	200 struct type *tmp = RB_ROOT(head); …
	201 int comp; …
	202 while (tmp) { …
	203 comp = cmp(elm, tmp); …
	204 if (comp < 0) …
	205 tmp = RB_LEFT(tmp, field); …
	206 else if (comp > 0) …
	207 tmp = RB_RIGHT(tmp, field); …
	208 else …
	209 return (tmp); …
	210 } …
	211 return (NULL); …
	212 }
	213
	214 #define RB_INSERT(name, x, y) name##_RB_INSERT(x, y)
	215 #define RB_FIND(name, x, y) name##_RB_FIND(x, y)
	216
	217 #endif /* TREE_H */