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1 | /* | ||
2 | * tree234.h: header defining functions in tree234.c. | ||
3 | * | ||
4 | * This file is copyright 1999-2001 Simon Tatham. | ||
5 | * | ||
6 | * Permission is hereby granted, free of charge, to any person | ||
7 | * obtaining a copy of this software and associated documentation | ||
8 | * files (the "Software"), to deal in the Software without | ||
9 | * restriction, including without limitation the rights to use, | ||
10 | * copy, modify, merge, publish, distribute, sublicense, and/or | ||
11 | * sell copies of the Software, and to permit persons to whom the | ||
12 | * Software is furnished to do so, subject to the following | ||
13 | * conditions: | ||
14 | * | ||
15 | * The above copyright notice and this permission notice shall be | ||
16 | * included in all copies or substantial portions of the Software. | ||
17 | * | ||
18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, | ||
19 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES | ||
20 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | ||
21 | * NONINFRINGEMENT. IN NO EVENT SHALL SIMON TATHAM BE LIABLE FOR | ||
22 | * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF | ||
23 | * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | ||
24 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | ||
25 | * SOFTWARE. | ||
26 | */ | ||
27 | |||
28 | #ifndef TREE234_H | ||
29 | #define TREE234_H | ||
30 | |||
31 | /* | ||
32 | * This typedef is opaque outside tree234.c itself. | ||
33 | */ | ||
34 | typedef struct tree234_Tag tree234; | ||
35 | |||
36 | typedef int (*cmpfn234)(void *, void *); | ||
37 | |||
38 | typedef void *(*copyfn234)(void *state, void *element); | ||
39 | |||
40 | /* | ||
41 | * Create a 2-3-4 tree. If `cmp' is NULL, the tree is unsorted, and | ||
42 | * lookups by key will fail: you can only look things up by numeric | ||
43 | * index, and you have to use addpos234() and delpos234(). | ||
44 | */ | ||
45 | tree234 *newtree234(cmpfn234 cmp); | ||
46 | |||
47 | /* | ||
48 | * Free a 2-3-4 tree (not including freeing the elements). | ||
49 | */ | ||
50 | void freetree234(tree234 *t); | ||
51 | |||
52 | /* | ||
53 | * Add an element e to a sorted 2-3-4 tree t. Returns e on success, | ||
54 | * or if an existing element compares equal, returns that. | ||
55 | */ | ||
56 | void *add234(tree234 *t, void *e); | ||
57 | |||
58 | /* | ||
59 | * Add an element e to an unsorted 2-3-4 tree t. Returns e on | ||
60 | * success, NULL on failure. (Failure should only occur if the | ||
61 | * index is out of range or the tree is sorted.) | ||
62 | * | ||
63 | * Index range can be from 0 to the tree's current element count, | ||
64 | * inclusive. | ||
65 | */ | ||
66 | void *addpos234(tree234 *t, void *e, int index); | ||
67 | |||
68 | /* | ||
69 | * Look up the element at a given numeric index in a 2-3-4 tree. | ||
70 | * Returns NULL if the index is out of range. | ||
71 | * | ||
72 | * One obvious use for this function is in iterating over the whole | ||
73 | * of a tree (sorted or unsorted): | ||
74 | * | ||
75 | * for (i = 0; (p = index234(tree, i)) != NULL; i++) consume(p); | ||
76 | * | ||
77 | * or | ||
78 | * | ||
79 | * int maxcount = count234(tree); | ||
80 | * for (i = 0; i < maxcount; i++) { | ||
81 | * p = index234(tree, i); | ||
82 | * assert(p != NULL); | ||
83 | * consume(p); | ||
84 | * } | ||
85 | */ | ||
86 | void *index234(tree234 *t, int index); | ||
87 | |||
88 | /* | ||
89 | * Find an element e in a sorted 2-3-4 tree t. Returns NULL if not | ||
90 | * found. e is always passed as the first argument to cmp, so cmp | ||
91 | * can be an asymmetric function if desired. cmp can also be passed | ||
92 | * as NULL, in which case the compare function from the tree proper | ||
93 | * will be used. | ||
94 | * | ||
95 | * Three of these functions are special cases of findrelpos234. The | ||
96 | * non-`pos' variants lack the `index' parameter: if the parameter | ||
97 | * is present and non-NULL, it must point to an integer variable | ||
98 | * which will be filled with the numeric index of the returned | ||
99 | * element. | ||
100 | * | ||
101 | * The non-`rel' variants lack the `relation' parameter. This | ||
102 | * parameter allows you to specify what relation the element you | ||
103 | * provide has to the element you're looking for. This parameter | ||
104 | * can be: | ||
105 | * | ||
106 | * REL234_EQ - find only an element that compares equal to e | ||
107 | * REL234_LT - find the greatest element that compares < e | ||
108 | * REL234_LE - find the greatest element that compares <= e | ||
109 | * REL234_GT - find the smallest element that compares > e | ||
110 | * REL234_GE - find the smallest element that compares >= e | ||
111 | * | ||
112 | * Non-`rel' variants assume REL234_EQ. | ||
113 | * | ||
114 | * If `rel' is REL234_GT or REL234_LT, the `e' parameter may be | ||
115 | * NULL. In this case, REL234_GT will return the smallest element | ||
116 | * in the tree, and REL234_LT will return the greatest. This gives | ||
117 | * an alternative means of iterating over a sorted tree, instead of | ||
118 | * using index234: | ||
119 | * | ||
120 | * // to loop forwards | ||
121 | * for (p = NULL; (p = findrel234(tree, p, NULL, REL234_GT)) != NULL ;) | ||
122 | * consume(p); | ||
123 | * | ||
124 | * // to loop backwards | ||
125 | * for (p = NULL; (p = findrel234(tree, p, NULL, REL234_LT)) != NULL ;) | ||
126 | * consume(p); | ||
127 | */ | ||
128 | enum { | ||
129 | REL234_EQ, REL234_LT, REL234_LE, REL234_GT, REL234_GE | ||
130 | }; | ||
131 | void *find234(tree234 *t, void *e, cmpfn234 cmp); | ||
132 | void *findrel234(tree234 *t, void *e, cmpfn234 cmp, int relation); | ||
133 | void *findpos234(tree234 *t, void *e, cmpfn234 cmp, int *index); | ||
134 | void *findrelpos234(tree234 *t, void *e, cmpfn234 cmp, int relation, | ||
135 | int *index); | ||
136 | |||
137 | /* | ||
138 | * Delete an element e in a 2-3-4 tree. Does not free the element, | ||
139 | * merely removes all links to it from the tree nodes. | ||
140 | * | ||
141 | * delpos234 deletes the element at a particular tree index: it | ||
142 | * works on both sorted and unsorted trees. | ||
143 | * | ||
144 | * del234 deletes the element passed to it, so it only works on | ||
145 | * sorted trees. (It's equivalent to using findpos234 to determine | ||
146 | * the index of an element, and then passing that index to | ||
147 | * delpos234.) | ||
148 | * | ||
149 | * Both functions return a pointer to the element they delete, for | ||
150 | * the user to free or pass on elsewhere or whatever. If the index | ||
151 | * is out of range (delpos234) or the element is already not in the | ||
152 | * tree (del234) then they return NULL. | ||
153 | */ | ||
154 | void *del234(tree234 *t, void *e); | ||
155 | void *delpos234(tree234 *t, int index); | ||
156 | |||
157 | /* | ||
158 | * Return the total element count of a tree234. | ||
159 | */ | ||
160 | int count234(tree234 *t); | ||
161 | |||
162 | /* | ||
163 | * Split a tree234 into two valid tree234s. | ||
164 | * | ||
165 | * splitpos234 splits at a given index. If `before' is TRUE, the | ||
166 | * items at and after that index are left in t and the ones before | ||
167 | * are returned; if `before' is FALSE, the items before that index | ||
168 | * are left in t and the rest are returned. | ||
169 | * | ||
170 | * split234 splits at a given key. You can pass any of the | ||
171 | * relations used with findrel234, except for REL234_EQ. The items | ||
172 | * in the tree that satisfy the relation are returned; the | ||
173 | * remainder are left. | ||
174 | */ | ||
175 | tree234 *splitpos234(tree234 *t, int index, int before); | ||
176 | tree234 *split234(tree234 *t, void *e, cmpfn234 cmp, int rel); | ||
177 | |||
178 | /* | ||
179 | * Join two tree234s together into a single one. | ||
180 | * | ||
181 | * All the elements in t1 are placed to the left of all the | ||
182 | * elements in t2. If the trees are sorted, there will be a test to | ||
183 | * ensure that this satisfies the ordering criterion, and NULL will | ||
184 | * be returned otherwise. If the trees are unsorted, there is no | ||
185 | * restriction on the use of join234. | ||
186 | * | ||
187 | * The tree returned is t1 (join234) or t2 (join234r), if the | ||
188 | * operation is successful. | ||
189 | */ | ||
190 | tree234 *join234(tree234 *t1, tree234 *t2); | ||
191 | tree234 *join234r(tree234 *t1, tree234 *t2); | ||
192 | |||
193 | /* | ||
194 | * Make a complete copy of a tree234. Element pointers will be | ||
195 | * reused unless copyfn is non-NULL, in which case it will be used | ||
196 | * to copy each element. (copyfn takes two `void *' parameters; the | ||
197 | * first is private state and the second is the element. A simple | ||
198 | * copy routine probably won't need private state.) | ||
199 | */ | ||
200 | tree234 *copytree234(tree234 *t, copyfn234 copyfn, void *copyfnstate); | ||
201 | |||
202 | #endif /* TREE234_H */ | ||