source: filezilla/trunk/fuentes/src/putty/tree234.h @ 130

Last change on this file since 130 was 130, checked in by jrpelegrina, 3 years ago

First release to xenial

File size: 5.5 KB
Line 
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 */
34typedef struct tree234_Tag tree234;
35
36typedef int (*cmpfn234) (void *, void *);
37
38/*
39 * Create a 2-3-4 tree. If `cmp' is NULL, the tree is unsorted, and
40 * lookups by key will fail: you can only look things up by numeric
41 * index, and you have to use addpos234() and delpos234().
42 */
43tree234 *newtree234(cmpfn234 cmp);
44
45/*
46 * Free a 2-3-4 tree (not including freeing the elements).
47 */
48void freetree234(tree234 * t);
49
50/*
51 * Add an element e to a sorted 2-3-4 tree t. Returns e on success,
52 * or if an existing element compares equal, returns that.
53 */
54void *add234(tree234 * t, void *e);
55
56/*
57 * Add an element e to an unsorted 2-3-4 tree t. Returns e on
58 * success, NULL on failure. (Failure should only occur if the
59 * index is out of range or the tree is sorted.)
60 *
61 * Index range can be from 0 to the tree's current element count,
62 * inclusive.
63 */
64void *addpos234(tree234 * t, void *e, int index);
65
66/*
67 * Look up the element at a given numeric index in a 2-3-4 tree.
68 * Returns NULL if the index is out of range.
69 *
70 * One obvious use for this function is in iterating over the whole
71 * of a tree (sorted or unsorted):
72 *
73 *   for (i = 0; (p = index234(tree, i)) != NULL; i++) consume(p);
74 *
75 * or
76 *
77 *   int maxcount = count234(tree);
78 *   for (i = 0; i < maxcount; i++) {
79 *       p = index234(tree, i);
80 *       assert(p != NULL);
81 *       consume(p);
82 *   }
83 */
84void *index234(tree234 * t, int index);
85
86/*
87 * Find an element e in a sorted 2-3-4 tree t. Returns NULL if not
88 * found. e is always passed as the first argument to cmp, so cmp
89 * can be an asymmetric function if desired. cmp can also be passed
90 * as NULL, in which case the compare function from the tree proper
91 * will be used.
92 *
93 * Three of these functions are special cases of findrelpos234. The
94 * non-`pos' variants lack the `index' parameter: if the parameter
95 * is present and non-NULL, it must point to an integer variable
96 * which will be filled with the numeric index of the returned
97 * element.
98 *
99 * The non-`rel' variants lack the `relation' parameter. This
100 * parameter allows you to specify what relation the element you
101 * provide has to the element you're looking for. This parameter
102 * can be:
103 *
104 *   REL234_EQ     - find only an element that compares equal to e
105 *   REL234_LT     - find the greatest element that compares < e
106 *   REL234_LE     - find the greatest element that compares <= e
107 *   REL234_GT     - find the smallest element that compares > e
108 *   REL234_GE     - find the smallest element that compares >= e
109 *
110 * Non-`rel' variants assume REL234_EQ.
111 *
112 * If `rel' is REL234_GT or REL234_LT, the `e' parameter may be
113 * NULL. In this case, REL234_GT will return the smallest element
114 * in the tree, and REL234_LT will return the greatest. This gives
115 * an alternative means of iterating over a sorted tree, instead of
116 * using index234:
117 *
118 *   // to loop forwards
119 *   for (p = NULL; (p = findrel234(tree, p, NULL, REL234_GT)) != NULL ;)
120 *       consume(p);
121 *
122 *   // to loop backwards
123 *   for (p = NULL; (p = findrel234(tree, p, NULL, REL234_LT)) != NULL ;)
124 *       consume(p);
125 */
126enum {
127    REL234_EQ, REL234_LT, REL234_LE, REL234_GT, REL234_GE
128};
129void *find234(tree234 * t, void *e, cmpfn234 cmp);
130void *findrel234(tree234 * t, void *e, cmpfn234 cmp, int relation);
131void *findpos234(tree234 * t, void *e, cmpfn234 cmp, int *index);
132void *findrelpos234(tree234 * t, void *e, cmpfn234 cmp, int relation,
133                    int *index);
134
135/*
136 * Delete an element e in a 2-3-4 tree. Does not free the element,
137 * merely removes all links to it from the tree nodes.
138 *
139 * delpos234 deletes the element at a particular tree index: it
140 * works on both sorted and unsorted trees.
141 *
142 * del234 deletes the element passed to it, so it only works on
143 * sorted trees. (It's equivalent to using findpos234 to determine
144 * the index of an element, and then passing that index to
145 * delpos234.)
146 *
147 * Both functions return a pointer to the element they delete, for
148 * the user to free or pass on elsewhere or whatever. If the index
149 * is out of range (delpos234) or the element is already not in the
150 * tree (del234) then they return NULL.
151 */
152void *del234(tree234 * t, void *e);
153void *delpos234(tree234 * t, int index);
154
155/*
156 * Return the total element count of a tree234.
157 */
158int count234(tree234 * t);
159
160#endif                          /* TREE234_H */
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