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Diffstat (limited to 'app/tools/halibut/tree234.h')
-rw-r--r-- | app/tools/halibut/tree234.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/app/tools/halibut/tree234.h b/app/tools/halibut/tree234.h new file mode 100644 index 0000000..f75c8f7 --- /dev/null +++ b/app/tools/halibut/tree234.h @@ -0,0 +1,202 @@ +/* + * tree234.h: header defining functions in tree234.c. + * + * This file is copyright 1999-2001 Simon Tatham. + * + * Permission is hereby granted, free of charge, to any person + * obtaining a copy of this software and associated documentation + * files (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, + * copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following + * conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES + * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL SIMON TATHAM BE LIABLE FOR + * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF + * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#ifndef TREE234_H +#define TREE234_H + +/* + * This typedef is opaque outside tree234.c itself. + */ +typedef struct tree234_Tag tree234; + +typedef int (*cmpfn234)(void *, void *); + +typedef void *(*copyfn234)(void *state, void *element); + +/* + * Create a 2-3-4 tree. If `cmp' is NULL, the tree is unsorted, and + * lookups by key will fail: you can only look things up by numeric + * index, and you have to use addpos234() and delpos234(). + */ +tree234 *newtree234(cmpfn234 cmp); + +/* + * Free a 2-3-4 tree (not including freeing the elements). + */ +void freetree234(tree234 *t); + +/* + * Add an element e to a sorted 2-3-4 tree t. Returns e on success, + * or if an existing element compares equal, returns that. + */ +void *add234(tree234 *t, void *e); + +/* + * Add an element e to an unsorted 2-3-4 tree t. Returns e on + * success, NULL on failure. (Failure should only occur if the + * index is out of range or the tree is sorted.) + * + * Index range can be from 0 to the tree's current element count, + * inclusive. + */ +void *addpos234(tree234 *t, void *e, int index); + +/* + * Look up the element at a given numeric index in a 2-3-4 tree. + * Returns NULL if the index is out of range. + * + * One obvious use for this function is in iterating over the whole + * of a tree (sorted or unsorted): + * + * for (i = 0; (p = index234(tree, i)) != NULL; i++) consume(p); + * + * or + * + * int maxcount = count234(tree); + * for (i = 0; i < maxcount; i++) { + * p = index234(tree, i); + * assert(p != NULL); + * consume(p); + * } + */ +void *index234(tree234 *t, int index); + +/* + * Find an element e in a sorted 2-3-4 tree t. Returns NULL if not + * found. e is always passed as the first argument to cmp, so cmp + * can be an asymmetric function if desired. cmp can also be passed + * as NULL, in which case the compare function from the tree proper + * will be used. + * + * Three of these functions are special cases of findrelpos234. The + * non-`pos' variants lack the `index' parameter: if the parameter + * is present and non-NULL, it must point to an integer variable + * which will be filled with the numeric index of the returned + * element. + * + * The non-`rel' variants lack the `relation' parameter. This + * parameter allows you to specify what relation the element you + * provide has to the element you're looking for. This parameter + * can be: + * + * REL234_EQ - find only an element that compares equal to e + * REL234_LT - find the greatest element that compares < e + * REL234_LE - find the greatest element that compares <= e + * REL234_GT - find the smallest element that compares > e + * REL234_GE - find the smallest element that compares >= e + * + * Non-`rel' variants assume REL234_EQ. + * + * If `rel' is REL234_GT or REL234_LT, the `e' parameter may be + * NULL. In this case, REL234_GT will return the smallest element + * in the tree, and REL234_LT will return the greatest. This gives + * an alternative means of iterating over a sorted tree, instead of + * using index234: + * + * // to loop forwards + * for (p = NULL; (p = findrel234(tree, p, NULL, REL234_GT)) != NULL ;) + * consume(p); + * + * // to loop backwards + * for (p = NULL; (p = findrel234(tree, p, NULL, REL234_LT)) != NULL ;) + * consume(p); + */ +enum { + REL234_EQ, REL234_LT, REL234_LE, REL234_GT, REL234_GE +}; +void *find234(tree234 *t, void *e, cmpfn234 cmp); +void *findrel234(tree234 *t, void *e, cmpfn234 cmp, int relation); +void *findpos234(tree234 *t, void *e, cmpfn234 cmp, int *index); +void *findrelpos234(tree234 *t, void *e, cmpfn234 cmp, int relation, + int *index); + +/* + * Delete an element e in a 2-3-4 tree. Does not free the element, + * merely removes all links to it from the tree nodes. + * + * delpos234 deletes the element at a particular tree index: it + * works on both sorted and unsorted trees. + * + * del234 deletes the element passed to it, so it only works on + * sorted trees. (It's equivalent to using findpos234 to determine + * the index of an element, and then passing that index to + * delpos234.) + * + * Both functions return a pointer to the element they delete, for + * the user to free or pass on elsewhere or whatever. If the index + * is out of range (delpos234) or the element is already not in the + * tree (del234) then they return NULL. + */ +void *del234(tree234 *t, void *e); +void *delpos234(tree234 *t, int index); + +/* + * Return the total element count of a tree234. + */ +int count234(tree234 *t); + +/* + * Split a tree234 into two valid tree234s. + * + * splitpos234 splits at a given index. If `before' is TRUE, the + * items at and after that index are left in t and the ones before + * are returned; if `before' is FALSE, the items before that index + * are left in t and the rest are returned. + * + * split234 splits at a given key. You can pass any of the + * relations used with findrel234, except for REL234_EQ. The items + * in the tree that satisfy the relation are returned; the + * remainder are left. + */ +tree234 *splitpos234(tree234 *t, int index, int before); +tree234 *split234(tree234 *t, void *e, cmpfn234 cmp, int rel); + +/* + * Join two tree234s together into a single one. + * + * All the elements in t1 are placed to the left of all the + * elements in t2. If the trees are sorted, there will be a test to + * ensure that this satisfies the ordering criterion, and NULL will + * be returned otherwise. If the trees are unsorted, there is no + * restriction on the use of join234. + * + * The tree returned is t1 (join234) or t2 (join234r), if the + * operation is successful. + */ +tree234 *join234(tree234 *t1, tree234 *t2); +tree234 *join234r(tree234 *t1, tree234 *t2); + +/* + * Make a complete copy of a tree234. Element pointers will be + * reused unless copyfn is non-NULL, in which case it will be used + * to copy each element. (copyfn takes two `void *' parameters; the + * first is private state and the second is the element. A simple + * copy routine probably won't need private state.) + */ +tree234 *copytree234(tree234 *t, copyfn234 copyfn, void *copyfnstate); + +#endif /* TREE234_H */ |