307 lines
9.6 KiB
C
307 lines
9.6 KiB
C
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/* The MIT License
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Copyright (c) 2021 by Attractive Chaos <attractor@live.co.uk>
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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*/
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/* An example:
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include "kavl-lite.h"
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struct my_node {
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char key;
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KAVLL_HEAD(struct my_node) head;
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};
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#define my_cmp(p, q) (((q)->key < (p)->key) - ((p)->key < (q)->key))
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KAVLL_INIT(my, struct my_node, head, my_cmp)
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int main(void) {
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const char *str = "MNOLKQOPHIA"; // from wiki, except a duplicate
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struct my_node *root = 0;
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int i, l = strlen(str);
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for (i = 0; i < l; ++i) { // insert in the input order
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struct my_node *q, *p = malloc(sizeof(*p));
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p->key = str[i];
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q = my_insert(&root, p);
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if (p != q) free(p); // if already present, free
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}
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my_itr_t itr;
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my_itr_first(root, &itr); // place at first
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do { // traverse
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const struct my_node *p = kavll_at(&itr);
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putchar(p->key);
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free((void*)p); // free node
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} while (my_itr_next(&itr));
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putchar('\n');
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return 0;
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}
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*/
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#ifndef KAVL_LITE_H
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#define KAVL_LITE_H
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#ifdef __STRICT_ANSI__
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#define inline __inline__
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#endif
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#define KAVLL_MAX_DEPTH 64
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#define KAVLL_HEAD(__type) \
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struct { \
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__type *p[2]; \
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signed char balance; /* balance factor */ \
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}
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#define __KAVLL_FIND(pre, __scope, __type, __head, __cmp) \
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__scope __type *pre##_find(const __type *root, const __type *x) { \
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const __type *p = root; \
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while (p != 0) { \
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int cmp; \
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cmp = __cmp(x, p); \
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if (cmp < 0) p = p->__head.p[0]; \
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else if (cmp > 0) p = p->__head.p[1]; \
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else break; \
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} \
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return (__type*)p; \
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}
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#define __KAVLL_ROTATE(pre, __type, __head) \
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/* one rotation: (a,(b,c)q)p => ((a,b)p,c)q */ \
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static inline __type *pre##_rotate1(__type *p, int dir) { /* dir=0 to left; dir=1 to right */ \
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int opp = 1 - dir; /* opposite direction */ \
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__type *q = p->__head.p[opp]; \
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p->__head.p[opp] = q->__head.p[dir]; \
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q->__head.p[dir] = p; \
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return q; \
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} \
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/* two consecutive rotations: (a,((b,c)r,d)q)p => ((a,b)p,(c,d)q)r */ \
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static inline __type *pre##_rotate2(__type *p, int dir) { \
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int b1, opp = 1 - dir; \
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__type *q = p->__head.p[opp], *r = q->__head.p[dir]; \
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p->__head.p[opp] = r->__head.p[dir]; \
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r->__head.p[dir] = p; \
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q->__head.p[dir] = r->__head.p[opp]; \
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r->__head.p[opp] = q; \
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b1 = dir == 0? +1 : -1; \
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if (r->__head.balance == b1) q->__head.balance = 0, p->__head.balance = -b1; \
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else if (r->__head.balance == 0) q->__head.balance = p->__head.balance = 0; \
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else q->__head.balance = b1, p->__head.balance = 0; \
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r->__head.balance = 0; \
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return r; \
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}
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#define __KAVLL_INSERT(pre, __scope, __type, __head, __cmp) \
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__scope __type *pre##_insert(__type **root_, __type *x) { \
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unsigned char stack[KAVLL_MAX_DEPTH]; \
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__type *path[KAVLL_MAX_DEPTH]; \
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__type *bp, *bq; \
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__type *p, *q, *r = 0; /* _r_ is potentially the new root */ \
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int which = 0, top, b1, path_len; \
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bp = *root_, bq = 0; \
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/* find the insertion location */ \
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for (p = bp, q = bq, top = path_len = 0; p; q = p, p = p->__head.p[which]) { \
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int cmp; \
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cmp = __cmp(x, p); \
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if (cmp == 0) return p; \
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if (p->__head.balance != 0) \
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bq = q, bp = p, top = 0; \
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stack[top++] = which = (cmp > 0); \
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path[path_len++] = p; \
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} \
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x->__head.balance = 0, x->__head.p[0] = x->__head.p[1] = 0; \
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if (q == 0) *root_ = x; \
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else q->__head.p[which] = x; \
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if (bp == 0) return x; \
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for (p = bp, top = 0; p != x; p = p->__head.p[stack[top]], ++top) /* update balance factors */ \
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if (stack[top] == 0) --p->__head.balance; \
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else ++p->__head.balance; \
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if (bp->__head.balance > -2 && bp->__head.balance < 2) return x; /* no re-balance needed */ \
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/* re-balance */ \
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which = (bp->__head.balance < 0); \
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b1 = which == 0? +1 : -1; \
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q = bp->__head.p[1 - which]; \
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if (q->__head.balance == b1) { \
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r = pre##_rotate1(bp, which); \
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q->__head.balance = bp->__head.balance = 0; \
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} else r = pre##_rotate2(bp, which); \
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if (bq == 0) *root_ = r; \
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else bq->__head.p[bp != bq->__head.p[0]] = r; \
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return x; \
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}
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#define __KAVLL_ERASE(pre, __scope, __type, __head, __cmp) \
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__scope __type *pre##_erase(__type **root_, const __type *x) { \
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__type *p, *path[KAVLL_MAX_DEPTH], fake; \
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unsigned char dir[KAVLL_MAX_DEPTH]; \
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int d = 0, cmp; \
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fake.__head.p[0] = *root_, fake.__head.p[1] = 0; \
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if (x) { \
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for (cmp = -1, p = &fake; cmp; cmp = __cmp(x, p)) { \
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int which = (cmp > 0); \
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dir[d] = which; \
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path[d++] = p; \
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p = p->__head.p[which]; \
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if (p == 0) return 0; \
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} \
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} else { \
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for (p = &fake; p; p = p->__head.p[0]) \
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dir[d] = 0, path[d++] = p; \
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p = path[--d]; \
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} \
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if (p->__head.p[1] == 0) { /* ((1,.)2,3)4 => (1,3)4; p=2 */ \
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path[d-1]->__head.p[dir[d-1]] = p->__head.p[0]; \
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} else { \
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__type *q = p->__head.p[1]; \
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if (q->__head.p[0] == 0) { /* ((1,2)3,4)5 => ((1)2,4)5; p=3 */ \
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q->__head.p[0] = p->__head.p[0]; \
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q->__head.balance = p->__head.balance; \
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path[d-1]->__head.p[dir[d-1]] = q; \
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path[d] = q, dir[d++] = 1; \
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} else { /* ((1,((.,2)3,4)5)6,7)8 => ((1,(2,4)5)3,7)8; p=6 */ \
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__type *r; \
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int e = d++; /* backup _d_ */\
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for (;;) { \
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dir[d] = 0; \
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path[d++] = q; \
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r = q->__head.p[0]; \
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if (r->__head.p[0] == 0) break; \
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q = r; \
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} \
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r->__head.p[0] = p->__head.p[0]; \
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q->__head.p[0] = r->__head.p[1]; \
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r->__head.p[1] = p->__head.p[1]; \
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r->__head.balance = p->__head.balance; \
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path[e-1]->__head.p[dir[e-1]] = r; \
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path[e] = r, dir[e] = 1; \
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} \
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} \
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while (--d > 0) { \
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__type *q = path[d]; \
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int which, other, b1 = 1, b2 = 2; \
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which = dir[d], other = 1 - which; \
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if (which) b1 = -b1, b2 = -b2; \
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q->__head.balance += b1; \
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if (q->__head.balance == b1) break; \
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else if (q->__head.balance == b2) { \
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__type *r = q->__head.p[other]; \
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if (r->__head.balance == -b1) { \
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path[d-1]->__head.p[dir[d-1]] = pre##_rotate2(q, which); \
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} else { \
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path[d-1]->__head.p[dir[d-1]] = pre##_rotate1(q, which); \
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if (r->__head.balance == 0) { \
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r->__head.balance = -b1; \
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q->__head.balance = b1; \
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break; \
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} else r->__head.balance = q->__head.balance = 0; \
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} \
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} \
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} \
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*root_ = fake.__head.p[0]; \
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return p; \
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}
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#define kavll_free(__type, __head, __root, __free) do { \
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__type *_p, *_q; \
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for (_p = __root; _p; _p = _q) { \
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if (_p->__head.p[0] == 0) { \
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_q = _p->__head.p[1]; \
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__free(_p); \
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} else { \
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_q = _p->__head.p[0]; \
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_p->__head.p[0] = _q->__head.p[1]; \
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_q->__head.p[1] = _p; \
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} \
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} \
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} while (0)
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#define kavll_size(__type, __head, __root, __cnt) do { \
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__type *_p, *_q; \
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*(__cnt) = 0; \
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for (_p = __root; _p; _p = _q) { \
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if (_p->__head.p[0] == 0) { \
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_q = _p->__head.p[1]; \
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++*(__cnt); \
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} else { \
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_q = _p->__head.p[0]; \
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_p->__head.p[0] = _q->__head.p[1]; \
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_q->__head.p[1] = _p; \
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} \
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} \
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} while (0)
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#define __KAVLL_ITR(pre, __scope, __type, __head, __cmp) \
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typedef struct pre##_itr_t { \
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const __type *stack[KAVLL_MAX_DEPTH], **top, *right; /* _right_ points to the right child of *top */ \
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} pre##_itr_t; \
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__scope void pre##_itr_first(const __type *root, struct pre##_itr_t *itr) { \
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const __type *p; \
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for (itr->top = itr->stack - 1, p = root; p; p = p->__head.p[0]) \
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*++itr->top = p; \
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itr->right = (*itr->top)->__head.p[1]; \
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} \
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__scope int pre##_itr_find(const __type *root, const __type *x, struct pre##_itr_t *itr) { \
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const __type *p = root; \
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itr->top = itr->stack - 1; \
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while (p != 0) { \
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int cmp; \
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cmp = __cmp(x, p); \
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if (cmp < 0) *++itr->top = p, p = p->__head.p[0]; \
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else if (cmp > 0) p = p->__head.p[1]; \
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else break; \
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} \
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if (p) { \
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*++itr->top = p; \
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itr->right = p->__head.p[1]; \
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return 1; \
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} else if (itr->top >= itr->stack) { \
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itr->right = (*itr->top)->__head.p[1]; \
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return 0; \
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} else return 0; \
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} \
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__scope int pre##_itr_next(struct pre##_itr_t *itr) { \
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for (;;) { \
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const __type *p; \
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for (p = itr->right, --itr->top; p; p = p->__head.p[0]) \
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*++itr->top = p; \
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if (itr->top < itr->stack) return 0; \
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itr->right = (*itr->top)->__head.p[1]; \
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return 1; \
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} \
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}
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#define kavll_at(itr) ((itr)->top < (itr)->stack? 0 : *(itr)->top)
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#define KAVLL_INIT2(pre, __scope, __type, __head, __cmp) \
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__KAVLL_FIND(pre, __scope, __type, __head, __cmp) \
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__KAVLL_ROTATE(pre, __type, __head) \
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__KAVLL_INSERT(pre, __scope, __type, __head, __cmp) \
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__KAVLL_ERASE(pre, __scope, __type, __head, __cmp) \
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__KAVLL_ITR(pre, __scope, __type, __head, __cmp)
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#define KAVLL_INIT(pre, __type, __head, __cmp) \
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KAVLL_INIT2(pre,, __type, __head, __cmp)
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#endif
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