cosmopolitan/libc/alg/critbit0_clear.c

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2020-06-15 14:18:57 +00:00
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/alg/alg.h"
#include "libc/alg/internal.h"
#include "libc/mem/mem.h"
static void critbit0_clear_traverse(void *top) {
unsigned char *p = top;
if (1 & (intptr_t)p) {
struct CritbitNode *q = (void *)(p - 1);
critbit0_clear_traverse(q->child[0]);
critbit0_clear_traverse(q->child[1]);
free(q), q = NULL;
} else {
free(p), p = NULL;
}
}
/**
* Removes all items from 𝑡.
* @param t tree
* @note h/t djb and agl
*/
void critbit0_clear(struct critbit0 *t) {
if (t->root) {
critbit0_clear_traverse(t->root);
t->root = NULL;
}
t->count = 0;
}