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This file is part of PulseAudio.
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Copyright 2008 Lennart Poettering
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PulseAudio is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation; either version 2 of the License,
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or (at your option) any later version.
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PulseAudio is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with PulseAudio; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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#include <pulse/xmalloc.h>
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#include <pulsecore/flist.h>
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struct pa_prioq_item {
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pa_prioq_item **items;
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pa_compare_func_t compare_func;
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PA_STATIC_FLIST_DECLARE(items, 0, pa_xfree);
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pa_prioq *pa_prioq_new(pa_compare_func_t compare_func) {
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q = pa_xnew(pa_prioq, 1);
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q->compare_func = compare_func;
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q->items = pa_xnew(pa_prioq_item*, q->n_allocated);
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void pa_prioq_free(pa_prioq *q, pa_free2_cb_t free_cb, void *userdata) {
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pa_prioq_item **i, **e;
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for (i = q->items, e = q->items + q->n_items; i < e; i++) {
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free_cb((*i)->value, userdata);
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static void shuffle_up(pa_prioq *q, pa_prioq_item *i) {
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if (q->compare_func(q->items[k]->value, i->value) < 0)
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q->items[j] = q->items[k];
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pa_prioq_item* pa_prioq_put(pa_prioq *q, void *p) {
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if (q->n_items >= q->n_allocated) {
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q->n_allocated = PA_MAX(q->n_items+1, q->n_allocated)*2;
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q->items = pa_xrealloc(q->items, sizeof(pa_prioq_item*) * q->n_allocated);
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if (!(i = pa_flist_pop(PA_STATIC_FLIST_GET(items))))
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i = pa_xnew(pa_prioq_item, 1);
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i->idx = q->n_items++;
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void* pa_prioq_peek(pa_prioq *q) {
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return q->items[0]->value;
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void* pa_prioq_pop(pa_prioq *q){
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return pa_prioq_remove(q, q->items[0]);
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static void swap(pa_prioq *q, unsigned j, unsigned k) {
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pa_assert(j < q->n_items);
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pa_assert(k < q->n_items);
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pa_assert(q->items[j]->idx == j);
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pa_assert(q->items[k]->idx == k);
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q->items[j]->idx = k;
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q->items[j] = q->items[k];
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q->items[k]->idx = j;
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static void shuffle_down(pa_prioq *q, unsigned idx) {
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pa_assert(idx < q->n_items);
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k = (idx+1)*2; /* right child */
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j = k-1; /* left child */
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if (q->compare_func(q->items[j]->value, q->items[idx]->value) < 0)
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/* So our left child is smaller than we are, let's
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* remember this fact */
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if (k < q->n_items &&
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q->compare_func(q->items[k]->value, q->items[s]->value) < 0)
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/* So our right child is smaller than we are, let's
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* remember this fact */
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/* s now points to the smallest of the three items */
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/* No swap necessary, we're done */
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void* pa_prioq_remove(pa_prioq *q, pa_prioq_item *i) {
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pa_assert(q->n_items >= 1);
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if (q->n_items-1 == i->idx) {
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/* We are the last entry, so let's just remove us and good */
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/* We are not the last entry, we need to replace ourselves
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* with the last node and reshuffle */
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q->items[i->idx] = q->items[q->n_items-1];
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q->items[i->idx]->idx = i->idx;
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shuffle_down(q, i->idx);
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if (pa_flist_push(PA_STATIC_FLIST_GET(items), i) < 0)
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unsigned pa_prioq_size(pa_prioq *q) {
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pa_bool_t pa_prioq_isempty(pa_prioq *q) {
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return q->n_items == 0;
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void pa_prioq_reshuffle(pa_prioq *q, pa_prioq_item *i) {
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/* This will move the entry down as far as necessary */
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shuffle_down(q, i->idx);
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/* And this will move the entry up as far as necessary */