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/*
* Copyright 2020 Google LLC
*
* Use of this source code is governed by a BSD-style
* license that can be found in the LICENSE file or at
* https://developers.google.com/open-source/licenses/bsd
*/
#include "pq.h"
#include "reftable-error.h"
#include "reftable-record.h"
#include "system.h"
#include "basics.h"
int pq_less(struct pq_entry *a, struct pq_entry *b)
{
int cmp, err;
err = reftable_record_cmp(a->rec, b->rec, &cmp);
if (err < 0)
return err;
if (cmp == 0)
return a->index > b->index;
return cmp < 0;
}
int merged_iter_pqueue_remove(struct merged_iter_pqueue *pq, struct pq_entry *out)
{
size_t i = 0;
struct pq_entry e = pq->heap[0];
pq->heap[0] = pq->heap[pq->len - 1];
pq->len--;
while (i < pq->len) {
size_t min = i;
size_t j = 2 * i + 1;
size_t k = 2 * i + 2;
int cmp;
if (j < pq->len) {
cmp = pq_less(&pq->heap[j], &pq->heap[i]);
if (cmp < 0)
return -1;
else if (cmp)
min = j;
}
if (k < pq->len) {
cmp = pq_less(&pq->heap[k], &pq->heap[min]);
if (cmp < 0)
return -1;
else if (cmp)
min = k;
}
if (min == i)
break;
REFTABLE_SWAP(pq->heap[i], pq->heap[min]);
i = min;
}
if (out)
*out = e;
return 0;
}
int merged_iter_pqueue_add(struct merged_iter_pqueue *pq, const struct pq_entry *e)
{
size_t i = 0;
REFTABLE_ALLOC_GROW_OR_NULL(pq->heap, pq->len + 1, pq->cap);
if (!pq->heap)
return REFTABLE_OUT_OF_MEMORY_ERROR;
pq->heap[pq->len++] = *e;
i = pq->len - 1;
while (i > 0) {
size_t j = (i - 1) / 2;
if (pq_less(&pq->heap[j], &pq->heap[i]))
break;
REFTABLE_SWAP(pq->heap[j], pq->heap[i]);
i = j;
}
return 0;
}
void merged_iter_pqueue_release(struct merged_iter_pqueue *pq)
{
REFTABLE_FREE_AND_NULL(pq->heap);
memset(pq, 0, sizeof(*pq));
}
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