69 lines
1.4 KiB
C
69 lines
1.4 KiB
C
/*
|
|
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-record.h"
|
|
#include "system.h"
|
|
#include "basics.h"
|
|
|
|
int pq_less(struct pq_entry *a, struct pq_entry *b)
|
|
{
|
|
int cmp = reftable_record_cmp(a->rec, b->rec);
|
|
if (cmp == 0)
|
|
return a->index > b->index;
|
|
return cmp < 0;
|
|
}
|
|
|
|
struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq)
|
|
{
|
|
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;
|
|
if (j < pq->len && pq_less(&pq->heap[j], &pq->heap[i]))
|
|
min = j;
|
|
if (k < pq->len && pq_less(&pq->heap[k], &pq->heap[min]))
|
|
min = k;
|
|
if (min == i)
|
|
break;
|
|
SWAP(pq->heap[i], pq->heap[min]);
|
|
i = min;
|
|
}
|
|
|
|
return e;
|
|
}
|
|
|
|
void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, const struct pq_entry *e)
|
|
{
|
|
size_t i = 0;
|
|
|
|
REFTABLE_ALLOC_GROW(pq->heap, pq->len + 1, pq->cap);
|
|
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;
|
|
SWAP(pq->heap[j], pq->heap[i]);
|
|
i = j;
|
|
}
|
|
}
|
|
|
|
void merged_iter_pqueue_release(struct merged_iter_pqueue *pq)
|
|
{
|
|
FREE_AND_NULL(pq->heap);
|
|
memset(pq, 0, sizeof(*pq));
|
|
}
|