107 lines
1.9 KiB
C
107 lines
1.9 KiB
C
/*
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Copyright 2020 Google LLC
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file or at
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https://developers.google.com/open-source/licenses/bsd
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*/
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#include "pq.h"
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#include "reftable-record.h"
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#include "system.h"
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#include "basics.h"
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int pq_less(struct pq_entry *a, struct pq_entry *b)
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{
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struct strbuf ak = STRBUF_INIT;
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struct strbuf bk = STRBUF_INIT;
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int cmp = 0;
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reftable_record_key(&a->rec, &ak);
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reftable_record_key(&b->rec, &bk);
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cmp = strbuf_cmp(&ak, &bk);
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strbuf_release(&ak);
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strbuf_release(&bk);
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if (cmp == 0)
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return a->index > b->index;
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return cmp < 0;
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}
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struct pq_entry merged_iter_pqueue_top(struct merged_iter_pqueue pq)
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{
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return pq.heap[0];
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}
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int merged_iter_pqueue_is_empty(struct merged_iter_pqueue pq)
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{
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return pq.len == 0;
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}
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struct pq_entry merged_iter_pqueue_remove(struct merged_iter_pqueue *pq)
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{
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int i = 0;
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struct pq_entry e = pq->heap[0];
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pq->heap[0] = pq->heap[pq->len - 1];
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pq->len--;
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i = 0;
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while (i < pq->len) {
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int min = i;
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int j = 2 * i + 1;
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int k = 2 * i + 2;
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if (j < pq->len && pq_less(&pq->heap[j], &pq->heap[i])) {
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min = j;
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}
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if (k < pq->len && pq_less(&pq->heap[k], &pq->heap[min])) {
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min = k;
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}
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if (min == i) {
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break;
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}
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SWAP(pq->heap[i], pq->heap[min]);
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i = min;
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}
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return e;
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}
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void merged_iter_pqueue_add(struct merged_iter_pqueue *pq, struct pq_entry e)
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{
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int i = 0;
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if (pq->len == pq->cap) {
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pq->cap = 2 * pq->cap + 1;
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pq->heap = reftable_realloc(pq->heap,
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pq->cap * sizeof(struct pq_entry));
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}
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pq->heap[pq->len++] = e;
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i = pq->len - 1;
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while (i > 0) {
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int j = (i - 1) / 2;
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if (pq_less(&pq->heap[j], &pq->heap[i])) {
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break;
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}
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SWAP(pq->heap[j], pq->heap[i]);
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i = j;
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}
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}
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void merged_iter_pqueue_release(struct merged_iter_pqueue *pq)
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{
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int i = 0;
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for (i = 0; i < pq->len; i++) {
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reftable_record_release(&pq->heap[i].rec);
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}
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FREE_AND_NULL(pq->heap);
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pq->len = pq->cap = 0;
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}
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