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3c57836988
Rename the .nr member to .nr_ so that callers outside prio-queue.c that directly reference .nr get a compilation error. This catches both existing misuse and future in-flight topics. Add prio_queue_size() for callers that need to know the element count and prio_queue_for_each() for callers that need to walk all elements. Convert all external .nr users: - Loop conditions: use prio_queue_size(), prio_queue_get(), or prio_queue_peek() as the loop condition - Array iterations: use prio_queue_for_each() Signed-off-by: Kristofer Karlsson <krka@spotify.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
119 lines
2.6 KiB
C
119 lines
2.6 KiB
C
#include "git-compat-util.h"
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#include "prio-queue.h"
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static inline int compare(struct prio_queue *queue, size_t i, size_t j)
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{
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int cmp = queue->compare(queue->array[i].data, queue->array[j].data,
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queue->cb_data);
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if (!cmp)
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cmp = (queue->array[i].ctr > queue->array[j].ctr) -
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(queue->array[i].ctr < queue->array[j].ctr);
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return cmp;
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}
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static inline void swap(struct prio_queue *queue, size_t i, size_t j)
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{
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SWAP(queue->array[i], queue->array[j]);
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}
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void prio_queue_reverse(struct prio_queue *queue)
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{
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size_t i, j;
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if (queue->compare)
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BUG("prio_queue_reverse() on non-LIFO queue");
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if (!queue->nr_)
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return;
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for (i = 0; i < (j = (queue->nr_ - 1) - i); i++)
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swap(queue, i, j);
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}
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void clear_prio_queue(struct prio_queue *queue)
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{
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FREE_AND_NULL(queue->array);
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queue->nr_ = 0;
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queue->alloc = 0;
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queue->insertion_ctr = 0;
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}
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void prio_queue_put(struct prio_queue *queue, void *thing)
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{
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size_t ix, parent;
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/* Append at the end */
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ALLOC_GROW(queue->array, queue->nr_ + 1, queue->alloc);
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queue->array[queue->nr_].ctr = queue->insertion_ctr++;
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queue->array[queue->nr_].data = thing;
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queue->nr_++;
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if (!queue->compare)
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return; /* LIFO */
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/* Bubble up the new one */
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for (ix = queue->nr_ - 1; ix; ix = parent) {
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parent = (ix - 1) / 2;
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if (compare(queue, parent, ix) <= 0)
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break;
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swap(queue, parent, ix);
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}
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}
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static void sift_down_root(struct prio_queue *queue)
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{
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size_t ix, child;
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/* Push down the one at the root */
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for (ix = 0; ix * 2 + 1 < queue->nr_; ix = child) {
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child = ix * 2 + 1; /* left */
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if (child + 1 < queue->nr_ &&
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compare(queue, child, child + 1) >= 0)
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child++; /* use right child */
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if (compare(queue, ix, child) <= 0)
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break;
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swap(queue, child, ix);
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}
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}
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void *prio_queue_get(struct prio_queue *queue)
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{
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void *result;
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if (!queue->nr_)
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return NULL;
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if (!queue->compare)
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return queue->array[--queue->nr_].data; /* LIFO */
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result = queue->array[0].data;
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if (!--queue->nr_)
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return result;
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queue->array[0] = queue->array[queue->nr_];
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sift_down_root(queue);
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return result;
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}
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void *prio_queue_peek(struct prio_queue *queue)
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{
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if (!queue->nr_)
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return NULL;
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if (!queue->compare)
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return queue->array[queue->nr_ - 1].data;
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return queue->array[0].data;
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}
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void prio_queue_replace(struct prio_queue *queue, void *thing)
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{
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if (!queue->nr_) {
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prio_queue_put(queue, thing);
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} else if (!queue->compare) {
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queue->array[queue->nr_ - 1].ctr = queue->insertion_ctr++;
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queue->array[queue->nr_ - 1].data = thing;
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} else {
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queue->array[0].ctr = queue->insertion_ctr++;
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queue->array[0].data = thing;
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sift_down_root(queue);
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}
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}
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