| #include "git-compat-util.h" |
| #include "alloc.h" |
| #include "prio-queue.h" |
| |
| static inline int compare(struct prio_queue *queue, int i, int j) |
| { |
| int cmp = queue->compare(queue->array[i].data, queue->array[j].data, |
| queue->cb_data); |
| if (!cmp) |
| cmp = queue->array[i].ctr - queue->array[j].ctr; |
| return cmp; |
| } |
| |
| static inline void swap(struct prio_queue *queue, int i, int j) |
| { |
| SWAP(queue->array[i], queue->array[j]); |
| } |
| |
| void prio_queue_reverse(struct prio_queue *queue) |
| { |
| int i, j; |
| |
| if (queue->compare) |
| BUG("prio_queue_reverse() on non-LIFO queue"); |
| for (i = 0; i < (j = (queue->nr - 1) - i); i++) |
| swap(queue, i, j); |
| } |
| |
| void clear_prio_queue(struct prio_queue *queue) |
| { |
| FREE_AND_NULL(queue->array); |
| queue->nr = 0; |
| queue->alloc = 0; |
| queue->insertion_ctr = 0; |
| } |
| |
| void prio_queue_put(struct prio_queue *queue, void *thing) |
| { |
| int ix, parent; |
| |
| /* Append at the end */ |
| ALLOC_GROW(queue->array, queue->nr + 1, queue->alloc); |
| queue->array[queue->nr].ctr = queue->insertion_ctr++; |
| queue->array[queue->nr].data = thing; |
| queue->nr++; |
| if (!queue->compare) |
| return; /* LIFO */ |
| |
| /* Bubble up the new one */ |
| for (ix = queue->nr - 1; ix; ix = parent) { |
| parent = (ix - 1) / 2; |
| if (compare(queue, parent, ix) <= 0) |
| break; |
| |
| swap(queue, parent, ix); |
| } |
| } |
| |
| void *prio_queue_get(struct prio_queue *queue) |
| { |
| void *result; |
| int ix, child; |
| |
| if (!queue->nr) |
| return NULL; |
| if (!queue->compare) |
| return queue->array[--queue->nr].data; /* LIFO */ |
| |
| result = queue->array[0].data; |
| if (!--queue->nr) |
| return result; |
| |
| queue->array[0] = queue->array[queue->nr]; |
| |
| /* Push down the one at the root */ |
| for (ix = 0; ix * 2 + 1 < queue->nr; ix = child) { |
| child = ix * 2 + 1; /* left */ |
| if (child + 1 < queue->nr && |
| compare(queue, child, child + 1) >= 0) |
| child++; /* use right child */ |
| |
| if (compare(queue, ix, child) <= 0) |
| break; |
| |
| swap(queue, child, ix); |
| } |
| return result; |
| } |
| |
| void *prio_queue_peek(struct prio_queue *queue) |
| { |
| if (!queue->nr) |
| return NULL; |
| if (!queue->compare) |
| return queue->array[queue->nr - 1].data; |
| return queue->array[0].data; |
| } |