Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "commit.h"
   3#include "prio-queue.h"
   4
   5void prio_queue_reverse(struct prio_queue *queue)
   6{
   7        int i, j;
   8
   9        if (queue->compare != NULL)
  10                die("BUG: prio_queue_reverse() on non-LIFO queue");
  11        for (i = 0; i <= (j = (queue->nr - 1) - i); i++) {
  12                struct commit *swap = queue->array[i];
  13                queue->array[i] = queue->array[j];
  14                queue->array[j] = swap;
  15        }
  16}
  17
  18void clear_prio_queue(struct prio_queue *queue)
  19{
  20        free(queue->array);
  21        queue->nr = 0;
  22        queue->alloc = 0;
  23        queue->array = NULL;
  24}
  25
  26void prio_queue_put(struct prio_queue *queue, void *thing)
  27{
  28        prio_queue_compare_fn compare = queue->compare;
  29        int ix, parent;
  30
  31        /* Append at the end */
  32        ALLOC_GROW(queue->array, queue->nr + 1, queue->alloc);
  33        queue->array[queue->nr++] = thing;
  34        if (!compare)
  35                return; /* LIFO */
  36
  37        /* Bubble up the new one */
  38        for (ix = queue->nr - 1; ix; ix = parent) {
  39                parent = (ix - 1) / 2;
  40                if (compare(queue->array[parent], queue->array[ix],
  41                            queue->cb_data) <= 0)
  42                        break;
  43
  44                thing = queue->array[parent];
  45                queue->array[parent] = queue->array[ix];
  46                queue->array[ix] = thing;
  47        }
  48}
  49
  50void *prio_queue_get(struct prio_queue *queue)
  51{
  52        void *result, *swap;
  53        int ix, child;
  54        prio_queue_compare_fn compare = queue->compare;
  55
  56        if (!queue->nr)
  57                return NULL;
  58        if (!compare)
  59                return queue->array[--queue->nr]; /* LIFO */
  60
  61        result = queue->array[0];
  62        if (!--queue->nr)
  63                return result;
  64
  65        queue->array[0] = queue->array[queue->nr];
  66
  67        /* Push down the one at the root */
  68        for (ix = 0; ix * 2 + 1 < queue->nr; ix = child) {
  69                child = ix * 2 + 1; /* left */
  70                if ((child + 1 < queue->nr) &&
  71                    (compare(queue->array[child], queue->array[child + 1],
  72                             queue->cb_data) >= 0))
  73                        child++; /* use right child */
  74
  75                if (compare(queue->array[ix], queue->array[child],
  76                            queue->cb_data) <= 0)
  77                        break;
  78
  79                swap = queue->array[child];
  80                queue->array[child] = queue->array[ix];
  81                queue->array[ix] = swap;
  82        }
  83        return result;
  84}