diff options
Diffstat (limited to 'sys/cam/cam_queue.c')
-rw-r--r-- | sys/cam/cam_queue.c | 57 |
1 files changed, 36 insertions, 21 deletions
diff --git a/sys/cam/cam_queue.c b/sys/cam/cam_queue.c index edebfd57fe29..1262b6e139bf 100644 --- a/sys/cam/cam_queue.c +++ b/sys/cam/cam_queue.c @@ -25,7 +25,7 @@ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * - * $Id: cam_queue.c,v 1.1 1998/09/15 06:33:23 gibbs Exp $ + * $Id: cam_queue.c,v 1.2 1999/04/07 22:57:48 gibbs Exp $ */ #include <sys/param.h> #include <sys/systm.h> @@ -72,6 +72,11 @@ camq_init(struct camq *camq, int size) printf("camq_init: - cannot malloc array!\n"); return (1); } + /* + * Heap algorithms like everything numbered from 1, so + * offset our pointer into the heap array by one element. + */ + camq->queue_array--; } return (0); } @@ -95,6 +100,11 @@ void camq_fini(struct camq *queue) { if (queue->queue_array != NULL) { + /* + * Heap algorithms like everything numbered from 1, so + * our pointer into the heap array is offset by one element. + */ + queue->queue_array++; free(queue->queue_array, M_DEVBUF); } } @@ -115,20 +125,26 @@ camq_resize(struct camq *queue, int new_size) /* Couldn't satisfy request */ return (CAM_RESRC_UNAVAIL); } + /* + * Heap algorithms like everything numbered from 1, so + * remember that our pointer into the heap array is offset + * by one element. + */ if (queue->queue_array != NULL) { + queue->queue_array++; bcopy(queue->queue_array, new_array, queue->entries * sizeof(cam_pinfo *)); free(queue->queue_array, M_DEVBUF); } - queue->queue_array = new_array; + queue->queue_array = new_array-1; queue->array_size = new_size; return (CAM_REQ_CMP); } /* * camq_insert: Given an array of cam_pinfo* elememnts with - * the Heap(0, num_elements) property and array_size - num_elements >= 1, - * output Heap(0, num_elements+1) including new_entry in the array. + * the Heap(1, num_elements) property and array_size - num_elements >= 1, + * output Heap(1, num_elements+1) including new_entry in the array. */ void camq_insert(struct camq *queue, cam_pinfo *new_entry) @@ -137,17 +153,17 @@ camq_insert(struct camq *queue, cam_pinfo *new_entry) if (queue->entries >= queue->array_size) panic("camq_insert: Attempt to insert into a full queue"); #endif + queue->entries++; queue->queue_array[queue->entries] = new_entry; new_entry->index = queue->entries; if (queue->entries != 0) heap_up(queue->queue_array, queue->entries); - queue->entries++; } /* * camq_remove: Given an array of cam_pinfo* elevements with the - * Heap(0, num_elements) property and an index such that 0 <= index <= - * num_elements, remove that entry and restore the Heap(0, num_elements-1) + * Heap(1, num_elements) property and an index such that 1 <= index <= + * num_elements, remove that entry and restore the Heap(1, num_elements-1) * property. */ cam_pinfo * @@ -155,22 +171,22 @@ camq_remove(struct camq *queue, int index) { cam_pinfo *removed_entry; - if ((queue->entries - index) <= 0) + if (index == 0 || index > queue->entries) return (NULL); removed_entry = queue->queue_array[index]; - queue->entries--; if (queue->entries != index) { queue->queue_array[index] = queue->queue_array[queue->entries]; queue->queue_array[index]->index = index; - heap_down(queue->queue_array, index, queue->entries); + heap_down(queue->queue_array, index, queue->entries - 1); } removed_entry->index = CAM_UNQUEUED_INDEX; + queue->entries--; return (removed_entry); } /* * camq_change_priority: Given an array of cam_pinfo* elements with the - * Heap(0, num_entries) property, an index such that 0 <= index <= num_elements, + * Heap(1, num_entries) property, an index such that 1 <= index <= num_elements, * and an new priority for the element at index, change the priority of * element index and restore the Heap(0, num_elements) property. */ @@ -352,8 +368,8 @@ swap(cam_pinfo **queue_array, int i, int j) /* * heap_up: Given an array of cam_pinfo* elements with the - * Heap(0, new_index-1) property and a new element in location - * new_index, output Heap(0, new_index). + * Heap(1, new_index-1) property and a new element in location + * new_index, output Heap(1, new_index). */ static void heap_up(cam_pinfo **queue_array, int new_index) @@ -363,9 +379,9 @@ heap_up(cam_pinfo **queue_array, int new_index) child = new_index; - while (child != 0) { + while (child != 1) { - parent = (child - 1) >> 1; + parent = child >> 1; if (queue_cmp(queue_array, parent, child) <= 0) break; swap(queue_array, parent, child); @@ -375,8 +391,8 @@ heap_up(cam_pinfo **queue_array, int new_index) /* * heap_down: Given an array of cam_pinfo* elements with the - * Heap(index + 1, num_entries - 1) property with index containing - * an unsorted entry, output Heap(0, num_entries - 1). + * Heap(index + 1, num_entries) property with index containing + * an unsorted entry, output Heap(index, num_entries). */ static void heap_down(cam_pinfo **queue_array, int index, int num_entries) @@ -385,10 +401,10 @@ heap_down(cam_pinfo **queue_array, int index, int num_entries) int parent; parent = index; - child = (parent << 1) + 1; - for (; child < num_entries; child = (parent << 1) + 1) { + child = parent << 1; + for (; child <= num_entries; child = parent << 1) { - if (child + 1 < num_entries) { + if (child < num_entries) { /* child+1 is the right child of parent */ if (queue_cmp(queue_array, child + 1, child) < 0) child++; @@ -400,4 +416,3 @@ heap_down(cam_pinfo **queue_array, int index, int num_entries) parent = child; } } - |