| #ifndef PRIO_QUEUE_H |
| #define PRIO_QUEUE_H |
| |
| /* |
| * A priority queue implementation, primarily for keeping track of |
| * commits in the 'date-order' so that we process them from new to old |
| * as they are discovered, but can be used to hold any pointer to |
| * struct. The caller is responsible for supplying a function to |
| * compare two "things". |
| * |
| * Alternatively, this data structure can also be used as a LIFO stack |
| * by specifying NULL as the comparison function. |
| */ |
| |
| /* |
| * Compare two "things", one and two; the third parameter is cb_data |
| * in the prio_queue structure. The result is returned as a sign of |
| * the return value, being the same as the sign of the result of |
| * subtracting "two" from "one" (i.e. negative if "one" sorts earlier |
| * than "two"). |
| */ |
| typedef int (*prio_queue_compare_fn)(const void *one, const void *two, void *cb_data); |
| |
| struct prio_queue { |
| prio_queue_compare_fn compare; |
| void *cb_data; |
| int alloc, nr; |
| void **array; |
| }; |
| |
| /* |
| * Add the "thing" to the queue. |
| */ |
| extern void prio_queue_put(struct prio_queue *, void *thing); |
| |
| /* |
| * Extract the "thing" that compares the smallest out of the queue, |
| * or NULL. If compare function is NULL, the queue acts as a LIFO |
| * stack. |
| */ |
| extern void *prio_queue_get(struct prio_queue *); |
| |
| extern void clear_prio_queue(struct prio_queue *); |
| |
| /* Reverse the LIFO elements */ |
| extern void prio_queue_reverse(struct prio_queue *); |
| |
| #endif /* PRIO_QUEUE_H */ |