95 lines
1.6 KiB
Text
95 lines
1.6 KiB
Text
#include <stdlib.h>
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#include <skipstone/queue.h>
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struct entry {
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void *value;
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struct entry *next, *prev;
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};
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struct _skipstone_queue {
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size_t count;
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struct entry *first, *last;
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};
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skipstone_queue *skipstone_queue_new() {
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skipstone_queue *queue;
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if ((queue = malloc(sizeof(*queue))) == NULL) {
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goto error_malloc_queue;
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}
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queue->count = 0;
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queue->first = NULL;
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queue->last = NULL;
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return queue;
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error_malloc_queue:
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return NULL;
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}
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void skipstone_queue_destroy(skipstone_queue *queue) {
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while (queue->first) {
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struct entry *entry = queue->first;
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queue->first = entry->next;
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free(entry);
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}
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free(queue);
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}
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size_t skipstone_queue_count(skipstone_queue *queue) {
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return queue->count;
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}
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int skipstone_queue_add(skipstone_queue *queue, void *value) {
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struct entry *next;
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if ((next = malloc(sizeof(*next))) == NULL) {
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goto error_malloc_next;
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}
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next->value = value;
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next->next = NULL;
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next->prev = queue->last;
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if (queue->first == NULL) {
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queue->first = next;
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}
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if (queue->last) {
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next->prev = queue->last;
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queue->last->next = next;
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}
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queue->last = next;
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queue->count++;
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return 0;
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error_malloc_next:
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return -1;
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}
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int skipstone_queue_remove(skipstone_queue *queue, void **value) {
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struct entry *first = queue->first;
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if (queue->count == 0) {
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return 0;
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}
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*value = first->value;
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queue->first = first->next;
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queue->count--;
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if (queue->count == 0) {
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queue->last = NULL;
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}
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free(first);
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return 1;
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}
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