/*
 * Copyright(C)2006 Sugimoto,Shigetoshi
 * All rights reserved.
 */

#include <general_queue.h>

static int push_item(general_queue_info_t *info, void *);
static void *get_item(general_queue_info_t *info);
static void print_queue(general_queue_info_t *info);

/*
 * queue初期化関数
 */
general_queue_info_t *init_general_queue(int size)
{
	general_queue_info_t *info;

	if (size <= 0) {
		return NULL;
	}
	info = (general_queue_info_t*)malloc(sizeof(general_queue_info_t));
	if (info == NULL) {
		return NULL;
	}
	info->head = NULL;
	info->tail = NULL;
	info->free = NULL;
	info->push_item = push_item;
	info->get_item = get_item;
	info->print_queue = print_queue;

	while (size--) {
		general_queue_item_t *q;

		q = (general_queue_item_t*)malloc(sizeof(general_queue_item_t));
		if (q == NULL) {
			break;
		}
		q->next = info->free;
		q->prev = NULL;
		q->data = NULL;
		info->free = q;
	}

	return info;
}

/*
 * queue要素を末尾に追加
 */
static int push_item(general_queue_info_t *info, void *data)
{
	general_queue_item_t *q;

	if (info->free == NULL) {
		return FALSE;
	}

	q = info->free;
	info->free = q->next;

	q->data = data;
	q->next = NULL;
	q->prev = info->tail;
	if (info->tail != NULL) {
		info->tail->next = q;
	}
	info->tail = q;
	if (info->head == NULL) {
		info->head = q;
	}

	return TRUE;
}

/*
 * queue要素を先頭から取り出し
 */
static void *get_item(general_queue_info_t *info)
{
	general_queue_item_t *q;
	void *data;

	if (info->head == NULL) {
		return NULL;
	}

	q = info->head;
	data = q->data;

	info->head = q->next;
	if (info->tail == q) {
		info->tail = NULL;
	}

	q->next = info->free;
	q->prev = NULL;
	q->data = NULL;
	info->free = q;

	return data;
}

void print_queue(general_queue_info_t *info)
{
	general_queue_item_t *item;

	if (info == NULL) {
		printf("info: 00000000\n");
		return;
	}
	printf("head: %08x\n", info->head);
	printf("tail: %08x\n", info->tail);
	printf("free: %08x\n", info->free);

	for (item = info->head; item; item = item->next) {
		printf("item %08x  next %08x  prev %08x\n",
			item, item->next, item->prev);
	}
}

// end of file