#include<stdio.h>
#include<stdlib.h>
#include<stdbool.h>
#include "array_index.h"
#include "../../common/common_user.h"

ARRAY g_user_index_head = { 0 };
ARRAY g_group_index_head = { 0 };

#define INDEX_LEN_16 

#ifdef INDEX_LEN_16
#define INDEX_LEN 16
#define INDEX_LOW_MASK 0x0000ffff
#define INDEX_HI_MASK 0xffff0000
#else
#endif


#define CUR_INDEX (head->cur)
#define MAX_INDEX (head->size)
#define HI_ELEMENT_GET(element)   ((element) >> INDEX_LEN)
#define HI_ELEMENT_SET(element, value)   (((element) & INDEX_LOW_MASK) | ((value) << INDEX_LEN))
#define LOW_ELEMENT_GET(element)  ((element) & INDEX_LOW_MASK)
#define LOW_ELEMENT_SET(element, value)   (((element) & INDEX_HI_MASK) | ((value) & INDEX_LOW_MASK))

/*
*初始化索引
*失败：1
*成功：0
*/
int init_array(ARRAY* head, int index_size)
{
	int i;

	head->array = malloc(sizeof(head->array) * index_size);
	if (NULL == head->array)
	{
		return 1;
	}

	//head->cur = 1;
	//head->size = index_size;
	CUR_INDEX = 1;
	MAX_INDEX = index_size;

	/*初始化第一个值*/
	head->array[0] = HI_ELEMENT_SET(head->array[0], 0);
	head->array[0] = LOW_ELEMENT_SET(head->array[0], 1);

	for (i = 1; i < index_size - 1; i++)
	{
		head->array[i] = HI_ELEMENT_SET(head->array[i], i - 1);
		head->array[i] = LOW_ELEMENT_SET(head->array[i], i + 1);
	}

	/*初始化最后一个值*/
	head->array[i] = HI_ELEMENT_SET(head->array[i], i - 1);
	head->array[i] = LOW_ELEMENT_SET(head->array[i], 0);
	return 0;
}

/* 顺序分配index */
unsigned short alloc_index(ARRAY* head)
{
	unsigned short index = CUR_INDEX;  //获取cur

	/*判断index无效，返回0*/
	if ((0 == index) || ((MAX_INDEX - 1) <= index))
	{
		return INVALID_INDEX;
	}

	CUR_INDEX = LOW_ELEMENT_GET(head->array[index]);  //移动cur
	head->array[index] = 0;  //被使用过的元素置0
	return index;  //返回被使用的下标作为ID

	//if ((0 < index) || ((MAX_INDEX-1) > index))

}

/* 指定分配index 
*成功返回：index
*失败返回：0
*/
unsigned short alloc_index_special(ARRAY* head, unsigned short index)
{
	unsigned short hi_index, low_index;

	/*判断index无效，返回0*/
	if ((0 == index) || ((MAX_INDEX - 1) <= index))
	{
		return INVALID_INDEX;
	}

	/* 判断已经被使用过了，返回0 */
	if (INVALID_INDEX == head->array[index])
	{
		return INVALID_INDEX;
	}

	/* 判断和顺序插入相同 */
	if (CUR_INDEX == index)
	{
		return alloc_index(head);
	}

	low_index = LOW_ELEMENT_GET(head->array[index]);
	hi_index = HI_ELEMENT_GET(head->array[index]);

	head->array[low_index] = HI_ELEMENT_SET(head->array[low_index], hi_index);
	head->array[hi_index] = LOW_ELEMENT_SET(head->array[hi_index], low_index);
	head->array[index] = 0;
	return index;
}

void free_index(ARRAY* head, unsigned short index)
{
	unsigned short cur_index = CUR_INDEX;

	if ((0 == index) || ((MAX_INDEX - 1) <= index))
	{
		return;
	}

	if (INVALID_INDEX != head->array[index])
	{
		return;
	}

	CUR_INDEX = index;
	head->array[index] = LOW_ELEMENT_SET(head->array[index], cur_index);
	head->array[cur_index] = HI_ELEMENT_SET(head->array[cur_index], index);
	return;
}