// NODEMGR.H - NodeMgr Class Header

#ifndef NODEMGR_HPP
#define NODEMGR_HPP

#include <stddef.h>
#include <stdio.h>
#include <string.h>

const stLeaf = -1; 
const stNotLeaf = 0;

const noEmpty = -1;
const noFull = -2;
const noDuplicate = -3; 
const noNoSelect = -4; 

class NodeMgr
{
private:
	int m_nBlockRecNum;
	int m_nIndexSize;
	int m_nKeyWordSize;
	int m_nCurrItemPtr;
	long m_lLeftNode;
	long m_lRightNode;
	short m_cItemNum;
	short m_cBuffLabel;
	long m_lSeemNoUse;

	long *m_plPointersOfBlock; // 塊中的關鍵字指向數據文件的指針
	char **m_pszKeyWordsOfBlock; // 塊中的關鍵字

	int getpos(char *pszKeyWord, int start, int stop);
public:

	NodeMgr(int m_nRecSize, int itsize);
	~NodeMgr(void);

	void read_data(char *buffer);
	void write_data(char *buffer);

	int erase(int itemno = -1);
	int insert(long ptr, char *pszKeyWord);

	int isleaf(void) { return (m_cBuffLabel == stLeaf); }

	long get_LeftNode(void) { return m_lLeftNode; }
	long get_RightNode(void) { return m_lRightNode; }
	void set_LeftNode(long node) { m_lLeftNode = node; }
	void set_RightNode(long node) { m_lRightNode = node; }
	void set_CurrItemPtr_low(void) { m_nCurrItemPtr = -1; }
	void set_CurrItemPtr_high(void) { m_nCurrItemPtr = m_cItemNum; }
	char *get_high_item(char *buffer) 
	{
		if (m_cItemNum == 0)
			return NULL;
		else
			memcpy(buffer, m_pszKeyWordsOfBlock[m_cItemNum - 1], m_nKeyWordSize);
		return buffer;
	}
	char *get_cur_item(char *buffer) 
	{
		if (m_nCurrItemPtr < 0 || m_nCurrItemPtr >= m_cItemNum)
			return NULL;
		else
			memcpy(buffer, m_pszKeyWordsOfBlock[m_nCurrItemPtr], m_nKeyWordSize);
		return buffer;
	}
	long read_ptr(int item) { return m_plPointersOfBlock[item]; }
	int get_ItemNum(void) { return m_cItemNum; }
	long find(char *pszKeyWord);
	long retrieve(void);
	long next(void);
	long prev(void);
	long ffwd_core(void);
	void reset(int st = stLeaf);
	void split(char *block1, char *block2);
	long get_SeemNoUse(void) { return m_lSeemNoUse; }
	int get_CurrItemPtr(void) { return m_nCurrItemPtr; }
	void set_CurrItemPtr(int pos) { m_nCurrItemPtr = pos; }
};

#endif