/**********************************************************************
File-based list utilities

(c) 1995 Innobase Oy

Created 11/28/1995 Heikki Tuuri
***********************************************************************/

#include "fut0fut.h"
#include "mtr0log.h"
#include "buf0buf.h"

/* We define the field offsets of a node for the list */
#define FLST_PREV	0	/* 6-byte address of the previous list element;
				the page part of address is FIL_NULL, if no
				previous element */
#define FLST_NEXT	FIL_ADDR_SIZE	/* 6-byte address of the next
				list element; the page part of address
				is FIL_NULL, if no next element */

/* We define the field offsets of a base node for the list */
#define FLST_LEN	0	/* 32-bit list length field */
#define	FLST_FIRST	4	/* 6-byte address of the first element
				of the list; undefined if empty list */
#define	FLST_LAST	(4 + FIL_ADDR_SIZE) /* 6-byte address of the
				last element of the list; undefined
				if empty list */

/************************************************************************
Writes a file address. */
UNIV_INLINE
void
flst_write_addr(
/*============*/
	fil_faddr_t*	faddr,	/* in: pointer to file faddress */
	fil_addr_t	addr,	/* in: file address */
	mtr_t*		mtr)	/* in: mini-transaction handle */
{
	ut_ad(faddr && mtr);
	ut_ad(mtr_memo_contains(mtr, buf_block_align(faddr),
							MTR_MEMO_PAGE_X_FIX));

	mlog_write_ulint(faddr + FIL_ADDR_PAGE, addr.page, MLOG_4BYTES, mtr); 
	mlog_write_ulint(faddr + FIL_ADDR_BYTE, addr.boffset,
							MLOG_2BYTES, mtr); 
}

/************************************************************************
Reads a file address. */
UNIV_INLINE
fil_addr_t
flst_read_addr(
/*===========*/
				/* out: file address */
	fil_faddr_t*	faddr,	/* in: pointer to file faddress */
	mtr_t*		mtr)	/* in: mini-transaction handle */
{
	fil_addr_t	addr;

	ut_ad(faddr && mtr);

	addr.page = mtr_read_ulint(faddr + FIL_ADDR_PAGE, MLOG_4BYTES, mtr); 
	addr.boffset = mtr_read_ulint(faddr + FIL_ADDR_BYTE, MLOG_2BYTES, 
								mtr);
	return(addr); 
}

/************************************************************************
Initializes a list base node. */
UNIV_INLINE
void
flst_init(
/*======*/
	flst_base_node_t*	base,	/* in: pointer to base node */
	mtr_t*			mtr)	/* in: mini-transaction handle */
{
	ut_ad(mtr_memo_contains(mtr, buf_block_align(base),
							MTR_MEMO_PAGE_X_FIX));
	mlog_write_ulint(base + FLST_LEN, 0, MLOG_4BYTES, mtr); 
	flst_write_addr(base + FLST_FIRST, fil_addr_null, mtr); 
	flst_write_addr(base + FLST_LAST, fil_addr_null, mtr); 
}

/************************************************************************
Gets list length. */
UNIV_INLINE
ulint
flst_get_len(
/*=========*/
					/* out: length */
	flst_base_node_t*	base,	/* in: pointer to base node */
	mtr_t*			mtr)	/* in: mini-transaction handle */
{
	return(mtr_read_ulint(base + FLST_LEN, MLOG_4BYTES, mtr));
}

/************************************************************************
Gets list first node address. */
UNIV_INLINE
fil_addr_t
flst_get_first(
/*===========*/
					/* out: file address */
	flst_base_node_t*	base,	/* in: pointer to base node */
	mtr_t*			mtr)	/* in: mini-transaction handle */
{
	return(flst_read_addr(base + FLST_FIRST, mtr));
}

/************************************************************************
Gets list last node address. */
UNIV_INLINE
fil_addr_t
flst_get_last(
/*==========*/
					/* out: file address */
	flst_base_node_t*	base,	/* in: pointer to base node */
	mtr_t*			mtr)	/* in: mini-transaction handle */
{
	return(flst_read_addr(base + FLST_LAST, mtr));
}

/************************************************************************
Gets list next node address. */
UNIV_INLINE
fil_addr_t
flst_get_next_addr(
/*===============*/
				/* out: file address */
	flst_node_t*	node,	/* in: pointer to node */
	mtr_t*		mtr)	/* in: mini-transaction handle */
{
	return(flst_read_addr(node + FLST_NEXT, mtr));
}

/************************************************************************
Gets list prev node address. */
UNIV_INLINE
fil_addr_t
flst_get_prev_addr(
/*===============*/
				/* out: file address */
	flst_node_t*	node,	/* in: pointer to node */
	mtr_t*		mtr)	/* in: mini-transaction handle */
{
	return(flst_read_addr(node + FLST_PREV, mtr));
}