/*****************************************************************************

Copyright (c) 1996, 2009, Innobase Oy. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA

*****************************************************************************/

/******************************************************
Transaction undo log record

Created 3/26/1996 Heikki Tuuri
*******************************************************/

/**************************************************************************
Reads from an undo log record the record type. */
UNIV_INLINE
ulint
trx_undo_rec_get_type(
/*==================*/
					/* out: record type */
	trx_undo_rec_t*	undo_rec)	/* in: undo log record */
{
	return(mach_read_from_1(undo_rec + 2) & (TRX_UNDO_CMPL_INFO_MULT - 1));
}

/**************************************************************************
Reads from an undo log record the record compiler info. */
UNIV_INLINE
ulint
trx_undo_rec_get_cmpl_info(
/*=======================*/
					/* out: compiler info */
	trx_undo_rec_t*	undo_rec)	/* in: undo log record */
{
	return(mach_read_from_1(undo_rec + 2) / TRX_UNDO_CMPL_INFO_MULT);
}

/**************************************************************************
Returns TRUE if an undo log record contains an extern storage field. */
UNIV_INLINE
ibool
trx_undo_rec_get_extern_storage(
/*============================*/
					/* out: TRUE if extern */
	trx_undo_rec_t*	undo_rec)	/* in: undo log record */
{
	if (mach_read_from_1(undo_rec + 2) & TRX_UNDO_UPD_EXTERN) {

		return(TRUE);
	}

	return(FALSE);
}

/**************************************************************************
Reads the undo log record number. */
UNIV_INLINE
dulint
trx_undo_rec_get_undo_no(
/*=====================*/
					/* out: undo no */
	trx_undo_rec_t*	undo_rec)	/* in: undo log record */
{
	byte*	ptr;

	ptr = undo_rec + 3;

	return(mach_dulint_read_much_compressed(ptr));
}

/**************************************************************************
Returns the start of the undo record data area. */
UNIV_INLINE
byte*
trx_undo_rec_get_ptr(
/*=================*/
					/* out: compiler info */
	trx_undo_rec_t*	undo_rec,	/* in: undo log record */
	dulint		undo_no)	/* in: undo no read from node */
{
	return (((byte*) undo_rec) + 3
		+ mach_dulint_get_much_compressed_size(undo_no));
}

/***************************************************************************
Copies the undo record to the heap. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_rec_copy(
/*==============*/
					/* out, own: copy of undo log record */
	trx_undo_rec_t*	undo_rec,	/* in: undo log record */
	mem_heap_t*	heap)		/* in: heap where copied */
{
	ulint		len;
	trx_undo_rec_t*	rec_copy;

	len = mach_read_from_2(undo_rec)
		- ut_align_offset(undo_rec, UNIV_PAGE_SIZE);
	rec_copy = mem_heap_alloc(heap, len);

	ut_memcpy(rec_copy, undo_rec, len);

	return(rec_copy);
}