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

Copyright (c) 1996, 2023, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
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*****************************************************************************/

/**************************************************//**
@file include/trx0rec.ic
Transaction undo log record

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

#ifndef UNIV_HOTBACKUP
/**********************************************************************//**
Reads from an undo log record the record type.
@return record type */
UNIV_INLINE
ulint
trx_undo_rec_get_type(
/*==================*/
	const 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.
@return compiler info */
UNIV_INLINE
ulint
trx_undo_rec_get_cmpl_info(
/*=======================*/
	const 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.
@return TRUE if extern */
UNIV_INLINE
ibool
trx_undo_rec_get_extern_storage(
/*============================*/
	const 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.
@return undo no */
UNIV_INLINE
undo_no_t
trx_undo_rec_get_undo_no(
/*=====================*/
	const trx_undo_rec_t*	undo_rec)	/*!< in: undo log record */
{
	const byte*	ptr;

	ptr = undo_rec + 3;

	return(mach_u64_read_much_compressed(ptr));
}

UNIV_INLINE
trx_undo_rec_t*
trx_undo_rec_copy(
	const page_t*	undo_page,
	ulint		undo_offset,
	mem_heap_t*	heap)
{
	ulint			len;
	ulint			next_undo_offset;
	trx_undo_rec_t*		undo_rec = (trx_undo_rec_t*) (undo_page + undo_offset);

	/* Read the offset of next undo record from the current undo record
	and subtract it from current undo record offset to get the length
	of record */

	ut_ad(undo_offset < UNIV_PAGE_SIZE);
	next_undo_offset = mach_read_from_2(undo_rec);
	ut_a(next_undo_offset > undo_offset);

	len = next_undo_offset - undo_offset;
	ut_a(len < UNIV_PAGE_SIZE);

	return((trx_undo_rec_t*) mem_heap_dup(heap, undo_rec, len));
}

#endif /* !UNIV_HOTBACKUP */