~drizzle-trunk/drizzle/development

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

The page cursor

(c) 1994-1996 Innobase Oy

Created 10/4/1994 Heikki Tuuri

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

#include "page0page.h"

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

Gets pointer to the page frame where the cursor is positioned. */

UNIV_INLINE

page_t*

page_cur_get_page(

/*==============*/

				/* out: page */

	page_cur_t*	cur)	/* in: page cursor */

{

	ut_ad(cur);

	return(buf_frame_align(cur->rec));

}

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

Gets the record where the cursor is positioned. */

UNIV_INLINE

rec_t*

page_cur_get_rec(

/*=============*/

				/* out: record */

	page_cur_t*	cur)	/* in: page cursor */

{

	ut_ad(cur);

	return(cur->rec);

}

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

Sets the cursor object to point before the first user record

on the page. */

UNIV_INLINE

void

page_cur_set_before_first(

/*======================*/

	page_t*		page,	/* in: index page */

	page_cur_t*	cur)	/* in: cursor */

{

	cur->rec = page_get_infimum_rec(page);

}

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

Sets the cursor object to point after the last user record on

the page. */

UNIV_INLINE

void

page_cur_set_after_last(

/*====================*/

	page_t*		page,	/* in: index page */

	page_cur_t*	cur)	/* in: cursor */

{

	cur->rec = page_get_supremum_rec(page);

}

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

Returns TRUE if the cursor is before first user record on page. */

UNIV_INLINE

ibool

page_cur_is_before_first(

/*=====================*/

					/* out: TRUE if at start */

	const page_cur_t*	cur)	/* in: cursor */

{

	return(page_rec_is_infimum(cur->rec));

}

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

Returns TRUE if the cursor is after last user record. */

UNIV_INLINE

ibool

page_cur_is_after_last(

/*===================*/

					/* out: TRUE if at end */

	const page_cur_t*	cur)	/* in: cursor */

{

	return(page_rec_is_supremum(cur->rec));

}

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

Positions the cursor on the given record. */

UNIV_INLINE

void

page_cur_position(

/*==============*/

	rec_t*		rec,	/* in: record on a page */

	page_cur_t*	cur)	/* in: page cursor */

{

	ut_ad(rec && cur);

	cur->rec = rec;

}

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

Invalidates a page cursor by setting the record pointer NULL. */

UNIV_INLINE

void

page_cur_invalidate(

/*================*/

	page_cur_t*	cur)	/* in: page cursor */

{

	ut_ad(cur);

	cur->rec = NULL;

}

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

Moves the cursor to the next record on page. */

UNIV_INLINE

void

page_cur_move_to_next(

/*==================*/

	page_cur_t*	cur)	/* in: cursor; must not be after last */

{

	ut_ad(!page_cur_is_after_last(cur));

	cur->rec = page_rec_get_next(cur->rec);

}

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

Moves the cursor to the previous record on page. */

UNIV_INLINE

void

page_cur_move_to_prev(

/*==================*/

	page_cur_t*	cur)	/* in: page cursor, not before first */

{

	ut_ad(!page_cur_is_before_first(cur));

	cur->rec = page_rec_get_prev(cur->rec);

}

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

Searches the right position for a page cursor. */

UNIV_INLINE

ulint

page_cur_search(

/*============*/

				/* out: number of matched fields on the left */

	page_t*		page,	/* in: index page */

	dict_index_t*	index,	/* in: record descriptor */

	dtuple_t*	tuple,	/* in: data tuple */

	ulint		mode,	/* in: PAGE_CUR_L, PAGE_CUR_LE, PAGE_CUR_G,

				or PAGE_CUR_GE */

	page_cur_t*	cursor)	/* out: page cursor */

{

	ulint		low_matched_fields = 0;

	ulint		low_matched_bytes = 0;

	ulint		up_matched_fields = 0;

	ulint		up_matched_bytes = 0;

	ut_ad(dtuple_check_typed(tuple));

	page_cur_search_with_match(page, index, tuple, mode,

				   &up_matched_fields,

				   &up_matched_bytes,

				   &low_matched_fields,

				   &low_matched_bytes,

				   cursor);

	return(low_matched_fields);

}

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

Inserts a record next to page cursor. Returns pointer to inserted record if

succeed, i.e., enough space available, NULL otherwise. The cursor stays at

the same position. */

UNIV_INLINE

rec_t*

page_cur_tuple_insert(

/*==================*/

				/* out: pointer to record if succeed, NULL

				otherwise */

	page_cur_t*	cursor,	/* in: a page cursor */

	dtuple_t*	tuple,	/* in: pointer to a data tuple */

	dict_index_t*	index,	/* in: record descriptor */

	mtr_t*		mtr)	/* in: mini-transaction handle */

{

	return(page_cur_insert_rec_low(cursor, tuple, index, NULL, NULL, mtr));

}

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

Inserts a record next to page cursor. Returns pointer to inserted record if

succeed, i.e., enough space available, NULL otherwise. The cursor stays at

the same position. */

UNIV_INLINE

rec_t*

page_cur_rec_insert(

/*================*/

				/* out: pointer to record if succeed, NULL

				otherwise */

	page_cur_t*	cursor,	/* in: a page cursor */

	rec_t*		rec,	/* in: record to insert */

	dict_index_t*	index,	/* in: record descriptor */

	ulint*		offsets,/* in: rec_get_offsets(rec, index) */

	mtr_t*		mtr)	/* in: mini-transaction handle */

{

	return(page_cur_insert_rec_low(cursor, NULL, index, rec,

				       offsets, mtr));

}