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

Copyright (c) 1997, 2011, Oracle and/or its affiliates. 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.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

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

/**************************************************//**
@file include/eval0eval.ic
SQL evaluator: evaluates simple data structures, like expressions, in
a query graph

Created 12/29/1997 Heikki Tuuri
*******************************************************/

#include "que0que.h"
#include "rem0cmp.h"
#include "pars0grm.h"

/*****************************************************************//**
Evaluates a function node. */
UNIV_INTERN
void
eval_func(
/*======*/
	func_node_t*	func_node);	/*!< in: function node */
/*****************************************************************//**
Allocate a buffer from global dynamic memory for a value of a que_node.
NOTE that this memory must be explicitly freed when the query graph is
freed. If the node already has allocated buffer, that buffer is freed
here. NOTE that this is the only function where dynamic memory should be
allocated for a query node val field.
@return	pointer to allocated buffer */
UNIV_INTERN
byte*
eval_node_alloc_val_buf(
/*====================*/
	que_node_t*	node,	/*!< in: query graph node; sets the val field
				data field to point to the new buffer, and
				len field equal to size */
	ulint		size);	/*!< in: buffer size */


/*****************************************************************//**
Allocates a new buffer if needed.
@return	pointer to buffer */
UNIV_INLINE
byte*
eval_node_ensure_val_buf(
/*=====================*/
	que_node_t*	node,	/*!< in: query graph node; sets the val field
				data field to point to the new buffer, and
				len field equal to size */
	ulint		size)	/*!< in: buffer size */
{
	dfield_t*	dfield;
	byte*		data;

	dfield = que_node_get_val(node);
	dfield_set_len(dfield, size);

	data = static_cast<byte*>(dfield_get_data(dfield));

	if (!data || que_node_get_val_buf_size(node) < size) {

		data = eval_node_alloc_val_buf(node, size);
	}

	return(data);
}

/*****************************************************************//**
Evaluates a symbol table symbol. */
UNIV_INLINE
void
eval_sym(
/*=====*/
	sym_node_t*	sym_node)	/*!< in: symbol table node */
{

	ut_ad(que_node_get_type(sym_node) == QUE_NODE_SYMBOL);

	if (sym_node->indirection) {
		/* The symbol table node is an alias for a variable or a
		column */

		dfield_copy_data(que_node_get_val(sym_node),
				 que_node_get_val(sym_node->indirection));
	}
}

/*****************************************************************//**
Evaluates an expression. */
UNIV_INLINE
void
eval_exp(
/*=====*/
	que_node_t*	exp_node)	/*!< in: expression */
{
	if (que_node_get_type(exp_node) == QUE_NODE_SYMBOL) {

		eval_sym((sym_node_t*) exp_node);

		return;
	}

	eval_func(static_cast<func_node_t*>(exp_node));
}

/*****************************************************************//**
Sets an integer value as the value of an expression node. */
UNIV_INLINE
void
eval_node_set_int_val(
/*==================*/
	que_node_t*	node,	/*!< in: expression node */
	lint		val)	/*!< in: value to set */
{
	dfield_t*	dfield;
	byte*		data;

	dfield = que_node_get_val(node);

	data = static_cast<byte*>(dfield_get_data(dfield));

	if (data == NULL) {
		data = eval_node_alloc_val_buf(node, 4);
	}

	ut_ad(dfield_get_len(dfield) == 4);

	mach_write_to_4(data, (ulint) val);
}

/*****************************************************************//**
Gets an integer non-SQL null value from an expression node.
@return	integer value */
UNIV_INLINE
lint
eval_node_get_int_val(
/*==================*/
	que_node_t*	node)	/*!< in: expression node */
{
	const byte*	ptr;
	dfield_t*	dfield;

	dfield = que_node_get_val(node);
	ptr = static_cast<byte*>(dfield_get_data(dfield));

	ut_ad(dfield_get_len(dfield) == 4);

	return((int) mach_read_from_4(ptr));
}

/*****************************************************************//**
Gets a iboolean value from a query node.
@return	iboolean value */
UNIV_INLINE
ibool
eval_node_get_ibool_val(
/*====================*/
	que_node_t*	node)	/*!< in: query graph node */
{
	dfield_t*	dfield;
	byte*		data;

	dfield = que_node_get_val(node);

	data = static_cast<byte*>(dfield_get_data(dfield));

	ut_ad(data != NULL);

	return(mach_read_from_1(data));
}

/*****************************************************************//**
Sets a iboolean value as the value of a function node. */
UNIV_INLINE
void
eval_node_set_ibool_val(
/*====================*/
	func_node_t*	func_node,	/*!< in: function node */
	ibool		val)		/*!< in: value to set */
{
	dfield_t*	dfield;
	byte*		data;

	dfield = que_node_get_val(func_node);

	data = static_cast<byte*>(dfield_get_data(dfield));

	if (data == NULL) {
		/* Allocate 1 byte to hold the value */

		data = eval_node_alloc_val_buf(func_node, 1);
	}

	ut_ad(dfield_get_len(dfield) == 1);

	mach_write_to_1(data, val);
}

/*****************************************************************//**
Copies a binary string value as the value of a query graph node. Allocates a
new buffer if necessary. */
UNIV_INLINE
void
eval_node_copy_and_alloc_val(
/*=========================*/
	que_node_t*	node,	/*!< in: query graph node */
	const byte*	str,	/*!< in: binary string */
	ulint		len)	/*!< in: string length or UNIV_SQL_NULL */
{
	byte*		data;

	if (len == UNIV_SQL_NULL) {
		dfield_set_len(que_node_get_val(node), len);

		return;
	}

	data = eval_node_ensure_val_buf(node, len);

	ut_memcpy(data, str, len);
}

/*****************************************************************//**
Copies a query node value to another node. */
UNIV_INLINE
void
eval_node_copy_val(
/*===============*/
	que_node_t*	node1,	/*!< in: node to copy to */
	que_node_t*	node2)	/*!< in: node to copy from */
{
	dfield_t*	dfield2;

	dfield2 = que_node_get_val(node2);

	eval_node_copy_and_alloc_val(
		node1,
		static_cast<byte*>(dfield_get_data(dfield2)),
		dfield_get_len(dfield2));
}