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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Copyright (C) 2008 Sun Microsystems
*
* 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 St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
@file
@brief
Buffers to save and compare item values
*/
#include "config.h"
#include <drizzled/cached_item.h>
#include <drizzled/sql_string.h>
#include <drizzled/session.h>
#include <algorithm>
using namespace drizzled;
using namespace std;
/**
Create right type of Cached_item for an item.
*/
Cached_item *new_Cached_item(Session *session, Item *item)
{
if (item->real_item()->type() == Item::FIELD_ITEM &&
!(((Item_field *) (item->real_item()))->field->flags & BLOB_FLAG))
{
Item_field *real_item= (Item_field *) item->real_item();
Field *cached_field= real_item->field;
return new Cached_item_field(cached_field);
}
switch (item->result_type()) {
case STRING_RESULT:
return new Cached_item_str(session, (Item_field *) item);
case INT_RESULT:
return new Cached_item_int((Item_field *) item);
case REAL_RESULT:
return new Cached_item_real(item);
case DECIMAL_RESULT:
return new Cached_item_decimal(item);
case ROW_RESULT:
default:
assert(0);
return 0;
}
}
Cached_item::~Cached_item() {}
/**
Compare with old value and replace value with new value.
@return
Return true if values have changed
*/
Cached_item_str::Cached_item_str(Session *session, Item *arg)
:item(arg), value(min(arg->max_length,
(uint32_t)session->variables.max_sort_length))
{}
bool Cached_item_str::cmp(void)
{
String *res;
bool tmp;
if ((res=item->val_str(&tmp_value)))
res->length(min(res->length(), value.alloced_length()));
if (null_value != item->null_value)
{
if ((null_value= item->null_value))
// New value was null
return(true);
tmp=true;
}
else if (null_value)
// new and old value was null
return(0);
else
tmp= sortcmp(&value,res,item->collation.collation) != 0;
if (tmp)
// Remember for next cmp
value.copy(*res);
return(tmp);
}
Cached_item_str::~Cached_item_str()
{
// Safety
item=0;
}
bool Cached_item_real::cmp(void)
{
double nr= item->val_real();
if (null_value != item->null_value || nr != value)
{
null_value= item->null_value;
value=nr;
return(true);
}
return(false);
}
bool Cached_item_int::cmp(void)
{
int64_t nr=item->val_int();
if (null_value != item->null_value || nr != value)
{
null_value= item->null_value;
value=nr;
return(true);
}
return(false);
}
Cached_item_field::Cached_item_field(Field *arg_field)
:
field(arg_field)
{
/* TODO: take the memory allocation below out of the constructor. */
buff= (unsigned char*) memory::sql_calloc(length= field->pack_length());
}
bool Cached_item_field::cmp(void)
{
// This is not a blob!
bool tmp= field->cmp(buff) != 0;
if (tmp)
field->get_image(buff,length,field->charset());
if (null_value != field->is_null())
{
null_value= !null_value;
tmp=true;
}
return(tmp);
}
Cached_item_decimal::Cached_item_decimal(Item *it)
:item(it)
{
my_decimal_set_zero(&value);
}
bool Cached_item_decimal::cmp()
{
my_decimal tmp;
my_decimal *ptmp= item->val_decimal(&tmp);
if (null_value != item->null_value ||
(!item->null_value && my_decimal_cmp(&value, ptmp)))
{
null_value= item->null_value;
/* Save only not null values */
if (!null_value)
{
my_decimal2decimal(ptmp, &value);
return true;
}
return false;
}
return false;
}
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