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119 lines
2.9 KiB
C++
119 lines
2.9 KiB
C++
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/* Buffers to save and compare item values */
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#include "mysql_priv.h"
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/*
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** Create right type of item_buffer for an item
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*/
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Item_buff *new_Item_buff(Item *item)
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{
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if (item->type() == Item::FIELD_ITEM &&
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!(((Item_field *) item)->field->flags & BLOB_FLAG))
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return new Item_field_buff((Item_field *) item);
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if (item->result_type() == STRING_RESULT)
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return new Item_str_buff((Item_field *) item);
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if (item->result_type() == INT_RESULT)
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return new Item_int_buff((Item_field *) item);
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return new Item_real_buff(item);
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}
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Item_buff::~Item_buff() {}
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/*
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** Compare with old value and replace value with new value
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** Return true if values have changed
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*/
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bool Item_str_buff::cmp(void)
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{
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String *res;
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bool tmp;
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res=item->val_str(&tmp_value);
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if (null_value != item->null_value)
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{
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if ((null_value= item->null_value))
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return TRUE; // New value was null
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tmp=TRUE;
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}
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else if (null_value)
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return 0; // new and old value was null
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else if (!item->binary)
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tmp= sortcmp(&value,res) != 0;
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else
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tmp= stringcmp(&value,res) != 0;
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if (tmp)
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value.copy(*res); // Remember for next cmp
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return tmp;
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}
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Item_str_buff::~Item_str_buff()
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{
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item=0; // Safety
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}
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bool Item_real_buff::cmp(void)
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{
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double nr=item->val();
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if (null_value != item->null_value || nr != value)
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{
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null_value= item->null_value;
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value=nr;
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return TRUE;
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}
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return FALSE;
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}
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bool Item_int_buff::cmp(void)
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{
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longlong nr=item->val_int();
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if (null_value != item->null_value || nr != value)
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{
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null_value= item->null_value;
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value=nr;
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return TRUE;
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}
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return FALSE;
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}
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bool Item_field_buff::cmp(void)
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{
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bool tmp= field->cmp(buff) != 0; // This is not a blob!
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if (tmp)
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field->get_image(buff,length);
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if (null_value != field->is_null())
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{
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null_value= !null_value;
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tmp=TRUE;
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}
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return tmp;
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}
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/*****************************************************************************
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** Instansiate templates
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*****************************************************************************/
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#ifdef __GNUC__
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template class List<Item_buff>;
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template class List_iterator<Item_buff>;
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#endif
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