117 lines
2.8 KiB
C++
117 lines
2.8 KiB
C++
/* Copyright (C) 1979-1996 TcX AB & Monty Program KB & Detron HB
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This software is distributed with NO WARRANTY OF ANY KIND. No author or
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distributor accepts any responsibility for the consequences of using it, or
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for whether it serves any particular purpose or works at all, unless he or
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she says so in writing. Refer to the Free Public License (the "License")
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for full details.
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Every copy of this file must include a copy of the License, normally in a
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plain ASCII text file named PUBLIC. The License grants you the right to
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copy, modify and redistribute this file, but only under certain conditions
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described in the License. Among other things, the License requires that
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the copyright notice and this notice be preserved on all copies. */
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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->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;
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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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