1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
|
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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; either version 2 of the License, or
(at your option) any later version.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* Buffers to save and compare item values */
#include "mysql_priv.h"
/*
** Create right type of item_buffer for an item
*/
Item_buff *new_Item_buff(THD *thd, Item *item)
{
if (item->type() == Item::FIELD_ITEM &&
!(((Item_field *) item)->field->flags & BLOB_FLAG))
return new Item_field_buff((Item_field *) item);
switch (item->result_type()) {
case STRING_RESULT:
return new Item_str_buff(thd, (Item_field *) item);
case INT_RESULT:
return new Item_int_buff((Item_field *) item);
case REAL_RESULT:
return new Item_real_buff(item);
case DECIMAL_RESULT:
return new Item_decimal_buff(item);
case ROW_RESULT:
default:
DBUG_ASSERT(0);
return 0;
}
}
Item_buff::~Item_buff() {}
/*
** Compare with old value and replace value with new value
** Return true if values have changed
*/
Item_str_buff::Item_str_buff(THD *thd, Item *arg)
:item(arg), value(min(arg->max_length, thd->variables.max_sort_length))
{}
bool Item_str_buff::cmp(void)
{
String *res;
bool tmp;
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))
return TRUE; // New value was null
tmp=TRUE;
}
else if (null_value)
return 0; // new and old value was null
else
tmp= sortcmp(&value,res,item->collation.collation) != 0;
if (tmp)
value.copy(*res); // Remember for next cmp
return tmp;
}
Item_str_buff::~Item_str_buff()
{
item=0; // Safety
}
bool Item_real_buff::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 Item_int_buff::cmp(void)
{
longlong nr=item->val_int();
if (null_value != item->null_value || nr != value)
{
null_value= item->null_value;
value=nr;
return TRUE;
}
return FALSE;
}
bool Item_field_buff::cmp(void)
{
bool tmp= field->cmp(buff) != 0; // This is not a blob!
if (tmp)
field->get_image(buff,length,field->charset());
if (null_value != field->is_null())
{
null_value= !null_value;
tmp=TRUE;
}
return tmp;
}
Item_decimal_buff::Item_decimal_buff(Item *it)
:item(it)
{
my_decimal_set_zero(&value);
}
bool Item_decimal_buff::cmp()
{
my_decimal tmp;
my_decimal *ptmp= item->val_decimal(&tmp);
if (null_value != item->null_value || my_decimal_cmp(&value, ptmp) == 0)
{
null_value= item->null_value;
my_decimal2decimal(ptmp, &value);
return TRUE;
}
return FALSE;
}
/*****************************************************************************
** Instansiate templates
*****************************************************************************/
#ifdef __GNUC__
template class List<Item_buff>;
template class List_iterator<Item_buff>;
#endif
|
