Drizzled Public API Documentation

null.h
1 /* - mode: c++ c-basic-offset: 2; indent-tabs-mode: nil; -*-
2  * vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
3  *
4  * Copyright (C) 2008 MySQL
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #pragma once
22 
23 #include <drizzled/field/str.h>
24 
25 namespace drizzled {
26 
27 /*
28  * Everything saved in this will disappear. It will always return NULL
29  */
30 
31 class Field_null : public Field_str
32 {
33  static unsigned char null;
34 public:
35 
36  using Field::store;
37  using Field::val_str;
38  using Field::cmp;
39  using Field::val_int;
40 
41  Field_null(unsigned char *ptr_arg, uint32_t len_arg, const char *field_name_arg) :
42  Field_str(ptr_arg, len_arg, &null, 1, field_name_arg, &my_charset_bin)
43  {}
44 
45  enum_field_types type() const
46  {
47  return DRIZZLE_TYPE_NULL;
48  }
49  int store(const char *, uint32_t, const charset_info_st * const)
50  {
51  return 0;
52  }
53  int store(double)
54  {
55  return 0;
56  }
57  int store(int64_t, bool)
58  {
59  return 0;
60  }
62  {
63  return 0;
64  }
65  int reset()
66  {
67  return 0;
68  }
69  double val_real() const
70  {
71  return 0.0;
72  }
73  int64_t val_int() const
74  {
75  return 0;
76  }
77  type::Decimal *val_decimal(type::Decimal *) const
78  {
79  return 0;
80  }
81  String *val_str(String *, String *value2) const
82  {
83  value2->length(0);
84  return value2;
85  }
86  int cmp(const unsigned char *, const unsigned char *)
87  {
88  return 0;
89  }
90  void sort_string(unsigned char *, uint32_t)
91  {}
92  uint32_t pack_length() const
93  {
94  return 0;
95  }
96  uint32_t size_of() const
97  {
98  return sizeof(*this);
99  }
100  uint32_t max_display_length()
101  {
102  return 4;
103  }
104 };
105 
106 } /* namespace drizzled */