Drizzled Public API Documentation

real.cc
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 #include <config.h>
22 #include <drizzled/field/real.h>
23 #include <drizzled/error.h>
24 #include <drizzled/table.h>
25 
26 #include <math.h>
27 
28 #include <limits>
29 
30 using namespace std;
31 
32 namespace drizzled {
33 
34 extern const double log_10[309];
35 
36 /*
37  Floating-point numbers
38  */
39 
40 unsigned char *
41 Field_real::pack(unsigned char *to, const unsigned char *from,
42  uint32_t max_length, bool low_byte_first)
43 {
44  assert(max_length >= pack_length());
45 #ifdef WORDS_BIGENDIAN
46  if (low_byte_first != getTable()->getShare()->db_low_byte_first)
47  {
48  const unsigned char *dptr= from + pack_length();
49  while (dptr-- > from)
50  *to++ = *dptr;
51  return(to);
52  }
53  else
54 #endif
55  return(Field::pack(to, from, max_length, low_byte_first));
56 }
57 
58 const unsigned char *
59 Field_real::unpack(unsigned char *to, const unsigned char *from,
60  uint32_t param_data, bool low_byte_first)
61 {
62 #ifdef WORDS_BIGENDIAN
63  if (low_byte_first != getTable()->getShare()->db_low_byte_first)
64  {
65  const unsigned char *dptr= from + pack_length();
66  while (dptr-- > from)
67  *to++ = *dptr;
68  return(from + pack_length());
69  }
70  else
71 #endif
72  return(Field::unpack(to, from, param_data, low_byte_first));
73 }
74 
75 /*
76  If a field has fixed length, truncate the double argument pointed to by 'nr'
77  appropriately.
78  Also ensure that the argument is within [-max_value; max_value] range.
79 */
80 
81 int Field_real::truncate(double *nr, double max_value)
82 {
83  int error= 1;
84  double res= *nr;
85 
86  if (res == numeric_limits<double>::quiet_NaN())
87  {
88  res= 0;
89  set_null();
90  set_warning(DRIZZLE_ERROR::WARN_LEVEL_WARN, ER_WARN_DATA_OUT_OF_RANGE, 1);
91  goto end;
92  }
93 
94  if (!not_fixed)
95  {
96  uint32_t order= field_length - dec;
97  uint32_t step= array_elements(log_10) - 1;
98  max_value= 1.0;
99  for (; order > step; order-= step)
100  max_value*= log_10[step];
101  max_value*= log_10[order];
102  max_value-= 1.0 / log_10[dec];
103 
104  /* Check for infinity so we don't get NaN in calculations */
105  if (res != numeric_limits<double>::infinity())
106  {
107  double tmp= rint((res - floor(res)) * log_10[dec]) / log_10[dec];
108  res= floor(res) + tmp;
109  }
110  }
111 
112  if (res < -max_value)
113  {
114  res= -max_value;
115  set_warning(DRIZZLE_ERROR::WARN_LEVEL_WARN, ER_WARN_DATA_OUT_OF_RANGE, 1);
116  }
117  else if (res > max_value)
118  {
119  res= max_value;
120  set_warning(DRIZZLE_ERROR::WARN_LEVEL_WARN, ER_WARN_DATA_OUT_OF_RANGE, 1);
121  }
122  else
123  error= 0;
124 
125 end:
126  *nr= res;
127  return error;
128 }
129 
130 
131 int Field_real::store_decimal(const type::Decimal *dm)
132 {
133  double dbl;
134  class_decimal2double(E_DEC_FATAL_ERROR, dm, &dbl);
135  return store(dbl);
136 }
137 
138 type::Decimal *Field_real::val_decimal(type::Decimal *decimal_value) const
139 {
140  ASSERT_COLUMN_MARKED_FOR_READ;
141 
142  double2_class_decimal(E_DEC_FATAL_ERROR, val_real(), decimal_value);
143  return decimal_value;
144 }
145 
146 } /* namespace drizzled */