Drizzled Public API Documentation

divide.cc
1 /* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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4  * Copyright (C) 2008 Sun Microsystems, Inc.
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13  * GNU General Public License for more details.
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17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18  */
19 
20 #include <config.h>
21 
22 #include <drizzled/function/math/divide.h>
23 #include <drizzled/session.h>
24 #include <drizzled/system_variables.h>
25 
26 #include <algorithm>
27 
28 using namespace std;
29 
30 namespace drizzled {
31 
32 double Item_func_div::real_op()
33 {
34  assert(fixed == 1);
35  double value= args[0]->val_real();
36  double val2= args[1]->val_real();
37  if ((null_value= args[0]->null_value || args[1]->null_value))
38  return 0.0;
39  if (val2 == 0.0)
40  {
41  signal_divide_by_null();
42  return 0.0;
43  }
44  return fix_result(value/val2);
45 }
46 
47 
48 type::Decimal *Item_func_div::decimal_op(type::Decimal *decimal_value)
49 {
50  type::Decimal value1, *val1;
51  type::Decimal value2, *val2;
52  int err;
53 
54  val1= args[0]->val_decimal(&value1);
55  if ((null_value= args[0]->null_value))
56  return 0;
57  val2= args[1]->val_decimal(&value2);
58  if ((null_value= args[1]->null_value))
59  return 0;
60  if ((err= class_decimal_div(E_DEC_FATAL_ERROR & ~E_DEC_DIV_ZERO, decimal_value,
61  val1, val2, prec_increment)) > 3)
62  {
63  if (err == E_DEC_DIV_ZERO)
64  signal_divide_by_null();
65  null_value= 1;
66  return 0;
67  }
68  return decimal_value;
69 }
70 
71 
72 void Item_func_div::result_precision()
73 {
74  uint32_t precision= min(args[0]->decimal_precision() + prec_increment,
75  (unsigned int)DECIMAL_MAX_PRECISION);
76  /* Integer operations keep unsigned_flag if one of arguments is unsigned */
77  if (result_type() == INT_RESULT)
78  unsigned_flag= args[0]->unsigned_flag | args[1]->unsigned_flag;
79  else
80  unsigned_flag= args[0]->unsigned_flag & args[1]->unsigned_flag;
81 
82  decimals= min(args[0]->decimals + prec_increment, (unsigned int)DECIMAL_MAX_SCALE);
83  max_length= class_decimal_precision_to_length(precision, decimals,
84  unsigned_flag);
85 }
86 
87 
88 void Item_func_div::fix_length_and_dec()
89 {
90  prec_increment= session->variables.div_precincrement;
91  Item_num_op::fix_length_and_dec();
92 
93  switch(hybrid_type)
94  {
95  case REAL_RESULT:
96  {
97  decimals= max(args[0]->decimals,args[1]->decimals)+prec_increment;
98  set_if_smaller(decimals, NOT_FIXED_DEC);
99  max_length= args[0]->max_length - args[0]->decimals + decimals;
100  uint32_t tmp= float_length(decimals);
101  set_if_smaller(max_length,tmp);
102  break;
103  }
104  case INT_RESULT:
105  hybrid_type= DECIMAL_RESULT;
106  result_precision();
107  break;
108  case DECIMAL_RESULT:
109  result_precision();
110  break;
111  default:
112  assert(0);
113  }
114  maybe_null= 1; // devision by zero
115  return;
116 }
117 
118 } /* namespace drizzled */
TODO: Rename this file - func.h is stupid.
drizzle_system_variables & variables
Definition: session.h:199