mcs/class/FirebirdSql.Data.Firebird/FirebirdSql.Data.Common/TypeDecoder.cs

   1 /*
   2  *      Firebird ADO.NET Data provider for .NET and Mono
   3  *
   4  *         The contents of this file are subject to the Initial
   5  *         Developer's Public License Version 1.0 (the "License");
   6  *         you may not use this file except in compliance with the
   7  *         License. You may obtain a copy of the License at
   8  *         http://www.firebirdsql.org/index.php?op=doc&id=idpl
   9  *
  10  *         Software distributed under the License is distributed on
  11  *         an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either
  12  *         express or implied. See the License for the specific
  13  *         language governing rights and limitations under the License.
  14  *
  15  *      Copyright (c) 2002, 2005 Carlos Guzman Alvarez
  16  *      All Rights Reserved.
  17  */
  18
  19 using System;
  20 using System.Globalization;
  21
  22 namespace FirebirdSql.Data.Common
  23 {
  24         internal sealed class TypeDecoder
  25         {
  26                 #region Constructors
  27
  28                 private TypeDecoder()
  29                 {
  30                 }
  31
  32                 #endregion
  33
  34                 #region Static Methods
  35
  36                 public static decimal DecodeDecimal(object value, int scale, int sqltype)
  37                 {
  38                         long divisor = 1;
  39                         decimal returnValue = Convert.ToDecimal(value, CultureInfo.InvariantCulture);
  40
  41                         if (scale < 0)
  42                         {
  43                                 divisor = (long)System.Math.Pow(10, scale * (-1));
  44                         }
  45
  46                         switch (sqltype & ~1)
  47                         {
  48                                 case IscCodes.SQL_SHORT:
  49                                 case IscCodes.SQL_LONG:
  50                                 case IscCodes.SQL_QUAD:
  51                                 case IscCodes.SQL_INT64:
  52                                         returnValue = returnValue / divisor;
  53                                         break;
  54                         }
  55
  56                         return returnValue;
  57                 }
  58
  59                 public static DateTime DecodeTime(int sql_time)
  60                 {
  61                         GregorianCalendar calendar = new GregorianCalendar();
  62
  63                         int millisInDay = sql_time / 10;
  64                         int hour = millisInDay / 3600000;
  65                         int minute = (millisInDay - hour * 3600000) / 60000;
  66                         int second = (millisInDay - hour * 3600000 - minute * 60000) / 1000;
  67                         int millisecond = millisInDay - hour * 3600000 - minute * 60000 - second * 1000;
  68
  69                         return new DateTime(1970, 1, 1, hour, minute, second, millisecond, calendar);
  70                 }
  71
  72                 public static DateTime DecodeDate(int sql_date)
  73                 {
  74                         int year, month, day, century;
  75
  76                         sql_date -= 1721119 - 2400001;
  77                         century = (4 * sql_date - 1) / 146097;
  78                         sql_date = 4 * sql_date - 1 - 146097 * century;
  79                         day = sql_date / 4;
  80
  81                         sql_date = (4 * day + 3) / 1461;
  82                         day = 4 * day + 3 - 1461 * sql_date;
  83                         day = (day + 4) / 4;
  84
  85                         month = (5 * day - 3) / 153;
  86                         day = 5 * day - 3 - 153 * month;
  87                         day = (day + 5) / 5;
  88
  89                         year = 100 * century + sql_date;
  90
  91                         if (month < 10)
  92                         {
  93                                 month += 3;
  94                         }
  95                         else
  96                         {
  97                                 month -= 9;
  98                                 year += 1;
  99                         }
 100
 101                         DateTime date = new System.DateTime(year, month, day);
 102
 103                         return date.Date;
 104                 }
 105
 106                 #endregion
 107         }
 108 }