mcs/class/referencesource/System.Data/System/Data/Common/DecimalStorage.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="DecimalStorage.cs" company="Microsoft">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 // <owner current="true" primary="true">Microsoft</owner>
   6 // <owner current="true" primary="false">Microsoft</owner>
   7 // <owner current="false" primary="false">Microsoft</owner>
   8 //------------------------------------------------------------------------------
   9
  10 namespace System.Data.Common {
  11     using System;
  12     using System.Xml;
  13     using System.Data.SqlTypes;
  14     using System.Collections;
  15
  16     internal sealed class DecimalStorage : DataStorage {
  17
  18         private static readonly Decimal defaultValue = Decimal.Zero;
  19
  20         private Decimal[] values;
  21
  22         internal DecimalStorage(DataColumn column)
  23         : base(column, typeof(Decimal), defaultValue, StorageType.Decimal) {
  24         }
  25
  26         override public Object Aggregate(int[] records, AggregateType kind) {
  27             bool hasData = false;
  28             try {
  29                 switch (kind) {
  30                     case AggregateType.Sum:
  31                         Decimal sum = defaultValue;
  32                         foreach (int record in records) {
  33                             if (HasValue(record)) {
  34                                 checked { sum += values[record];}
  35                                 hasData = true;
  36                             }
  37                         }
  38                         if (hasData) {
  39                             return sum;
  40                         }
  41                         return NullValue;
  42
  43                     case AggregateType.Mean:
  44                         Decimal meanSum = (Decimal)defaultValue;
  45                         int meanCount = 0;
  46                         foreach (int record in records) {
  47                             if (HasValue(record)) {
  48                                 checked { meanSum += (Decimal)values[record];}
  49                                 meanCount++;
  50                                 hasData = true;
  51                             }
  52                         }
  53                         if (hasData) {
  54                             Decimal mean;
  55                             checked {mean = (meanSum /(Decimal) meanCount);}
  56                             return mean;
  57                         }
  58                         return NullValue;
  59
  60                     case AggregateType.Var:
  61                     case AggregateType.StDev:
  62                         int count = 0;
  63                         double var = (double)defaultValue;
  64                         double prec = (double)defaultValue;
  65                         double dsum = (double)defaultValue;
  66                         double sqrsum = (double)defaultValue;
  67
  68                         foreach (int record in records) {
  69                             if (HasValue(record)) {
  70                                 dsum += (double)values[record];
  71                                 sqrsum += (double)values[record]*(double)values[record];
  72                                 count++;
  73                             }
  74                         }
  75
  76                         if (count > 1) {
  77                             var = ((double)count * sqrsum - (dsum * dsum));
  78                             prec = var / (dsum * dsum);
  79
  80                             // we are dealing with the risk of a cancellation error
  81                             // double is guaranteed only for 15 digits so a difference
  82                             // with a result less than 1e-15 should be considered as zero
  83
  84                             if ((prec < 1e-15) || (var <0))
  85                                 var = 0;
  86                             else
  87                                 var = var / (count * (count -1));
  88
  89                             if (kind == AggregateType.StDev) {
  90                                 return Math.Sqrt(var);
  91                             }
  92                             return var;
  93                         }
  94                         return NullValue;
  95
  96                     case AggregateType.Min:
  97                         Decimal min = Decimal.MaxValue;
  98                         for (int i = 0; i < records.Length; i++) {
  99                             int record = records[i];
 100                             if (HasValue(record)) {
 101                                 min=Math.Min(values[record], min);
 102                                 hasData = true;
 103                             }
 104                         }
 105                         if (hasData) {
 106                             return min;
 107                         }
 108                         return NullValue;
 109
 110                     case AggregateType.Max:
 111                         Decimal max = Decimal.MinValue;
 112                         for (int i = 0; i < records.Length; i++) {
 113                             int record = records[i];
 114                             if (HasValue(record)) {
 115                                 max=Math.Max(values[record], max);
 116                                 hasData = true;
 117                             }
 118                         }
 119                         if (hasData) {
 120                             return max;
 121                         }
 122                         return NullValue;
 123
 124                     case AggregateType.First:
 125                         if (records.Length > 0) {
 126                             return values[records[0]];
 127                         }
 128                         return null;
 129
 130                     case AggregateType.Count:
 131                         return base.Aggregate(records, kind);
 132
 133                 }
 134             }
 135             catch (OverflowException) {
 136                 throw ExprException.Overflow(typeof(Decimal));
 137             }
 138             throw ExceptionBuilder.AggregateException(kind, DataType);
 139         }
 140
 141         override public int Compare(int recordNo1, int recordNo2) {
 142             Decimal valueNo1 = values[recordNo1];
 143             Decimal valueNo2 = values[recordNo2];
 144
 145             if (valueNo1 == defaultValue || valueNo2 == defaultValue) {
 146                 int bitCheck = CompareBits(recordNo1, recordNo2);
 147                 if (0 != bitCheck)
 148                     return bitCheck;
 149             }
 150             return Decimal.Compare(valueNo1, valueNo2); // InternalCall
 151         }
 152
 153         public override int CompareValueTo(int recordNo, object value) {
 154             System.Diagnostics.Debug.Assert(0 <= recordNo, "Invalid record");
 155             System.Diagnostics.Debug.Assert(null != value, "null value");
 156
 157             if (NullValue == value) {
 158                 return (HasValue(recordNo) ? 1 : 0);
 159             }
 160
 161             Decimal valueNo1 = values[recordNo];
 162             if ((defaultValue == valueNo1) && !HasValue(recordNo)) {
 163                 return -1;
 164             }
 165             return Decimal.Compare(valueNo1, (Decimal)value);
 166         }
 167
 168         public override object ConvertValue(object value) {
 169             if (NullValue != value) {
 170                 if (null != value) {
 171                     value = ((IConvertible)value).ToDecimal(FormatProvider);
 172                 }
 173                 else {
 174                     value = NullValue;
 175                 }
 176             }
 177             return value;
 178         }
 179
 180         override public void Copy(int recordNo1, int recordNo2) {
 181             CopyBits(recordNo1, recordNo2);
 182             values[recordNo2] = values[recordNo1];
 183         }
 184
 185         override public Object Get(int record) {
 186             return (HasValue(record) ? values[record] : NullValue);
 187         }
 188
 189         override public void Set(int record, Object value) {
 190             System.Diagnostics.Debug.Assert(null != value, "null value");
 191             if (NullValue == value) {
 192                 values[record] = defaultValue;
 193                 SetNullBit(record, true);
 194             }
 195             else {
 196                 values[record] = ((IConvertible)value).ToDecimal(FormatProvider);
 197                 SetNullBit(record, false);
 198             }
 199         }
 200
 201         override public void SetCapacity(int capacity) {
 202             Decimal[] newValues = new Decimal[capacity];
 203             if (null != values) {
 204                 Array.Copy(values, 0, newValues, 0, Math.Min(capacity, values.Length));
 205             }
 206             values = newValues;
 207             base.SetCapacity(capacity);
 208         }
 209
 210         override public object ConvertXmlToObject(string s) {
 211             return XmlConvert.ToDecimal(s);
 212         }
 213
 214         override public string ConvertObjectToXml(object value) {
 215             return XmlConvert.ToString((Decimal)value);
 216         }
 217
 218         override protected object GetEmptyStorage(int recordCount) {
 219             return new Decimal[recordCount];
 220         }
 221
 222         override protected void CopyValue(int record, object store, BitArray nullbits, int storeIndex) {
 223             Decimal[] typedStore = (Decimal[]) store;
 224             typedStore[storeIndex] = values[record];
 225             nullbits.Set(storeIndex, !HasValue(record));
 226         }
 227
 228         override protected void SetStorage(object store, BitArray nullbits) {
 229             values = (Decimal[]) store;
 230             SetNullStorage(nullbits);
 231         }
 232     }
 233 }