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 
DecimalStorage(DataColumn column)22         internal DecimalStorage(DataColumn column)
23         : base(column, typeof(Decimal), defaultValue, StorageType.Decimal) {
24         }
25 
Aggregate(int[] records, AggregateType kind)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 
Compare(int recordNo1, int recordNo2)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 
CompareValueTo(int recordNo, object value)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 
ConvertValue(object value)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 
Copy(int recordNo1, int recordNo2)180         override public void Copy(int recordNo1, int recordNo2) {
181             CopyBits(recordNo1, recordNo2);
182             values[recordNo2] = values[recordNo1];
183         }
184 
Get(int record)185         override public Object Get(int record) {
186             return (HasValue(record) ? values[record] : NullValue);
187         }
188 
Set(int record, Object value)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 
SetCapacity(int capacity)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 
ConvertXmlToObject(string s)210         override public object ConvertXmlToObject(string s) {
211             return XmlConvert.ToDecimal(s);
212         }
213 
ConvertObjectToXml(object value)214         override public string ConvertObjectToXml(object value) {
215             return XmlConvert.ToString((Decimal)value);
216         }
217 
GetEmptyStorage(int recordCount)218         override protected object GetEmptyStorage(int recordCount) {
219             return new Decimal[recordCount];
220         }
221 
CopyValue(int record, object store, BitArray nullbits, int storeIndex)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 
SetStorage(object store, BitArray nullbits)228         override protected void SetStorage(object store, BitArray nullbits) {
229             values = (Decimal[]) store;
230             SetNullStorage(nullbits);
231         }
232     }
233 }
234