mcs/class/referencesource/System.Data/System/Data/Common/UInt32Storage.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="UInt32Storage.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 UInt32Storage : DataStorage {
  17
  18         private const UInt32 defaultValue = UInt32.MinValue;
  19
  20         private UInt32[] values;
  21
  22         public UInt32Storage(DataColumn column)
  23         : base(column, typeof(UInt32), defaultValue, StorageType.UInt32) {
  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                         UInt64 sum = defaultValue;
  32                         foreach (int record in records) {
  33                             if (HasValue(record)) {
  34                                 checked { sum += (UInt64) values[record];}
  35                                 hasData = true;
  36                             }
  37                         }
  38                         if (hasData) {
  39                             return sum;
  40                         }
  41                         return NullValue;
  42
  43                     case AggregateType.Mean:
  44                         Int64 meanSum = (Int64)defaultValue;
  45                         int meanCount = 0;
  46                         foreach (int record in records) {
  47                             if (HasValue(record)) {
  48                                 checked { meanSum += (Int64)values[record];}
  49                                 meanCount++;
  50                                 hasData = true;
  51                             }
  52                         }
  53                         if (hasData) {
  54                             UInt32 mean;
  55                             checked {mean = (UInt32)(meanSum / meanCount);}
  56                             return mean;
  57                         }
  58                         return NullValue;
  59
  60                     case AggregateType.Var:
  61                     case AggregateType.StDev:
  62                         int count = 0;
  63                         double var = 0.0f;
  64                         double prec = 0.0f;
  65                         double dsum = 0.0f;
  66                         double sqrsum = 0.0f;
  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                         UInt32 min = UInt32.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                         UInt32 max = UInt32.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                         count = 0;
 132                         for (int i = 0; i < records.Length; i++) {
 133                             if (HasValue(records[i]))
 134                                 count++;
 135                         }
 136                         return count;
 137                 }
 138             }
 139             catch (OverflowException) {
 140                 throw ExprException.Overflow(typeof(UInt32));
 141             }
 142             throw ExceptionBuilder.AggregateException(kind, DataType);
 143         }
 144
 145
 146         override public int Compare(int recordNo1, int recordNo2) {
 147             UInt32 valueNo1 = values[recordNo1];
 148             UInt32 valueNo2 = values[recordNo2];
 149
 150             if (valueNo1 == defaultValue || valueNo2 == defaultValue) {
 151                 int bitCheck = CompareBits(recordNo1, recordNo2);
 152                 if (0 != bitCheck) {
 153                     return bitCheck;
 154                 }
 155             }
 156             //return valueNo1.CompareTo(valueNo2);
 157             return(valueNo1 < valueNo2 ? -1 : (valueNo1 > valueNo2 ? 1 : 0)); // similar to UInt32.CompareTo(UInt32)
 158         }
 159
 160         public override int CompareValueTo(int recordNo, object value) {
 161             System.Diagnostics.Debug.Assert(0 <= recordNo, "Invalid record");
 162             System.Diagnostics.Debug.Assert(null != value, "null value");
 163
 164             if (NullValue == value) {
 165                 return (HasValue(recordNo) ? 1 : 0);
 166             }
 167
 168             UInt32 valueNo1 = values[recordNo];
 169             if ((defaultValue == valueNo1) && !HasValue(recordNo)) {
 170                 return -1;
 171             }
 172             return valueNo1.CompareTo((UInt32)value);
 173             //return(valueNo1 < valueNo2 ? -1 : (valueNo1 > valueNo2 ? 1 : 0)); // similar to UInt32.CompareTo(UInt32)
 174         }
 175
 176         public override object ConvertValue(object value) {
 177             if (NullValue != value) {
 178                 if (null != value) {
 179                     value = ((IConvertible)value).ToUInt32(FormatProvider);
 180                 }
 181                 else {
 182                     value = NullValue;
 183                 }
 184             }
 185             return value;
 186         }
 187
 188         override public void Copy(int recordNo1, int recordNo2) {
 189             CopyBits(recordNo1, recordNo2);
 190             values[recordNo2] = values[recordNo1];
 191         }
 192
 193         override public Object Get(int record) {
 194             UInt32 value = values[record];
 195             if (!value.Equals(defaultValue)) {
 196                 return value;
 197             }
 198             return GetBits(record);
 199         }
 200
 201         override public void Set(int record, Object value) {
 202             System.Diagnostics.Debug.Assert(null != value, "null value");
 203             if (NullValue == value) {
 204                 values[record] = defaultValue;
 205                 SetNullBit(record, true);
 206             }
 207             else {
 208                 values[record] = ((IConvertible)value).ToUInt32(FormatProvider);
 209                 SetNullBit(record, false);
 210             }
 211         }
 212
 213         override public void SetCapacity(int capacity) {
 214             UInt32[] newValues = new UInt32[capacity];
 215             if (null != values) {
 216                 Array.Copy(values, 0, newValues, 0, Math.Min(capacity, values.Length));
 217             }
 218             values = newValues;
 219             base.SetCapacity(capacity);
 220         }
 221
 222         override public object ConvertXmlToObject(string s) {
 223             return XmlConvert.ToUInt32(s);
 224         }
 225
 226         override public string ConvertObjectToXml(object value) {
 227             return XmlConvert.ToString((UInt32)value);
 228         }
 229
 230         override protected object GetEmptyStorage(int recordCount) {
 231             return new UInt32[recordCount];
 232         }
 233
 234         override protected void CopyValue(int record, object store, BitArray nullbits, int storeIndex) {
 235             UInt32[] typedStore = (UInt32[]) store;
 236             typedStore[storeIndex] = values[record];
 237             nullbits.Set(storeIndex, !HasValue(record));
 238         }
 239
 240         override protected void SetStorage(object store, BitArray nullbits) {
 241             values = (UInt32[]) store;
 242             SetNullStorage(nullbits);
 243         }
 244     }
 245 }