UInt16Storage.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / Common / UInt16Storage.cs / 1 / UInt16Storage.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
// [....] 
//----------------------------------------------------------------------------- 

namespace System.Data.Common { 
    using System;
    using System.Xml;
    using System.Data.SqlTypes;
    using System.Collections; 

    internal sealed class UInt16Storage : DataStorage { 
 
        private static readonly UInt16 defaultValue = UInt16.MinValue;
 
        private UInt16[] values;

        public UInt16Storage(DataColumn column)
        : base(column, typeof(UInt16), defaultValue) { 
        }
 
        override public Object Aggregate(int[] records, AggregateType kind) { 
            bool hasData = false;
            try { 
                switch (kind) {
                    case AggregateType.Sum:
                        UInt64 sum = defaultValue;
                        foreach (int record in records) { 
                            if (HasValue(record)) {
                                checked { sum += values[record];} 
                                hasData = true; 
                            }
                        } 
                        if (hasData) {
                            return sum;
                        }
                        return NullValue; 

                    case AggregateType.Mean: 
                        Int64 meanSum = (Int64)defaultValue; 
                        int meanCount = 0;
                        foreach (int record in records) { 
                            if (HasValue(record)) {
                                checked { meanSum += (Int64)values[record];}
                                meanCount++;
                                hasData = true; 
                            }
                        } 
                        if (hasData) { 
                            UInt16 mean;
                            checked {mean = (UInt16)(meanSum / meanCount);} 
                            return mean;
                        }
                        return NullValue;
 
                    case AggregateType.Var:
                    case AggregateType.StDev: 
                        int count = 0; 
                        double var = 0.0f;
                        double prec = 0.0f; 
                        double dsum = 0.0f;
                        double sqrsum = 0.0f;

                        foreach (int record in records) { 
                            if (HasValue(record)) {
                                dsum += (double)values[record]; 
                                sqrsum += (double)values[record]*(double)values[record]; 
                                count++;
                            } 
                        }

                        if (count > 1) {
                            var = ((double)count * sqrsum - (dsum * dsum)); 
                            prec = var / (dsum * dsum);
 
                            // we are dealing with the risk of a cancellation error 
                            // double is guaranteed only for 15 digits so a difference
                            // with a result less than 1e-15 should be considered as zero 

                            if ((prec < 1e-15) || (var <0))
                                var = 0;
                            else 
                                var = var / (count * (count -1));
 
                            if (kind == AggregateType.StDev) { 
                                return Math.Sqrt(var);
                            } 
                            return var;
                        }
                        return NullValue;
 
                    case AggregateType.Min:
                        UInt16 min = UInt16.MaxValue; 
                        for (int i = 0; i < records.Length; i++) { 
                            int record = records[i];
                            if (HasValue(record)) { 
                                min=Math.Min(values[record], min);
                                hasData = true;
                            }
                        } 
                        if (hasData) {
                            return min; 
                        } 
                        return NullValue;
 
                    case AggregateType.Max:
                        UInt16 max = UInt16.MinValue;
                        for (int i = 0; i < records.Length; i++) {
                            int record = records[i]; 
                            if (HasValue(record)) {
                                max=Math.Max(values[record], max); 
                                hasData = true; 
                            }
                        } 
                        if (hasData) {
                            return max;
                        }
                        return NullValue; 

                    case AggregateType.First: 
                        if (records.Length > 0) { 
                            return values[records[0]];
                        } 
                        return null;

                    case AggregateType.Count:
                        count = 0; 
                        for (int i = 0; i < records.Length; i++) {
                            if (HasValue(records[i])) { 
                                count++; 
                            }
                        } 
                        return count;
                }
            }
            catch (OverflowException) { 
                throw ExprException.Overflow(typeof(UInt16));
            } 
            throw ExceptionBuilder.AggregateException(kind, DataType); 
        }
 
        override public int Compare(int recordNo1, int recordNo2) {
            UInt16 valueNo1 = values[recordNo1];
            UInt16 valueNo2 = values[recordNo2];
 
            if (valueNo1 == defaultValue || valueNo2 == defaultValue) {
                int bitCheck = CompareBits(recordNo1, recordNo2); 
                if (0 != bitCheck) { 
                    return bitCheck;
                } 
            }
            //return valueNo1.CompareTo(valueNo2);
            return ((int)valueNo1 - (int)valueNo2); // copied from UInt16.CompareTo(UInt16)
        } 

        public override int CompareValueTo(int recordNo, object value) { 
            System.Diagnostics.Debug.Assert(0 <= recordNo, "Invalid record"); 
            System.Diagnostics.Debug.Assert(null != value, "null value");
 
            if (NullValue == value) {
                return (HasValue(recordNo) ? 1 : 0);
            }
 
            UInt16 valueNo1 = values[recordNo];
            if ((defaultValue == valueNo1) && !HasValue(recordNo)) { 
                return -1; 
            }
            return valueNo1.CompareTo((UInt16)value); 
            //return ((int)valueNo1 - (int)valueNo2); // copied from UInt16.CompareTo(UInt16)
        }

        public override object ConvertValue(object value) { 
            if (NullValue != value) {
                if (null != value) { 
                    value = ((IConvertible)value).ToUInt16(FormatProvider); 
                }
                else { 
                    value = NullValue;
                }
            }
            return value; 
        }
 
        override public void Copy(int recordNo1, int recordNo2) { 
            CopyBits(recordNo1, recordNo2);
            values[recordNo2] = values[recordNo1]; 
        }

        override public Object Get(int record) {
            UInt16 value = values[record]; 
            if (!value.Equals(defaultValue)) {
                return value; 
            } 
            return GetBits(record);
        } 

        override public void Set(int record, Object value) {
            System.Diagnostics.Debug.Assert(null != value, "null value");
            if (NullValue == value) { 
                values[record] = defaultValue;
                SetNullBit(record, true); 
            } 
            else {
                values[record] = ((IConvertible)value).ToUInt16(FormatProvider); 
                SetNullBit(record, false);
            }
        }
 
        override public void SetCapacity(int capacity) {
            UInt16[] newValues = new UInt16[capacity]; 
            if (null != values) { 
                Array.Copy(values, 0, newValues, 0, Math.Min(capacity, values.Length));
            } 
            values = newValues;
            base.SetCapacity(capacity);
        }
 
        override public object ConvertXmlToObject(string s) {
            return XmlConvert.ToUInt16(s); 
        } 

        override public string ConvertObjectToXml(object value) { 
            return XmlConvert.ToString((UInt16)value);
        }

        override protected object GetEmptyStorage(int recordCount) { 
            return new UInt16[recordCount];
        } 
 
        override protected void CopyValue(int record, object store, BitArray nullbits, int storeIndex) {
            UInt16[] typedStore = (UInt16[]) store; 
            typedStore[storeIndex] = values[record];
            nullbits.Set(storeIndex, !HasValue(record));
        }
 
        override protected void SetStorage(object store, BitArray nullbits) {
            values = (UInt16[]) store; 
            SetNullStorage(nullbits); 
        }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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UInt16Storage.cs source code in C# .NET

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