|
//------------------------------------------------------------------------------
// <copyright file="Int16Storage.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
// <owner current="false" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------
namespace System.Data.Common {
using System;
using System.Xml;
using System.Data.SqlTypes;
using System.Collections;
internal sealed class Int16Storage : DataStorage {
private const Int16 defaultValue = 0;
private Int16[] values;
internal Int16Storage(DataColumn column)
: base(column, typeof(Int16), defaultValue, StorageType.Int16) {
}
override public Object Aggregate(int[] records, AggregateType kind) {
bool hasData = false;
try {
switch (kind) {
case AggregateType.Sum:
Int64 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) {
Int16 mean;
checked {mean = (Int16)(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:
Int16 min = Int16.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:
Int16 max = Int16.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(Int16));
}
throw ExceptionBuilder.AggregateException(kind, DataType);
}
override public int Compare(int recordNo1, int recordNo2) {
Int16 valueNo1 = values[recordNo1];
Int16 valueNo2 = values[recordNo2];
if (valueNo1 == defaultValue || valueNo2 == defaultValue) {
int bitCheck = CompareBits(recordNo1, recordNo2);
if (0 != bitCheck) {
return bitCheck;
}
}
//return valueNo1.CompareTo(valueNo2);
return(valueNo1 - valueNo2); // copied from Int16.CompareTo(Int16)
}
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);
}
Int16 valueNo1 = values[recordNo];
if ((defaultValue == valueNo1) && !HasValue(recordNo)) {
return -1;
}
return valueNo1.CompareTo((Int16)value);
//return(valueNo1 - valueNo2); // copied from Int16.CompareTo(Int16)
}
public override object ConvertValue(object value) {
if (NullValue != value) {
if (null != value) {
value = ((IConvertible)value).ToInt16(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) {
Int16 value = values[record];
if (value != 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).ToInt16(FormatProvider);
SetNullBit(record, false);
}
}
override public void SetCapacity(int capacity) {
Int16[] newValues = new Int16[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.ToInt16(s);
}
override public string ConvertObjectToXml(object value) {
return XmlConvert.ToString((Int16) value);
}
override protected object GetEmptyStorage(int recordCount) {
return new Int16[recordCount];
}
override protected void CopyValue(int record, object store, BitArray nullbits, int storeIndex) {
Int16[] typedStore = (Int16[]) store;
typedStore[storeIndex] = values[record];
nullbits.Set(storeIndex, !HasValue(record));
}
override protected void SetStorage(object store, BitArray nullbits) {
values = (Int16[]) store;
SetNullStorage(nullbits);
}
}
}
|