File: System\Data\SQLTypes\SQLByte.cs
Project: ndp\fx\src\data\System.Data.csproj (System.Data)
//------------------------------------------------------------------------------
// <copyright file="SQLByte.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
//  </copyright>
// <owner current="true" primary="true">junfang</owner>
// <owner current="true" primary="false">Microsoft</owner>
// <owner current="true" primary="false">Microsoft</owner>
//------------------------------------------------------------------------------
 
//**************************************************************************
// @File: SqlByte.cs
//
// Create by:    JunFang
//
// Purpose: Implementation of SqlByte which is equivalent to
//            data type "smallint" in SQL Server
//
// Notes:
//
// History:
//
//   11/1/99  JunFang    Created.
//
// @EndHeader@
//**************************************************************************
 
using System;
using System.Data.Common;
using System.Runtime.InteropServices;
using System.Globalization;
using System.Xml;
using System.Xml.Schema;
using System.Xml.Serialization;
 
namespace System.Data.SqlTypes {
 
    /// <devdoc>
    ///    <para>
    ///       Represents an 8-bit unsigned integer to be stored in
    ///       or retrieved from a database.
    ///    </para>
    /// </devdoc>
    [Serializable]
 
    [StructLayout(LayoutKind.Sequential)]
    [XmlSchemaProvider("GetXsdType")]
    public struct SqlByte : INullable, IComparable, IXmlSerializable {
 
        private bool    m_fNotNull; // false if null
        private byte    m_value;
 
        private const int x_iBitNotByteMax    = ~0xff;
 
        // constructor
        // construct a Null
        private SqlByte(bool fNull) {
            m_fNotNull = false;
            m_value = 0;
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public SqlByte(byte value) {
            m_value = value;
            m_fNotNull = true;
        }
 
        // INullable
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public bool IsNull {
            get { return !m_fNotNull;}
        }
 
        // property: Value
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public byte Value {
            get {
                if (m_fNotNull)
                    return m_value;
                else
                    throw new SqlNullValueException();
            }
        }
 
        // Implicit conversion from byte to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static implicit operator SqlByte(byte x) {
            return new SqlByte(x);
        }
 
        // Explicit conversion from SqlByte to byte. Throw exception if x is Null.
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator byte(SqlByte x) {
            return x.Value;
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public override String ToString() {
            return IsNull ? SQLResource.NullString : m_value.ToString((IFormatProvider)null);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte Parse(String s) {
            if (s == SQLResource.NullString)
                return SqlByte.Null;
            else 
                return new SqlByte(Byte.Parse(s, (IFormatProvider)null));
        }
 
        // Unary operators
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator ~(SqlByte x) {
            return x.IsNull ? Null : new SqlByte((byte)~x.m_value);
        }
 
 
        // Binary operators
 
        // Arithmetic operators
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator +(SqlByte x, SqlByte y) {
            if (x.IsNull || y.IsNull)
                return Null;
 
            int iResult = (int)x.m_value + (int)y.m_value;
            if ((iResult & x_iBitNotByteMax) != 0)
                throw new OverflowException(SQLResource.ArithOverflowMessage);
            else
                return new SqlByte((byte)iResult);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator -(SqlByte x, SqlByte y) {
            if (x.IsNull || y.IsNull)
                return Null;
 
            int iResult = (int)x.m_value - (int)y.m_value;
            if ((iResult & x_iBitNotByteMax) != 0)
                throw new OverflowException(SQLResource.ArithOverflowMessage);
            else
                return new SqlByte((byte)iResult);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator *(SqlByte x, SqlByte y) {
            if (x.IsNull || y.IsNull)
                return Null;
 
            int iResult = (int)x.m_value * (int)y.m_value;
            if ((iResult & x_iBitNotByteMax) != 0)
                throw new OverflowException(SQLResource.ArithOverflowMessage);
            else
                return new SqlByte((byte)iResult);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator /(SqlByte x, SqlByte y) {
            if (x.IsNull || y.IsNull)
                return Null;
 
            if (y.m_value != 0) {
                return new SqlByte((byte)(x.m_value / y.m_value));
            }
            else
                throw new DivideByZeroException(SQLResource.DivideByZeroMessage);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator %(SqlByte x, SqlByte y) {
            if (x.IsNull || y.IsNull)
                return Null;
 
            if (y.m_value != 0) {
                return new SqlByte((byte)(x.m_value % y.m_value));
            }
            else
                throw new DivideByZeroException(SQLResource.DivideByZeroMessage);
        }
 
        // Bitwise operators
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator &(SqlByte x, SqlByte y) {
            return(x.IsNull || y.IsNull) ? Null : new SqlByte((byte)(x.m_value & y.m_value));
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator |(SqlByte x, SqlByte y) {
            return(x.IsNull || y.IsNull) ? Null : new SqlByte((byte)(x.m_value | y.m_value));
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlByte operator ^(SqlByte x, SqlByte y) {
            return(x.IsNull || y.IsNull) ? Null : new SqlByte((byte)(x.m_value ^ y.m_value));
        }
 
 
 
        // Implicit conversions
 
        // Implicit conversion from SqlBoolean to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlBoolean x) {
            return x.IsNull ? Null : new SqlByte((byte)(x.ByteValue));
        }
 
 
        // Explicit conversions
 
        // Explicit conversion from SqlMoney to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlMoney x) {
            return x.IsNull ? Null : new SqlByte(checked((byte)x.ToInt32()));
        }
 
        // Explicit conversion from SqlInt16 to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlInt16 x) {
            if (x.IsNull)
                return Null;
 
            if (x.Value > (short)Byte.MaxValue || x.Value < (short)Byte.MinValue)
                throw new OverflowException(SQLResource.ArithOverflowMessage);
 
            return x.IsNull ? Null : new SqlByte((byte)(x.Value));
        }
 
        // Explicit conversion from SqlInt32 to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlInt32 x) {
            if (x.IsNull)
                return Null;
 
            if (x.Value > (int)Byte.MaxValue || x.Value < (int)Byte.MinValue)
                throw new OverflowException(SQLResource.ArithOverflowMessage);
 
            return x.IsNull ? Null : new SqlByte((byte)(x.Value));
        }
 
        // Explicit conversion from SqlInt64 to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlInt64 x) {
            if (x.IsNull)
                return Null;
 
            if (x.Value > (long)Byte.MaxValue || x.Value < (long)Byte.MinValue)
                throw new OverflowException(SQLResource.ArithOverflowMessage);
 
            return x.IsNull ? Null : new SqlByte((byte)(x.Value));
        }
 
        // Explicit conversion from SqlSingle to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlSingle x) {
            if (x.IsNull)
                return Null;
 
            if (x.Value > (float)Byte.MaxValue || x.Value < (float)Byte.MinValue)
                throw new OverflowException(SQLResource.ArithOverflowMessage);
 
            return x.IsNull ? Null : new SqlByte((byte)(x.Value));
        }
 
        // Explicit conversion from SqlDouble to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlDouble x) {
            if (x.IsNull)
                return Null;
 
            if (x.Value > (double)Byte.MaxValue || x.Value < (double)Byte.MinValue)
                throw new OverflowException(SQLResource.ArithOverflowMessage);
 
            return x.IsNull ? Null : new SqlByte((byte)(x.Value));
        }
 
        // Explicit conversion from SqlDecimal to SqlByte
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlDecimal x) {
            return(SqlByte)(SqlInt32)x;
        }
 
        // Implicit conversion from SqlString to SqlByte
        // Throws FormatException or OverflowException if necessary.
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static explicit operator SqlByte(SqlString x) {
            return x.IsNull ? Null : new SqlByte(Byte.Parse(x.Value, (IFormatProvider)null));
        }
 
        // Overloading comparison operators
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlBoolean operator==(SqlByte x, SqlByte y) {
            return(x.IsNull || y.IsNull) ? SqlBoolean.Null : new SqlBoolean(x.m_value == y.m_value);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlBoolean operator!=(SqlByte x, SqlByte y) {
            return ! (x == y);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlBoolean operator<(SqlByte x, SqlByte y) {
            return(x.IsNull || y.IsNull) ? SqlBoolean.Null : new SqlBoolean(x.m_value < y.m_value);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlBoolean operator>(SqlByte x, SqlByte y) {
            return(x.IsNull || y.IsNull) ? SqlBoolean.Null : new SqlBoolean(x.m_value > y.m_value);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlBoolean operator<=(SqlByte x, SqlByte y) {
            return(x.IsNull || y.IsNull) ? SqlBoolean.Null : new SqlBoolean(x.m_value <= y.m_value);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static SqlBoolean operator>=(SqlByte x, SqlByte y) {
            return(x.IsNull || y.IsNull) ? SqlBoolean.Null : new SqlBoolean(x.m_value >= y.m_value);
        }
 
        //--------------------------------------------------
        // Alternative methods for overloaded operators
        //--------------------------------------------------
 
        // Alternative method for operator ~
        public static SqlByte OnesComplement(SqlByte x) {
            return ~x;
        }
 
        // Alternative method for operator +
        public static SqlByte Add(SqlByte x, SqlByte y) {
            return x + y;
        }
 
        // Alternative method for operator -
        public static SqlByte Subtract(SqlByte x, SqlByte y) {
            return x - y;
        }
 
        // Alternative method for operator *
        public static SqlByte Multiply(SqlByte x, SqlByte y) {
            return x * y;
        }
 
        // Alternative method for operator /
        public static SqlByte Divide(SqlByte x, SqlByte y) {
            return x / y;
        }
 
        // Alternative method for operator %
        public static SqlByte Mod(SqlByte x, SqlByte y) {
            return x % y;
        }
        
        public static SqlByte Modulus(SqlByte x, SqlByte y) {
            return x % y;
        }
 
        // Alternative method for operator &
        public static SqlByte BitwiseAnd(SqlByte x, SqlByte y) {
            return x & y;
        }
 
        // Alternative method for operator |
        public static SqlByte BitwiseOr(SqlByte x, SqlByte y) {
            return x | y;
        }
 
        // Alternative method for operator ^
        public static SqlByte Xor(SqlByte x, SqlByte y) {
            return x ^ y;
        }
 
        // Alternative method for operator ==
        public static SqlBoolean Equals(SqlByte x, SqlByte y) {
            return (x == y);
        }
 
        // Alternative method for operator !=
        public static SqlBoolean NotEquals(SqlByte x, SqlByte y) {
            return (x != y);
        }
 
        // Alternative method for operator <
        public static SqlBoolean LessThan(SqlByte x, SqlByte y) {
            return (x < y);
        }
 
        // Alternative method for operator >
        public static SqlBoolean GreaterThan(SqlByte x, SqlByte y) {
            return (x > y);
        }
 
        // Alternative method for operator <=
        public static SqlBoolean LessThanOrEqual(SqlByte x, SqlByte y) {
            return (x <= y);
        }
 
        // Alternative method for operator >=
        public static SqlBoolean GreaterThanOrEqual(SqlByte x, SqlByte y) {
            return (x >= y);
        }
 
        // Alternative method for conversions.
 
        public SqlBoolean ToSqlBoolean() {
            return (SqlBoolean)this;
        }
 
        public SqlDouble ToSqlDouble() {
            return (SqlDouble)this;
        }
 
        public SqlInt16 ToSqlInt16() {
            return (SqlInt16)this;
        }
 
        public SqlInt32 ToSqlInt32() {
            return (SqlInt32)this;
        }
 
        public SqlInt64 ToSqlInt64() {
            return (SqlInt64)this;
        }
 
        public SqlMoney ToSqlMoney() {
            return (SqlMoney)this;
        }
 
        public SqlDecimal ToSqlDecimal() {
            return (SqlDecimal)this;
        }
 
        public SqlSingle ToSqlSingle() {
            return (SqlSingle)this;
        }
 
        public SqlString ToSqlString() {
            return (SqlString)this;
        }
 
 
 
        // IComparable
        // Compares this object to another object, returning an integer that
        // indicates the relationship.
        // Returns a value less than zero if this < object, zero if this = object,
        // or a value greater than zero if this > object.
        // null is considered to be less than any instance.
        // If object is not of same type, this method throws an ArgumentException.
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public int CompareTo(Object value) {
            if (value is SqlByte) {
                SqlByte i = (SqlByte)value;
 
                return CompareTo(i);
            }
            throw ADP.WrongType(value.GetType(), typeof(SqlByte));
        }
 
        public int CompareTo(SqlByte value) {
            // If both Null, consider them equal.
            // Otherwise, Null is less than anything.
            if (IsNull)
                return value.IsNull ? 0  : -1;
            else if (value.IsNull)
                return 1;
 
            if (this < value) return -1;
            if (this > value) return 1;
            return 0;
        }
 
        // Compares this instance with a specified object
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public override bool Equals(Object value) {
            if (!(value is SqlByte)) {
                return false;
            }
 
            SqlByte i = (SqlByte)value;
 
            if (i.IsNull || IsNull)
                return (i.IsNull && IsNull);
            else
                return (this == i).Value;
        }
 
        // For hashing purpose
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public override int GetHashCode() {
            return IsNull ? 0 : Value.GetHashCode();
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        XmlSchema IXmlSerializable.GetSchema() { return null; }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        void IXmlSerializable.ReadXml(XmlReader reader) {
            string isNull = reader.GetAttribute("nil", XmlSchema.InstanceNamespace);
            if (isNull != null && XmlConvert.ToBoolean(isNull)) {
                // VSTFDevDiv# 479603 - SqlTypes read null value infinitely and never read the next value. Fix - Read the next value.
                reader.ReadElementString();
                m_fNotNull = false;
            }
            else {
                m_value = XmlConvert.ToByte(reader.ReadElementString());
                m_fNotNull = true;
            }
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        void IXmlSerializable.WriteXml(XmlWriter writer) {
            if (IsNull) {
                writer.WriteAttributeString("xsi", "nil", XmlSchema.InstanceNamespace, "true");
            }
            else {
                writer.WriteString(XmlConvert.ToString(m_value));
            }
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static XmlQualifiedName GetXsdType(XmlSchemaSet schemaSet) {
            return new XmlQualifiedName("unsignedByte", XmlSchema.Namespace);
        }
 
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static readonly SqlByte Null     = new SqlByte(true);
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static readonly SqlByte Zero     = new SqlByte(0);
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static readonly SqlByte MinValue = new SqlByte(Byte.MinValue);
        /// <devdoc>
        ///    <para>[To be supplied.]</para>
        /// </devdoc>
        public static readonly SqlByte MaxValue = new SqlByte(Byte.MaxValue);
 
    } // SqlByte
 
} // namespace System