FileLogRecordHeader.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / WCF / Log / System / IO / Log / FileLogRecordHeader.cs / 1305376 / FileLogRecordHeader.cs
                        

                        
                            //------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------
namespace System.IO.Log
{ 
    using System.IO;
    using System.Diagnostics; 
 
    internal struct FileLogRecordHeader
    { 
        [Flags]
        enum LowFlags : byte
        {
            RestartArea = 0x01 
        }
 
        internal const int Size = 20; 
        internal const byte MAJORVER = 1;
        internal const byte MINORVER = 0; 

        const int MajorVersionOffset = 0;
        const int MinorVersionOffset = 1;
        const int LowFlagsOffset = 2; 
        const int HighFlagsOffset = 3;
        const int PreviousLsnOffsetHigh = 4; 
        const int NextUndoLsnOffsetHigh = 12; 

        byte[] bits; 

        internal FileLogRecordHeader(byte[] bits)
        {
            if (bits == null) 
            {
                this.bits = new Byte[Size]; 
                this.bits[MajorVersionOffset] = MAJORVER; 
                this.bits[MinorVersionOffset] = MINORVER;
            } 
            else
            {
                if (bits.Length < Size)
                { 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(Error.LogCorrupt());
                } 
 
                // if version not supported then ???
                if (bits[MajorVersionOffset] != MAJORVER) 
                    throw DiagnosticUtility.ExceptionUtility.ThrowHelperError(Error.IncompatibleVersion());

                this.bits = bits;
            } 
        }
 
        internal bool IsRestartArea 
        {
            get 
            {
                return (((LowFlags)bits[LowFlagsOffset] & LowFlags.RestartArea) != 0);
            }
 
            set
            { 
                LowFlags flags = (LowFlags)bits[LowFlagsOffset]; 
                if (value)
                    flags |= LowFlags.RestartArea; 
                else
                    flags &= ~LowFlags.RestartArea;
                bits[LowFlagsOffset] = (byte)(flags);
            } 
        }
 
        internal SequenceNumber PreviousLsn 
        {
            get 
            {
                return new SequenceNumber(
                    BitConverter.ToUInt64(this.bits, PreviousLsnOffsetHigh));
            } 

            set { SequenceNumber.WriteUInt64(value.High, this.bits, PreviousLsnOffsetHigh); } 
        } 

        internal SequenceNumber NextUndoLsn 
        {
            get { return new SequenceNumber(BitConverter.ToUInt64(this.bits, NextUndoLsnOffsetHigh)); }

            set { SequenceNumber.WriteUInt64(value.High, this.bits, NextUndoLsnOffsetHigh); } 
        }
 
        internal byte[] Bits 
        {
            get { return this.bits; } 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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