PropertyIDSet.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / OleDb / PropertyIDSet.cs / 1 / PropertyIDSet.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 
 
using System;
using System.Data; 
using System.Data.Common;
using System.Data.ProviderBase;
using System.Diagnostics;
using System.Runtime.InteropServices; 
using System.Runtime.CompilerServices;
using System.Security; 
using System.Security.Permissions; 

namespace System.Data.OleDb { 

    internal sealed class PropertyIDSet : DbBuffer {

        static private readonly int PropertyIDSetAndValueSize = ODB.SizeOf_tagDBPROPIDSET + ADP.PtrSize; // sizeof(tagDBPROPIDSET) + sizeof(int) 
        static private readonly int PropertyIDSetSize = ODB.SizeOf_tagDBPROPIDSET;
 
        private int _count; 

        // the PropertyID is stored at the end of the tagDBPROPIDSET structure 
        // this way only a single memory allocation is required instead of two
        internal PropertyIDSet(Guid propertySet, int propertyID) : base(PropertyIDSetAndValueSize) {
            _count = 1;
 
            // rgPropertyIDs references where that PropertyID is stored
            // depending on IntPtr.Size, tagDBPROPIDSET is either 24 or 28 bytes long 
            IntPtr ptr = ADP.IntPtrOffset(base.handle, PropertyIDSetSize); 
            Marshal.WriteIntPtr(base.handle, 0, ptr);
 
            Marshal.WriteInt32(base.handle, ADP.PtrSize, /*propertyid count*/1);

            ptr = ADP.IntPtrOffset(base.handle, ODB.OffsetOf_tagDBPROPIDSET_PropertySet);
            Marshal.StructureToPtr(propertySet, ptr, false/*deleteold*/); 

            // write the propertyID at the same offset 
            Marshal.WriteInt32(base.handle, PropertyIDSetSize, propertyID); 
        }
 
        // no propertyIDs, just the propertyset guids
        internal PropertyIDSet(Guid[] propertySets) : base(PropertyIDSetSize * propertySets.Length) {
            _count = propertySets.Length;
            for(int i = 0; i < propertySets.Length; ++i) { 
                IntPtr ptr = ADP.IntPtrOffset(base.handle, (i * PropertyIDSetSize) + ODB.OffsetOf_tagDBPROPIDSET_PropertySet);
                Marshal.StructureToPtr(propertySets[i], ptr, false/*deleteold*/); 
            } 
        }
 
        internal int Count {
            get {
                return _count;
            } 
        }
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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