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//------------------------------------------------------------------------------
// <copyright file="PropertyIDSet.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>
//------------------------------------------------------------------------------
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;
}
}
}
}
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