//---------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation.  All rights reserved.
// 
// Description: Checked pointers for various types
//
// History:  
//  05/09/2005: Garyyang Created the file 
//
//---------------------------------------------------------------------------
 
using System;
using System.Security;
using MS.Internal.Shaping;
using MS.Internal.FontCache;
 
//
// The file contains wrapper structs for various pointer types. 
// This is to allow us passing these pointers safely in layout code and provides 
// some bound checking. Only construction and probing into these pointers are security critical.
//
namespace MS.Internal
{
    /// <summary>
    /// Checked pointer for (Char*)
    /// </summary>
    internal struct CheckedCharPointer    
    {
        /// <SecurityNote>
        /// Critical - The method takes unsafe pointer
        /// </SecurityNote>
        [SecurityCritical]
        internal unsafe CheckedCharPointer(char * pointer, int length)
        {
            _checkedPointer = new CheckedPointer(pointer, length * sizeof(char));
        }
 
        /// <SecurityNote>
        /// Critical - The method returns unsafe pointer
        /// </SecurityNote>        
        [SecurityCritical]
        internal unsafe char * Probe(int offset, int length)
        {
            return (char*) _checkedPointer.Probe(offset * sizeof(char), length * sizeof(char));
        }
        
        private CheckedPointer _checkedPointer;
    }
 
    /// <summary>
    /// Checked pointer for (int*)
    /// </summary>
    internal struct CheckedIntPointer
    {
        /// <SecurityNote>
        /// Critical - The method takes unsafe pointer
        /// </SecurityNote>    
        [SecurityCritical]
        internal unsafe CheckedIntPointer(int * pointer, int length)
        {
            _checkedPointer = new CheckedPointer(pointer, length * sizeof(int));
        }
        
        /// <SecurityNote>
        /// Critical - The method returns unsafe pointer
        /// </SecurityNote>        
        [SecurityCritical]
        internal unsafe int * Probe(int offset, int length)
        {
            return (int *) _checkedPointer.Probe(offset * sizeof(int), length * sizeof(int));
        }
        
        private CheckedPointer _checkedPointer;
    }
 
    /// <summary>
    /// Checked pointer for (ushort*)
    /// </summary>
    internal struct CheckedUShortPointer
    {
        /// <SecurityNote>
        /// Critical - The method takes unsafe pointer
        /// </SecurityNote>    
        [SecurityCritical]
        internal unsafe CheckedUShortPointer(ushort * pointer, int length)
        {
            _checkedPointer = new CheckedPointer(pointer, length * sizeof(ushort));
        }
 
        /// <SecurityNote>
        /// Critical - The method returns unsafe pointer
        /// </SecurityNote>                
        [SecurityCritical]
        internal unsafe ushort * Probe(int offset, int length)
        {
            return (ushort *) _checkedPointer.Probe(offset * sizeof(ushort), length * sizeof(ushort));
        }
 
        private CheckedPointer _checkedPointer;
    }
}