ArgIterator.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / ArgIterator.cs / 1 / ArgIterator.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
namespace System {
 
    using System; 
    using System.Runtime.InteropServices;
    using System.Runtime.CompilerServices; 

    // This class will not be marked serializable

    [StructLayout(LayoutKind.Auto)] 
    public struct ArgIterator
    { 
        [MethodImplAttribute(MethodImplOptions.InternalCall)] 
        private extern ArgIterator(IntPtr arglist);
 
        // create an arg iterator that points at the first argument that
        // is not statically declared (that is the first ... arg)
        // 'arglist' is the value returned by the ARGLIST instruction
        public ArgIterator(RuntimeArgumentHandle arglist) : this(arglist.Value) 

        { 
        } 

        [MethodImplAttribute(MethodImplOptions.InternalCall)] 
        private unsafe extern ArgIterator(IntPtr arglist, void *ptr);

        // create an arg iterator that points just past 'firstArg'.
        // 'arglist' is the value returned by the ARGLIST instruction 
        // This is much like the C va_start macro
 
        [CLSCompliant(false)] 

        public unsafe ArgIterator(RuntimeArgumentHandle arglist, void* ptr) : this(arglist.Value, ptr) 

        {
        }
 
        // Fetch an argument as a typed referece, advance the iterator.
        // Throws an exception if past end of argument list 
        [CLSCompliant(false)] 
        public TypedReference GetNextArg()
        { 
            TypedReference result = new TypedReference ();
            // reference to TypedReference is banned, so have to pass result as pointer
            unsafe
            { 
                FCallGetNextArg (&result);
            } 
            return result; 
        }
 
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        // reference to TypedReference is banned, so have to pass result as void pointer
        private unsafe extern void FCallGetNextArg(void * result);
 
        // Alternate version of GetNextArg() intended primarily for IJW code
        // generated by VC's "va_arg()" construct. 
        [CLSCompliant(false)] 
        public TypedReference GetNextArg(RuntimeTypeHandle rth)
        { 
            if (sigPtr != IntPtr.Zero)
            {
                // This is an ordinary ArgIterator capable of determining
                // types from a signature. Just do a regular GetNextArg. 
                return GetNextArg();
            } 
            else 
            {
                // Prevent abuse of this API with a default ArgIterator (it 
                // doesn't require permission to create a zero-inited value
                // type). Check that ArgPtr isn't zero or this API will allow a
                // malicious caller to increment the pointer to an arbitrary
                // location in memory and read the contents. 
                if (ArgPtr == IntPtr.Zero)
                    throw new ArgumentNullException(); 
 
                TypedReference result = new TypedReference ();
                // reference to TypedReference is banned, so have to pass result as pointer 
                unsafe
                {
                    InternalGetNextArg(&result, rth);
                } 
                return result;
            } 
        } 

 
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        // reference to TypedReference is banned, so have to pass result as void pointer
        private unsafe extern void InternalGetNextArg(void * result, RuntimeTypeHandle rth);
 
        // This method should invalidate the iterator (va_end). It is not supported yet.
        public void End() 
        { 
        }
 
        // How many arguments are left in the list
        [MethodImplAttribute(MethodImplOptions.InternalCall)]
        public extern int GetRemainingCount();
 
        // Gets the type of the current arg, does NOT advance the iterator
        [MethodImplAttribute(MethodImplOptions.InternalCall)] 
        private extern unsafe void* _GetNextArgType(); 
        public unsafe RuntimeTypeHandle GetNextArgType()
 
        {
            return new RuntimeTypeHandle(_GetNextArgType());
        }
 
        public override int GetHashCode()
        { 
            return unchecked((int)((long)ArgCookie)); 
        }
 
        // Inherited from object
        public override bool Equals(Object o)
        {
            throw new NotSupportedException(Environment.GetResourceString("NotSupported_NYI")); 
        }
 
        private IntPtr ArgCookie;               // Cookie from the EE. 
        // The SigPtr structure consists of the following members
            private IntPtr sigPtr;                  // Pointer to remaining signature. 
            private IntPtr sigPtrLen;               // Remaining length of the pointer

        // Note, sigPtrLen is actually a DWORD, but on 64bit systems this structure becomes
        // 8-byte aligned, which requires us to pad it. 

        private IntPtr ArgPtr;                  // Pointer to remaining args. 
        private int    RemainingArgs;           // # of remaining args. 
    }
}

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