/*
 * Process Hacker - 
 *   IntPtr extension functions
 *
 * Copyright (C) 2009 wj32
 * Copyright (C) 2009 Flavio Erlich
 * 
 * This file is part of Process Hacker.
 * 
 * Process Hacker is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Process Hacker is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Process Hacker.  If not, see <http://www.gnu.org/licenses/>.
 */

using System;
using System.Runtime.InteropServices;

namespace ProcessHacker.Native
{
    public static class IntPtrExtensions
    {
        public static int CompareTo(this IntPtr ptr, IntPtr ptr2)
        {
            if (ptr.ToInt64() > ptr2.ToInt64())
                return 1;
            if (ptr.ToInt64() < ptr2.ToInt64())
                return -1;
            return 0;
        }

        public static int CompareTo(this IntPtr ptr, int ptr2)
        {
            if (ptr.ToInt64() > ptr2)
                return 1;
            if (ptr.ToInt64() < ptr2)
                return -1;
            return 0;
        }

        public static IntPtr Decrement(this IntPtr ptr, IntPtr ptr2)
        {
            if (IntPtr.Size == sizeof(Int32))
                return new IntPtr(ptr.ToInt32() - ptr2.ToInt32());
            else
                return new IntPtr(ptr.ToInt64() - ptr2.ToInt64());
        }

        public static IntPtr Decrement(this IntPtr ptr, int value)
        {
            return Increment(ptr, -value);
        }

        public static IntPtr Decrement(this IntPtr ptr, long value)
        {
            return Increment(ptr, -value);
        }

        public static T ElementAt<T>(this IntPtr ptr, int index)
        {
            var offset = Marshal.SizeOf(typeof(T)) * index;
            var offsetPtr = ptr.Increment(offset);
            return (T)Marshal.PtrToStructure(offsetPtr, typeof(T));
        }

        public static IntPtr Increment(this IntPtr ptr, int value)
        {
            unchecked
            {
                if (IntPtr.Size == sizeof(Int32))
                    return new IntPtr(ptr.ToInt32() + value);
                else
                    return new IntPtr(ptr.ToInt64() + value);
            }
        }

        public static IntPtr Increment(this IntPtr ptr, long value)
        {
            unchecked
            {
                if (IntPtr.Size == sizeof(Int32))
                    return new IntPtr(ptr.ToInt32() + value);
                else
                    return new IntPtr(ptr.ToInt64() + value);
            }
        }

        public static IntPtr Increment(this IntPtr ptr, IntPtr ptr2)
        {
            unchecked
            {
                if (IntPtr.Size == sizeof(Int32))
                    return new IntPtr(ptr.ToInt32() + ptr2.ToInt32());
                else
                    return new IntPtr(ptr.ToInt64() + ptr2.ToInt64());
            }
        }

        public static IntPtr Increment<T>(this IntPtr ptr)
        {
            return ptr.Increment(Marshal.SizeOf(typeof(T)));
        }

        public static uint ToUInt32(this IntPtr ptr)
        {
            return (uint)ptr.ToInt32();
        }

        public static ulong ToUInt64(this IntPtr ptr)
        {
            return (ulong)ptr.ToInt64();
        }
    }
}