path: root/src/Input/KeyboardState.cs

 #region License
 //
 // The Open Toolkit Library License
 //
 // Copyright (c) 2006 - 2009 the Open Toolkit library.
 //
 // Permission is hereby granted, free of charge, to any person obtaining a copy
 // of this software and associated documentation files (the "Software"), to deal
 // in the Software without restriction, including without limitation the rights to
 // use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 // the Software, and to permit persons to whom the Software is furnished to do
 // so, subject to the following conditions:
 //
 // The above copyright notice and this permission notice shall be included in all
 // copies or substantial portions of the Software.
 //
 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 // OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 // HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 // WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 // OTHER DEALINGS IN THE SOFTWARE.
 //
 #endregion

using System;
using System.Collections.Specialized;
using System.Text;

namespace Crow
{
    /// <summary>
    /// Encapsulates the state of a Keyboard device.
    /// </summary>
    public struct KeyboardState : IEquatable<KeyboardState>
    {
	#region Fields

	// Allocate enough ints to store all keyboard keys
	const int IntSize = sizeof(int);
	const int NumInts = ((int)Key.LastKey + IntSize - 1) / IntSize;
	// The following line triggers bogus CS0214 in gmcs 2.0.1, sigh...
	unsafe fixed int Keys[NumInts];
	bool is_connected;

	#endregion

	#region Public Members

	/// <summary>
	/// Gets a <see cref="System.Boolean"/> indicating whether the specified
	/// <see cref="OpenTK.Input.Key"/> is pressed.
	/// </summary>
	/// <param name="key">The <see cref="OpenTK.Input.Key"/> to check.</param>
	/// <returns>True if key is pressed; false otherwise.</returns>
	public bool this[Key key]
	{
	    get { return IsKeyDown(key); }
	    internal set { SetKeyState(key, value); }
	}

	/// <summary>
	/// Gets a <see cref="System.Boolean"/> indicating whether the specified
	/// <see cref="OpenTK.Input.Key"/> is pressed.
	/// </summary>
	/// <param name="code">The scancode to check.</param>
	/// <returns>True if code is pressed; false otherwise.</returns>
	public bool this[short code]
	{
	    get { return IsKeyDown((Key)code); }
	}

	/// <summary>
	/// Gets a <see cref="System.Boolean"/> indicating whether this key is down.
	/// </summary>
	/// <param name="key">The <see cref="OpenTK.Input.Key"/> to check.</param>
	public bool IsKeyDown(Key key)
	{
	    return ReadBit((int)key);
	}

	/// <summary>
	/// Gets a <see cref="System.Boolean"/> indicating whether this scan code is down.
	/// </summary>
	/// <param name="code">The scan code to check.</param>
	public bool IsKeyDown(short code)
	{
	    return code >= 0 && code < (short)Key.LastKey && ReadBit(code);
	}

	/// <summary>
	/// Gets a <see cref="System.Boolean"/> indicating whether this key is up.
	/// </summary>
	/// <param name="key">The <see cref="OpenTK.Input.Key"/> to check.</param>
	public bool IsKeyUp(Key key)
	{
	    return !ReadBit((int)key);
	}

	/// <summary>
	/// Gets a <see cref="System.Boolean"/> indicating whether this scan code is down.
	/// </summary>
	/// <param name="code">The scan code to check.</param>
	public bool IsKeyUp(short code)
	{
	    return !IsKeyDown(code);
	}

	/// <summary>
	/// Gets a <see cref="System.Boolean"/> indicating whether this keyboard
	/// is connected.
	/// </summary>
	public bool IsConnected
	{
	    get { return is_connected; }
	    internal set { is_connected = value; }
	}

#if false
	// Disabled until the correct cross-platform API can be determined.
	public bool IsLedOn(KeyboardLeds led)
	{
	    return false;
	}

	public bool IsLedOff(KeyboardLeds led)
	{
	    return false;
	}
#endif

	/// <summary>
	/// Checks whether two <see cref="KeyboardState" /> instances are equal.
	/// </summary>
	/// <param name="left">
	/// A <see cref="KeyboardState"/> instance.
	/// </param>
	/// <param name="right">
	/// A <see cref="KeyboardState"/> instance.
	/// </param>
	/// <returns>
	/// True if both left is equal to right; false otherwise.
	/// </returns>
	public static bool operator ==(KeyboardState left, KeyboardState right)
	{
	    return left.Equals(right);
	}

	/// <summary>
	/// Checks whether two <see cref="KeyboardState" /> instances are not equal.
	/// </summary>
	/// <param name="left">
	/// A <see cref="KeyboardState"/> instance.
	/// </param>
	/// <param name="right">
	/// A <see cref="KeyboardState"/> instance.
	/// </param>
	/// <returns>
	/// True if both left is not equal to right; false otherwise.
	/// </returns>
	public static bool operator !=(KeyboardState left, KeyboardState right)
	{
	    return !left.Equals(right);
	}

	/// <summary>
	/// Compares to an object instance for equality.
	/// </summary>
	/// <param name="obj">
	/// The <see cref="System.Object"/> to compare to.
	/// </param>
	/// <returns>
	/// True if this instance is equal to obj; false otherwise.
	/// </returns>
	public override bool Equals(object obj)
	{
	    if (obj is KeyboardState)
	    {
		return this == (KeyboardState)obj;
	    }
	    else
	    {
		return false;
	    }
	}

	/// <summary>
	/// Generates a hashcode for the current instance.
	/// </summary>
	/// <returns>
	/// A <see cref="System.Int32"/> represting the hashcode for this instance.
	/// </returns>
	public override int GetHashCode()
	{
	    unsafe
	    {
		fixed (int* k = Keys)
		{
		    int hashcode = 0;
		    for (int i = 0; i < NumInts; i++)
			hashcode ^= (k + i)->GetHashCode();
		    return hashcode;
		}
	    }
	}

	#endregion

	#region Internal Members

	public void SetKeyState(Key key, bool down)
	{
	    if (down)
	    {
		EnableBit((int)key);
	    }
	    else
	    {
		DisableBit((int)key);
	    }
	}

	internal bool ReadBit(int offset)
	{
	    ValidateOffset(offset);

	    int int_offset = offset / 32;
	    int bit_offset = offset % 32;
	    unsafe
	    {
		fixed (int* k = Keys) { return (*(k + int_offset) & (1 << bit_offset)) != 0u; }
	    }
	}

	internal void EnableBit(int offset)
	{
	    //ValidateOffset(offset);

	    int int_offset = offset / 32;
	    int bit_offset = offset % 32;
	    unsafe
	    {
		fixed (int* k = Keys) { *(k + int_offset) |= 1 << bit_offset; }
	    }
	}

	internal void DisableBit(int offset)
	{
	    ValidateOffset(offset);

	    int int_offset = offset / 32;
	    int bit_offset = offset % 32;
	    unsafe
	    {
		fixed (int* k = Keys) { *(k + int_offset) &= ~(1 << bit_offset); }
	    }
	}

	internal void MergeBits(KeyboardState other)
	{
	    unsafe
	    {
		int* k2 = other.Keys;
		fixed (int* k1 = Keys)
		{
		    for (int i = 0; i < NumInts; i++)
			*(k1 + i) |= *(k2 + i);
		}
	    }
	    IsConnected |= other.IsConnected;
	}

	internal void SetIsConnected(bool value)
	{
	    IsConnected = value;
	}

	#endregion

	#region Private Members

	static void ValidateOffset(int offset)
	{
	    if (offset < 0 || offset >= NumInts * IntSize)
		throw new ArgumentOutOfRangeException();
	}

	#endregion

	#region IEquatable<KeyboardState> Members

	/// <summary>
	/// Compares two KeyboardState instances.
	/// </summary>
	/// <param name="other">The instance to compare two.</param>
	/// <returns>True, if both instances are equal; false otherwise.</returns>
	public bool Equals(KeyboardState other)
	{
	    bool equal = true;
	    unsafe
	    {
		int* k2 = other.Keys;
		fixed (int* k1 = Keys)
		{
		    for (int i = 0; equal && i < NumInts; i++)
			equal &= *(k1 + i) == *(k2 + i);
		}
	    }
	    return equal;
	}

	#endregion
    }
}