#region License
#endregion
#region Using Statements
using System.Collections.Generic;
#endregion
namespace Microsoft.Xna.Framework.Input
{
/// <summary>
/// Holds the state of keystrokes by a keyboard.
/// </summary>
public struct KeyboardState
{
#region Public Properties
/// <summary>
/// Returns the state of a specified key.
/// </summary>
/// <param name="key">The key to query.</param>
/// <returns>The state of the key.</returns>
public KeyState this[Keys key]
{
get
{
return InternalGetKey(key) ? KeyState.Down : KeyState.Up;
}
}
#endregion
#region Private Variables
uint keys0, keys1, keys2, keys3, keys4, keys5, keys6, keys7;
#endregion
#region Private Static Variables
static Keys[] empty = new Keys[0];
#endregion
#region Public Constructor
/// <summary>
/// Initializes a new instance of the <see cref="KeyboardState"/> class.
/// </summary>
/// <param name="keys">List of keys to be flagged as pressed on initialization.</param>
public KeyboardState(params Keys[] keys)
{
keys0 = 0;
keys1 = 0;
keys2 = 0;
keys3 = 0;
keys4 = 0;
keys5 = 0;
keys6 = 0;
keys7 = 0;
if (keys != null)
{
foreach (Keys k in keys)
{
InternalSetKey(k);
}
}
}
#endregion
#region Internal Constructor
/// <summary>
/// Initializes a new instance of the <see cref="KeyboardState"/> class.
/// </summary>
/// <param name="keys">List of keys to be flagged as pressed on initialization.</param>
internal KeyboardState(List<Keys> keys)
{
keys0 = 0;
keys1 = 0;
keys2 = 0;
keys3 = 0;
keys4 = 0;
keys5 = 0;
keys6 = 0;
keys7 = 0;
if (keys != null)
{
foreach (Keys k in keys)
{
InternalSetKey(k);
}
}
}
#endregion
#region Public Methods
/// <summary>
/// Gets whether given key is currently being pressed.
/// </summary>
/// <param name="key">The key to query.</param>
/// <returns>true if the key is pressed; false otherwise.</returns>
public bool IsKeyDown(Keys key)
{
return InternalGetKey(key);
}
/// <summary>
/// Gets whether given key is currently being not pressed.
/// </summary>
/// <param name="key">The key to query.</param>
/// <returns>true if the key is not pressed; false otherwise.</returns>
public bool IsKeyUp(Keys key)
{
return !InternalGetKey(key);
}
/// <summary>
/// Returns an array of values holding keys that are currently being pressed.
/// </summary>
/// <returns>The keys that are currently being pressed.</returns>
public Keys[] GetPressedKeys()
{
uint count = (
CountBits(keys0) +
CountBits(keys1) +
CountBits(keys2) +
CountBits(keys3) +
CountBits(keys4) +
CountBits(keys5) +
CountBits(keys6) +
CountBits(keys7)
);
if (count == 0)
{
return empty;
}
Keys[] keys = new Keys[count];
int index = 0;
if (keys0 != 0)
{
index = AddKeysToArray(keys0, 0 * 32, keys, index);
}
if (keys1 != 0)
{
index = AddKeysToArray(keys1, 1 * 32, keys, index);
}
if (keys2 != 0)
{
index = AddKeysToArray(keys2, 2 * 32, keys, index);
}
if (keys3 != 0)
{
index = AddKeysToArray(keys3, 3 * 32, keys, index);
}
if (keys4 != 0)
{
index = AddKeysToArray(keys4, 4 * 32, keys, index);
}
if (keys5 != 0)
{
index = AddKeysToArray(keys5, 5 * 32, keys, index);
}
if (keys6 != 0)
{
index = AddKeysToArray(keys6, 6 * 32, keys, index);
}
if (keys7 != 0)
{
index = AddKeysToArray(keys7, 7 * 32, keys, index);
}
return keys;
}
#endregion
#region Private Methods
bool InternalGetKey(Keys key)
{
uint mask = (uint) 1 << (((int) key) & 0x1f);
uint element;
switch (((int) key) >> 5)
{
case 0: element = keys0; break;
case 1: element = keys1; break;
case 2: element = keys2; break;
case 3: element = keys3; break;
case 4: element = keys4; break;
case 5: element = keys5; break;
case 6: element = keys6; break;
case 7: element = keys7; break;
default: element = 0; break;
}
return (element & mask) != 0;
}
void InternalSetKey(Keys key)
{
uint mask = (uint) 1 << (((int) key) & 0x1f);
switch (((int) key) >> 5)
{
case 0: keys0 |= mask; break;
case 1: keys1 |= mask; break;
case 2: keys2 |= mask; break;
case 3: keys3 |= mask; break;
case 4: keys4 |= mask; break;
case 5: keys5 |= mask; break;
case 6: keys6 |= mask; break;
case 7: keys7 |= mask; break;
}
}
void InternalClearKey(Keys key)
{
uint mask = (uint) 1 << (((int) key) & 0x1f);
switch (((int) key) >> 5)
{
case 0: keys0 &= ~mask; break;
case 1: keys1 &= ~mask; break;
case 2: keys2 &= ~mask; break;
case 3: keys3 &= ~mask; break;
case 4: keys4 &= ~mask; break;
case 5: keys5 &= ~mask; break;
case 6: keys6 &= ~mask; break;
case 7: keys7 &= ~mask; break;
}
}
void InternalClearAllKeys()
{
keys0 = 0;
keys1 = 0;
keys2 = 0;
keys3 = 0;
keys4 = 0;
keys5 = 0;
keys6 = 0;
keys7 = 0;
}
#endregion
#region Public Static Operators and Override Methods
/// <summary>
/// Gets the hash code for <see cref="KeyboardState"/> instance.
/// </summary>
/// <returns>Hash code of the object.</returns>
public override int GetHashCode()
{
return (int) (keys0 ^ keys1 ^ keys2 ^ keys3 ^ keys4 ^ keys5 ^ keys6 ^ keys7);
}
/// <summary>
/// Compares whether two <see cref="KeyboardState"/> instances are equal.
/// </summary>
/// <param name="a"><see cref="KeyboardState"/> instance to the left of the equality operator.</param>
/// <param name="b"><see cref="KeyboardState"/> instance to the right of the equality operator.</param>
/// <returns>true if the instances are equal; false otherwise.</returns>
public static bool operator ==(KeyboardState a, KeyboardState b)
{
return ( a.keys0 == b.keys0 &&
a.keys1 == b.keys1 &&
a.keys2 == b.keys2 &&
a.keys3 == b.keys3 &&
a.keys4 == b.keys4 &&
a.keys5 == b.keys5 &&
a.keys6 == b.keys6 &&
a.keys7 == b.keys7 );
}
/// <summary>
/// Compares whether two <see cref="KeyboardState"/> instances are not equal.
/// </summary>
/// <param name="a"><see cref="KeyboardState"/> instance to the left of the inequality operator.</param>
/// <param name="b"><see cref="KeyboardState"/> instance to the right of the inequality operator.</param>
/// <returns>true if the instances are different; false otherwise.</returns>
public static bool operator !=(KeyboardState a, KeyboardState b)
{
return !(a == b);
}
/// <summary>
/// Compares whether current instance is equal to specified object.
/// </summary>
/// <param name="obj">The <see cref="KeyboardState"/> to compare.</param>
/// <returns>true if the provided <see cref="KeyboardState"/> instance is same with current; false otherwise.</returns>
public override bool Equals(object obj)
{
return obj is KeyboardState && this == (KeyboardState) obj;
}
#endregion
#region Private Static Methods
private static uint CountBits(uint v)
{
v = v - ((v >> 1) & 0x55555555);
v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24;
}
private static int AddKeysToArray(uint keys, int offset, Keys[] pressedKeys, int index)
{
for (int i = 0; i < 32; i += 1)
{
if ((keys & (1 << i)) != 0)
{
pressedKeys[index++] = (Keys) (offset + i);
}
}
return index;
}
#endregion
}
}
