StateStack.java

/*
 * Copyright (c) 2002-2008 LWJGL Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'LWJGL' nor the names of
 *   its contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 */
package org.lwjgl.opengl;

class StateStack {
	private int[] state_stack;
	private int stack_pos;

	public int getState() {
		return state_stack[stack_pos];
	}

	public void pushState(int new_state) {
		int pos = ++stack_pos;
		if (pos == state_stack.length) {
			growState();
		}
		state_stack[pos] = new_state;
	}

	public int popState() {
		return state_stack[stack_pos--];
	}

	public void growState() {
		int[] new_state_stack = new int[state_stack.length + 1];
		System.arraycopy(state_stack, 0, new_state_stack, 0, state_stack.length);
		state_stack = new_state_stack;
	}

	StateStack(int initial_value) {
		state_stack = new int[1];
		stack_pos = 0;
		state_stack[stack_pos] = initial_value;
	}
}