/*******************************************************************************
* Copyright (c) 2015 Luaj.org. All rights reserved.
*
* 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.
******************************************************************************/
package org.luaj.vm2.compiler;

import org.luaj.vm2.LocVars;
import org.luaj.vm2.Lua;
import org.luaj.vm2.LuaError;
import org.luaj.vm2.LuaString;
import org.luaj.vm2.LuaValue;
import org.luaj.vm2.Prototype;
import org.luaj.vm2.Upvaldesc;

/**
 * Constants used by the LuaC compiler and related classes.
 * 
 * @see LuaC
 * @see FuncState
 */
public class Constants extends Lua {
	
	/** Maximum stack size of a luaj vm interpreter instance. */
	public static final int MAXSTACK = 1024;

	static final int LUAI_MAXUPVAL = 0xff;
	static final int LUAI_MAXVARS = 1024;
	static final int NO_REG		 = MAXARG_A;
	

	/* OpMode - basic instruction format */
	static final int
		iABC = 0,
		iABx = 1,
		iAsBx = 2;

	/* OpArgMask */
	static final int
	  OpArgN = 0,  /* argument is not used */
	  OpArgU = 1,  /* argument is used */
	  OpArgR = 2,  /* argument is a register or a jump offset */
	  OpArgK = 3;   /* argument is a constant or register/constant */


	protected static void _assert(boolean b) {
		if (!b)
			throw new LuaError("compiler assert failed");
	}

	static void SET_OPCODE(InstructionPtr i,int o) {
		i.set( ( i.get() & (MASK_NOT_OP)) | ((o << POS_OP) & MASK_OP) );
	}
	
	static void SETARG_A(int[] code, int index, int u) {
		code[index] = (code[index] & (MASK_NOT_A)) | ((u << POS_A) & MASK_A);
	}

	static void SETARG_A(InstructionPtr i,int u) {
		i.set( ( i.get() & (MASK_NOT_A)) | ((u << POS_A) & MASK_A) );
	}

	static void SETARG_B(InstructionPtr i,int u) {
		i.set( ( i.get() & (MASK_NOT_B)) | ((u << POS_B) & MASK_B) );
	}

	static void SETARG_C(InstructionPtr i,int u) {
		i.set( ( i.get() & (MASK_NOT_C)) | ((u << POS_C) & MASK_C) );
	}
	
	static void SETARG_Bx(InstructionPtr i,int u) {
		i.set( ( i.get() & (MASK_NOT_Bx)) | ((u << POS_Bx) & MASK_Bx) );
	}
	
	static void SETARG_sBx(InstructionPtr i,int u) {
		SETARG_Bx( i, u + MAXARG_sBx );
	}

	static int CREATE_ABC(int o, int a, int b, int c) {
		return ((o << POS_OP) & MASK_OP) |
				((a << POS_A) & MASK_A) |
				((b << POS_B) & MASK_B) |
				((c << POS_C) & MASK_C) ;
	}
	
	static int CREATE_ABx(int o, int a, int bc) {
		return ((o << POS_OP) & MASK_OP) |
				((a << POS_A) & MASK_A) |
				((bc << POS_Bx) & MASK_Bx) ;
 	}
	
	static int CREATE_Ax(int o, int a) {
		return ((o << POS_OP) & MASK_OP) |
				((a << POS_Ax) & MASK_Ax) ;
 	}

	// vector reallocation
	
	static LuaValue[] realloc(LuaValue[] v, int n) {
		LuaValue[] a = new LuaValue[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static Prototype[] realloc(Prototype[] v, int n) {
		Prototype[] a = new Prototype[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static LuaString[] realloc(LuaString[] v, int n) {
		LuaString[] a = new LuaString[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static LocVars[] realloc(LocVars[] v, int n) {
		LocVars[] a = new LocVars[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static Upvaldesc[] realloc(Upvaldesc[] v, int n) {
		Upvaldesc[] a = new Upvaldesc[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static LexState.Vardesc[] realloc(LexState.Vardesc[] v, int n) {
		LexState.Vardesc[] a = new LexState.Vardesc[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static LexState.Labeldesc[] grow(LexState.Labeldesc[] v, int min_n) {
		return v == null ? new LexState.Labeldesc[2] : v.length < min_n ? realloc(v, v.length*2) : v;
	}
	
	static LexState.Labeldesc[] realloc(LexState.Labeldesc[] v, int n) {
		LexState.Labeldesc[] a = new LexState.Labeldesc[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static int[] realloc(int[] v, int n) {
		int[] a = new int[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static byte[] realloc(byte[] v, int n) {
		byte[] a = new byte[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	static char[] realloc(char[] v, int n) {
		char[] a = new char[n];
		if ( v != null )
			System.arraycopy(v, 0, a, 0, Math.min(v.length,n));
		return a;
	}

	protected Constants() {}
}
