content: /*******************************************************************************
  * Copyright (c) 2009-2011 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;
  
  /**
   * Prototype representing compiled lua code. 
   * 
   * <p>
   * This is both a straight translation of the corresponding C type, 
   * and the main data structure for execution of compiled lua bytecode. 
   * 
   * <p>
   * Generally, the {@link Protoytpe} is not constructed directly is an intermediate result
   * as lua code is loaded using {@link Globals.load}:
   * <pre> {@code
   * Globals globals = JsePlatform.standardGlobals();
   * globals.load( new StringReader("print 'hello'"), "main.lua" ).call(); 
   * } </pre>
   * 
   * <p>
   * To create a {@link Prototype} directly, a compiler such as {@link LuaC} may be used:
   * <pre> {@code
   * InputStream is = new ByteArrayInputStream("print('hello,world')".getBytes());
   * Prototype p = LuaC.instance.compile(is, "script");
   * }</pre> 
   * 
   * To simplify loading, the {@link Globals#compilePrototype} method may be used: 
   * <pre> {@code
   * Prototype p = globals.compileProtoytpe(is, "script");
   * }</pre>
   * 
   * It may also be loaded from a {@link java.io.Reader} : 
   * <pre> {@code
   * Prototype p = globals.compileProtoytpe(new StringReader(script), "script");
   * }</pre>
   * 
   * To un-dump a binary file known to be a binary lua file that has been dumped to a string,
   * the {@link Globals#Undumper} interface may be used: 
   * <pre> {@code
   * FileInputStream lua_binary_file = new FileInputStream("foo.lc");  // Known to be compiled lua.
   * Prototype p = globals.undumper.undump(lua_binary_file, "foo.lua");
   * }</pre>
   * 
   * To execute the code represented by the {@link Prototype} it must be supplied to 
   * the constructor of a {@link LuaClosure}:
   * <pre> {@code
   * Globals globals = JsePlatform.standardGlobals();
   * LuaClosure f = new LuaClosure(p, globals);
   * f.call();
   * }</pre> 
   * 
   * To simplify the debugging of prototype values, the contents may be printed using {@link Print#print}:
   * <pre> {@code
   * Print.print(p);
   * }</pre>
   * <p>
   *  
   * @see LuaClosure
   * @see Globals
   * @see Globals#Undumper
   * @see Globasl#Compiler
   * @see Print#print
   */
  
  public class Prototype {
  	/* constants used by the function */
  	public LuaValue[] k; 
  	public int[] code;
  	/* functions defined inside the function */
  	public Prototype[] p;
  	/* map from opcodes to source lines */
  	public int[] lineinfo;
  	/* information about local variables */
  	public LocVars[] locvars;
  	/* upvalue information */
  	public Upvaldesc[] upvalues;
  	public LuaString  source;
  	public int linedefined;
  	public int lastlinedefined;
  	public int numparams;
  	public int is_vararg;
  	public int maxstacksize;
  
  
  	public Prototype() {}
  	
  	public Prototype(int n_upvalues) {
  		upvalues = new Upvaldesc[n_upvalues];
  	}
  	
  	public String toString() {
  		return source + ":" + linedefined+"-"+lastlinedefined;
  	}
  	
  	/** Get the name of a local variable.
  	 * 
  	 * @param number the local variable number to look up
  	 * @param pc the program counter
  	 * @return the name, or null if not found
  	 */
  	public LuaString getlocalname(int number, int pc) {
  	  int i;
  	  for (i = 0; i<locvars.length && locvars[i].startpc <= pc; i++) {
  	    if (pc < locvars[i].endpc) {  /* is variable active? */
  	    	number--;
  	      if (number == 0)
  	        return locvars[i].varname;
  	    }
  	  }
  	  return null;  /* not found */
  	}
  	
  	public String shortsource() {
  		String name = source.tojstring();
          if ( name.startsWith("@") || name.startsWith("=") )
  			name = name.substring(1);
  		else if ( name.startsWith("\033") )
  			name = "binary string";
          return name;
  	}
  }
  