content: /*******************************************************************************
  * Copyright (c) 2009 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
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  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  ******************************************************************************/
  package org.luaj.vm2.lib.jse;
  
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.luaj.vm2.LuaValue;
  import org.luaj.vm2.lib.BaseLib;
  import org.luaj.vm2.lib.LibFunction;
  import org.luaj.vm2.lib.ResourceFinder;
  
  /** 
   * Subclass of {@link BaseLib} and {@link LibFunction} which implements the lua basic library functions
   * and provides a directory based {@link ResourceFinder} as the {@link #finder}. 
   * <p>
   * Since JME has no file system by default, {@link BaseLib} implements 
   * {@link ResourceFinder} using {@link Class#getResource(String)}. 
   * The {@link JseBaseLib} implements {@link finder} by scanning the current directory
   * first, then falling back to   {@link Class#getResource(String)} if that fails.
   * Otherwise, the behavior is the same as that of {@link BaseLib}.  
   * <p>  
   * Typically, this library is included as part of a call to 
   * {@link JsePlatform#standardGlobals()}
   * <pre> {@code
   * Globals globals = JsePlatform.standardGlobals();
   * globals.get("print").call(LuaValue.valueOf("hello, world"));
   * } </pre>
   * <p>
   * For special cases where the smallest possible footprint is desired, 
   * a minimal set of libraries could be loaded
   * directly via {@link Globals#load(LuaValue)} using code such as:
   * <pre> {@code
   * Globals globals = new Globals();
   * globals.load(new JseBaseLib());
   * globals.get("print").call(LuaValue.valueOf("hello, world"));
   * } </pre>
   * <p>However, other libraries such as <em>PackageLib</em> are not loaded in this case.
   * <p>
   * This is a direct port of the corresponding library in C.
   * @see Globals
   * @see BaseLib
   * @see ResourceFinder
   * @see {@link Globals.finder}
   * @see LibFunction
   * @see JsePlatform
   * @see org.luaj.vm2.lib.jme.JmePlatform
   * @see <a href="http://www.lua.org/manual/5.2/manual.html#6.1">Lua 5.2 Base Lib Reference</a>
   */
  
  public class JseBaseLib extends org.luaj.vm2.lib.BaseLib {
  
  	/** Extend the library loading to set the default value for {@link Globals.STDIN} */
  	public LuaValue call(LuaValue modname, LuaValue env) {
  		super.call(modname, env);
  		env.checkglobals().STDIN = System.in;
  		return env;
  	}
  
  
  	/** 
  	 * Try to open a file in the current working directory, 
  	 * or fall back to base opener if not found.
  	 * 
  	 * This implementation attempts to open the file using new File(filename).  
  	 * It falls back to the base implementation that looks it up as a resource
  	 * in the class path if not found as a plain file. 
  	 *  
  	 * @see org.luaj.vm2.lib.BaseLib
  	 * @see org.luaj.vm2.lib.ResourceFinder
  	 * 
  	 * @param filename
  	 * @return InputStream, or null if not found. 
  	 */
  	public InputStream findResource(String filename) {
  		File f = new File(filename);
  		if ( ! f.exists() )
  			return super.findResource(filename);
  		try {
  			return new FileInputStream(f);
  		} catch ( IOException ioe ) {
  			return null;
  		}
  	}
  }
  