import java.io.*;
import java.net.*;

/**
 *  A class to read values from a file, URL or stream
 *
 *  @version 1.0 21.1.2000
 *  @author Anthony Steed
 */

public class SceneReader {

  /*
   * Private variables 
   */ 
  private BufferedReader stream;
  private StreamTokenizer reader;
  private boolean eof=false;
    
  /** 
    * Create a SceneReader from a File
    * @param f the file to read from
    * @throw java.lang.Exception
    * on various file access errors
    */
  SceneReader(File f) throws Exception {
    stream = new BufferedReader(new FileReader(f));
    reader = new StreamTokenizer(stream);
    initCommon();
  }
    
  /** 
    * Create a SceneReader from a URL
    * @param u the url specifying the file location
    * @throw java.lang.Exception
    * on various URL access errors
    */
  SceneReader(URL u) throws Exception {
    stream = new BufferedReader(new InputStreamReader(u.openStream()));
    reader = new StreamTokenizer(stream);
    initCommon();
  }

  /** 
    * Create a SceneReader from a stream
    * @param is the stream specifying the file location
    * @throw java.lang.Exception
    * on various stream access errors
    */
  SceneReader(InputStream is) throws Exception {
    stream = new BufferedReader(new InputStreamReader(is));
    reader = new StreamTokenizer(stream);
    initCommon();
  }

  /*
   * Configure the tokenizer
   */
  private void initCommon() {
    reader.commentChar('#');
    reader.parseNumbers();
  }

    
  /**
    * Close the file when finished
    * @throw java.io.IOException
    * on various access errors
    */
  public void close() throws IOException {
    stream.close() ;
  }

  /**
    * Return <code>true</code> if the end of file has been reached.
    * @return boolean value 
    */
  public boolean eof()    {
    return eof ;
  }

  /**
    * Read an <code>int</code> value from file.
    * @throw java.io.IOException
    * if source is unreadable
    * @throw java.lang.NumberFormatException
    * if number formating error
    */
  public final synchronized int readInt() 
    throws IOException, NumberFormatException {

      Double input;
      int val = 0 ;

      // Read next word via tokeniser
      input = nextNumber();

      //  Convert to a int
      val = input.intValue();
      return val ;
  }
    
  /**
    * Read a <code>long</code> value from file.
    * @return a long value
    * @throw java.io.IOException
    * if source is unreadable
    * @throw java.lang.NumberFormatException
    * if number formating error
    */
  public final synchronized long readLong() 
    throws IOException, NumberFormatException {

      Double input;
      long val = 0L ;

      // Read next word via tokeniser
      input = nextNumber();
	
      //  Parse the String to construct a long value.
      val = input.longValue();
      return val ;
  }

  /**
    * Read a <code>double</code> value from file.
    * @return a double value
    * @throw java.io.IOException
    * if source is unreadable
    * @throw java.lang.NumberFormatException
    * if number formating error
    */
  public final synchronized double readDouble() 
    throws IOException, NumberFormatException {

      Double input;
      double val = 0.0D ;

      // Read next word via tokeniser
      input = nextNumber();

      //  Convert to a double
      val = input.doubleValue();

      return val ;
  }

  /**
    * Read a <code>float</code> value from file.
    * @return a float value
    * @throw java.io.IOException
    * if source is unreadable
    * @throw java.lang.NumberFormatException
    * if number formating error
    */
  public final synchronized float readFloat() 
    throws IOException, NumberFormatException {

      Double input;
      float val = 0.0F ;

      // Read next word via tokeniser
      input = nextNumber();

      //  Convert to a long
      val = input.longValue();
	
      return val ;
  }

  /**
    * Read a <code>char</code> value from file.
    * @return a char value
    * @throw java.io.IOException
    * if source is unreadable
    */
  public final synchronized char readChar() throws IOException {
    char c = ' ';

    //  No need to parse anything, just get a character and return
    //  it..
    int n = stream.read() ;
    if (n == -1) {
      eof = true ;
    }
    else {
      c = (char)n ;
    }
    return c ;
  }

  /**
    * Read an <code>String</code> value from file.
    * @return a string value
    * @throw java.io.IOException
    * if source is unreadable
    */
  public final synchronized String readString() throws IOException {

    //  No need to parse anything, just get a string and return
    //  it..
    String s = "" ;
    s = stream.readLine() ;
    if (s == null) {
      eof = true ;
      s = ""; ;
    }
    return s ;
  }

  /*
   * Helper function to access tokenizer
   */
  private Double nextNumber() 
    throws IOException, NumberFormatException {
      double input;
      int tokenVal;

      //
      //  Read a String of characters from the file.
      //
      tokenVal = reader.nextToken();

      switch(tokenVal) {
      case StreamTokenizer.TT_NUMBER:
	input = reader.nval; 
	break;
      case StreamTokenizer.TT_EOL:
	eof=true;
	throw new IOException("End of file");
      default:
	throw new NumberFormatException("Next token was not a number " + reader.toString());
      }
      return new Double(input);
  }
}