Scala example source code file (AbstractFileReader.scala)

This example Scala source code file (AbstractFileReader.scala) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Scala tags/keywords

abstractfile, abstractfilereader, array, array, byte, byte, char, char, double, float, int, int, long

The Scala AbstractFileReader.scala source code

/* NSC -- new Scala compiler
 * Copyright 2005-2011 LAMP/EPFL
 * @author  Martin Odersky
 */


package scala.tools.nsc
package symtab
package classfile

import java.lang.Float.intBitsToFloat
import java.lang.Double.longBitsToDouble

import scala.tools.nsc.io.AbstractFile

/** 
 * This class reads files byte per byte. Only used by ClassFileParser
 *
 * @author Philippe Altherr
 * @version 1.0, 23/03/2004
 */
class AbstractFileReader(val file: AbstractFile) {

  /** the buffer containing the file
   */
  val buf: Array[Byte] = file.toByteArray

  /** the current input pointer
   */
  var bp: Int = 0

  /** return byte at offset 'pos'
   */
  @throws(classOf[IndexOutOfBoundsException])
  def byteAt(pos: Int): Byte = buf(pos)

  /** read a byte
   */
  @throws(classOf[IndexOutOfBoundsException])
  def nextByte: Byte = {
    val b = buf(bp)
    bp += 1
    b
  }

  /** read some bytes
   */
  def nextBytes(len: Int): Array[Byte] = {
    bp += len
    buf.slice(bp - len, bp)
  }

  /** read a character
   */
  def nextChar: Char =
    (((nextByte & 0xff) << 8) + (nextByte & 0xff)).toChar

  /** read an integer
   */
  def nextInt: Int =
    ((nextByte & 0xff) << 24) + ((nextByte & 0xff) << 16) +
    ((nextByte & 0xff) <<  8) +  (nextByte & 0xff)


  /** extract a character at position bp from buf
   */
  def getChar(mybp: Int): Char =
    (((buf(mybp) & 0xff) << 8) + (buf(mybp+1) & 0xff)).toChar

  /** extract an integer at position bp from buf
   */
  def getInt(mybp: Int): Int =
    ((buf(mybp  ) & 0xff) << 24) + ((buf(mybp+1) & 0xff) << 16) +
    ((buf(mybp+2) & 0xff) << 8) + (buf(mybp+3) & 0xff)

  /** extract a long integer at position bp from buf
   */
  def getLong(mybp: Int): Long =
    (getInt(mybp).toLong << 32) + (getInt(mybp + 4) & 0xffffffffL)

  /** extract a float at position bp from buf
   */
  def getFloat(mybp: Int): Float = intBitsToFloat(getInt(mybp))

  /** extract a double at position bp from buf
   */
  def getDouble(mybp: Int): Double = longBitsToDouble(getLong(mybp))

  /** skip next 'n' bytes
   */
  def skip(n: Int) { bp += n }

}