Scala example source code file (AbstractFileReader.scala)

This example Scala source code file (AbstractFileReader.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

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

The AbstractFileReader.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2005-2013 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

  /** 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] = { // used in ide
    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 }

}