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Scala example source code file (JavaCharArrayReader.scala)

This example Scala source code file (JavaCharArrayReader.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

boolean, boolean, char, char, indexedseq, int, int, javachararrayreader, javachararrayreader, lf, string, su, su's, unit

The Scala JavaCharArrayReader.scala source code

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

package scala.tools.nsc
package util

import Chars._

class JavaCharArrayReader(buf: IndexedSeq[Char], start: Int, /* startline: int, startcol: int, */
                      decodeUni: Boolean, error: String => Unit) extends Iterator[Char] with Cloneable {

  def this(buf: IndexedSeq[Char], decodeUni: Boolean, error: String => Unit) =
    this(buf, 0, /* 1, 1, */ decodeUni, error)

  /** produce a duplicate of this char array reader which starts reading
    *  at current position, independent of what happens to original reader
	*/
  def dup: JavaCharArrayReader = clone().asInstanceOf[JavaCharArrayReader]

  /** layout constant
   */
  val tabinc = 8

  /** the line and column position of the current character
  */
  var ch: Char = _
  var bp = start
  var oldBp = -1
  var oldCh: Char = _
  
  //private var cline: Int = _
  //private var ccol: Int = _
  def cpos = bp
  var isUnicode: Boolean = _
  var lastLineStartPos: Int = 0
  var lineStartPos: Int = 0
  var lastBlankLinePos: Int = 0

  private var onlyBlankChars = false
  //private var nextline = startline
  //private var nextcol = startcol

  private def markNewLine() {
    lastLineStartPos = lineStartPos
    if (onlyBlankChars) lastBlankLinePos = lineStartPos
    lineStartPos = bp
    onlyBlankChars = true
    //nextline += 1
    //nextcol = 1
  }

  def hasNext: Boolean = if (bp < buf.length) true 
  else {
    false
  }

  def last: Char = if (bp > start + 2) buf(bp - 2) else ' ' // XML literals

  def next: Char = {
    //cline = nextline
    //ccol = nextcol
    val buf = this.buf.asInstanceOf[collection.mutable.WrappedArray[Char]].array
    if(!hasNext) {
      ch = SU
      return SU  // there is an endless stream of SU's at the end 
    }
    oldBp = bp
    oldCh = ch
    ch = buf(bp)
    isUnicode = false
    bp = bp + 1
    ch match {
      case '\t' =>
        // nextcol = ((nextcol - 1) / tabinc * tabinc) + tabinc + 1;
      case CR =>
        if (bp < buf.size && buf(bp) == LF) {
          ch = LF
          bp += 1
        }
        markNewLine()
      case LF | FF =>
        markNewLine()
      case '\\' =>
        def evenSlashPrefix: Boolean = {
          var p = bp - 2
          while (p >= 0 && buf(p) == '\\') p -= 1
          (bp - p) % 2 == 0
        }
        def udigit: Int = {
          val d = digit2int(buf(bp), 16)
          if (d >= 0) { bp += 1; /* nextcol = nextcol + 1 */ }
          else error("error in unicode escape");
          d
        }
        // nextcol += 1
        if (buf(bp) == 'u' && decodeUni && evenSlashPrefix) {
          do {
            bp += 1 //; nextcol += 1
          } while (buf(bp) == 'u');
          val code = udigit << 12 | udigit << 8 | udigit << 4 | udigit
          ch = code.asInstanceOf[Char]
          isUnicode = true
        }
      case _ =>
        if (ch > ' ') onlyBlankChars = false
        // nextcol += 1
    }
    ch
  }

  def rewind() {
    if (oldBp == -1) throw new IllegalArgumentException
    bp = oldBp
    ch = oldCh
    oldBp = -1
    oldCh = 'x'
  }

  def copy: JavaCharArrayReader =
    new JavaCharArrayReader(buf, bp, /* nextcol, nextline, */ decodeUni, error)
}

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