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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2006-2009, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.util.parsing.input
import java.io.BufferedReader
import scala.collection.immutable.PagedSeq
/** An object to create a StreamReader from a <code>java.io.Reader</code>.
*
* @param in the <code>java.io.Reader</code> that provides the underlying
* stream of characters for this Reader.
*
* @author Miles Sabin
*/
object StreamReader {
final val EofCh = '\032'
def apply(in: java.io.Reader): StreamReader = {
new StreamReader(PagedSeq.fromReader(in), 0, 1)
}
}
/** A StreamReader reads from a character sequence, typically created as a PagedSeq
* from a java.io.Reader
*
* NOTE:
* StreamReaders do not really fulfill the new contract for readers, which
* requires a `source' CharSequence representing the full input.
* Instead source is treated line by line.
* As a consequence, regex matching cannot extend beyond a single line
* when a StreamReader are used for input.
*
* If you need to match regexes spanning several lines you should consider
* class <code>PagedSeqReader</code> instead.
*
* @author Miles Sabin
* @author Martin Odersky
*/
sealed class StreamReader(seq: PagedSeq[Char], off: Int, lnum: Int) extends PagedSeqReader(seq, off) {
import StreamReader._
override def rest: StreamReader =
if (off == seq.length) this
else if (seq(off) == '\n')
new StreamReader(seq.slice(off + 1), 0, lnum + 1)
else new StreamReader(seq, off + 1, lnum)
private def nextEol = {
var i = off
while (i < seq.length && seq(i) != '\n' && seq(i) != EofCh) i += 1
i
}
override def drop(n: Int): StreamReader = {
val eolPos = nextEol
if (eolPos < off + n && eolPos < seq.length)
new StreamReader(seq.slice(eolPos + 1), 0, lnum + 1).drop(off + n - (eolPos + 1))
else
new StreamReader(seq, off + n, lnum)
}
override def pos: Position = new Position {
def line = lnum
def column = off + 1
def lineContents = seq.slice(0, nextEol).toString
}
}
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