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/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2006-2007, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id$
package scala.util.parsing.input
import java.io.BufferedReader
/** 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(new LazyCharSequence(in), 0, 1)
}
}
/** A character array reader reads a stream of characters (keeping track of
* their positions) from an array.
*
* 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 lines
* when a StreamReader are used for input.
*
* @param bin the underlying java.io.BufferedReader
* @param sourceLine the line at column `col' in the stream
* @param line the 1-based line number of the character returned by `first'
* @param column the 1-based column number of the character returned by `first'
*
* @author Miles Sabin
*/
sealed class StreamReader(source: CharSequence, offset: Int, lnum: Int) extends CharSequenceReader(source, offset) {
import StreamReader._
override def rest: CharSequenceReader =
if (offset == source.length) this
else if (source(offset) == '\n') new StreamReader(source.subSequence(offset + 1), 0, lnum + 1)
else new StreamReader(source, offset + 1, lnum)
private def nextEol = {
var i = offset
while (i < source.length && source(i) != '\n' && source(i) != EofCh) i += 1
i
}
override def drop(n: Int): StreamReader = {
val eolPos = nextEol
if (eolPos < offset + n && eolPos < source.length)
new StreamReader(source.subSequence(eolPos + 1), 0, lnum + 1).drop(offset + n - (eolPos + 1))
else
new StreamReader(source, offset + n, lnum)
}
override def pos: Position = new Position {
def line = lnum
def column = offset + 1
def lineContents = source.subSequence(0, nextEol).toString
}
}
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