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Scala example source code file (Streamable.scala)
The Streamable.scala Scala example source code/* NSC -- new Scala compiler * Copyright 2005-2013 LAMP/EPFL * @author Paul Phillips */ package scala package reflect package io import java.net.{ URI, URL } import java.io.{ BufferedInputStream, InputStream, PrintStream } import java.io.{ BufferedReader, InputStreamReader, Closeable => JCloseable } import scala.io.{ Codec, BufferedSource, Source } import scala.collection.mutable.ArrayBuffer import Path.fail /** Traits for objects which can be represented as Streams. * * @author Paul Phillips * @since 2.8 * * ''Note: This library is considered experimental and should not be used unless you know what you are doing.'' */ object Streamable { /** Traits which can be viewed as a sequence of bytes. Source types * which know their length should override def length: Long for more * efficient method implementations. * * ''Note: This library is considered experimental and should not be used unless you know what you are doing.'' */ trait Bytes { def inputStream(): InputStream def length: Long = -1 def bufferedInput() = new BufferedInputStream(inputStream()) def bytes(): Iterator[Byte] = bytesAsInts() map (_.toByte) def bytesAsInts(): Iterator[Int] = { val in = bufferedInput() Iterator continually in.read() takeWhile (_ != -1) } /** This method aspires to be the fastest way to read * a stream of known length into memory. */ def toByteArray(): Array[Byte] = { // if we don't know the length, fall back on relative inefficiency if (length == -1L) return (new ArrayBuffer[Byte]() ++= bytes()).toArray val arr = new Array[Byte](length.toInt) val len = arr.length lazy val in = bufferedInput() var offset = 0 def loop() { if (offset < len) { val read = in.read(arr, offset, len - offset) if (read >= 0) { offset += read loop() } } } try loop() finally in.close() if (offset == arr.length) arr else fail("Could not read entire source (%d of %d bytes)".format(offset, len)) } } /** For objects which can be viewed as Chars. * * ''Note: This library is considered experimental and should not be used unless you know what you are doing.'' */ trait Chars extends Bytes { /** Calls to methods requiring byte<->char transformations should be offered * in a form which allows specifying the codec. When it is not specified, * the one discovered at creation time will be used, which will always find the * one in scala.io.Codec if no other is available. This can be overridden * to use a different default. */ def creationCodec: Codec = implicitly[Codec] def chars(codec: Codec): BufferedSource = Source.fromInputStream(inputStream())(codec) def lines(): Iterator[String] = lines(creationCodec) def lines(codec: Codec): Iterator[String] = chars(codec).getLines() /** Obtains an InputStreamReader wrapped around a FileInputStream. */ def reader(codec: Codec): InputStreamReader = new InputStreamReader(inputStream(), codec.charSet) /** Wraps a BufferedReader around the result of reader(). */ def bufferedReader(): BufferedReader = bufferedReader(creationCodec) def bufferedReader(codec: Codec) = new BufferedReader(reader(codec)) /** Creates a BufferedReader and applies the closure, automatically closing it on completion. */ def applyReader[T](f: BufferedReader => T): T = { val in = bufferedReader() try f(in) finally in.close() } /** Convenience function to import entire file into a String. */ def slurp(): String = slurp(creationCodec) def slurp(codec: Codec) = { val src = chars(codec) try src.mkString finally src.close() // Always Be Closing } } /** Call a function on something Closeable, finally closing it. */ def closing[T <: JCloseable, U](stream: T)(f: T => U): U = try f(stream) finally stream.close() def bytes(is: => InputStream): Array[Byte] = (new Bytes { def inputStream() = is }).toByteArray() def slurp(is: => InputStream)(implicit codec: Codec): String = new Chars { def inputStream() = is } slurp codec def slurp(url: URL)(implicit codec: Codec): String = slurp(url.openStream()) } Other Scala source code examplesHere is a short list of links related to this Scala Streamable.scala source code file: |
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