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/* ____ ____ ____ ____ ______ *\
** / __// __ \/ __// __ \/ ____/ SOcos COmpiles Scala **
** __\_ \/ /_/ / /__/ /_/ /\_ \ (c) 2002-2006, LAMP/EPFL **
** /_____/\____/\___/\____/____/ **
\* */
// $Id$
package scala.tools.nsc.io;
import java.io.{File, FileInputStream, IOException};
import java.nio.{ByteBuffer, CharBuffer};
import java.nio.channels.{FileChannel, ReadableByteChannel};
import java.nio.charset.{CharsetDecoder, CoderResult};
/** This class implements methods to read and decode source files. */
class SourceReader(decoder: CharsetDecoder) {
import SourceReader.{decode, flush}
//########################################################################
// Private Fields
/** The input byte buffer (small enough to fit in cache) */
private val bytes: ByteBuffer = ByteBuffer.allocate(0x4000);
/** The output character buffer */
private var chars: CharBuffer = CharBuffer.allocate(0x4000);
//########################################################################
// Public Methods
/** Reads the file with the specified name. */
def read(filename: String): Array[Char]= read(new File(filename));
/** Reads the specified file. */
def read(file: File): Array[Char] = {
val channel: FileChannel = new FileInputStream(file).getChannel();
try {
read(channel);
} finally {
channel.close();
}
}
/** Reads the specified file. */
def read(file: AbstractFile): Array[Char] = {
val decoder: CharsetDecoder = this.decoder.reset();
val bytes: ByteBuffer = ByteBuffer.wrap(file.read);
val chars: CharBuffer = this.chars; chars.clear();
terminate(flush(decoder, decode(decoder, bytes, chars, true)));
}
/** Reads the specified byte channel. */
def read(input: ReadableByteChannel): Array[Char] = {
val decoder: CharsetDecoder = this.decoder.reset();
val bytes: ByteBuffer = this.bytes; bytes.clear();
var chars: CharBuffer = this.chars; chars.clear();
var endOfInput: Boolean = false
while (!endOfInput ) {
endOfInput = input.read(bytes) < 0;
bytes.flip();
chars = decode(decoder, bytes, chars, endOfInput);
}
terminate(flush(decoder, chars));
}
//########################################################################
// Private Methods
/**
* Sets the specified char buffer as the new output buffer and
* reads and returns its content.
*/
private def terminate(chars: CharBuffer): Array[Char] = {
val result = new Array[Char](chars.length());
chars.get(result);
this.chars = chars;
result;
}
}
object SourceReader {
/**
* Decodes the content of the specified byte buffer with the
* specified decoder into the specified char buffer, allocating
* bigger ones if necessary, then compacts the byte buffer and
* returns the last allocated char buffer. The "endOfInput"
* argument indicates whether the byte buffer contains the last
* chunk of the input file.
*/
def decode(decoder: CharsetDecoder, bytes: ByteBuffer, chars: CharBuffer,
endOfInput: boolean): CharBuffer =
{
val result: CoderResult = decoder.decode(bytes, chars, endOfInput);
if (result.isUnderflow()) {
bytes.compact();
chars;
} else {
if (result.isError()) throw new IOException(result.toString());
assert(result.isOverflow());
decode(decoder, bytes, increaseCapacity(chars), endOfInput);
}
}
/**
* Flushes the specified decoder into the specified char buffer,
* allocating bigger ones if necessary and then flips and returns
* the last allocated char buffer.
*/
def flush(decoder: CharsetDecoder, chars: CharBuffer): CharBuffer = {
val result: CoderResult = decoder.flush(chars);
if (result.isUnderflow()) {
chars.flip();
chars;
} else {
if (result.isError()) throw new IOException(result.toString());
assert(result.isOverflow());
flush(decoder, increaseCapacity(chars));
}
}
/**
* Flips the specified buffer and returns a new one with the same
* content but with an increased capacity.
*/
private def increaseCapacity(buffer: CharBuffer): CharBuffer = {
buffer.flip();
val capacity = 2 * buffer.capacity();
CharBuffer.allocate(capacity).put(buffer);
}
}
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