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|
/* __ *\
** ________ ___ / / ___ __ ____ Scala.js API **
** / __/ __// _ | / / / _ | __ / // __/ (c) 2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ |/_// /_\ \ http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | |__/ /____/ **
** |/____/ **
\* */
package scala.scalajs.niocharset
import scala.annotation.tailrec
import java.nio._
import java.nio.charset._
/** This is a very specific common implementation for UTF_16BE and UTF_16LE.
*/
private[niocharset] abstract class UTF_16_Common protected (
name: String, aliases: Array[String],
private val endianness: Int) extends Charset(name, aliases) {
import UTF_16_Common._
def contains(that: Charset): Boolean = true
def newDecoder(): CharsetDecoder = new Decoder
def newEncoder(): CharsetEncoder = new Encoder
private class Decoder extends CharsetDecoder(
UTF_16_Common.this, 0.5f, 1.0f) {
private var endianness = UTF_16_Common.this.endianness
override protected def implReset(): Unit = {
super.implReset()
endianness = UTF_16_Common.this.endianness
}
def decodeLoop(in: ByteBuffer, out: CharBuffer): CoderResult = {
@inline
@tailrec
def loop(): CoderResult = {
if (in.remaining < 2) CoderResult.UNDERFLOW
else {
val b1 = in.get() & 0xff
val b2 = in.get() & 0xff
val wasBOM = if (endianness == AutoEndian) {
// Read BOM
if (b1 == 0xfe && b2 == 0xff) {
endianness = BigEndian
true
} else if (b1 == 0xff && b2 == 0xfe) {
endianness = LittleEndian
true
} else {
// Not a valid BOM: default to BigEndian and start reading
endianness = BigEndian
false
}
} else false
if (wasBOM) {
loop()
} else {
val bigEndian = endianness == BigEndian
@inline def bytes2char(hi: Int, lo: Int): Char =
(if (bigEndian) (hi << 8) | lo else (lo << 8) | hi).toChar
val c1 = bytes2char(b1, b2)
if (Character.isLowSurrogate(c1)) {
in.position(in.position - 2)
CoderResult.malformedForLength(2)
} else if (!Character.isHighSurrogate(c1)) {
if (out.remaining == 0) {
in.position(in.position - 2)
CoderResult.OVERFLOW
} else {
out.put(c1)
loop()
}
} else {
if (in.remaining < 2) {
in.position(in.position - 2)
CoderResult.UNDERFLOW
} else {
val b3 = in.get() & 0xff
val b4 = in.get() & 0xff
val c2 = bytes2char(b3, b4)
if (!Character.isLowSurrogate(c2)) {
in.position(in.position - 4)
CoderResult.malformedForLength(2)
} else {
if (out.remaining < 2) {
in.position(in.position - 4)
CoderResult.OVERFLOW
} else {
out.put(c1)
out.put(c2)
loop()
}
}
}
}
}
}
}
loop()
}
}
private class Encoder extends CharsetEncoder(
UTF_16_Common.this, 2.0f, 2.0f,
// Character 0xfffd
if (endianness == LittleEndian) Array(-3, -1) else Array(-1, -3)) {
private var needToWriteBOM: Boolean = endianness == AutoEndian
override protected def implReset(): Unit = {
super.implReset()
needToWriteBOM = endianness == AutoEndian
}
def encodeLoop(in: CharBuffer, out: ByteBuffer): CoderResult = {
if (needToWriteBOM) {
if (out.remaining < 2) {
return CoderResult.OVERFLOW
} else {
// Always encode in big endian
out.put(0xfe.toByte)
out.put(0xff.toByte)
needToWriteBOM = false
}
}
val bigEndian = endianness != LittleEndian
@inline
def putChar(c: Char): Unit = {
if (bigEndian) {
out.put((c >> 8).toByte)
out.put(c.toByte)
} else {
out.put(c.toByte)
out.put((c >> 8).toByte)
}
}
@inline
@tailrec
def loop(): CoderResult = {
if (in.remaining == 0) CoderResult.UNDERFLOW
else {
val c1 = in.get()
if (Character.isLowSurrogate(c1)) {
in.position(in.position - 1)
CoderResult.malformedForLength(1)
} else if (!Character.isHighSurrogate(c1)) {
if (out.remaining < 2) {
in.position(in.position - 1)
CoderResult.OVERFLOW
} else {
putChar(c1)
loop()
}
} else {
if (in.remaining < 1) {
in.position(in.position - 1)
CoderResult.UNDERFLOW
} else {
val c2 = in.get()
if (!Character.isLowSurrogate(c2)) {
in.position(in.position - 2)
CoderResult.malformedForLength(1)
} else {
if (out.remaining < 4) {
in.position(in.position - 2)
CoderResult.OVERFLOW
} else {
putChar(c1)
putChar(c2)
loop()
}
}
}
}
}
}
loop()
}
}
}
private[niocharset] object UTF_16_Common {
final val AutoEndian = 0
final val BigEndian = 1
final val LittleEndian = 2
}
|
