/*
* Copyright (c) 2015 Mozilla Foundation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
package nu.validator.encoding;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CoderResult;
public class Big5Decoder extends Decoder {
private int big5Lead = 0;
private char pendingTrail = '\u0000';
protected Big5Decoder(Charset cs) {
super(cs, 0.5f, 1.0f);
}
@Override protected CoderResult decodeLoop(ByteBuffer in, CharBuffer out) {
assert !(this.report && (big5Lead != 0)):
"When reporting, this method should never return with big5Lead set.";
if (pendingTrail != '\u0000') {
if (!out.hasRemaining()) {
return CoderResult.OVERFLOW;
}
out.put(pendingTrail);
pendingTrail = '\u0000';
}
for (;;) {
if (!in.hasRemaining()) {
return CoderResult.UNDERFLOW;
}
if (!out.hasRemaining()) {
return CoderResult.OVERFLOW;
}
int b = ((int) in.get() & 0xFF);
if (big5Lead == 0) {
if (b <= 0x7F) {
out.put((char) b);
continue;
}
if (b >= 0x81 && b <= 0xFE) {
if (this.report && !in.hasRemaining()) {
// The Java API is badly documented. Need to do this
// crazy thing and hope the caller knows about the
// undocumented aspects of the API!
in.position(in.position() - 1);
return CoderResult.UNDERFLOW;
}
big5Lead = b;
continue;
}
if (this.report) {
in.position(in.position() - 1);
return CoderResult.malformedForLength(1);
}
out.put('\uFFFD');
continue;
}
int lead = big5Lead;
big5Lead = 0;
int offset = (b < 0x7F) ? 0x40 : 0x62;
if ((b >= 0x40 && b <= 0x7E) || (b >= 0xA1 && b <= 0xFE)) {
int pointer = (lead - 0x81) * 157 + (b - offset);
char outTrail;
switch (pointer) {
case 1133:
out.put('\u00CA');
outTrail = '\u0304';
break;
case 1135:
out.put('\u00CA');
outTrail = '\u030C';
break;
case 1164:
out.put('\u00EA');
outTrail = '\u0304';
break;
case 1166:
out.put('\u00EA');
outTrail = '\u030C';
break;
default:
char lowBits = Big5Data.lowBits(pointer);
if (lowBits == '\u0000') {
// The following |if| block fixes
// https://github.com/whatwg/encoding/issues/5
if (b <= 0x7F) {
// prepend byte to stream
// Always legal, since we've always just read a byte
// if we come here.
in.position(in.position() - 1);
}
if (this.report) {
// This can go past the start of the buffer
// if the caller does not conform to the
// undocumented aspects of the API.
in.position(in.position() - 1);
return CoderResult.malformedForLength(b <= 0x7F ? 1 : 2);
}
out.put('\uFFFD');
continue;
}
if (Big5Data.isAstral(pointer)) {
int codePoint = lowBits | 0x20000;
out.put((char) (0xD7C0 + (codePoint >> 10)));
outTrail = (char) (0xDC00 + (codePoint & 0x3FF));
break;
}
out.put(lowBits);
continue;
}
if (!out.hasRemaining()) {
pendingTrail = outTrail;
return CoderResult.OVERFLOW;
}
out.put(outTrail);
continue;
}
// pointer is null
if (b <= 0x7F) {
// prepend byte to stream
// Always legal, since we've always just read a byte
// if we come here.
in.position(in.position() - 1);
}
if (this.report) {
// if position() == 0, the caller is not using the
// undocumented part of the API right and the line
// below will throw!
in.position(in.position() - 1);
return CoderResult.malformedForLength(b <= 0x7F ? 1 : 2);
}
out.put('\uFFFD');
continue;
}
}
@Override protected CoderResult implFlush(CharBuffer out) {
if (pendingTrail != '\u0000') {
if (!out.hasRemaining()) {
return CoderResult.OVERFLOW;
}
out.put(pendingTrail);
pendingTrail = '\u0000';
}
if (big5Lead != 0) {
assert !this.report: "How come big5Lead got to be non-zero when decodeLoop() returned in the reporting mode?";
if (!out.hasRemaining()) {
return CoderResult.OVERFLOW;
}
out.put('\uFFFD');
big5Lead = 0;
}
return CoderResult.UNDERFLOW;
}
@Override protected void implReset() {
big5Lead = 0;
pendingTrail = '\u0000';
}
}