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/*
* 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 Big5Encoder extends Encoder {
private char utf16Lead = '\u0000';
private byte pendingTrail = 0;
protected Big5Encoder(Charset cs) {
super(cs, 1.5f, 2.0f);
}
@Override protected CoderResult encodeLoop(CharBuffer in, ByteBuffer out) {
assert !((this.reportMalformed || this.reportUnmappable) && (utf16Lead != '\u0000')):
"When reporting, this method should never return with utf16Lead set.";
if (pendingTrail != 0) {
if (!out.hasRemaining()) {
return CoderResult.OVERFLOW;
}
out.put(pendingTrail);
pendingTrail = 0;
}
for (;;) {
if (!in.hasRemaining()) {
return CoderResult.UNDERFLOW;
}
if (!out.hasRemaining()) {
return CoderResult.OVERFLOW;
}
boolean isAstral; // true means Plane 2, false means BMP
char lowBits; // The low 16 bits of the code point
char codeUnit = in.get();
int highBits = (codeUnit & 0xFC00);
if (highBits == 0xD800) {
// high surrogate
if (utf16Lead != '\u0000') {
// High surrogate follows another high surrogate. The
// *previous* code unit is in error.
if (this.reportMalformed) {
// The caller had better adhere to the API contract.
// Otherwise, this may throw.
in.position(in.position() - 2);
utf16Lead = '\u0000';
return CoderResult.malformedForLength(1);
}
out.put((byte) '?');
}
utf16Lead = codeUnit;
continue;
}
if (highBits == 0xDC00) {
// low surrogate
if (utf16Lead == '\u0000') {
// Got low surrogate without a previous high surrogate
if (this.reportMalformed) {
in.position(in.position() - 1);
return CoderResult.malformedForLength(1);
}
out.put((byte) '?');
continue;
}
int codePoint = (utf16Lead << 10) + codeUnit - 56613888;
utf16Lead = '\u0000';
// Plane 2 is the only astral plane that has potentially
// Big5-encodable characters.
if ((0xFF0000 & codePoint) != 0x20000) {
if (this.reportUnmappable) {
in.position(in.position() - 2);
return CoderResult.unmappableForLength(2);
}
out.put((byte) '?');
continue;
}
isAstral = true;
lowBits = (char)(codePoint & 0xFFFF);
} else {
// not a surrogate
if (utf16Lead != '\u0000') {
// Non-surrogate follows a high surrogate. The *previous*
// code unit is in error.
utf16Lead = '\u0000';
if (this.reportMalformed) {
// The caller had better adhere to the API contract.
// Otherwise, this may throw.
in.position(in.position() - 2);
return CoderResult.malformedForLength(1);
}
out.put((byte) '?');
// Let's unconsume this code unit and reloop in order to
// re-check if the output buffer still has space.
in.position(in.position() - 1);
continue;
}
isAstral = false;
lowBits = codeUnit;
}
// isAstral now tells us if we have a Plane 2 or a BMP character.
// lowBits tells us the low 16 bits.
// After all the above setup to deal with UTF-16, we are now
// finally ready to follow the spec.
if (!isAstral && lowBits <= 0x7F) {
out.put((byte)lowBits);
continue;
}
int pointer = Big5Data.findPointer(lowBits, isAstral);
if (pointer == 0) {
if (this.reportUnmappable) {
if (isAstral) {
in.position(in.position() - 2);
return CoderResult.unmappableForLength(2);
}
in.position(in.position() - 1);
return CoderResult.unmappableForLength(1);
}
out.put((byte)'?');
continue;
}
int lead = pointer / 157 + 0x81;
int trail = pointer % 157;
if (trail < 0x3F) {
trail += 0x40;
} else {
trail += 0x62;
}
out.put((byte)lead);
if (!out.hasRemaining()) {
pendingTrail = (byte)trail;
return CoderResult.OVERFLOW;
}
out.put((byte)trail);
continue;
}
}
@Override protected CoderResult implFlush(ByteBuffer out) {
if (pendingTrail != 0) {
if (!out.hasRemaining()) {
return CoderResult.OVERFLOW;
}
out.put(pendingTrail);
pendingTrail = 0;
}
if (utf16Lead != '\u0000') {
assert !this.reportMalformed: "How come utf16Lead got to be non-zero when decodeLoop() returned in the reporting mode?";
if (!out.hasRemaining()) {
return CoderResult.OVERFLOW;
}
out.put((byte)'?');
utf16Lead = '\u0000';
}
return CoderResult.UNDERFLOW;
}
@Override protected void implReset() {
utf16Lead = '\u0000';
pendingTrail = 0;
}
}
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