com.oracle.graal.python.charset.PythonUnicodeEscapeCharsetDecoder Maven / Gradle / Ivy
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package com.oracle.graal.python.charset;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;
import java.nio.charset.StandardCharsets;
import com.oracle.graal.python.builtins.objects.str.StringUtils;
public class PythonUnicodeEscapeCharsetDecoder extends CharsetDecoder {
// Decoding octals is annoying, because they are variable length and we don't
// have variable lookahead. We have to incrementally remember the current code
// point and emit it only when we know the octal has really ended
private int octalCodePoint;
private int octalLength;
protected PythonUnicodeEscapeCharsetDecoder(Charset cs) {
super(cs, 1, 1);
}
static CoderResult decodeHexUnicodeEscape(ByteBuffer source, CharBuffer target, byte b, int initialPosition) {
int count;
switch (b) {
case 'x':
count = 2;
break;
case 'u':
count = 4;
break;
case 'U':
count = 8;
break;
default:
throw new IllegalArgumentException();
}
if (source.remaining() < count) {
source.position(initialPosition);
return CoderResult.UNDERFLOW;
}
byte[] numbuf = new byte[count];
source.get(numbuf, 0, count);
int codePoint;
try {
codePoint = Integer.parseInt(new String(numbuf, 0, count, StandardCharsets.US_ASCII), 16);
} catch (NumberFormatException e) {
int pos = source.position();
source.position(initialPosition);
return CoderResult.malformedForLength(pos - initialPosition);
}
return outputCodePoint(source, target, codePoint, initialPosition);
}
static CoderResult outputCodePoint(ByteBuffer source, CharBuffer target, int codePoint, int initialPosition) {
if (!Character.isValidCodePoint(codePoint)) {
int pos = source.position();
source.position(initialPosition);
return CoderResult.malformedForLength(pos - initialPosition);
}
if (Character.charCount(codePoint) == 2) {
target.put(Character.highSurrogate(codePoint));
if (!target.hasRemaining()) {
source.position(initialPosition);
target.position(target.position() - 1);
return CoderResult.OVERFLOW;
}
target.put(Character.lowSurrogate(codePoint));
} else {
target.put((char) codePoint);
}
return null;
}
@Override
protected CoderResult decodeLoop(ByteBuffer source, CharBuffer target) {
while (true) {
if (!source.hasRemaining()) {
return CoderResult.UNDERFLOW;
}
if (!target.hasRemaining()) {
return CoderResult.OVERFLOW;
}
int initialPosition = source.position();
byte b = source.get();
CoderResult result;
if (b == '\\') {
if (!source.hasRemaining()) {
source.position(initialPosition);
return CoderResult.UNDERFLOW;
}
b = source.get();
if (b >= '0' && b <= '7') {
octalLength = 1;
octalCodePoint = b - '0';
continue;
}
switch (b) {
case '\\':
target.put('\\');
continue;
case 'a':
target.put('\u0007');
continue;
case 'b':
target.put('\b');
continue;
case 'f':
target.put('\f');
continue;
case 'n':
target.put('\n');
continue;
case 'r':
target.put('\r');
continue;
case 't':
target.put('\t');
continue;
case 'v':
target.put('\u000b');
continue;
case '\"':
target.put('\"');
continue;
case '\'':
target.put('\'');
continue;
case '\r':
case '\n':
continue;
case 'u':
case 'U':
case 'x':
result = decodeHexUnicodeEscape(source, target, b, initialPosition);
if (result != null) {
return result;
}
continue;
case 'N':
if (!source.hasRemaining()) {
source.position(initialPosition);
return CoderResult.UNDERFLOW;
}
b = source.get();
if (b != '{') {
source.position(initialPosition);
return CoderResult.malformedForLength(2);
}
do {
if (!source.hasRemaining()) {
source.position(initialPosition);
return CoderResult.UNDERFLOW;
}
b = source.get();
} while (b != '}');
int end = source.position();
source.position(initialPosition + 3);
byte[] nameBytes = new byte[end - source.position() - 1];
source.get(nameBytes);
int codePoint = StringUtils.getCodePoint(new String(nameBytes, StandardCharsets.US_ASCII));
if (codePoint < 0) {
source.position(initialPosition);
return CoderResult.malformedForLength(end - initialPosition);
}
result = outputCodePoint(source, target, codePoint, initialPosition);
if (result != null) {
return result;
}
continue;
default:
// TODO warning?
target.put('\\');
source.position(source.position() - 1);
continue;
}
} else if (octalLength > 0 && b >= '0' && b <= '7') {
octalLength++;
octalCodePoint = octalCodePoint * 8 + (b - '0');
if (octalLength >= 3) {
outputOctal(target);
}
} else {
if (octalLength >= 1) {
outputOctal(target);
if (!target.hasRemaining()) {
return CoderResult.OVERFLOW;
}
}
target.put((char) (b & 0xFF));
}
}
}
private void outputOctal(CharBuffer target) {
assert Character.isValidCodePoint(octalCodePoint) && Character.charCount(octalCodePoint) == 1;
target.put((char) octalCodePoint);
octalCodePoint = 0;
octalLength = 0;
}
@Override
protected void implReset() {
octalCodePoint = 0;
octalLength = 0;
}
@Override
protected CoderResult implFlush(CharBuffer target) {
if (octalLength > 0) {
if (!target.hasRemaining()) {
return CoderResult.OVERFLOW;
}
outputOctal(target);
}
return CoderResult.UNDERFLOW;
}
}
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