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org.apache.tomcat.util.buf.Utf8Decoder Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.tomcat.util.buf;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;
import java.nio.charset.StandardCharsets;
/**
* Decodes bytes to UTF-8. Extracted from Apache Harmony and modified to reject
* code points from U+D800 to U+DFFF as per RFC3629. The standard Java decoder
* does not reject these. It has also been modified to reject code points
* greater than U+10FFFF which the standard Java decoder rejects but the harmony
* one does not.
*/
public class Utf8Decoder extends CharsetDecoder {
// The next table contains information about UTF-8 charset and
// correspondence of 1st byte to the length of sequence
// For information please visit http://www.ietf.org/rfc/rfc3629.txt
//
// Please note, o means 0, actually.
// -------------------------------------------------------------------
// 0 1 2 3 Value
// -------------------------------------------------------------------
// oxxxxxxx 00000000 00000000 0xxxxxxx
// 11oyyyyy 1oxxxxxx 00000000 00000yyy yyxxxxxx
// 111ozzzz 1oyyyyyy 1oxxxxxx 00000000 zzzzyyyy yyxxxxxx
// 1111ouuu 1ouuzzzz 1oyyyyyy 1oxxxxxx 000uuuuu zzzzyyyy yyxxxxxx
private static final int remainingBytes[] = {
// 1owwwwww
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
// 11oyyyyy
-1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
// 111ozzzz
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
// 1111ouuu
3, 3, 3, 3, 3, -1, -1, -1,
// > 11110111
-1, -1, -1, -1, -1, -1, -1, -1};
private static final int remainingNumbers[] = {0, // 0 1 2 3
4224, // (01o00000b << 6)+(1o000000b)
401536, // (011o0000b << 12)+(1o000000b << 6)+(1o000000b)
29892736 // (0111o000b << 18)+(1o000000b << 12)+(1o000000b <<
// 6)+(1o000000b)
};
private static final int lowerEncodingLimit[] = {-1, 0x80, 0x800, 0x10000};
public Utf8Decoder() {
super(StandardCharsets.UTF_8, 1.0f, 1.0f);
}
@Override
protected CoderResult decodeLoop(ByteBuffer in, CharBuffer out) {
if (in.hasArray() && out.hasArray()) {
return decodeHasArray(in, out);
}
return decodeNotHasArray(in, out);
}
private CoderResult decodeNotHasArray(ByteBuffer in, CharBuffer out) {
int outRemaining = out.remaining();
int pos = in.position();
int limit = in.limit();
try {
while (pos < limit) {
if (outRemaining == 0) {
return CoderResult.OVERFLOW;
}
int jchar = in.get();
if (jchar < 0) {
jchar = jchar & 0x7F;
int tail = remainingBytes[jchar];
if (tail == -1) {
return CoderResult.malformedForLength(1);
}
if (limit - pos < 1 + tail) {
// No early test for invalid sequences here as peeking
// at the next byte is harder
return CoderResult.UNDERFLOW;
}
int nextByte;
for (int i = 0; i < tail; i++) {
nextByte = in.get() & 0xFF;
if ((nextByte & 0xC0) != 0x80) {
return CoderResult.malformedForLength(1 + i);
}
jchar = (jchar << 6) + nextByte;
}
jchar -= remainingNumbers[tail];
if (jchar < lowerEncodingLimit[tail]) {
// Should have been encoded in a fewer octets
return CoderResult.malformedForLength(1);
}
pos += tail;
}
// Apache Tomcat added test
if (jchar >= 0xD800 && jchar <= 0xDFFF) {
return CoderResult.unmappableForLength(3);
}
// Apache Tomcat added test
if (jchar > 0x10FFFF) {
return CoderResult.unmappableForLength(4);
}
if (jchar <= 0xffff) {
out.put((char) jchar);
outRemaining--;
} else {
if (outRemaining < 2) {
return CoderResult.OVERFLOW;
}
out.put((char) ((jchar >> 0xA) + 0xD7C0));
out.put((char) ((jchar & 0x3FF) + 0xDC00));
outRemaining -= 2;
}
pos++;
}
return CoderResult.UNDERFLOW;
} finally {
in.position(pos);
}
}
private CoderResult decodeHasArray(ByteBuffer in, CharBuffer out) {
int outRemaining = out.remaining();
int pos = in.position();
int limit = in.limit();
final byte[] bArr = in.array();
final char[] cArr = out.array();
final int inIndexLimit = limit + in.arrayOffset();
int inIndex = pos + in.arrayOffset();
int outIndex = out.position() + out.arrayOffset();
// if someone would change the limit in process,
// they would face consequences
for (; inIndex < inIndexLimit && outRemaining > 0; inIndex++) {
int jchar = bArr[inIndex];
if (jchar < 0) {
jchar = jchar & 0x7F;
// If first byte is invalid, tail will be set to -1
int tail = remainingBytes[jchar];
if (tail == -1) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
// Additional checks to detect invalid sequences ASAP
// Checks derived from Unicode 6.2, Chapter 3, Table 3-7
// Check 2nd byte
int tailAvailable = inIndexLimit - inIndex - 1;
if (tailAvailable > 0) {
// First byte C2..DF, second byte 80..BF
if (jchar > 0x41 && jchar < 0x60 &&
(bArr[inIndex + 1] & 0xC0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
// First byte E0, second byte A0..BF
if (jchar == 0x60 && (bArr[inIndex + 1] & 0xE0) != 0xA0) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
// First byte E1..EC, second byte 80..BF
if (jchar > 0x60 && jchar < 0x6D &&
(bArr[inIndex + 1] & 0xC0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
// First byte ED, second byte 80..9F
if (jchar == 0x6D && (bArr[inIndex + 1] & 0xE0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
// First byte EE..EF, second byte 80..BF
if (jchar > 0x6D && jchar < 0x70 &&
(bArr[inIndex + 1] & 0xC0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
// First byte F0, second byte 90..BF
if (jchar == 0x70 &&
((bArr[inIndex + 1] & 0xFF) < 0x90 ||
(bArr[inIndex + 1] & 0xFF) > 0xBF)) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
// First byte F1..F3, second byte 80..BF
if (jchar > 0x70 && jchar < 0x74 &&
(bArr[inIndex + 1] & 0xC0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
// First byte F4, second byte 80..8F
if (jchar == 0x74 &&
(bArr[inIndex + 1] & 0xF0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
}
// Check third byte if present and expected
if (tailAvailable > 1 && tail > 1) {
if ((bArr[inIndex + 2] & 0xC0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(2);
}
}
// Check fourth byte if present and expected
if (tailAvailable > 2 && tail > 2) {
if ((bArr[inIndex + 3] & 0xC0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(3);
}
}
if (tailAvailable < tail) {
break;
}
for (int i = 0; i < tail; i++) {
int nextByte = bArr[inIndex + i + 1] & 0xFF;
if ((nextByte & 0xC0) != 0x80) {
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1 + i);
}
jchar = (jchar << 6) + nextByte;
}
jchar -= remainingNumbers[tail];
if (jchar < lowerEncodingLimit[tail]) {
// Should have been encoded in fewer octets
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.malformedForLength(1);
}
inIndex += tail;
}
// Apache Tomcat added test
if (jchar >= 0xD800 && jchar <= 0xDFFF) {
return CoderResult.unmappableForLength(3);
}
// Apache Tomcat added test
if (jchar > 0x10FFFF) {
return CoderResult.unmappableForLength(4);
}
if (jchar <= 0xffff) {
cArr[outIndex++] = (char) jchar;
outRemaining--;
} else {
if (outRemaining < 2) {
// Encoded with 4 bytes. inIndex currently points
// to the final byte. Move it back to first byte.
inIndex -= 3;
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return CoderResult.OVERFLOW;
}
cArr[outIndex++] = (char) ((jchar >> 0xA) + 0xD7C0);
cArr[outIndex++] = (char) ((jchar & 0x3FF) + 0xDC00);
outRemaining -= 2;
}
}
in.position(inIndex - in.arrayOffset());
out.position(outIndex - out.arrayOffset());
return (outRemaining == 0 && inIndex < inIndexLimit) ?
CoderResult.OVERFLOW :
CoderResult.UNDERFLOW;
}
}
