/*
* Copyright (c) 2007 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 org.whattf.io;
import java.io.IOException;
import java.io.Reader;
import java.net.MalformedURLException;
public final class Utf8PercentDecodingReader extends Reader {
private final Reader delegate;
private char pending = '\u0000';
/**
* @param delegate
*/
public Utf8PercentDecodingReader(final Reader delegate) {
this.delegate = delegate;
}
/**
* @see java.io.Reader#read()
*/
@Override
public int read() throws IOException {
if (pending != '\u0000') {
char rv = pending;
pending = '\u0000';
return rv;
}
int byteVal = 0;
int codePoint = 0;
int c = delegate.read();
int trailBytes = 0;
if (c == -1) {
return -1;
} if (c == '%') {
byteVal = readHexByte();
if (byteVal < 0x80) {
return byteVal;
} else if ((0xE0 & byteVal) == 0xC0) {
trailBytes = 1;
codePoint = byteVal & 0x1F;
} else if ((0xF0 & byteVal) == 0xE0) {
trailBytes = 2;
codePoint = byteVal & 0x0F;
} else if ((0xF8 & byteVal) == 0xF0) {
trailBytes = 3;
codePoint = byteVal & 0x07;
} else {
throw new MalformedURLException("Percent escape decodes to a byte that is not a valid UTF-8 lead byte.");
}
for (int i = 0; i < trailBytes; i++) {
byteVal = readPercentHexByte();
if ((0xC0 & byteVal) == 0x80) {
codePoint = (codePoint << 6) | (byteVal & 0x3F);
} else {
throw new MalformedURLException("Percent escape decodes to a byte that is not a valid UTF-8 trail byte.");
}
}
switch (trailBytes) {
case 3:
if (codePoint <= 0xFFFF) {
throw new MalformedURLException("Non-shortest form UTF-8 percent escape sequence.");
} else {
int rv = (0xD7C0 + (codePoint >> 10));
pending = (char) (0xDC00 + (codePoint & 0x3FF));
return rv;
}
case 2:
if (codePoint <= 0x07FF) {
throw new MalformedURLException("Non-shortest form UTF-8 percent escape sequence.");
} else {
return codePoint;
}
default:
if (codePoint <= 0x007F) {
throw new MalformedURLException("Non-shortest form UTF-8 percent escape sequence.");
} else {
return codePoint;
}
}
} else {
return c;
}
}
private int readPercentHexByte() throws IOException {
int c = delegate.read();
if (c != '%') {
throw new MalformedURLException("Percent-encoded trail byte missing.");
}
return readHexByte();
}
private int readHexByte() throws IOException {
int c = delegate.read();
if (isHexDigit(c)) {
int hi = Character.getNumericValue(c) << 4;
c = delegate.read();
if (isHexDigit(c)) {
return hi | Character.getNumericValue(c);
} else {
throw new MalformedURLException("Malformed percent escape.");
}
} else {
throw new MalformedURLException("Malformed percent escape.");
}
}
private boolean isHexDigit(int c) {
return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
}
@Override
public void close() throws IOException {
pending = '\u0000';
delegate.close();
}
@Override
public int read(char[] cbuf, int off, int len) throws IOException {
int i = 0;
while (i < len) {
int c = read();
if (c == -1) {
if (i == 0) {
return -1;
} else {
return i;
}
}
cbuf[off] = (char) c;
off++;
i++;
}
return i;
}
}