com.hazelcast.org.codehaus.janino.UnicodeUnescapeReader Maven / Gradle / Ivy
/*
* Janino - An embedded Java[TM] com.hazelcast.com.iler
*
* Copyright (c) 2001-2010 Arno Unkrig. All rights reserved.
* Copyright (c) 2015-2016 TIBCO Software Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
* following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.hazelcast.org.codehaus.janino;
import java.io.FilterReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import com.hazelcast.org.codehaus.com.hazelcast.com.ons.nullanalysis.Nullable;
/**
* A {@link FilterReader} that unescapes the "Unicode Escapes" as described in JLS7 3.10.6.
*
* Notice that it is possible to formulate invalid escape sequences, e.g. "\u123g" ("g" is not a valid hex
* character). This is handled by throwing a {@link java.lang.RuntimeException}-derived {@link
* UnicodeUnescapeException}.
*
*/
public
class UnicodeUnescapeReader extends FilterReader {
public
UnicodeUnescapeReader(Reader in) { super(in); }
/**
* Overrides {@link FilterReader#read()}.
*
* @throws UnicodeUnescapeException Invalid escape sequence encountered
*/
@Override public int
read() throws IOException {
int c;
// Read next character.
if (this.unreadChar == -1) {
c = this.in.read();
} else {
c = this.unreadChar;
this.unreadChar = -1;
}
// Check for backslash-u escape sequence, preceded with an even number
// of backslashes.
if (c != '\\' || this.oddPrecedingBackslashes) {
this.oddPrecedingBackslashes = false;
return c;
}
// Read one character ahead and check if it is a "u".
c = this.in.read();
if (c != 'u') {
this.unreadChar = c;
this.oddPrecedingBackslashes = true;
return '\\';
}
// Skip redundant "u"s.
do {
c = this.in.read();
if (c == -1) throw new UnicodeUnescapeException("Incomplete escape sequence");
} while (c == 'u');
// Decode escape sequence.
char[] ca = new char[4];
ca[0] = (char) c;
if (this.in.read(ca, 1, 3) != 3) throw new UnicodeUnescapeException("Incomplete escape sequence");
try {
return Integer.parseInt(new String(ca), 16);
} catch (NumberFormatException ex) {
throw new UnicodeUnescapeException("Invalid escape sequence \"\\u" + new String(ca) + "\"", ex);
}
}
/**
* Overrides {@link FilterReader#read(char[], int, int)}.
*/
@Override public int
read(@Nullable char[] cbuf, int off, int len) throws IOException {
assert cbuf != null;
if (len == 0) return 0;
int res = 0;
do {
int c = this.read();
if (c == -1) break;
cbuf[off++] = (char) c;
} while (++res < len);
return res == 0 ? -1 : res;
}
/**
* Simple unit testing.
*/
public static void
main(String[] args) throws IOException {
Reader r = new UnicodeUnescapeReader(new StringReader(args[0]));
for (;;) {
int c = r.read();
if (c == -1) break;
System.out.print((char) c);
}
System.out.println();
}
private int unreadChar = -1; // -1 == none
private boolean oddPrecedingBackslashes;
}