org.apache.commons.text.translate.UnicodeEscaper 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.commons.text.translate;
import java.io.IOException;
import java.io.Writer;
/**
* Translates codepoints to their Unicode escaped value.
*
* @since 1.0
*/
public class UnicodeEscaper extends CodePointTranslator {
/** int value representing the lowest codepoint boundary. */
private final int below;
/** int value representing the highest codepoint boundary. */
private final int above;
/** whether to escape between the boundaries or outside them. */
private final boolean between;
/**
* Constructs a UnicodeEscaper for all characters.
*
*/
public UnicodeEscaper() {
this(0, Integer.MAX_VALUE, true);
}
/**
* Constructs a UnicodeEscaper for the specified range. This is
* the underlying method for the other constructors/builders. The below
* and above boundaries are inclusive when between is
* true and exclusive when it is false.
*
* @param below int value representing the lowest codepoint boundary
* @param above int value representing the highest codepoint boundary
* @param between whether to escape between the boundaries or outside them
*/
protected UnicodeEscaper(final int below, final int above, final boolean between) {
this.below = below;
this.above = above;
this.between = between;
}
/**
* Constructs a UnicodeEscaper below the specified value (exclusive).
*
* @param codepoint below which to escape
* @return the newly created {@code UnicodeEscaper} instance
*/
public static UnicodeEscaper below(final int codepoint) {
return outsideOf(codepoint, Integer.MAX_VALUE);
}
/**
* Constructs a UnicodeEscaper above the specified value (exclusive).
*
* @param codepoint above which to escape
* @return the newly created {@code UnicodeEscaper} instance
*/
public static UnicodeEscaper above(final int codepoint) {
return outsideOf(0, codepoint);
}
/**
* Constructs a UnicodeEscaper outside of the specified values (exclusive).
*
* @param codepointLow below which to escape
* @param codepointHigh above which to escape
* @return the newly created {@code UnicodeEscaper} instance
*/
public static UnicodeEscaper outsideOf(final int codepointLow, final int codepointHigh) {
return new UnicodeEscaper(codepointLow, codepointHigh, false);
}
/**
* Constructs a UnicodeEscaper between the specified values (inclusive).
*
* @param codepointLow above which to escape
* @param codepointHigh below which to escape
* @return the newly created {@code UnicodeEscaper} instance
*/
public static UnicodeEscaper between(final int codepointLow, final int codepointHigh) {
return new UnicodeEscaper(codepointLow, codepointHigh, true);
}
/**
* {@inheritDoc}
*/
@Override
public boolean translate(final int codepoint, final Writer out) throws IOException {
if (between) {
if (codepoint < below || codepoint > above) {
return false;
}
} else {
if (codepoint >= below && codepoint <= above) {
return false;
}
}
if (codepoint > 0xffff) {
out.write(toUtf16Escape(codepoint));
} else {
out.write("\\u");
out.write(HEX_DIGITS[(codepoint >> 12) & 15]);
out.write(HEX_DIGITS[(codepoint >> 8) & 15]);
out.write(HEX_DIGITS[(codepoint >> 4) & 15]);
out.write(HEX_DIGITS[(codepoint) & 15]);
}
return true;
}
/**
* Converts the given codepoint to a hex string of the form {@code "\\uXXXX"}.
*
* @param codepoint
* a Unicode code point
* @return the hex string for the given codepoint
*
*/
protected String toUtf16Escape(final int codepoint) {
return "\\u" + hex(codepoint);
}
}