io.jooby.internal.apt.escape.UnicodeEscaper Maven / Gradle / Ivy
/*
* Jooby https://jooby.io
* Apache License Version 2.0 https://jooby.io/LICENSE.txt
* Copyright 2014 Edgar Espina
*/
package io.jooby.internal.apt.escape;
import java.io.IOException;
import java.io.Writer;
/**
* Translates code points to their Unicode escaped value.
*
* @since 1.0
*/
class UnicodeEscaper extends CodePointTranslator {
/**
* Constructs a {@code 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 {@code 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 {@code 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);
}
/**
* Constructs a {@code 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);
}
/** int value representing the lowest code point boundary. */
private final int below;
/** int value representing the highest code point boundary. */
private final int above;
/** whether to escape between the boundaries or outside them. */
private final boolean between;
/** Constructs a {@code UnicodeEscaper} for all characters. */
public UnicodeEscaper() {
this(0, Integer.MAX_VALUE, true);
}
/**
* Constructs a {@code UnicodeEscaper} for the specified range. This is the underlying method for
* the other constructors/builders. The {@code below} and {@code above} boundaries are inclusive
* when {@code between} is {@code true} and exclusive when it is {@code false}.
*
* @param below int value representing the lowest code point boundary
* @param above int value representing the highest code point 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;
}
/**
* Converts the given code point to a hex string of the form {@code "\\uXXXX"}.
*
* @param codePoint a Unicode code point
* @return The hex string for the given code point
*/
protected String toUtf16Escape(final int codePoint) {
return "\\u" + hex(codePoint);
}
/** {@inheritDoc} */
@Override
public boolean translate(final int codePoint, final Writer writer) throws IOException {
if (between) {
if (codePoint < below || codePoint > above) {
return false;
}
} else if (codePoint >= below && codePoint <= above) {
return false;
}
if (codePoint > 0xffff) {
writer.write(toUtf16Escape(codePoint));
} else {
writer.write("\\u");
writer.write(HEX_DIGITS[codePoint >> 12 & 15]);
writer.write(HEX_DIGITS[codePoint >> 8 & 15]);
writer.write(HEX_DIGITS[codePoint >> 4 & 15]);
writer.write(HEX_DIGITS[codePoint & 15]);
}
return true;
}
}