com.vaadin.util.EncodeUtil Maven / Gradle / Ivy
/*
* Vaadin Framework 7
*
* Copyright (C) 2000-2024 Vaadin Ltd
*
* This program is available under Vaadin Commercial License and Service Terms.
*
* See for the full
* license.
*/
package com.vaadin.util;
import java.nio.charset.Charset;
/**
* Utilities related to various encoding schemes.
*
* @author Vaadin Ltd
* @since 7.7.7
*/
public class EncodeUtil {
private static final Charset utf8 = Charset.forName("UTF-8");
private EncodeUtil() {
// Static utils only
}
/**
* Encodes the given string to UTF-8 value-chars as defined in
* RFC5987 for use in e.g. the Content-Disposition HTTP header.
*
* @param value
* the string to encode, not null
* @return the encoded string
*/
public static String rfc5987Encode(String value) {
StringBuilder builder = new StringBuilder();
for (int i = 0; i < value.length();) {
int cp = value.codePointAt(i);
if (cp < 127 && (Character.isLetterOrDigit(cp) || cp == '.')) {
builder.append((char) cp);
} else {
// Create string from a single code point
String cpAsString = new String(new int[] { cp }, 0, 1);
appendHexBytes(builder, cpAsString.getBytes(utf8));
}
// Advance to the next code point
i += Character.charCount(cp);
}
return builder.toString();
}
private static void appendHexBytes(StringBuilder builder, byte[] bytes) {
for (byte byteValue : bytes) {
// mask with 0xFF to compensate for "negative" values
int intValue = byteValue & 0xFF;
String hexCode = Integer.toString(intValue, 16);
builder.append('%').append(hexCode);
}
}
}