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Java 1.8+ Library with tons of utility classes required in all projects
/*
* Copyright (C) 2014-2022 Philip Helger (www.helger.com)
* philip[at]helger[dot]com
*
* Licensed 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 com.helger.commons.text.util;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;
import com.helger.commons.annotation.PresentForCodeCoverage;
import com.helger.commons.codec.DecodeException;
import com.helger.commons.codec.EncodeException;
import com.helger.commons.text.codepoint.CodepointHelper;
import com.helger.commons.text.codepoint.CodepointIteratorCharArray;
import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
/**
* Implementation of the Punycode encoding scheme used by IDNA and RFC 3492
* Source: https://www.ietf.org/rfc/rfc3492.txt
*
* @author Apache Abdera
*/
@Immutable
public final class Punycode
{
private static final int BASE = 0x24; // 36
private static final int TMIN = 0x01; // 1
private static final int TMAX = 0x1A; // 26
private static final int SKEW = 0x26; // 38
private static final int DAMP = 0x02BC; // 700
private static final int INITIAL_BIAS = 0x48; // 72
private static final int INITIAL_N = 0x80; // 0x80
private static final int DELIMITER = 0x2D; // 0x2D
@PresentForCodeCoverage
private static final Punycode INSTANCE = new Punycode ();
private Punycode ()
{}
private static boolean _basic (final int cp)
{
return cp < 0x80;
}
private static boolean _delim (final int cp)
{
return cp == DELIMITER;
}
private static boolean _flagged (final int bcp)
{
return (bcp - 'A') < 26;
}
private static int _decode_digit (final int cp)
{
if (cp - '0' < 10)
return cp - 22;
if (cp - 'A' < 26)
return cp - 'A';
if (cp - 'a' < 26)
return cp - 'a';
return BASE;
}
private static int _t (final boolean c)
{
return c ? 1 : 0;
}
private static int _encode_digit (final int d, final boolean upper)
{
return (d + 22 + 75 * _t (d < 26)) - (_t (upper) << 5);
}
private static int _adapt (final int pdelta, final int numpoints, final boolean firsttime)
{
int delta = pdelta;
int k;
delta = (firsttime) ? delta / DAMP : delta >> 1;
delta += delta / numpoints;
for (k = 0; delta > ((BASE - TMIN) * TMAX) / 2; k += BASE)
{
delta /= BASE - TMIN;
}
return k + (BASE - TMIN + 1) * delta / (delta + SKEW);
}
@Nullable
public static String getEncoded (@Nullable final String s)
{
if (s == null)
return null;
return getEncoded (s.toCharArray (), null);
}
public static String getEncoded (@Nonnull final char [] aChars, @Nullable final boolean [] aCaseFlags)
{
final StringBuilder aSB = new StringBuilder ();
final CodepointIteratorCharArray aIter = new CodepointIteratorCharArray (aChars);
int n = INITIAL_N;
int delta = 0;
int bias = INITIAL_BIAS;
while (aIter.hasNext ())
{
final int i = aIter.next ().getValue ();
if (_basic (i))
if (aCaseFlags == null)
aSB.append ((char) i);
}
final int b = aSB.length ();
int h = b;
if (b > 0)
aSB.append ((char) DELIMITER);
while (h < aChars.length)
{
aIter.position (0);
int m = Integer.MAX_VALUE;
while (aIter.hasNext ())
{
final int i = aIter.next ().getValue ();
if (i >= n && i < m)
m = i;
}
if (m - n > (Integer.MAX_VALUE - delta) / (h + 1))
throw new EncodeException ("Overflow");
delta += (m - n) * (h + 1);
n = m;
aIter.position (0);
while (aIter.hasNext ())
{
final int i = aIter.next ().getValue ();
if (i < n)
{
++delta;
if (delta == 0)
throw new EncodeException ("Overflow");
}
if (i == n)
{
int q = delta;
int k = BASE;
while (true)
{
final int t;
if (k <= bias)
t = TMIN;
else
if (k >= bias + TMAX)
t = TMAX;
else
t = k - bias;
if (q < t)
break;
aSB.append ((char) _encode_digit (t + (q - t) % (BASE - t), false));
q = (q - t) / (BASE - t);
k += BASE;
}
aSB.append ((char) _encode_digit (q, aCaseFlags != null && aCaseFlags[aIter.position () - 1]));
bias = _adapt (delta, h + 1, h == b);
delta = 0;
++h;
}
}
++delta;
++n;
}
return aSB.toString ();
}
@Nullable
public static String getDecoded (@Nullable final String s)
{
if (s == null)
return null;
return getDecoded (s.toCharArray (), null);
}
@SuppressFBWarnings ("QF_QUESTIONABLE_FOR_LOOP")
@Nonnull
public static String getDecoded (@Nonnull final char [] aChars, @Nullable final boolean [] aCaseFlags)
{
final StringBuilder aSB = new StringBuilder ();
int n = INITIAL_N;
int out = 0;
int i = 0;
int bias = INITIAL_BIAS;
int b = 0;
for (int j = 0; j < aChars.length; ++j)
if (_delim (aChars[j]))
b = j;
for (int j = 0; j < b; ++j)
{
if (aCaseFlags != null)
aCaseFlags[out] = _flagged (aChars[j]);
if (!_basic (aChars[j]))
throw new DecodeException ("Bad Input");
aSB.append (aChars[j]);
}
out = aSB.length ();
for (int in = (b > 0) ? b + 1 : 0; in < aChars.length; ++out)
{
final int oldi = i;
int w = 1;
for (int k = BASE;; k += BASE)
{
if (in >= aChars.length)
throw new DecodeException ("Bad input");
final int digit = _decode_digit (aChars[in]);
in++;
if (digit >= BASE)
throw new DecodeException ("Bad input");
if (digit > (Integer.MAX_VALUE - i) / w)
throw new DecodeException ("Overflow");
i += digit * w;
final int t;
if (k <= bias)
t = TMIN;
else
if (k >= bias + TMAX)
t = TMAX;
else
t = k - bias;
if (digit < t)
break;
if (w > Integer.MAX_VALUE / (BASE - t))
throw new DecodeException ("Overflow");
w *= (BASE - t);
}
bias = _adapt (i - oldi, out + 1, oldi == 0);
if (i / (out + 1) > Integer.MAX_VALUE - n)
throw new DecodeException ("Overflow");
n += i / (out + 1);
i %= (out + 1);
if (aCaseFlags != null)
{
// not sure if this is right
System.arraycopy (aCaseFlags, i, aCaseFlags, i + Character.charCount (n), aCaseFlags.length - i);
}
CodepointHelper.insert (aSB, i++, n);
}
return aSB.toString ();
}
}