org.apache.abdera.i18n.text.Punycode Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* 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. For additional information regarding
* copyright in this work, please see the NOTICE file in the top level
* directory of this distribution.
*/
package org.apache.abdera.i18n.text;
import java.io.IOException;
/**
* Implementation of the Punycode encoding scheme used by IDNA
*/
public final class Punycode {
static final int base = 0x24; // 36
static final int tmin = 0x01; // 1
static final int tmax = 0x1A; // 26
static final int skew = 0x26; // 38
static final int damp = 0x02BC; // 700
static final int initial_bias = 0x48; // 72
static final int initial_n = 0x80; // 0x80
static final int delimiter = 0x2D; // 0x2D
Punycode() {
}
private static boolean basic(int cp) {
return cp < 0x80;
}
private static boolean delim(int cp) {
return cp == delimiter;
}
private static boolean flagged(int bcp) {
return (bcp - 65) < 26;
}
private static int decode_digit(int cp) {
return (cp - 48 < 10) ? cp - 22 : (cp - 65 < 26) ? cp - 65 : (cp - 97 < 26) ? cp - 97 : base;
}
private static int t(boolean c) {
return (c) ? 1 : 0;
}
private static int encode_digit(int d, boolean upper) {
return (d + 22 + 75 * t(d < 26)) - (t(upper) << 5);
}
private static int adapt(int delta, int numpoints, boolean firsttime) {
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);
}
public static String encode(char[] chars, boolean[] case_flags) throws IOException {
StringBuilder buf = new StringBuilder();
CodepointIterator ci = CodepointIterator.forCharArray(chars);
int n, delta, h, b, bias, m, q, k, t;
n = initial_n;
delta = 0;
bias = initial_bias;
int i = -1;
while (ci.hasNext()) {
i = ci.next().getValue();
if (basic(i)) {
if (case_flags != null) {
} else {
buf.append((char)i);
}
}
}
h = b = buf.length();
if (b > 0)
buf.append((char)delimiter);
while (h < chars.length) {
ci.position(0);
i = -1;
m = Integer.MAX_VALUE;
while (ci.hasNext()) {
i = ci.next().getValue();
if (i >= n && i < m)
m = i;
}
if (m - n > (Integer.MAX_VALUE - delta) / (h + 1))
throw new IOException("Overflow");
delta += (m - n) * (h + 1);
n = m;
ci.position(0);
i = -1;
while (ci.hasNext()) {
i = ci.next().getValue();
if (i < n) {
if (++delta == 0)
throw new IOException("Overflow");
}
if (i == n) {
for (q = delta, k = base;; k += base) {
t = k <= bias ? tmin : k >= bias + tmax ? tmax : k - bias;
if (q < t)
break;
buf.append((char)encode_digit(t + (q - t) % (base - t), false));
q = (q - t) / (base - t);
}
buf.append((char)encode_digit(q, (case_flags != null) ? case_flags[ci.position() - 1] : false));
bias = adapt(delta, h + 1, h == b);
delta = 0;
++h;
}
}
++delta;
++n;
}
return buf.toString();
}
public static String encode(String s) {
try {
if (s == null)
return null;
return encode(s.toCharArray(), null).toString();
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
public static String decode(String s) {
try {
if (s == null)
return null;
return decode(s.toCharArray(), null).toString();
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
public static String decode(char[] chars, boolean[] case_flags) throws IOException {
StringBuilder buf = new StringBuilder();
int n, out, i, bias, b, j, in, oldi, w, k, digit, t;
n = initial_n;
out = i = 0;
bias = initial_bias;
for (b = j = 0; j < chars.length; ++j)
if (delim(chars[j]))
b = j;
for (j = 0; j < b; ++j) {
if (case_flags != null)
case_flags[out] = flagged(chars[j]);
if (!basic(chars[j]))
throw new IOException("Bad Input");
buf.append((char)chars[j]);
}
out = buf.length();
for (in = (b > 0) ? b + 1 : 0; in < chars.length; ++out) {
for (oldi = i, w = 1, k = base;; k += base) {
if (in > chars.length)
throw new IOException("Bad input");
digit = decode_digit(chars[in++]);
if (digit >= base)
throw new IOException("Bad input");
if (digit > (Integer.MAX_VALUE - i) / w)
throw new IOException("Overflow");
i += digit * w;
t = (k <= bias) ? tmin : (k >= bias + tmax) ? tmax : k - bias;
if (digit < t)
break;
if (w > Integer.MAX_VALUE / (base - t))
throw new IOException("Overflow");
w *= (base - t);
}
bias = adapt(i - oldi, out + 1, oldi == 0);
if (i / (out + 1) > Integer.MAX_VALUE - n)
throw new IOException("Overflow");
n += i / (out + 1);
i %= (out + 1);
if (case_flags != null) {
System.arraycopy( // not sure if this is right
case_flags,
i,
case_flags,
i + CharUtils.length(n),
case_flags.length - i);
}
CharUtils.insert(buf, i++, n);
}
return buf.toString();
}
}
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