The Tor Browser: mobile/android/thirdparty/ch/boye/httpclientandroidlib/client/utils/Rfc3492Idn.java@fc2d59ddac77

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     3  * $Revision$

     4  * $Date$

     5  *

     6  * ====================================================================

     7  *

     8  *  Licensed to the Apache Software Foundation (ASF) under one or more

     9  *  contributor license agreements.  See the NOTICE file distributed with

    10  *  this work for additional information regarding copyright ownership.

    11  *  The ASF licenses this file to You under the Apache License, Version 2.0

    12  *  (the "License"); you may not use this file except in compliance with

    13  *  the License.  You may obtain a copy of the License at

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    15  *      http://www.apache.org/licenses/LICENSE-2.0

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    20  *  See the License for the specific language governing permissions and

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    24  * This software consists of voluntary contributions made by many

    25  * individuals on behalf of the Apache Software Foundation.  For more

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    31 package ch.boye.httpclientandroidlib.client.utils;

    33 import java.util.StringTokenizer;

    35 import ch.boye.httpclientandroidlib.annotation.Immutable;

    37 /**

    38  * Implementation from pseudo code in RFC 3492.

    39  *

    40  * @since 4.0

    41  */

    42 @Immutable

    43 public class Rfc3492Idn implements Idn {

    44     private static final int base = 36;

    45     private static final int tmin = 1;

    46     private static final int tmax = 26;

    47     private static final int skew = 38;

    48     private static final int damp = 700;

    49     private static final int initial_bias = 72;

    50     private static final int initial_n = 128;

    51     private static final char delimiter = '-';

    52     private static final String ACE_PREFIX = "xn--";

    54     private int adapt(int delta, int numpoints, boolean firsttime) {

    55         if (firsttime) delta = delta / damp;

    56         else delta = delta / 2;

    57         delta = delta + (delta / numpoints);

    58         int k = 0;

    59         while (delta > ((base - tmin) * tmax) / 2) {

    60           delta = delta / (base - tmin);

    61           k = k + base;

    62         }

    63         return k + (((base - tmin + 1) * delta) / (delta + skew));

    64     }

    66     private int digit(char c) {

    67         if ((c >= 'A') && (c <= 'Z')) return (c - 'A');

    68         if ((c >= 'a') && (c <= 'z')) return (c - 'a');

    69         if ((c >= '0') && (c <= '9')) return (c - '0') + 26;

    70         throw new IllegalArgumentException("illegal digit: "+ c);

    71     }

    73     public String toUnicode(String punycode) {

    74         StringBuilder unicode = new StringBuilder(punycode.length());

    75         StringTokenizer tok = new StringTokenizer(punycode, ".");

    76         while (tok.hasMoreTokens()) {

    77             String t = tok.nextToken();

    78             if (unicode.length() > 0) unicode.append('.');

    79             if (t.startsWith(ACE_PREFIX)) t = decode(t.substring(4));

    80             unicode.append(t);

    81         }

    82         return unicode.toString();

    83     }

    85     protected String decode(String input) {

    86         int n = initial_n;

    87         int i = 0;

    88         int bias = initial_bias;

    89         StringBuilder output = new StringBuilder(input.length());

    90         int lastdelim = input.lastIndexOf(delimiter);

    91         if (lastdelim != -1) {

    92             output.append(input.subSequence(0, lastdelim));

    93             input = input.substring(lastdelim + 1);

    94         }

    96         while (input.length() > 0) {

    97             int oldi = i;

    98             int w = 1;

    99             for (int k = base;; k += base) {

   100                 if (input.length() == 0) break;

   101                 char c = input.charAt(0);

   102                 input = input.substring(1);

   103                 int digit = digit(c);

   104                 i = i + digit * w; // FIXME fail on overflow

   105                 int t;

   106                 if (k <= bias + tmin) {

   107                     t = tmin;

   108                 } else if (k >= bias + tmax) {

   109                     t = tmax;

   110                 } else {

   111                     t = k - bias;

   112                 }

   113                 if (digit < t) break;

   114                 w = w * (base - t); // FIXME fail on overflow

   115             }

   116             bias = adapt(i - oldi, output.length() + 1, (oldi == 0));

   117             n = n + i / (output.length() + 1); // FIXME fail on overflow

   118             i = i % (output.length() + 1);

   119             // {if n is a basic code point then fail}

   120             output.insert(i, (char) n);

   121             i++;

   122         }

   123         return output.toString();

   124     }

   126 }

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