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      1 /*
      2  *  Licensed to the Apache Software Foundation (ASF) under one or more
      3  *  contributor license agreements.  See the NOTICE file distributed with
      4  *  this work for additional information regarding copyright ownership.
      5  *  The ASF licenses this file to You under the Apache License, Version 2.0
      6  *  (the "License"); you may not use this file except in compliance with
      7  *  the License.  You may obtain a copy of the License at
      8  *
      9  *     http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  *  Unless required by applicable law or agreed to in writing, software
     12  *  distributed under the License is distributed on an "AS IS" BASIS,
     13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  *  See the License for the specific language governing permissions and
     15  *  limitations under the License.
     16  */
     17 
     18 package org.apache.harmony.luni.util;
     19 
     20 import java.io.ByteArrayOutputStream;
     21 import java.io.UnsupportedEncodingException;
     22 
     23 public final class Util {
     24     /**
     25      * '%' and two following hex digit characters are converted to the
     26      * equivalent byte value. All other characters are passed through
     27      * unmodified. e.g. "ABC %24%25" -> "ABC $%"
     28      *
     29      * @param s
     30      *            java.lang.String The encoded string.
     31      * @return java.lang.String The decoded version.
     32      */
     33     public static String decode(String s, boolean convertPlus) {
     34         return decode(s, convertPlus, null);
     35     }
     36 
     37     /**
     38      * '%' and two following hex digit characters are converted to the
     39      * equivalent byte value. All other characters are passed through
     40      * unmodified. e.g. "ABC %24%25" -> "ABC $%"
     41      *
     42      * @param s
     43      *            java.lang.String The encoded string.
     44      * @param encoding
     45      *            the specified encoding
     46      * @return java.lang.String The decoded version.
     47      */
     48     public static String decode(String s, boolean convertPlus, String encoding) {
     49         if (!convertPlus && s.indexOf('%') == -1)
     50             return s;
     51         StringBuilder result = new StringBuilder(s.length());
     52         ByteArrayOutputStream out = new ByteArrayOutputStream();
     53         for (int i = 0; i < s.length();) {
     54             char c = s.charAt(i);
     55             if (convertPlus && c == '+')
     56                 result.append(' ');
     57             else if (c == '%') {
     58                 out.reset();
     59                 do {
     60                     if (i + 2 >= s.length()) {
     61                         throw new IllegalArgumentException("Incomplete % sequence at: " + i);
     62                     }
     63                     int d1 = Character.digit(s.charAt(i + 1), 16);
     64                     int d2 = Character.digit(s.charAt(i + 2), 16);
     65                     if (d1 == -1 || d2 == -1) {
     66                         throw new IllegalArgumentException("Invalid % sequence " +
     67                                 s.substring(i, i + 3) + " at " + i);
     68                     }
     69                     out.write((byte) ((d1 << 4) + d2));
     70                     i += 3;
     71                 } while (i < s.length() && s.charAt(i) == '%');
     72                 if (encoding == null) {
     73                     result.append(out.toString());
     74                 } else {
     75                     try {
     76                         result.append(out.toString(encoding));
     77                     } catch (UnsupportedEncodingException e) {
     78                         throw new IllegalArgumentException(e);
     79                     }
     80                 }
     81                 continue;
     82             } else
     83                 result.append(c);
     84             i++;
     85         }
     86         return result.toString();
     87     }
     88 
     89     public static String toASCIILowerCase(String s) {
     90         int len = s.length();
     91         StringBuilder buffer = new StringBuilder(len);
     92         for (int i = 0; i < len; i++) {
     93             char c = s.charAt(i);
     94             if ('A' <= c && c <= 'Z') {
     95                 buffer.append((char) (c + ('a' - 'A')));
     96             } else {
     97                 buffer.append(c);
     98             }
     99         }
    100         return buffer.toString();
    101     }
    102 
    103     public static String toASCIIUpperCase(String s) {
    104         int len = s.length();
    105         StringBuilder buffer = new StringBuilder(len);
    106         for (int i = 0; i < len; i++) {
    107             char c = s.charAt(i);
    108             if ('a' <= c && c <= 'z') {
    109                 buffer.append((char) (c - ('a' - 'A')));
    110             } else {
    111                 buffer.append(c);
    112             }
    113         }
    114         return buffer.toString();
    115     }
    116 }
    117