/****************************************************************************** * The MIT License * Copyright (c) 2003 Novell Inc. www.novell.com * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the Software), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. *******************************************************************************/ // // Novell.Directory.Ldap.Utilclass.Base64.cs // // Author: // Sunil Kumar (Sunilk@novell.com) // // (C) 2003 Novell, Inc (http://www.novell.com) // using System; namespace Novell.Directory.Ldap.Utilclass { /// <summary> The Base64 utility class performs base64 encoding and decoding. /// /// The Base64 Content-Transfer-Encoding is designed to represent /// arbitrary sequences of octets in a form that need not be humanly /// readable. The encoding and decoding algorithms are simple, but the /// encoded data are consistently only about 33 percent larger than the /// unencoded data. The base64 encoding algorithm is defined by /// RFC 2045. /// </summary> public class Base64 { /* **************UTF-8 Validation methods and members******************* * The following text is taken from draft-yergeau-rfc2279bis-02 and explains * UTF-8 encoding: * *In UTF-8, characters are encoded using sequences of 1 to 6 octets. * If the range of character numbers is restricted to U+0000..U+10FFFF * (the UTF-16 accessible range), then only sequences of one to four * octets will occur. The only octet of a "sequence" of one has the * higher-order bit set to 0, the remaining 7 bits being used to encode * the character number. In a sequence of n octets, n>1, the initial * octet has the n higher-order bits set to 1, followed by a bit set to * 0. The remaining bit(s) of that octet contain bits from the number * of the character to be encoded. The following octet(s) all have the * higher-order bit set to 1 and the following bit set to 0, leaving 6 * bits in each to contain bits from the character to be encoded. * * The table below summarizes the format of these different octet types. * The letter x indicates bits available for encoding bits of the * character number. * * <pre> * Char. number range | UTF-8 octet sequence * (hexadecimal) | (binary) * --------------------+--------------------------------------------- * 0000 0000-0000 007F | 0xxxxxxx * 0000 0080-0000 07FF | 110xxxxx 10xxxxxx * 0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx * 0001 0000-001F FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx * 0020 0000-03FF FFFF | 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx * 0400 0000-7FFF FFFF | 1111110x 10xxxxxx ... 10xxxxxx * </pre> */ /// <summary> Given the first byte in a sequence, getByteCount returns the number of /// additional bytes in a UTF-8 character sequence (not including the first /// byte). /// /// </summary> /// <param name="b"> The first byte in a UTF-8 character sequence. /// /// </param> /// <returns> the number of additional bytes in a UTF-8 character sequence. /// </returns> private static int getByteCount(sbyte b) { if (b > 0) return 0; if ((b & 0xE0) == 0xC0) { return 1; //one additional byte (2 bytes total) } if ((b & 0xF0) == 0xE0) { return 2; //two additional bytes (3 bytes total) } if ((b & 0xF8) == 0xF0) { return 3; //three additional bytes (4 bytes total) } if ((b & 0xFC) == 0xF8) { return 4; //four additional bytes (5 bytes total) } if ((b & 0xFF) == 0xFC) { return 5; //five additional bytes (6 bytes total) } return - 1; } } }