base64.cpp

Window环境下的TCP/IP通讯开发包

/* =================================================================
//  class: CBase64
//  File:  Base64.cpp
//  
//  Purpose:
//  
//  several Internet protocols uses Base64 mechanism  
//  This mecahnism:
//	1)  enables the transfer of binarry data over a UTF-8 
//  compatible media.
//	2) The data transfered is  not humannly readable which may add 
//  some sence of privacy to the comunication (Notice this is not a secure implementation)
//
//	The MIME (Multipurpose Internet Mail Extensions) specification
//	(RFC 1341 and successors e.g 2045-49) defines a mechanism for encoding 
//	arbitrary binary information for transmission by electronic mail.
//	Triplets of 8-bit octets are encoded as groups of four characters,
//	each representing 6 bits of the source 24 bits. 
//	Only characters present in all variants of ASCII and EBCDIC are used,
//	avoiding incompatibilities in other forms of encoding such as uuencode/uudecode
//
//	The Base64 Content-Transfer-Encoding is designed to represent arbitrary 
//	sequences of octets in a form that is not humanly readable. 
//	The encoding and decoding algorithms are simple, but the encoded 
//	data are consistently only about 33 percent larger than the unencoded data.
//	 This encoding is based on the one used in Privacy Enhanced Mail applications,
//	 as defined in RFC 1113. The base64 encoding is adapted from RFC 1113, 
//	with one change: base64 eliminates the "*" mechanism for embedded clear text
// See RFC 1341
// 
// ===================================================================
// Ultimate TCP/IP v4.2
// This software along with its related components, documentation and files ("The Libraries")
// is