学步园

/*<br /> base64.cpp and base64.h</p> <p> Copyright (C) 2004-2008 René Nyffenegger</p> <p> This source code is provided 'as-is', without any express or implied<br /> warranty. In no event will the author be held liable for any damages<br /> arising from the use of this software.</p> <p> Permission is granted to anyone to use this software for any purpose,<br /> including commercial applications, and to alter it and redistribute it<br /> freely, subject to the following restrictions:</p> <p> 1. The origin of this source code must not be misrepresented; you must not<br /> claim that you wrote the original source code. If you use this source code<br /> in a product, an acknowledgment in the product documentation would be<br /> appreciated but is not required.</p> <p> 2. Altered source versions must be plainly marked as such, and must not be<br /> misrepresented as being the original source code.</p> <p> 3. This notice may not be removed or altered from any source distribution.</p> <p> René Nyffenegger rene.nyffenegger@adp-gmbh.ch</p> <p>*/</p> <p>#include "base64.h"<br /> #include <iostream></p> <p>static const std::string base64_chars =<br /> "ABCDEFGHIJKLMNOPQRSTUVWXYZ"<br /> "abcdefghijklmnopqrstuvwxyz"<br /> "0123456789+/";</p> <p>static inline bool is_base64(unsigned char c) {<br /> return (isalnum(c) || (c == '+') || (c == '/'));<br /> }</p> <p>std::string base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len) {<br /> std::string ret;<br /> int i = 0;<br /> int j = 0;<br /> unsigned char char_array_3[3];<br /> unsigned char char_array_4[4];</p> <p> while (in_len--) {<br /> char_array_3[i++] = *(bytes_to_encode++);<br /> if (i == 3) {<br /> char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;<br /> char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);<br /> char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);<br /> char_array_4[3] = char_array_3[2] & 0x3f;</p> <p> for(i = 0; (i <4) ; i++)<br /> ret += base64_chars[char_array_4[i]];<br /> i = 0;<br /> }<br /> }</p> <p> if (i)<br /> {<br /> for(j = i; j < 3; j++)<br /> char_array_3[j] = '/0';</p> <p> char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;<br /> char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);<br /> char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);<br /> char_array_4[3] = char_array_3[2] & 0x3f;</p> <p> for (j = 0; (j < i + 1); j++)<br /> ret += base64_chars[char_array_4[j]];</p> <p> while((i++ < 3))<br /> ret += '=';</p> <p> }</p> <p> return ret;</p> <p>}</p> <p>std::string base64_decode(std::string const& encoded_string) {<br /> int in_len = encoded_string.size();<br /> int i = 0;<br /> int j = 0;<br /> int in_ = 0;<br /> unsigned char char_array_4[4], char_array_3[3];<br /> std::string ret;</p> <p> while (in_len-- && ( encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {<br /> char_array_4[i++] = encoded_string[in_]; in_++;<br /> if (i ==4) {<br /> for (i = 0; i <4; i++)<br /> char_array_4[i] = base64_chars.find(char_array_4[i]);</p> <p> char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);<br /> char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);<br /> char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];</p> <p> for (i = 0; (i < 3); i++)<br /> ret += char_array_3[i];<br /> i = 0;<br /> }<br /> }</p> <p> if (i) {<br /> for (j = i; j <4; j++)<br /> char_array_4[j] = 0;</p> <p> for (j = 0; j <4; j++)<br /> char_array_4[j] = base64_chars.find(char_array_4[j]);</p> <p> char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);<br /> char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);<br /> char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];</p> <p> for (j = 0; (j < i - 1); j++) ret += char_array_3[j];<br /> }</p> <p> return ret;<br /> }<br />

#ifndef BASE_64_H_<br /> #define BASE_64_H_</p> <p>#include <string></p> <p>std::string base64_encode(unsigned char const* , unsigned int len);<br /> std::string base64_decode(std::string const& s);</p> <p>#endif

#include "base64.h"<br /> #include <iostream></p> <p>int main() {<br /> const std::string s = "ADP GmbH/nAnalyse Design & Programmierung/nGesellschaft mit beschränkter Haftung" ;</p> <p> std::string encoded = base64_encode(reinterpret_cast<const unsigned char*>(s.c_str()), s.length());<br /> std::string decoded = base64_decode(encoded);</p> <p> std::cout << "encoded: " << encoded << std::endl;<br /> std::cout << "decoded: " << decoded << std::endl;</p> <p> return 0;<br /> }<br />