base64.hpp

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/*
    ******
    base64.hpp is a repackaging of the base64.cpp and base64.h files into a
    single header suitable for use as a header only library. This conversion was
    done by Peter Thorson (webmaster@zaphoyd.com) in 2012. All modifications to
    the code are redistributed under the same license as the original, which is
    listed below.
    ******

   base64.cpp and base64.h

   Copyright (C) 2004-2008 René Nyffenegger

   This source code is provided 'as-is', without any express or implied
   warranty. In no event will the author be held liable for any damages
   arising from the use of this software.

   Permission is granted to anyone to use this software for any purpose,
   including commercial applications, and to alter it and redistribute it
   freely, subject to the following restrictions:

   1. The origin of this source code must not be misrepresented; you must not
      claim that you wrote the original source code. If you use this source code
      in a product, an acknowledgment in the product documentation would be
      appreciated but is not required.

   2. Altered source versions must be plainly marked as such, and must not be
      misrepresented as being the original source code.

   3. This notice may not be removed or altered from any source distribution.

   René Nyffenegger rene.nyffenegger@adp-gmbh.ch

*/

#ifndef _BASE64_HPP_
#define _BASE64_HPP_

#include <string>

namespace websocketpp {

static std::string const base64_chars =
             "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
             "abcdefghijklmnopqrstuvwxyz"
             "0123456789+/";


static inline bool is_base64(unsigned char c) {
    return (c == 43 || // +
           (c >= 47 && c <= 57) || // /-9
           (c >= 65 && c <= 90) || // A-Z
           (c >= 97 && c <= 122)); // a-z
}


inline std::string base64_encode(unsigned char const * input, size_t len) {
    std::string ret;
    int i = 0;
    int j = 0;
    unsigned char char_array_3[3];
    unsigned char char_array_4[4];

    while (len--) {
        char_array_3[i++] = *(input++);
        if (i == 3) {
            char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
            char_array_4[1] = ((char_array_3[0] & 0x03) << 4) +
                              ((char_array_3[1] & 0xf0) >> 4);
            char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) +
                              ((char_array_3[2] & 0xc0) >> 6);
            char_array_4[3] = char_array_3[2] & 0x3f;

            for(i = 0; (i <4) ; i++) {
                ret += base64_chars[char_array_4[i]];
            }
            i = 0;
        }
    }

    if (i) {
        for(j = i; j < 3; j++) {
            char_array_3[j] = '\0';
        }

        char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
        char_array_4[1] = ((char_array_3[0] & 0x03) << 4) +
                          ((char_array_3[1] & 0xf0) >> 4);
        char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) +
                          ((char_array_3[2] & 0xc0) >> 6);
        char_array_4[3] = char_array_3[2] & 0x3f;

        for (j = 0; (j < i + 1); j++) {
            ret += base64_chars[char_array_4[j]];
        }

        while((i++ < 3)) {
            ret += '=';
        }
    }

    return ret;
}


inline std::string base64_encode(std::string const & input) {
    return base64_encode(
        reinterpret_cast<const unsigned char *>(input.data()),
        input.size()
    );
}


inline std::string base64_decode(std::string const & input) {
    size_t in_len = input.size();
    int i = 0;
    int j = 0;
    int in_ = 0;
    unsigned char char_array_4[4], char_array_3[3];
    std::string ret;

    while (in_len-- && ( input[in_] != '=') && is_base64(input[in_])) {
        char_array_4[i++] = input[in_]; in_++;
        if (i ==4) {
            for (i = 0; i <4; i++) {
                char_array_4[i] = static_cast<unsigned char>(base64_chars.find(char_array_4[i]));
            }

            char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
            char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
            char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

            for (i = 0; (i < 3); i++) {
                ret += char_array_3[i];
            }
            i = 0;
        }
    }

    if (i) {
        for (j = i; j <4; j++)
            char_array_4[j] = 0;

        for (j = 0; j <4; j++)
            char_array_4[j] = static_cast<unsigned char>(base64_chars.find(char_array_4[j]));

        char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
        char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
        char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

        for (j = 0; (j < i - 1); j++) {
            ret += static_cast<std::string::value_type>(char_array_3[j]);
        }
    }

    return ret;
}

} // namespace websocketpp

#endif // _BASE64_HPP_