rcpp_framework/libs/brynet/base/crypto/Base64.hpp

#ifndef _BRYNET_BASE_BASE64_H
#define _BRYNET_BASE_BASE64_H

#include <string>

namespace brynet { namespace base { namespace crypto {

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

    static bool is_base64(unsigned char c)
    {
        return (isalnum(c) || (c == '+') || (c == '/'));
    }

    static std::string base64_encode(unsigned char const* bytes_to_encode, unsigned int in_len)
    {
        std::string ret;
        int i = 0;
        int j = 0;
        unsigned char char_array_3[3];
        unsigned char char_array_4[4];

        while (in_len--) {
            char_array_3[i++] = *(bytes_to_encode++);
            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;
    }

    static std::string base64_decode(std::string const& encoded_string)
    {
        int in_len = encoded_string.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-- && (encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
            char_array_4[i++] = encoded_string[in_]; in_++;
            if (i == 4) {
                for (i = 0; i < 4; i++)
                    char_array_4[i] = 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] = 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 += char_array_3[j];
        }

        return ret;
    }

} } }

#endif