Base64.cpp

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/*
Copyright (C) 2004,2005  Anders Hedstrom

This library is made available under the terms of the GNU GPL.

If you would like to use this library in a closed-source application,
a separate license agreement is available. For information about
the closed-source license agreement for the C++ sockets library,
please visit http://www.alhem.net/Sockets/license.html and/or
email license@alhem.net.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/
#include "Base64.h"

#ifdef SOCKETS_NAMESPACE
namespace SOCKETS_NAMESPACE {
#endif


const char *Base64::bstr =
    "ABCDEFGHIJKLMNOPQ"
    "RSTUVWXYZabcdefgh"
    "ijklmnopqrstuvwxy"
    "z0123456789+/";

const char Base64::rstr[] = {
      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
      0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  62,   0,   0,   0,  63,
     52,  53,  54,  55,  56,  57,  58,  59,  60,  61,   0,   0,   0,   0,   0,   0,
      0,   0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,  13,  14,
     15,  16,  17,  18,  19,  20,  21,  22,  23,  24,  25,   0,   0,   0,   0,   0,
      0,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  38,  39,  40,
     41,  42,  43,  44,  45,  46,  47,  48,  49,  50,  51,   0,   0,   0,   0,   0};


void Base64::encode(FILE *fil, std::string& output, bool add_crlf)
{
    size_t remain;
    size_t i = 0;
    size_t o = 0;
    char input[4];

    output = "";
    remain = fread(input,1,3,fil);
    while (remain > 0)
    {
        if (add_crlf && o && o % 76 == 0)
            output += "\n";
        switch (remain)
        {
        case 1:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) ];
            output += "==";
            break;
        case 2:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) + ((input[i + 1] >> 4) & 0x0f) ];
            output += bstr[ ((input[i + 1] << 2) & 0x3c) ];
            output += "=";
            break;
        default:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) + ((input[i + 1] >> 4) & 0x0f) ];
            output += bstr[ ((input[i + 1] << 2) & 0x3c) + ((input[i + 2] >> 6) & 0x03) ];
            output += bstr[ (input[i + 2] & 0x3f) ];
        }
        o += 4;
        //
        remain = fread(input,1,3,fil);
    }
}


void Base64::encode(const std::string& str_in, std::string& str_out, bool add_crlf)
{
    encode(str_in.c_str(), str_in.size(), str_out, add_crlf);
}


void Base64::encode(const char* input,size_t l,std::string& output, bool add_crlf)
{
    size_t i = 0;
    size_t o = 0;

    output = "";
    while (i < l)
    {
        size_t remain = l - i;
        if (add_crlf && o && o % 76 == 0)
            output += "\n";
        switch (remain)
        {
        case 1:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) ];
            output += "==";
            break;
        case 2:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) + ((input[i + 1] >> 4) & 0x0f) ];
            output += bstr[ ((input[i + 1] << 2) & 0x3c) ];
            output += "=";
            break;
        default:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) + ((input[i + 1] >> 4) & 0x0f) ];
            output += bstr[ ((input[i + 1] << 2) & 0x3c) + ((input[i + 2] >> 6) & 0x03) ];
            output += bstr[ (input[i + 2] & 0x3f) ];
        }
        o += 4;
        i += 3;
    }
}


void Base64::encode(unsigned char* input,size_t l,std::string& output,bool add_crlf)
{
    size_t i = 0;
    size_t o = 0;

    output = "";
    while (i < l)
    {
        size_t remain = l - i;
        if (add_crlf && o && o % 76 == 0)
            output += "\n";
        switch (remain)
        {
        case 1:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) ];
            output += "==";
            break;
        case 2:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) + ((input[i + 1] >> 4) & 0x0f) ];
            output += bstr[ ((input[i + 1] << 2) & 0x3c) ];
            output += "=";
            break;
        default:
            output += bstr[ ((input[i] >> 2) & 0x3f) ];
            output += bstr[ ((input[i] << 4) & 0x30) + ((input[i + 1] >> 4) & 0x0f) ];
            output += bstr[ ((input[i + 1] << 2) & 0x3c) + ((input[i + 2] >> 6) & 0x03) ];
            output += bstr[ (input[i + 2] & 0x3f) ];
        }
        o += 4;
        i += 3;
    }
}


void Base64::decode(const std::string& input,std::string& output)
{
    size_t i = 0;
    size_t l = input.size();

    output = "";
    while (i < l)
    {
        while (i < l && (input[i] == 13 || input[i] == 10))
            ++i;
        if (i < l)
        {
            char b1 = (char)((rstr[(int)input[i]] << 2 & 0xfc) +
                    (rstr[(int)input[i + 1]] >> 4 & 0x03));
            output += b1;
            if (input[i + 2] != '=')
            {
                char b2 = (char)((rstr[(int)input[i + 1]] << 4 & 0xf0) +
                        (rstr[(int)input[i + 2]] >> 2 & 0x0f));
                output += b2;
            }
            if (input[i + 3] != '=')
            {
                char b3 = (char)((rstr[(int)input[i + 2]] << 6 & 0xc0) +
                        rstr[(int)input[i + 3]]);
                output += b3;
            }
            i += 4;
        }
    }
}


void Base64::decode(const std::string& input, unsigned char *output, size_t& sz)
{
    size_t i = 0;
    size_t l = input.size();
    size_t j = 0;

    while (i < l)
    {
        while (i < l && (input[i] == 13 || input[i] == 10))
            ++i;
        if (i < l)
        {
            unsigned char b1 = (unsigned char)((rstr[(int)input[i]] << 2 & 0xfc) +
                    (rstr[(int)input[i + 1]] >> 4 & 0x03));
            if (output)
            {
                output[j] = b1;
            }
            ++j;
            if (input[i + 2] != '=')
            {
                unsigned char b2 = (unsigned char)((rstr[(int)input[i + 1]] << 4 & 0xf0) +
                        (rstr[(int)input[i + 2]] >> 2 & 0x0f));
                if (output)
                {
                    output[j] = b2;
                }
                ++j;
            }
            if (input[i + 3] != '=')
            {
                unsigned char b3 = (unsigned char)((rstr[(int)input[i + 2]] << 6 & 0xc0) +
                        rstr[(int)input[i + 3]]);
                if (output)
                {
                    output[j] = b3;
                }
                ++j;
            }
            i += 4;
        }
    }
    sz = j;
}


size_t Base64::decode_length(const std::string& str64)
{
    if (!str64.size() || str64.size() % 4)
        return 0;
    size_t l = 3 * (str64.size() / 4 - 1) + 1;
    if (str64[str64.size() - 2] != '=')
        ++l;
    if (str64[str64.size() - 1] != '=')
        ++l;
    return l;
}


#ifdef SOCKETS_NAMESPACE
}
#endif