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/* Copyright (C) 2016 The giomm Development Team
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include <giomm.h>
#include <iostream>
#include <string>
#include <cstdlib>
// A simple custom stream that base64 encodes data.
// Do not copy it to your code, because it's very slow.
class Base64OutputStream : public Gio::FilterOutputStream
{
public:
unsigned get_column_width() const { return column_width; }
void set_column_width(unsigned cw) { column_width = cw; }
static Glib::RefPtr<Base64OutputStream> create(const Glib::RefPtr<OutputStream>& base_stream)
{
return Glib::make_refptr_for_instance<Base64OutputStream>(new Base64OutputStream(base_stream));
}
protected:
explicit Base64OutputStream(const Glib::RefPtr<Gio::OutputStream>& base_stream)
: Gio::FilterOutputStream(base_stream), column(0), bit_count(0), bit_buffer(0), column_width(72) {}
gssize write_vfunc(const void* buffer, gsize count, const Glib::RefPtr<Gio::Cancellable>& cancellable) override
{
char const *byte = (char const *) buffer;
for (unsigned i = 0; i < count; ++i, ++byte)
{
// kindergarten implementation, because the object is not performance :)
bit_buffer <<= 8;
bit_buffer |= (*byte & 0xff);
bit_count += 8;
if (bit_count == 24)
{
clear_pending(); // TODO why is this necessary to avoid an outstanding op. exception?
flush(cancellable);
set_pending();
bit_count = 0;
}
if (cancellable && cancellable->is_cancelled())
throw Gio::Error(Gio::Error::CANCELLED, "Operation cancelled");
}
return count;
}
bool flush_vfunc(const Glib::RefPtr<Gio::Cancellable>& cancellable) override
{
if (bit_count != 24)
return true;
char to_write[5];
gsize len = 4;
for (unsigned i=0; i<4; ++i)
{
unsigned index = (bit_buffer & (0x3f<<(i*6))) >> (i*6);
to_write[3-i] = base64_encode_str[index];
}
column += 4;
// Yes, I know this is completely wrong.
if (column >= column_width)
{
column = 0;
to_write[4] = '\n';
++len;
}
get_base_stream()->write(&to_write, len, cancellable);
bit_count = 0;
bit_buffer = 0;
return true;
}
bool close_vfunc(const Glib::RefPtr<Gio::Cancellable>& cancellable) override
{
char to_write[5] = "====";
//get any last bytes (1 or 2) out of the buffer
switch (bit_count)
{
case 16:
bit_buffer <<= 2; //pad to make 18 bits
to_write[0] = base64_encode_str[(bit_buffer & (0x3f << 12)) >> 12];
to_write[1] = base64_encode_str[(bit_buffer & (0x3f << 6)) >> 6];
to_write[2] = base64_encode_str[bit_buffer & 0x3f];
break;
case 8:
bit_buffer <<= 4; //pad to make 12 bits
to_write[0] = base64_encode_str[(bit_buffer & (0x3f << 6)) >> 6];
to_write[1] = base64_encode_str[bit_buffer & 0x3f];
break;
}
if (bit_count > 0)
{
get_base_stream()->write(&to_write, 5, cancellable);
}
else
{
// null terminate output
get_base_stream()->write("", 1, cancellable);
}
if (get_close_base_stream())
get_base_stream()->close(cancellable);
return true;
}
private:
static char const *const base64_encode_str;
unsigned column;
unsigned bit_count;
unsigned bit_buffer;
unsigned column_width;
};
char const *const Base64OutputStream::base64_encode_str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
int main(int, char**)
{
Glib::init();
Gio::init();
try
{
char result[256];
Glib::RefPtr<Gio::MemoryOutputStream> memory_chunk = Gio::MemoryOutputStream::create(result, 256, nullptr, nullptr);
Glib::RefPtr<Base64OutputStream> base64 = Base64OutputStream::create(memory_chunk);
std::string data = "Custom GIO streams are cool!";
base64->set_close_base_stream(true);
base64->write(data);
base64->close();
const std::string base64_should_be("Q3VzdG9tIEdJTyBzdHJlYW1zIGFyZSBjb29sIQ==");
std::cout << "Original data: " << data << std::endl;
std::cout << "base64-encoded data: " << result << std::endl;
std::cout << "base64 should be: " << base64_should_be << std::endl;
if (base64_should_be != result)
{
std::cout << "Not correct!" << std::endl;
return EXIT_FAILURE;
}
}
catch (const Gio::Error& e)
{
std::cout << "Gio error: " << e.what() << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
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