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/*
CLAW - a C++ Library Absolutely Wonderful
CLAW is a free library without any particular aim but being useful to
anyone.
Copyright (C) 2005-2011 Julien Jorge
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, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
contact: julien.jorge@gamned.org
*/
#include <claw/lzw_encoder.hpp>
#include <claw/buffered_istream.hpp>
#include <claw/buffered_ostream.hpp>
#include <claw/bit_ostream.hpp>
#include <iostream>
#include <limits>
#include <cassert>
#include <fstream>
/*----------------------------------------------------------------------------*/
/**
* \brief The input_buffer is the stream where raw data is read by the LZW
* encoder.
*/
class input_buffer
{
public:
input_buffer( std::istream& is )
: stream(is)
{
stream.read_more(1024);
}
bool end_of_data() const { return !stream; }
unsigned int symbols_count() const
{
return (unsigned int)std::numeric_limits<unsigned char>::max() + 2;
}
unsigned int get_next()
{
assert(stream.remaining() > 0);
unsigned int result = (unsigned char)stream.get_next();
if ( stream.remaining() == 0 )
stream.read_more(1024);
return result;
}
private:
claw::buffered_istream<std::istream> stream;
};
/*----------------------------------------------------------------------------*/
/**
* \brief The output_buffer is an interface between the LZW encoder and the
* stream where the encoded data is written.
*/
class output_buffer
{
public:
output_buffer( std::ostream& os, const unsigned int max )
: buffer(os), stream(buffer), m_max_code(max), m_code_size(9),
m_code_limit(1 << m_code_size)
{ }
unsigned int max_code() const
{
return m_max_code;
}
void reset()
{
m_code_size = 9;
m_code_limit = 1 << m_code_size;
}
void new_code( unsigned int code )
{
if (code == m_code_limit)
{
++m_code_size;
m_code_limit = 1 << m_code_size;
}
}
void write( unsigned int code )
{
stream.write( (char*)&code, m_code_size );
}
private:
claw::buffered_ostream<std::ostream> buffer;
claw::bit_ostream< claw::buffered_ostream<std::ostream> > stream;
const unsigned int m_max_code;
unsigned int m_code_size;
unsigned int m_code_limit;
};
/*----------------------------------------------------------------------------*/
int main( int argc, char* argv[] )
{
if ( argc != 1 )
{
std::cerr << "This program encodes a stream using LZW algorithm. The data"
<< " to encode is read on standard input, and the result is"
<< " written in standard output." << std::endl;
}
else
{
claw::lzw_encoder<input_buffer, output_buffer> encoder;
input_buffer input(std::cin);
output_buffer output(std::cout, 4096);
while ( !input.end_of_data() )
{
output.reset();
encoder.encode(input, output);
output.write(256);
}
}
return 0;
}
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