dlib C++ Library - bit_stream_kernel_1.cpp

// Copyright (C) 2003 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_BIT_STREAM_KERNEL_1_CPp_
#define DLIB_BIT_STREAM_KERNEL_1_CPp_
#include "bit_stream_kernel_1.h"
#include "../algs.h"
#include <iostream>
namespace dlib
{
 inline void swap (
 bit_stream_kernel_1& a, 
 bit_stream_kernel_1& b
 ) { a.swap(b); }
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
 // member function definitions
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
 void bit_stream_kernel_1::
 clear (
 )
 {
 if (write_mode)
 {
 write_mode = false;
 // flush output buffer
 if (buffer_size > 0)
 {
 buffer <<= 8 - buffer_size;
 osp->write(reinterpret_cast<char*>(&buffer),1);
 }
 }
 else
 read_mode = false;
 }
// ----------------------------------------------------------------------------------------
 void bit_stream_kernel_1::
 set_input_stream (
 std::istream& is
 )
 {
 isp = &is;
 read_mode = true;
 buffer_size = 0;
 }
// ----------------------------------------------------------------------------------------
 void bit_stream_kernel_1::
 set_output_stream (
 std::ostream& os
 )
 {
 osp = &os;
 write_mode = true;
 buffer_size = 0;
 }
// ----------------------------------------------------------------------------------------
 void bit_stream_kernel_1::
 close (
 )
 {
 if (write_mode)
 {
 write_mode = false;
 // flush output buffer
 if (buffer_size > 0)
 {
 buffer <<= 8 - buffer_size;
 osp->write(reinterpret_cast<char*>(&buffer),1);
 }
 }
 else
 read_mode = false;
 }
// ----------------------------------------------------------------------------------------
 bool bit_stream_kernel_1::
 is_in_write_mode (
 ) const
 {
 return write_mode;
 }
// ----------------------------------------------------------------------------------------
 bool bit_stream_kernel_1::
 is_in_read_mode (
 ) const
 {
 return read_mode;
 }
// ----------------------------------------------------------------------------------------
 void bit_stream_kernel_1::
 write (
 int bit
 )
 {
 // flush buffer if necessary
 if (buffer_size == 8)
 {
 buffer <<= 8 - buffer_size;
 if (osp->rdbuf()->sputn(reinterpret_cast<char*>(&buffer),1) == 0)
 {
 throw std::ios_base::failure("error occurred in the bit_stream object");
 }
 buffer_size = 0;
 }
 ++buffer_size;
 buffer <<= 1;
 buffer += static_cast<unsigned char>(bit);
 }
// ----------------------------------------------------------------------------------------
 bool bit_stream_kernel_1::
 read (
 int& bit
 )
 {
 // get new byte if necessary
 if (buffer_size == 0)
 {
 if (isp->rdbuf()->sgetn(reinterpret_cast<char*>(&buffer), 1) == 0)
 {
 // if we didn't read anything then return false
 return false;
 }
 buffer_size = 8;
 }
 // put the most significant bit from buffer into bit
 bit = static_cast<int>(buffer >> 7);
 // shift out the bit that was just read
 buffer <<= 1;
 --buffer_size;
 return true;
 }
// ----------------------------------------------------------------------------------------
 void bit_stream_kernel_1::
 swap (
 bit_stream_kernel_1& item
 )
 {
 std::istream* isp_temp = item.isp;
 std::ostream* osp_temp = item.osp;
 bool write_mode_temp = item.write_mode;
 bool read_mode_temp = item.read_mode;
 unsigned char buffer_temp = item.buffer;
 unsigned short buffer_size_temp = item.buffer_size;
 item.isp = isp;
 item.osp = osp;
 item.write_mode = write_mode;
 item.read_mode = read_mode;
 item.buffer = buffer;
 item.buffer_size = buffer_size;
 isp = isp_temp;
 osp = osp_temp;
 write_mode = write_mode_temp;
 read_mode = read_mode_temp;
 buffer = buffer_temp;
 buffer_size = buffer_size_temp;
 }
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_BIT_STREAM_KERNEL_1_CPp_