ibrcommon/ibrcommon/data/iobuffer.cpp

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/*
 * iobuffer.cpp
 *
 *  Created on: 14.02.2011
 *      Author: morgenro
 */

#include "ibrcommon/data/iobuffer.h"
#include "ibrcommon/thread/MutexLock.h"
#include <string.h>

namespace ibrcommon
{
        iobuffer::iobuffer(const size_t buffer)
         : _eof(false), _data_size(0), _buf_size(buffer), _input_buf(new char[buffer]), _interim_buf(new char[buffer]), _output_buf(new char[buffer])
        {
                // Initialize get pointer.  This should be zero so that underflow is called upon first read.
                setg(0, 0, 0);
                setp(_input_buf, _input_buf + _buf_size - 1);
        }

        iobuffer::~iobuffer()
        {
                delete[] _input_buf;
                delete[] _output_buf;
                delete[] _interim_buf;
        }

        void iobuffer::finalize()
        {
                ibrcommon::MutexLock l(_data_cond);
                _eof = true;
                _data_cond.signal(true);
        }

        int iobuffer::sync()
        {
                int ret = std::char_traits<char>::eq_int_type(this->overflow(
                                std::char_traits<char>::eof()), std::char_traits<char>::eof()) ? -1
                                : 0;

                return ret;
        }

        std::char_traits<char>::int_type iobuffer::overflow(std::char_traits<char>::int_type c)
        {
                char *ibegin = _input_buf;
                char *iend = pptr();

                // mark the buffer as free
                setp(_input_buf, _input_buf + _buf_size - 1);

                if (!std::char_traits<char>::eq_int_type(c, std::char_traits<char>::eof()))
                {
                        *iend++ = std::char_traits<char>::to_char_type(c);
                }

                // if there is nothing to send, just return
                if ((iend - ibegin) == 0)
                {
                        return std::char_traits<char>::not_eof(c);
                }

                ibrcommon::MutexLock l(_data_cond);

                // wait until the buffer is empty
                while (_data_size > 0)
                {
                        if (_eof) throw ibrcommon::Exception("iobuffer was finalized");
                        _data_cond.wait();
                }

                // set the new output data size
                _data_size = (iend - ibegin);

                // copy the data to the interim buffer
                ::memcpy(_interim_buf, _input_buf, _data_size);

                // signal the new data
                _data_cond.signal(true);

                return std::char_traits<char>::not_eof(c);
        }

        std::char_traits<char>::int_type iobuffer::underflow()
        {
                ibrcommon::MutexLock l(_data_cond);

                // wait until some data is available
                while (_data_size == 0)
                {
                        // return EOF if the end of the file is reached
                        if (_eof) return std::char_traits<char>::eof();

                        _data_cond.wait();
                }

                // copy the data to the output buffer
                ::memcpy(_output_buf, _interim_buf, _data_size);

                // Since the input buffer content is now valid (or is new)
                // the get pointer should be initialized (or reset).
                setg(_output_buf, _output_buf, _output_buf + _data_size);

                // signal the empty buffer
                _data_size = 0;
                _data_cond.signal(true);

                return std::char_traits<char>::not_eof((unsigned char) _output_buf[0]);
        }
}