/*
   Copyright (C) 2009 Her Majesty the Queen in Right of Canada (Communications
   Research Center Canada)

   Copyright (C) 2013 Matthias P. Braendli
   http://mpb.li

   Base class for buffered inputs

   */
/*
   This file is part of CRC-DabMux.

   CRC-DabMux 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 3 of the
   License, or (at your option) any later version.

   CRC-DabMux 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 CRC-DabMux.  If not, see <http://www.gnu.org/licenses/>.
   */

#include "inputs/Input.h"


#include "TcpLog.h"

#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

#ifndef _WIN32
#   define O_BINARY 0
#endif

extern TcpLog etiLog;

int InputBuffered::ReadFrame(void* buffer, int size)
{
    int retval = 0;
    bool rc;

    switch (m_bufferstate) {
        case PREBUFFERING:
            rc = FillBuffer();
            if (rc) {
                m_prebuffer_count--;
            }
            if (m_prebuffer_count == 0) {
                etiLog.print(TcpLog::NOTICE, "input %s: pre-buffering complete\n",
                        GetName());
                m_bufferstate = RUNNING;
            }
            break;

        case RUNNING:
            rc = FillBuffer();
            if (m_buffer.empty()) {
                etiLog.print(TcpLog::WARNING,
                        "input %s input empty, re-enabling pre-buffering\n",
                        GetName());

                // reinitialise prebuffering
                m_bufferstate = PREBUFFERING;
                m_prebuffer_count = m_prebuffer_stages;
            }
            else {
                std::vector<char> &buffer_head = m_buffer.front();

                memcpy(buffer, &buffer_head.front(), size);
                etiLog.print(TcpLog::NOTICE,
                        "input %s got %d, %d\n",
                        GetName(), rc, m_buffer.size());

                m_buffer.pop_front();
                retval = size;
            }
            break;
    }

    // If we haven't filled buffer, return a nulled one
    if (retval == 0) {
        memset(buffer, 0, size);
        retval = size;
    }

    return retval;
}

// This implemenation of FillBuffer assumes that
// input and output frames have same size.
// That's not the case with DAB+ superframes
bool InputBuffered::FillBuffer()
{
    if (m_buffer.size() > m_overfull_thresh) {
        etiLog.print(TcpLog::WARNING,
                "input %s buffer full, dropping frame !\n",
                GetName());

        // drop the surplus
        int num_frames_to_drop = m_buffer.size() - m_overfull_thresh;
        while (num_frames_to_drop--)
            m_buffer.pop_front();

        return true;
    }
    else {
        // copy the input frame into the frame_buffer one to one
        std::vector<char> frame(m_source_size);
        int rc = ReadSource(&frame.front(), m_source_size);
        if (rc == m_source_size)
        {
            m_buffer.push_back(frame);
            return true;
        }
        else
        {
            return false;
        }
    }
}