CInterfaceFTDI_common.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#include "comms-precomp.h"  // Precompiled headers

#include <mrpt/comms/CInterfaceFTDI.h>
#include <algorithm>  // min()

using namespace mrpt;
using namespace mrpt::comms;

size_t CInterfaceFTDI::Read(void* Buffer, size_t Count)
{
    if (!Count) return 0;

    // Employ a circular_buffer to speed-up lots of small readings:
    if (m_readBuffer.size() >= Count)
    {
        // It's enough with the data in the buffer:
        m_readBuffer.pop_many(reinterpret_cast<uint8_t*>(Buffer), Count);
        return Count;
    }
    else
    {
        // More data must be read:
        uint8_t buf[4000];

        unsigned long nActualRead = 0;
        unsigned long to_read = std::min(m_readBuffer.available(), sizeof(buf));

        ftdi_read(
            buf, to_read,
            &nActualRead);  // ftdi_read(Buffer,(unsigned long)Count, &ret );

        // Save data into the circular buffer:
        m_readBuffer.push_many(buf, nActualRead);

        // Read the required amount of bytes:
        size_t nActualReturn = std::min(m_readBuffer.size(), Count);

        m_readBuffer.pop_many(
            reinterpret_cast<uint8_t*>(Buffer), nActualReturn);

        return nActualReturn;
    }
}

size_t CInterfaceFTDI::Write(const void* Buffer, size_t Count)
{
    unsigned long ret = 0;
    ftdi_write(Buffer, (unsigned long)Count, &ret);
    return (size_t)ret;
}

uint64_t CInterfaceFTDI::Seek(int64_t Offset, CStream::TSeekOrigin Origin)
{
    return 0;
}

uint64_t CInterfaceFTDI::getTotalBytesCount() const { return 0; }
uint64_t CInterfaceFTDI::getPosition() const { return 0; }
size_t CInterfaceFTDI::ReadBufferImmediate(void* Buffer, size_t Count)
{
    unsigned long nRead;
    ftdi_read(Buffer, Count, &nRead);
    return nRead;
}