CFileGZInputStream.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

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

#include <mrpt/core/exceptions.h>
#include <mrpt/io/CFileGZInputStream.h>
#include <mrpt/system/filesystem.h>
#include <cerrno>
#include <cstring>  // strerror

#include <zlib.h>

using namespace mrpt::io;
using namespace std;

static_assert(
    !std::is_copy_constructible_v<CFileGZInputStream> &&
        !std::is_copy_assignable_v<CFileGZInputStream>,
    "Copy Check");

struct CFileGZInputStream::Impl
{
    gzFile f{nullptr};
};

CFileGZInputStream::CFileGZInputStream()
    : m_f(mrpt::make_impl<CFileGZInputStream::Impl>())
{
}

CFileGZInputStream::CFileGZInputStream(const string& fileName)
    : CFileGZInputStream()
{
    MRPT_START
    open(fileName);
    MRPT_END
}

bool CFileGZInputStream::open(
    const std::string& fileName, mrpt::optional_ref<std::string> error_msg)
{
    MRPT_START

    if (m_f->f) gzclose(m_f->f);

    // Get compressed file size:
    m_file_size = mrpt::system::getFileSize(fileName);
    if (m_file_size == uint64_t(-1))
    {
        if (error_msg)
            error_msg.value().get() =
                mrpt::format("Couldn't access the file '%s'", fileName.c_str());
        return false;
    }

    // Open gz stream:
    m_f->f = gzopen(fileName.c_str(), "rb");
    if (m_f->f == nullptr && error_msg)
        error_msg.value().get() = std::string(strerror(errno));

    return m_f->f != nullptr;
    MRPT_END
}

void CFileGZInputStream::close()
{
    if (m_f->f)
    {
        gzclose(m_f->f);
        m_f->f = nullptr;
    }
}

CFileGZInputStream::~CFileGZInputStream() { close(); }
size_t CFileGZInputStream::Read(void* Buffer, size_t Count)
{
    if (!m_f->f)
    {
        THROW_EXCEPTION("File is not open.");
    }

    return gzread(m_f->f, Buffer, Count);
}

size_t CFileGZInputStream::Write(
    [[maybe_unused]] const void* Buffer, [[maybe_unused]] size_t Count)
{
    THROW_EXCEPTION("Trying to write to an input file stream.");
}

uint64_t CFileGZInputStream::getTotalBytesCount() const
{
    if (!m_f->f)
    {
        THROW_EXCEPTION("File is not open.");
    }
    return m_file_size;
}

uint64_t CFileGZInputStream::getPosition() const
{
    if (!m_f->f)
    {
        THROW_EXCEPTION("File is not open.");
    }
    return gztell(m_f->f);
}

bool CFileGZInputStream::fileOpenCorrectly() const { return m_f->f != nullptr; }
bool CFileGZInputStream::checkEOF()
{
    if (!m_f->f)
        return true;
    else
        return 0 != gzeof(m_f->f);
}

uint64_t CFileGZInputStream::Seek(int64_t, CStream::TSeekOrigin)
{
    THROW_EXCEPTION("Method not available in this class.");
}