memorymapped.cpp

/*
* memorymapped.cpp
* Original Copyright (c) 2013 Stephan Brumme. All rights reserved.
* see http://create.stephan-brumme.com/disclaimer.html
*/

#include <sstream>
#include <cstdio>
#include "memorymapped.h"

// OS-specific
#if defined(MEMMAPPED_USING_WINDOWS)
    // Windows
    #include <windows.h>
#else
    // Linux
    // enable large file support on 32 bit systems
    #ifndef _LARGEFILE64_SOURCE
        #define _LARGEFILE64_SOURCE
    #endif
    #ifdef  _FILE_OFFSET_BITS
        #undef  _FILE_OFFSET_BITS
    #endif
    #define _FILE_OFFSET_BITS 64
    #ifndef O_LARGEFILE
        #define O_LARGEFILE 0
    #endif
    // and include needed headers
    #include <sys/stat.h>
    #include <sys/mman.h>
    #include <fcntl.h>
    #include <errno.h>
    #include <unistd.h>
#endif

namespace MemoryMapped
{
    File::File():
        m_filename   (),
        m_filesize   (0),
        m_hint       (Normal),
        m_handle     (0),
        m_mappedBytes(0),
        m_mappedView (NULL),
        m_mappedFile (NULL)
    {
    }

    File::File(const std::string& filename, size_t mappedBytes, CacheHint hint):
        m_filename   (filename),
        m_filesize   (0),
        m_hint       (hint),
        m_handle     (0),
        m_mappedBytes(mappedBytes),
        m_mappedView (NULL),
        m_mappedFile (NULL)
    {
        open(filename, mappedBytes, hint);
    }

    File::~File()
    {
        close();
    }

    bool File::open(const std::string& filename, size_t mappedBytes, CacheHint hint)
    {
        m_filename = filename;
        return openReal(mappedBytes, hint);
    }

    bool File::errOffset()
    {
         throw IOError(m_filename, "trying to read beyond file (offset > filesize)");
         return false;
    }

    unsigned char File::operator[](size_t offset) const
    {
        return data()[offset];
    }

    unsigned char File::at(size_t offset) const
    {
        // checks
        if(!m_mappedView)
        {
            throw IOError(m_filename, "no view mapped");
        }
        if (offset >= m_filesize)
        {
            throw IOError(m_filename, "mapped view is not large enough");
        }
        return operator[](offset);
    }

    const unsigned char* File::data() const
    {
        return (const unsigned char*)m_mappedView;
    }

    bool File::isValid() const
    {
        return (m_mappedView != NULL);
    }

    uint64_t File::size() const
    {
        return m_filesize;
    }

    size_t File::mappedSize() const
    {
        return m_mappedBytes;
    }
}

#if defined(MEMMAPPED_USING_WINDOWS)
    #include "impl.win32.cpp"
#else
    #include "impl.linux.cpp"
#endif