eventmachine/eventmachine

/*****************************************************************************

$Id: mapper.cpp 4527 2007-07-04 10:21:34Z francis $

File:     mapper.cpp
Date:     02Jul07

Copyright (C) 2007 by Francis Cianfrocca. All Rights Reserved.
Gmail: garbagecat10

This program is free software; you can redistribute it and/or modify
it under the terms of either: 1) the GNU General Public License
as published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version; or 2) Ruby's License.

See the file COPYING for complete licensing information.

*****************************************************************************/


//////////////////////////////////////////////////////////////////////
// UNIX implementation
//////////////////////////////////////////////////////////////////////


#ifdef OS_UNIX

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>

#include <iostream>
#include <string>
#include <cstring>
#include <stdexcept>

#include "mapper.h"

/******************
Mapper_t::Mapper_t
******************/

Mapper_t::Mapper_t (const std::string &filename)
{
    /* We ASSUME we can open the file.
     * (More precisely, we assume someone else checked before we got here.)
     */

    Fd = open (filename.c_str(), O_RDONLY);
    if (Fd < 0)
        throw std::runtime_error (strerror (errno));

    struct stat st;
    if (fstat (Fd, &st))
        throw std::runtime_error (strerror (errno));
    FileSize = st.st_size;

    #ifdef OS_WIN32
    MapPoint = (char*) mmap (0, FileSize, PROT_READ, MAP_SHARED, Fd, 0);
    #else
    MapPoint = (const char*) mmap (0, FileSize, PROT_READ, MAP_SHARED, Fd, 0);
    #endif
    if (MapPoint == MAP_FAILED)
        throw std::runtime_error (strerror (errno));
}


/*******************
Mapper_t::~Mapper_t
*******************/

Mapper_t::~Mapper_t()
{
    Close();
}


/***************
Mapper_t::Close
***************/

void Mapper_t::Close()
{
    // Can be called multiple times.
    // Calls to GetChunk are invalid after a call to Close.
    if (MapPoint) {
        #ifdef CC_SUNWspro
        // TODO: The void * cast works fine on Solaris 11, but
        // I don't know at what point that changed from older Solaris.
        munmap ((char*)MapPoint, FileSize);
        #else
        munmap ((void*)MapPoint, FileSize);
        #endif
        MapPoint = NULL;
    }
    if (Fd >= 0) {
        close (Fd);
        Fd = -1;
    }
}

/******************
Mapper_t::GetChunk
******************/

const char *Mapper_t::GetChunk (unsigned start)
{
    return MapPoint + start;
}



#endif // OS_UNIX


//////////////////////////////////////////////////////////////////////
// WINDOWS implementation
//////////////////////////////////////////////////////////////////////

#ifdef OS_WIN32

#include <windows.h>

#include <iostream>
#include <string>
#include <stdexcept>

#include "mapper.h"

/******************
Mapper_t::Mapper_t
******************/

Mapper_t::Mapper_t (const std::string &filename)
{
    /* We ASSUME we can open the file.
     * (More precisely, we assume someone else checked before we got here.)
     */

    hFile = INVALID_HANDLE_VALUE;
    hMapping = NULL;
    MapPoint = NULL;
    FileSize = 0;

    hFile = CreateFile (filename.c_str(), GENERIC_READ|GENERIC_WRITE, FILE_SHARE_DELETE|FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

    if (hFile == INVALID_HANDLE_VALUE)
        throw std::runtime_error ("File not found");

    BY_HANDLE_FILE_INFORMATION i;
    if (GetFileInformationByHandle (hFile, &i))
        FileSize = i.nFileSizeLow;

    hMapping = CreateFileMapping (hFile, NULL, PAGE_READWRITE, 0, 0, NULL);
    if (!hMapping)
        throw std::runtime_error ("File not mapped");

    #ifdef OS_WIN32
    MapPoint = (char*) MapViewOfFile (hMapping, FILE_MAP_WRITE, 0, 0, 0);
    #else
    MapPoint = (const char*) MapViewOfFile (hMapping, FILE_MAP_WRITE, 0, 0, 0);
    #endif
    if (!MapPoint)
        throw std::runtime_error ("Mappoint not read");
}


/*******************
Mapper_t::~Mapper_t
*******************/

Mapper_t::~Mapper_t()
{
    Close();
}

/***************
Mapper_t::Close
***************/

void Mapper_t::Close()
{
    // Can be called multiple times.
    // Calls to GetChunk are invalid after a call to Close.
    if (MapPoint) {
        UnmapViewOfFile (MapPoint);
        MapPoint = NULL;
    }
    if (hMapping != NULL) {
        CloseHandle (hMapping);
        hMapping = NULL;
    }
    if (hFile != INVALID_HANDLE_VALUE) {
        CloseHandle (hFile);
        hFile = INVALID_HANDLE_VALUE;
    }
}


/******************
Mapper_t::GetChunk
******************/

const char *Mapper_t::GetChunk (unsigned start)
{
    return MapPoint + start;
}



#endif // OS_WINDOWS