MemoryMap.cpp

Go to the documentation of this file.

#include "MemoryMap.h"


MemoryMap::MemoryMap ()
{
    hFile = NULL;
    hMap = NULL;
    dataPtr = NULL;
    fileSizeLow = 0;
    fileSizeHigh = 0;
}

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


void MemoryMap::close()
{
    if (dataPtr)
        UnmapViewOfFile (dataPtr);

    if (hMap)
        CloseHandle (hMap);

    if (hFile)
        CloseHandle(hFile);

    dataPtr = NULL;
    hMap = NULL;
    hFile = NULL;

    fileSizeLow = 0;
    fileSizeHigh = 0;
}

void MemoryMap::load (const char *filename)
{
    close();

    try 
    {
        hFile = CreateFile (
            filename, 
            GENERIC_READ,
            FILE_SHARE_READ,
            NULL,
            OPEN_EXISTING,
            FILE_ATTRIBUTE_NORMAL,
            NULL);
        
        if (INVALID_HANDLE_VALUE == hFile)
            throw RuntimeError ("Couldn't open file: %s", filename);
        
        BY_HANDLE_FILE_INFORMATION info;

        GetFileInformationByHandle (
            hFile,
            &info);

        fileSizeLow = info.nFileSizeLow;
        fileSizeHigh = info.nFileSizeHigh;

        hMap = CreateFileMapping (
            hFile,
            NULL,
            PAGE_READONLY,
            info.nFileSizeHigh,
            info.nFileSizeLow,
            NULL);


        if (hMap == NULL)
            throw DiskError ("Couldn't create mapping for file: %s", filename);

        dataPtr = MapViewOfFile (
            hMap,
            FILE_MAP_READ,
            0, 0,
            0); // whole file

        if (dataPtr == NULL)
            throw DiskError ("Couldn't map view of file: %s", filename);

    }
    catch (...)
    {
        close();
        throw;
    }
}

---