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filesPAL.hpp

Go to the documentation of this file.

#ifndef __FILES_WIN32_PAL_HPP__
#define __FILES_WIN32_PAL_HPP__

//#include <winbase.h>
#include <assert.h>
#include <windows.h>

namespace lfc
{
namespace win32PAL
{


namespace files
{

const int MAX_ERROR_CODE = 4;

enum ErrorCodes
{
    errOk,
    errGeneric,
    errNotSupported,
    errAlreadyExists,
    errCantTruncate,
};

extern const char *messagesTable[MAX_ERROR_CODE + 1];


typedef ::HANDLE Handle;

const Handle NULL_HANDLE = INVALID_HANDLE_VALUE;

const int
    seekSet         = 0x0001,
    seekCurrent     = 0x0002,
    seekEnd         = 0x0004;

const int
    flAppend        = 0x0001,
    flRead          = 0x0002,
    flWrite         = 0x0004,
    flTruncate      = 0x0008,
    flOpenExisting  = 0x0010,
    flCreateNew     = 0x0020,
    flTemp          = 0x0040;

const int
    shRead      = 0x0001,
    shWrite     = 0x0002;


// forward declarations
inline int close(Handle handle);
inline int seek(Handle handle, long offset, int mode, long &pos);
inline int setEof(Handle handle);



inline int init()
{
    return errOk;
}


inline int cleanup()
{
    return errOk;
}


inline int open(Handle &handle, const char *name, int flags, int shareFlags)
{
    DWORD dwAccess = 0;
    dwAccess |= (flags & flRead ? GENERIC_READ : 0);
    dwAccess |= (flags & flWrite ? GENERIC_WRITE : 0);

    DWORD dwShare = 0;
    dwShare |= (shareFlags & shRead ? FILE_SHARE_READ : 0);
    dwShare |= (shareFlags & shWrite ? FILE_SHARE_WRITE : 0);

    DWORD dwCreation = 0;
    if(flags & flOpenExisting)
        dwCreation = OPEN_EXISTING;
    else if(flags & flCreateNew)
        dwCreation = CREATE_NEW;
    else if(flags & flTruncate)
        dwCreation = CREATE_ALWAYS;
    else
        dwCreation = OPEN_ALWAYS;

    DWORD dwFlagsAndAttrs = FILE_ATTRIBUTE_NORMAL;
    dwFlagsAndAttrs |= (flags & flTemp ? FILE_FLAG_DELETE_ON_CLOSE : 0);

    ::SetLastError(NO_ERROR);
    HANDLE h = ::CreateFile(name, dwAccess, dwShare, NULL, dwCreation,
        FILE_ATTRIBUTE_NORMAL, NULL);

    if(h != INVALID_HANDLE_VALUE)
    {
        handle = h;
        return errOk;
    }
    else
        switch(::GetLastError())
        {
        case ERROR_NOT_SUPPORTED:
            return errNotSupported;

        case ERROR_ALREADY_EXISTS:
            return errAlreadyExists;

        default:
            return errGeneric;
        }
}


inline int close(Handle handle)
{
    assert(handle != NULL_HANDLE);
    return ::CloseHandle(handle) ? errOk : errGeneric;
}


inline int seek(Handle handle, long offset, int mode, long &pos)
{
    DWORD dwMode = 0;
    switch(mode)
    {
    case seekSet: dwMode = FILE_BEGIN; break;
    case seekCurrent: dwMode = FILE_CURRENT; break;
    case seekEnd: dwMode = FILE_END; break;
    default:
        assert(false);
    }

    ::SetLastError(NO_ERROR);
    long newPos = ::SetFilePointer(handle, offset, NULL, dwMode);

    if(::GetLastError() == NO_ERROR)
    {
        pos = newPos;
        return errOk;
    }
    else
        return errGeneric;
}


inline int setEof(Handle handle)
{
    return ::SetEndOfFile(handle) ? errOk : errGeneric;
}


inline int write(Handle handle, const void *buff, long count, long &written)
{
    DWORD dwCount = static_cast<DWORD>(count);
    DWORD dwWritten = 0;

    if(::WriteFile(handle, buff, dwCount, &dwWritten, NULL))
    {
        written = static_cast<long>(dwWritten);
        return errOk;
    }
    else
        return errGeneric;
}


inline int read(Handle handle, void *buff, long count, long &read)
{
    DWORD dwCount = static_cast<DWORD>(count);
    DWORD dwRead = 0;

    if(::ReadFile(handle, buff, dwCount, &dwRead, NULL))
    {
        read = static_cast<long>(dwRead);
        return errOk;
    }
    else
        return errGeneric;
}



inline int flush(Handle handle)
{
    return ::FlushFileBuffers(handle) ? errOk : errGeneric;
}



inline const char *message(int index)
{
    assert(index >= 0 && index <= MAX_ERROR_CODE);
    return messagesTable[index];
}


} // namespace win32PAL::files
} // namespace win32PAL

namespace pal = win32PAL;

} // namespace lfc


#endif  // __FILES_WIN32_PAL_HPP__

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