byte* FileIo::mmap(bool isWriteable)
    {
        assert(p_->fp_ != 0);
        if (munmap() != 0) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerCallFailed, wpath(), strError().c_str(), "munmap");
            }
            else
#endif
            {
                throw Error(kerCallFailed, path(), strError(), "munmap");
            }
        }
        p_->mappedLength_ = size();
        p_->isWriteable_ = isWriteable;
        if (p_->isWriteable_ && p_->switchMode(Impl::opWrite) != 0) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerFailedToMapFileForReadWrite, wpath(), strError().c_str());
            }
            else
#endif
            {
                throw Error(kerFailedToMapFileForReadWrite, path(), strError());
            }
        }
#if defined EXV_HAVE_MMAP && defined EXV_HAVE_MUNMAP
        int prot = PROT_READ;
        if (p_->isWriteable_) {
            prot |= PROT_WRITE;
        }
        void* rc = ::mmap(0, p_->mappedLength_, prot, MAP_SHARED, fileno(p_->fp_), 0);
        if (MAP_FAILED == rc) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerCallFailed, wpath(), strError().c_str(), "mmap");
            }
            else
#endif
            {
                throw Error(kerCallFailed, path(), strError(), "mmap");
            }
        }
        p_->pMappedArea_ = static_cast<byte*>(rc);

#elif defined WIN32 && !defined __CYGWIN__
        // Windows implementation

        // TODO: An attempt to map a file with a length of 0 (zero) fails with
        // an error code of ERROR_FILE_INVALID.
        // Applications should test for files with a length of 0 (zero) and
        // reject those files.

        DWORD dwAccess = FILE_MAP_READ;
        DWORD flProtect = PAGE_READONLY;
        if (isWriteable) {
            dwAccess = FILE_MAP_WRITE;
            flProtect = PAGE_READWRITE;
        }
        HANDLE hPh = GetCurrentProcess();
        HANDLE hFd = (HANDLE)_get_osfhandle(fileno(p_->fp_));
        if (hFd == INVALID_HANDLE_VALUE) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerCallFailed, wpath(), "MSG1", "_get_osfhandle");
            }
            else
#endif
            {
                throw Error(kerCallFailed, path(), "MSG1", "_get_osfhandle");
            }
        }
        if (!DuplicateHandle(hPh, hFd, hPh, &p_->hFile_, 0, false, DUPLICATE_SAME_ACCESS)) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerCallFailed, wpath(), "MSG2", "DuplicateHandle");
            }
            else
#endif
            {
                throw Error(kerCallFailed, path(), "MSG2", "DuplicateHandle");
            }
        }
        p_->hMap_ = CreateFileMapping(p_->hFile_, 0, flProtect, 0, (DWORD) p_->mappedLength_, 0);
        if (p_->hMap_ == 0 ) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerCallFailed, wpath(), "MSG3", "CreateFileMapping");
            }
            else
#endif
            {
                throw Error(kerCallFailed, path(), "MSG3", "CreateFileMapping");
            }
        }
        void* rc = MapViewOfFile(p_->hMap_, dwAccess, 0, 0, 0);
        if (rc == 0) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerCallFailed, wpath(), "MSG4", "CreateFileMapping");
            }
            else
#endif
            {
                throw Error(kerCallFailed, path(), "MSG4", "CreateFileMapping");
            }
        }
        p_->pMappedArea_ = static_cast<byte*>(rc);
#else
        // Workaround for platforms without mmap: Read the file into memory
        DataBuf buf(static_cast<long>(p_->mappedLength_));
        if (read(buf.pData_, buf.size_) != buf.size_) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerCallFailed, wpath(), strError().c_str(), "FileIo::read");
            }
            else
#endif
            {
                throw Error(kerCallFailed, path(), strError(), "FileIo::read");
            }
        }
        if (error()) {
#ifdef EXV_UNICODE_PATH
            if (p_->wpMode_ == Impl::wpUnicode) {
                throw WError(kerCallFailed, wpath(), strError().c_str(), "FileIo::mmap");
            }
            else
#endif
            {
                throw Error(kerCallFailed, path(), strError(), "FileIo::mmap");
            }
        }
        p_->pMappedArea_ = buf.release().first;
        p_->isMalloced_ = true;
#endif
        return p_->pMappedArea_;
    }