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Generalized String Manipulation: Access Shims and Type Tunneling

Listing 12: String length shims

Listing 12: String length shims

/* /////////////////////////////////////////////////////////////
 * Extract from stlsoft_string_access.h, comstl_string_access.h,
 *              mfcstl_string_access.h, winstl_string_access.h
 * www:,
 * Copyright (C) 2002, Synesis Software Pty Ltd.
 * (Licensed under the Synesis Software Standard Source License:
 * ////////////////////////////////////////////////////////// */

namespace stlsoft
  /* C-style Unicode string */
  inline size_t c_str_len(wchar_t const *s)
    return (s == 0) ? 0 : char_traits<wchar_t>::length(s);
} // namespace stlsoft

namespace comstl
  const size_t COMSTL_CCH_GUID = 38; // Fixed format & length

  /* GUID */
  inline size_t c_str_len(GUID const &/* guid */)
    return COMSTL_CCH_GUID;
  /* VARIANT */
  inline size_t c_str_len(VARIANT const &v)
    if(v.vt == VT_BSTR)
      return ::SysStringLen(v.bstrVal);
      // Do a copy and conversion to VT_BSTR and get
      // length from that
} // namespace comstl

namespace mfcstl
  /* CString */
  inline size_t c_str_len(CString const &s)
    return s.GetLength();
} // namespace mfcstl

namespace winstl
  /* HWND */
  inline size_t c_str_len(HWND h)
    return static_cast<size_t>(::GetWindowTextLength(h));
  inline size_t c_str_len(LSA_UNICODE_STRING const &s)
    return s.Length;
} // namespace winstl

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