Automatic conversion from LEX_STRING to LEX_CSTRING

struct st_mysql_lex_string

{

  char *str;

  size_t length;

#ifdef __cplusplus

  // Allow automatic cast from LEX_STRING to LEX_CSTRING in c++.

  operator struct st_mysql_const_lex_string() const

  {

    return {str, length};

  }

#endif

  Lex_cstring_with_compare(const LEX_STRING src) :

    Lex_cstring(src.str, src.length)

  { }

  Lex_cstring_with_compare(const LEX_CSTRING src) : Lex_cstring(src.str, src.length)

  { }

  Storage_engine_name(const LEX_CSTRING &name)

   :m_storage_engine_name(name)

  { }

  Storage_engine_name(const LEX_STRING &name)

  {

    m_storage_engine_name.str= name.str;

    m_storage_engine_name.length= name.length;

  }

  // Append with optional character set conversion from ASCII (e.g. to UCS2)

  bool append(const LEX_STRING *ls)

  {

    DBUG_ASSERT(ls->length < UINT_MAX32 &&

                ((ls->length == 0 && !ls->str) ||

                 ls->length == strlen(ls->str)));

    return append(ls->str, (uint32) ls->length);

  }

  bool append(const LEX_CSTRING *ls)

  {

    DBUG_ASSERT(ls->length < UINT_MAX32 &&

                ((ls->length == 0 && !ls->str) ||

                 ls->length == strlen(ls->str)));

    return append(ls->str, (uint32) ls->length);

  }