------------------------------------------------------------------------------ -- -- -- GNAT RUN-TIME COMPONENTS -- -- -- -- S Y S T E M . W C H _ C N V -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2024, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- This package contains generic subprograms used for converting between -- sequences of Character and Wide_Character. Wide_Wide_Character values -- are also handled, but represented using integer range types defined in -- this package, so that this package can be used from applications that -- are restricted to Ada 95 compatibility (such as the compiler itself). -- All the algorithms for encoding and decoding are isolated in this package -- and in System.WCh_JIS and should not be duplicated elsewhere. The only -- exception to this is that GNAT.Decode_String and GNAT.Encode_String have -- their own circuits for UTF-8 conversions, for improved efficiency. -- This unit may be used directly from an application program by providing -- an appropriate WITH, and the interface can be expected to remain stable. with System.WCh_Con; package System.WCh_Cnv is pragma Pure; type UTF_32_Code is range 0 .. 16#7FFF_FFFF#; for UTF_32_Code'Size use 32; -- Range of allowed UTF-32 encoding values type UTF_32_String is array (Positive range <>) of UTF_32_Code; generic with function In_Char return Character; function Char_Sequence_To_Wide_Char (C : Character; EM : System.WCh_Con.WC_Encoding_Method) return Wide_Character; -- C is the first character of a sequence of one or more characters which -- represent a wide character sequence. Calling the function In_Char for -- additional characters as required, Char_To_Wide_Char returns the -- corresponding wide character value. Constraint_Error is raised if the -- sequence of characters encountered is not a valid wide character -- sequence for the given encoding method. -- -- Note on the use of brackets encoding (WCEM_Brackets). The brackets -- encoding method is ambiguous in the context of this function, since -- there is no way to tell if ["1234"] is eight unencoded characters or -- one encoded character. In the context of Ada sources, any sequence -- starting [" must be the start of an encoding (since that sequence is -- not valid in Ada source otherwise). The routines in this package use -- the same approach. If the input string contains the sequence [" then -- this is assumed to be the start of a brackets encoding sequence, and -- if it does not match the syntax, an error is raised. generic with function In_Char return Character; function Char_Sequence_To_UTF_32 (C : Character; EM : System.WCh_Con.WC_Encoding_Method) return UTF_32_Code; -- This is similar to the above, but the function returns a code from -- the full UTF_32 code set, which covers the full range of possible -- values in Wide_Wide_Character. The result can be converted to -- Wide_Wide_Character form using Wide_Wide_Character'Val. generic with procedure Out_Char (C : Character); procedure Wide_Char_To_Char_Sequence (WC : Wide_Character; EM : System.WCh_Con.WC_Encoding_Method); -- Given a wide character, converts it into a sequence of one or -- more characters, calling the given Out_Char procedure for each. -- Constraint_Error is raised if the given wide character value is -- not a valid value for the given encoding method. -- -- Note on brackets encoding (WCEM_Brackets). For the input routines above, -- upper half characters can be represented as ["hh"] but this procedure -- will only use brackets encodings for codes higher than 16#FF#, so upper -- half characters will be output as single Character values. generic with procedure Out_Char (C : Character); procedure UTF_32_To_Char_Sequence (Val : UTF_32_Code; EM : System.WCh_Con.WC_Encoding_Method); -- This is similar to the above, but the input value is a code from the -- full UTF_32 code set, which covers the full range of possible values -- in Wide_Wide_Character. To convert a Wide_Wide_Character value, the -- caller can use Wide_Wide_Character'Pos in the call. end System.WCh_Cnv;