1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                             W I D E C H A R                              --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 1992-2019, Free Software Foundation, Inc.         --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  Note: this package uses the generic subprograms in System.WCh_Cnv, which
33--  completely encapsulate the set of wide character encoding methods, so no
34--  modifications are required when adding new encoding methods.
35
36with Opt; use Opt;
37
38with System.WCh_Cnv; use System.WCh_Cnv;
39with System.WCh_Con; use System.WCh_Con;
40
41package body Widechar is
42
43   ---------------------------
44   -- Is_Start_Of_Wide_Char --
45   ---------------------------
46
47   function Is_Start_Of_Wide_Char
48     (S : Source_Buffer_Ptr;
49      P : Source_Ptr) return Boolean
50   is
51   begin
52      case Wide_Character_Encoding_Method is
53
54         --  For Hex mode, just test for an ESC character. The ESC character
55         --  cannot appear in any other context in a legal Ada program.
56
57         when WCEM_Hex =>
58            return S (P) = ASCII.ESC;
59
60         --  For brackets, just test ["x where x is a hex character. This is
61         --  sufficient test, since this sequence cannot otherwise appear in a
62         --  legal Ada program.
63
64         when WCEM_Brackets =>
65            return P <= S'Last - 2
66              and then S (P) = '['
67              and then S (P + 1) = '"'
68              and then (S (P + 2) in '0' .. '9'
69                            or else
70                           S (P + 2) in 'a' .. 'f'
71                            or else
72                        S (P + 2) in 'A' .. 'F');
73
74         --  All other encoding methods use the upper bit set in the first
75         --  character to uniquely represent a wide character.
76
77         when WCEM_EUC
78            | WCEM_Shift_JIS
79            | WCEM_Upper
80            | WCEM_UTF8
81         =>
82            return S (P) >= Character'Val (16#80#);
83      end case;
84   end Is_Start_Of_Wide_Char;
85
86   -----------------
87   -- Length_Wide --
88   -----------------
89
90   function Length_Wide return Nat is
91   begin
92      return WC_Longest_Sequence;
93   end Length_Wide;
94
95   ---------------
96   -- Scan_Wide --
97   ---------------
98
99   procedure Scan_Wide
100     (S   : Source_Buffer_Ptr;
101      P   : in out Source_Ptr;
102      C   : out Char_Code;
103      Err : out Boolean)
104   is
105      P_Init : constant Source_Ptr := P;
106      Chr    : Character;
107
108      function In_Char return Character;
109      --  Function to obtain characters of wide character escape sequence
110
111      -------------
112      -- In_Char --
113      -------------
114
115      function In_Char return Character is
116      begin
117         P := P + 1;
118         return S (P - 1);
119      end In_Char;
120
121      function WC_In is new Char_Sequence_To_UTF_32 (In_Char);
122
123   --  Start of processing for Scan_Wide
124
125   begin
126      Chr := In_Char;
127
128      --  Scan out the wide character. If the first character is a bracket,
129      --  we allow brackets encoding regardless of the standard encoding
130      --  method being used, but otherwise we use this standard method.
131
132      if Chr = '[' then
133         C := Char_Code (WC_In (Chr, WCEM_Brackets));
134      else
135         C := Char_Code (WC_In (Chr, Wide_Character_Encoding_Method));
136      end if;
137
138      Err := False;
139      Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);
140
141   exception
142      when Constraint_Error =>
143         C := Char_Code (0);
144         P := P - 1;
145         Err := True;
146   end Scan_Wide;
147
148   --------------
149   -- Set_Wide --
150   --------------
151
152   procedure Set_Wide
153     (C : Char_Code;
154      S : in out String;
155      P : in out Natural)
156   is
157      procedure Out_Char (C : Character);
158      --  Procedure to store one character of wide character sequence
159
160      --------------
161      -- Out_Char --
162      --------------
163
164      procedure Out_Char (C : Character) is
165      begin
166         P := P + 1;
167         S (P) := C;
168      end Out_Char;
169
170      procedure WC_Out is new UTF_32_To_Char_Sequence (Out_Char);
171
172   --  Start of processing for Set_Wide
173
174   begin
175      WC_Out (UTF_32_Code (C), Wide_Character_Encoding_Method);
176   end Set_Wide;
177
178   ---------------
179   -- Skip_Wide --
180   ---------------
181
182   procedure Skip_Wide (S : String; P : in out Natural) is
183      P_Init : constant Natural := P;
184
185      function Skip_Char return Character;
186      --  Function to skip one character of wide character escape sequence
187
188      ---------------
189      -- Skip_Char --
190      ---------------
191
192      function Skip_Char return Character is
193      begin
194         P := P + 1;
195         return S (P - 1);
196      end Skip_Char;
197
198      function WC_Skip is new Char_Sequence_To_UTF_32 (Skip_Char);
199
200      Discard : UTF_32_Code;
201      pragma Warnings (Off, Discard);
202
203   --  Start of processing for Skip_Wide
204
205   begin
206      Discard := WC_Skip (Skip_Char, Wide_Character_Encoding_Method);
207      Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);
208   end Skip_Wide;
209
210   ---------------
211   -- Skip_Wide --
212   ---------------
213
214   procedure Skip_Wide (S : Source_Buffer_Ptr; P : in out Source_Ptr) is
215      P_Init : constant Source_Ptr := P;
216
217      function Skip_Char return Character;
218      --  Function to skip one character of wide character escape sequence
219
220      ---------------
221      -- Skip_Char --
222      ---------------
223
224      function Skip_Char return Character is
225      begin
226         P := P + 1;
227         return S (P - 1);
228      end Skip_Char;
229
230      function WC_Skip is new Char_Sequence_To_UTF_32 (Skip_Char);
231
232      Discard : UTF_32_Code;
233      pragma Warnings (Off, Discard);
234
235   --  Start of processing for Skip_Wide
236
237   begin
238      Discard := WC_Skip (Skip_Char, Wide_Character_Encoding_Method);
239      Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);
240   end Skip_Wide;
241
242end Widechar;
243