summaryrefslogtreecommitdiff
path: root/gcc/ada/a-stuten.adb
blob: fc669b56ee431c0bc136fa34ffc2672bd18d85c5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUN-TIME COMPONENTS                         --
--                                                                          --
--              A D A . S T R I N G S . U T F _ E N C O D I N G             --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--             Copyright (C) 2010, 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    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

package body Ada.Strings.UTF_Encoding is
   use Interfaces;

   --------------
   -- Encoding --
   --------------

   function Encoding
     (Item    : UTF_String;
      Default : Encoding_Scheme := UTF_8) return Encoding_Scheme
   is
   begin
      if Item'Length >= 2 then
         if Item (Item'First .. Item'First + 1) = BOM_16BE then
            return UTF_16BE;

         elsif Item (Item'First .. Item'First + 1) = BOM_16LE then
            return UTF_16LE;

         elsif Item'Length >= 3
           and then Item (Item'First .. Item'First + 2) = BOM_8
         then
            return UTF_8;
         end if;
      end if;

      return Default;
   end Encoding;

   -----------------
   -- From_UTF_16 --
   -----------------

   function From_UTF_16
     (Item          : UTF_16_Wide_String;
      Output_Scheme : UTF_XE_Encoding;
      Output_BOM    : Boolean := False) return UTF_String
   is
      BSpace : constant Natural := 2 * Boolean'Pos (Output_BOM);
      Result : UTF_String (1 .. 2 * Item'Length + BSpace);
      Len    : Natural;
      C      : Unsigned_16;
      Iptr   : Natural;

   begin
      if Output_BOM then
         Result (1 .. 2) :=
           (if Output_Scheme = UTF_16BE then BOM_16BE else BOM_16LE);
         Len := 2;
      else
         Len := 0;
      end if;

      --  Skip input BOM

      Iptr := Item'First;

      if Iptr <= Item'Last and then Item (Iptr) = BOM_16 (1) then
         Iptr := Iptr + 1;
      end if;

      --  UTF-16BE case

      if Output_Scheme = UTF_16BE then
         while Iptr <= Item'Last loop
            C := To_Unsigned_16 (Item (Iptr));
            Result (Len + 1) := Character'Val (Shift_Right (C, 8));
            Result (Len + 2) := Character'Val (C and 16#00_FF#);
            Len := Len + 2;
            Iptr := Iptr + 1;
         end loop;

      --  UTF-16LE case

      else
         while Iptr <= Item'Last loop
            C := To_Unsigned_16 (Item (Iptr));
            Result (Len + 1) := Character'Val (C and 16#00_FF#);
            Result (Len + 2) := Character'Val (Shift_Right (C, 8));
            Len := Len + 2;
            Iptr := Iptr + 1;
         end loop;
      end if;

      return Result (1 .. Len);
   end From_UTF_16;

   --------------------------
   -- Raise_Encoding_Error --
   --------------------------

   procedure Raise_Encoding_Error (Index : Natural) is
      Val : constant String := Index'Img;
   begin
      raise Encoding_Error with
        "bad input at Item (" & Val (Val'First + 1 .. Val'Last) & ')';
   end Raise_Encoding_Error;

   ---------------
   -- To_UTF_16 --
   ---------------

   function To_UTF_16
     (Item         : UTF_String;
      Input_Scheme : UTF_XE_Encoding;
      Output_BOM   : Boolean := False) return UTF_16_Wide_String
   is
      Result : UTF_16_Wide_String (1 .. Item'Length / 2 + 1);
      Len    : Natural;
      Iptr   : Natural;

   begin
      if Item'Length mod 2 /= 0 then
         raise Encoding_Error with "UTF-16BE/LE string has odd length";
      end if;

      --  Deal with input BOM, skip if OK, error if bad BOM

      Iptr := Item'First;

      if Item'Length >= 2 then
         if Item (Iptr .. Iptr + 1) = BOM_16BE then
            if Input_Scheme = UTF_16BE then
               Iptr := Iptr + 2;
            else
               Raise_Encoding_Error (Iptr);
            end if;

         elsif Item (Iptr .. Iptr + 1) = BOM_16LE then
            if Input_Scheme = UTF_16LE then
               Iptr := Iptr + 2;
            else
               Raise_Encoding_Error (Iptr);
            end if;

         elsif Item'Length >= 3 and then Item (Iptr .. Iptr + 2) = BOM_8 then
            Raise_Encoding_Error (Iptr);
         end if;
      end if;

      --  Output BOM if specified

      if Output_BOM then
         Result (1) := BOM_16 (1);
         Len := 1;
      else
         Len := 0;
      end if;

      --  UTF-16BE case

      if Input_Scheme = UTF_16BE then
         while Iptr < Item'Last loop
            Len := Len + 1;
            Result (Len) :=
              Wide_Character'Val
                (Character'Pos (Item (Iptr)) * 256 +
                   Character'Pos (Item (Iptr + 1)));
            Iptr := Iptr + 2;
         end loop;

      --  UTF-16LE case

      else
         while Iptr < Item'Last loop
            Len := Len + 1;
            Result (Len) :=
              Wide_Character'Val
                (Character'Pos (Item (Iptr)) +
                 Character'Pos (Item (Iptr + 1)) * 256);
            Iptr := Iptr + 2;
         end loop;
      end if;

      return Result (1 .. Len);
   end To_UTF_16;

end Ada.Strings.UTF_Encoding;