1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUN-TIME COMPONENTS                         --
4--                                                                          --
5--                        S Y S T E M . U T F _ 3 2                         --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2005-2013, 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--  This package is an internal package that provides basic character
33--  classification capabilities needed by the compiler for handling full
34--  32-bit wide wide characters. We avoid the use of the actual type
35--  Wide_Wide_Character, since we want to use these routines in the compiler
36--  itself, and we want to be able to compile the compiler with old versions
37--  of GNAT that did not implement Wide_Wide_Character.
38
39--  System.UTF_32 should not be directly used from an application program, but
40--  an equivalent package GNAT.UTF_32 can be used directly and provides exactly
41--  the same services. The reason this package is in System is so that it can
42--  with'ed by other packages in the Ada and System hierarchies.
43
44pragma Compiler_Unit_Warning;
45
46package System.UTF_32 is
47   pragma Pure;
48
49   type UTF_32 is range 0 .. 16#7FFF_FFFF#;
50   --  So far, the only defined character codes are in 0 .. 16#01_FFFF#
51
52   --  The following type defines the categories from the unicode definitions.
53   --  The one addition we make is Fe, which represents the characters FFFE
54   --  and FFFF in any of the planes.
55
56   type Category is (
57     Cc,   --  Other, Control
58     Cf,   --  Other, Format
59     Cn,   --  Other, Not Assigned
60     Co,   --  Other, Private Use
61     Cs,   --  Other, Surrogate
62     Ll,   --  Letter, Lowercase
63     Lm,   --  Letter, Modifier
64     Lo,   --  Letter, Other
65     Lt,   --  Letter, Titlecase
66     Lu,   --  Letter, Uppercase
67     Mc,   --  Mark, Spacing Combining
68     Me,   --  Mark, Enclosing
69     Mn,   --  Mark, Nonspacing
70     Nd,   --  Number, Decimal Digit
71     Nl,   --  Number, Letter
72     No,   --  Number, Other
73     Pc,   --  Punctuation, Connector
74     Pd,   --  Punctuation, Dash
75     Pe,   --  Punctuation, Close
76     Pf,   --  Punctuation, Final quote
77     Pi,   --  Punctuation, Initial quote
78     Po,   --  Punctuation, Other
79     Ps,   --  Punctuation, Open
80     Sc,   --  Symbol, Currency
81     Sk,   --  Symbol, Modifier
82     Sm,   --  Symbol, Math
83     So,   --  Symbol, Other
84     Zl,   --  Separator, Line
85     Zp,   --  Separator, Paragraph
86     Zs,   --  Separator, Space
87     Fe);  --  relative position FFFE/FFFF in any plane
88
89   function Get_Category (U : UTF_32) return Category;
90   --  Given a UTF32 code, returns corresponding Category, or Cn if
91   --  the code does not have an assigned unicode category.
92
93   --  The following functions perform category tests corresponding to lexical
94   --  classes defined in the Ada standard. There are two interfaces for each
95   --  function. The second takes a Category (e.g. returned by Get_Category).
96   --  The first takes a UTF_32 code. The form taking the UTF_32 code is
97   --  typically more efficient than calling Get_Category, but if several
98   --  different tests are to be performed on the same code, it is more
99   --  efficient to use Get_Category to get the category, then test the
100   --  resulting category.
101
102   function Is_UTF_32_Letter (U : UTF_32)   return Boolean;
103   function Is_UTF_32_Letter (C : Category) return Boolean;
104   pragma Inline (Is_UTF_32_Letter);
105   --  Returns true iff U is a letter that can be used to start an identifier,
106   --  or if C is one of the corresponding categories, which are the following:
107   --    Letter, Uppercase (Lu)
108   --    Letter, Lowercase (Ll)
109   --    Letter, Titlecase (Lt)
110   --    Letter, Modifier  (Lm)
111   --    Letter, Other     (Lo)
112   --    Number, Letter    (Nl)
113
114   function Is_UTF_32_Digit (U : UTF_32)   return Boolean;
115   function Is_UTF_32_Digit (C : Category) return Boolean;
116   pragma Inline (Is_UTF_32_Digit);
117   --  Returns true iff U is a digit that can be used to extend an identifier,
118   --  or if C is one of the corresponding categories, which are the following:
119   --    Number, Decimal_Digit (Nd)
120
121   function Is_UTF_32_Line_Terminator (U : UTF_32) return Boolean;
122   pragma Inline (Is_UTF_32_Line_Terminator);
123   --  Returns true iff U is an allowed line terminator for source programs,
124   --  if U is in the category Zp (Separator, Paragraph), or Zl (Separator,
125   --  Line), or if U is a conventional line terminator (CR, LF, VT, FF).
126   --  There is no category version for this function, since the set of
127   --  characters does not correspond to a set of Unicode categories.
128
129   function Is_UTF_32_Mark (U : UTF_32)   return Boolean;
130   function Is_UTF_32_Mark (C : Category) return Boolean;
131   pragma Inline (Is_UTF_32_Mark);
132   --  Returns true iff U is a mark character which can be used to extend an
133   --  identifier, or if C is one of the corresponding categories, which are
134   --  the following:
135   --    Mark, Non-Spacing (Mn)
136   --    Mark, Spacing Combining (Mc)
137
138   function Is_UTF_32_Other (U : UTF_32)   return Boolean;
139   function Is_UTF_32_Other (C : Category) return Boolean;
140   pragma Inline (Is_UTF_32_Other);
141   --  Returns true iff U is an other format character, which means that it
142   --  can be used to extend an identifier, but is ignored for the purposes of
143   --  matching of identifiers, or if C is one of the corresponding categories,
144   --  which are the following:
145   --    Other, Format (Cf)
146
147   function Is_UTF_32_Punctuation (U : UTF_32)   return Boolean;
148   function Is_UTF_32_Punctuation (C : Category) return Boolean;
149   pragma Inline (Is_UTF_32_Punctuation);
150   --  Returns true iff U is a punctuation character that can be used to
151   --  separate pieces of an identifier, or if C is one of the corresponding
152   --  categories, which are the following:
153   --    Punctuation, Connector (Pc)
154
155   function Is_UTF_32_Space (U : UTF_32)   return Boolean;
156   function Is_UTF_32_Space (C : Category) return Boolean;
157   pragma Inline (Is_UTF_32_Space);
158   --  Returns true iff U is considered a space to be ignored, or if C is one
159   --  of the corresponding categories, which are the following:
160   --    Separator, Space (Zs)
161
162   function Is_UTF_32_Non_Graphic (U : UTF_32)   return Boolean;
163   function Is_UTF_32_Non_Graphic (C : Category) return Boolean;
164   pragma Inline (Is_UTF_32_Non_Graphic);
165   --  Returns true iff U is considered to be a non-graphic character, or if C
166   --  is one of the corresponding categories, which are the following:
167   --    Other, Control (Cc)
168   --    Other, Private Use (Co)
169   --    Other, Surrogate (Cs)
170   --    Separator, Line (Zl)
171   --    Separator, Paragraph (Zp)
172   --    FFFE or FFFF positions in any plane (Fe)
173   --
174   --  Note that the Ada category format effector is subsumed by the above
175   --  list of Unicode categories.
176   --
177   --  Note that Other, Unassigned (Cn) is quite deliberately not included
178   --  in the list of categories above. This means that should any of these
179   --  code positions be defined in future with graphic characters they will
180   --  be allowed without a need to change implementations or the standard.
181   --
182   --  Note that Other, Format (Cf) is also quite deliberately not included
183   --  in the list of categories above. This means that these characters can
184   --  be included in character and string literals.
185
186   --  The following function is used to fold to upper case, as required by
187   --  the Ada 2005 standard rules for identifier case folding. Two
188   --  identifiers are equivalent if they are identical after folding all
189   --  letters to upper case using this routine. A corresponding routine to
190   --  fold to lower case is also provided.
191
192   function UTF_32_To_Lower_Case (U : UTF_32) return UTF_32;
193   pragma Inline (UTF_32_To_Lower_Case);
194   --  If U represents an upper case letter, returns the corresponding lower
195   --  case letter, otherwise U is returned unchanged. The folding rule is
196   --  simply that if the code corresponds to a 10646 entry whose name contains
197   --  the string CAPITAL LETTER, and there is a corresponding entry whose name
198   --  is the same but with CAPITAL LETTER replaced by SMALL LETTER, then the
199   --  code is folded to this SMALL LETTER code. Otherwise the input code is
200   --  returned unchanged.
201
202   function UTF_32_To_Upper_Case (U : UTF_32) return UTF_32;
203   pragma Inline (UTF_32_To_Upper_Case);
204   --  If U represents a lower case letter, returns the corresponding lower
205   --  case letter, otherwise U is returned unchanged. The folding rule is
206   --  simply that if the code corresponds to a 10646 entry whose name contains
207   --  the string SMALL LETTER, and there is a corresponding entry whose name
208   --  is the same but with SMALL LETTER replaced by CAPITAL LETTER, then the
209   --  code is folded to this CAPITAL LETTER code. Otherwise the input code is
210   --  returned unchanged.
211
212end System.UTF_32;
213