1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              S T R I N G T                               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2020, 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.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
19-- http://www.gnu.org/licenses for a complete copy of the license.          --
20--                                                                          --
21-- GNAT was originally developed  by the GNAT team at  New York University. --
22-- Extensive contributions were provided by Ada Core Technologies Inc.      --
23--                                                                          --
24------------------------------------------------------------------------------
25
26with Namet;  use Namet;
27with System;
28with Types;  use Types;
29
30package Stringt is
31   pragma Elaborate_Body;
32   --  This is to make sure Null_String_Id is properly initialized
33
34--  This package contains routines for handling the strings table which is
35--  used to store string constants encountered in the source, and also those
36--  additional string constants generated by compile time concatenation and
37--  other similar processing.
38
39--  WARNING: There is a C version of this package. Any changes to this
40--  source file must be properly reflected in the C header file stringt.h
41
42--  A string constant in this table consists of a series of Char_Code values,
43--  so that 16-bit character codes can be properly handled if this feature
44--  is implemented in the scanner.
45
46--  There is no guarantee that hashing is used in the implementation, although
47--  it may be. This means that the caller cannot count on having the same Id
48--  value for two identical strings stored separately and also cannot count on
49--  the two such Id values being different.
50
51   Null_String_Id : String_Id;
52   --  Gets set to a null string with length zero
53
54   --------------------------------------
55   -- String Table Access Subprograms --
56   --------------------------------------
57
58   procedure Initialize;
59   --  Initializes the strings table for a new compilation.
60
61   procedure Lock;
62   --  Lock internal tables before calling back end
63
64   procedure Unlock;
65   --  Unlock internal tables, in case back end needs to modify them
66
67   procedure Mark;
68   --  Take a snapshot of the internal tables. Used in conjunction with Release
69   --  when computing temporary string values that need not be preserved.
70
71   procedure Release;
72   --  Restore the internal tables to the situation when Mark was last called.
73   --  If Release is called with no prior call to Mark, the entire string table
74   --  is cleared to its initial (empty) setting.
75
76   procedure Start_String;
77   --  Sets up for storing a new string in the table. To store a string, a
78   --  call is first made to Start_String, then successive calls are
79   --  made to Store_String_Character to store the characters of the string.
80   --  Finally, a call to End_String terminates the entry and returns it Id.
81
82   procedure Start_String (S : String_Id);
83   --  Like Start_String with no parameter, except that the contents of the
84   --  new string is initialized to be a copy of the given string. A test is
85   --  made to see if S is the last created string, and if so it is shared,
86   --  rather than copied, this can be particularly helpful for the case of
87   --  a continued concatenation of string constants.
88
89   procedure Store_String_Char (C : Char_Code);
90   procedure Store_String_Char (C : Character);
91   --  Store next character of string, see description above for Start_String
92
93   procedure Store_String_Chars (S : String);
94   procedure Store_String_Chars (S : String_Id);
95   --  Store character codes of given string in sequence
96
97   procedure Store_String_Int (N : Int);
98   --  Stored decimal representation of integer with possible leading minus
99
100   procedure Unstore_String_Char;
101   --  Undoes effect of previous Store_String_Char call, used in some error
102   --  situations of unterminated string constants.
103
104   function End_String return String_Id;
105   --  Terminates current string and returns its Id
106
107   function String_Length (Id : String_Id) return Nat;
108   --  Returns length of previously stored string
109
110   function Get_String_Char (Id : String_Id; Index : Int) return Char_Code;
111   pragma Inline (Get_String_Char);
112   --  Obtains the specified character from a stored string. The lower bound
113   --  of stored strings is always 1, so the range is 1 .. String_Length (Id).
114
115   function String_Equal (L, R : String_Id) return Boolean;
116   --  Determines if two string literals represent the same string
117
118   function String_To_Name (S : String_Id) return Name_Id;
119   --  Convert String_Id to Name_Id
120
121   procedure Append (Buf : in out Bounded_String; S : String_Id);
122   --  Append characters of given string to Buf. Error if any characters are
123   --  out of Character range. Does not attempt to do any encoding of
124   --  characters.
125
126   function To_String (S : String_Id) return String;
127   --  Return S as a String
128
129   procedure String_To_Name_Buffer (S : String_Id);
130   --  Place characters of given string in Name_Buffer, setting Name_Len.
131   --  Error if any characters are out of Character range. Does not attempt
132   --  to do any encoding of any characters.
133
134   function String_Chars_Address return System.Address;
135   --  Return address of String_Chars table (used by Back_End call to Gigi)
136
137   function String_From_Name_Buffer
138     (Buf : Bounded_String := Global_Name_Buffer) return String_Id;
139   --  Given a name stored in Buf, returns a string of the corresponding value.
140
141   function Strings_Address return System.Address;
142   --  Return address of Strings table (used by Back_End call to Gigi)
143
144   procedure Write_Char_Code (Code : Char_Code);
145   --  Procedure to write a character code value, used for debugging purposes
146   --  for writing character codes. If the character code is in the range
147   --  16#20# .. 16#7E#, then the single graphic character corresponding to
148   --  the code is output. For any other codes in the range 16#00# .. 16#FF#,
149   --  the code is output as ["hh"] where hh is the two digit hex value for
150   --  the code. Codes greater than 16#FF# are output as ["hhhh"] where hhhh
151   --  is the four digit hex representation of the code value (high order
152   --  byte first). Hex letters are always in lower case.
153
154   procedure Write_String_Table_Entry (Id : String_Id);
155   --  Writes a string value with enclosing quotes to the current file using
156   --  routines in package Output. Does not write an end of line character.
157   --  This procedure is used for debug output purposes, and also for output
158   --  of strings specified by pragma Linker Option to the ali file. 7-bit
159   --  ASCII graphics (except for double quote) are output literally.
160   --  The double quote appears as two successive double quotes.
161   --  All other codes, are output as described for Write_Char_Code. For
162   --  example, the string created by folding "A" & ASCII.HT & "Hello" will
163   --  print as "A["09"]Hello". A No_String value prints simply as "no string"
164   --  without surrounding quote marks.
165
166private
167   pragma Inline (End_String);
168   pragma Inline (String_Length);
169
170end Stringt;
171