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------------------------------------------------------------------------------
--                                                                          --
--                          GNAT SYSTEM UTILITIES                           --
--                                                                          --
--                              X O S C O N S                               --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 2008-2009, 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.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license.          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------
 
--  This program generates the spec of System.OS_Constants (s-oscons.ads)
 
--  It works in conjunction with a C template file which must be pre-processed
--  and compiled using the cross compiler. Two input files are used:
--    - the preprocessed C file: s-oscons-tmplt.i
--    - the generated assembly file: s-oscons-tmplt.s
 
--  The contents of s-oscons.ads is written on standard output
 
with Ada.Characters.Handling; use Ada.Characters.Handling;
with Ada.Exceptions;          use Ada.Exceptions;
with Ada.Strings.Fixed;       use Ada.Strings.Fixed;
with Ada.Text_IO;             use Ada.Text_IO;
with Ada.Streams.Stream_IO;   use Ada.Streams.Stream_IO;
 
pragma Warnings (Off);
--  System.Unsigned_Types is an internal GNAT unit
with System.Unsigned_Types;   use System.Unsigned_Types;
pragma Warnings (On);
 
with GNAT.Table;
 
with XUtil;                   use XUtil;
 
procedure XOSCons is
 
   use ASCII;
   use Ada.Strings;
 
   Unit_Name : constant String := "s-oscons";
   Tmpl_Name : constant String := Unit_Name & "-tmplt";
 
   -------------------------------------------------
   -- Information retrieved from assembly listing --
   -------------------------------------------------
 
   type String_Access is access all String;
   --  Note: we can't use GNAT.Strings for this definition, since that unit
   --  is not available in older base compilers.
 
   --  We need to deal with integer values that can be signed or unsigned, so
   --  we need to accommodate the maximum range of both cases.
 
   type Int_Value_Type is record
      Positive  : Boolean;
      Abs_Value : Long_Unsigned := 0;
   end record;
 
   type Asm_Info_Kind is
     (CND,     --  Named number (decimal)
      CNS,     --  Named number (freeform text)
      C,       --  Constant object
      TXT);    --  Literal text
   --  Recognized markers found in assembly file. These markers are produced by
   --  the same-named macros from the C template.
 
   subtype Named_Number is Asm_Info_Kind range CND .. CNS;
 
   type Asm_Info (Kind : Asm_Info_Kind := TXT) is record
      Line_Number   : Integer;
      --  Line number in C source file
 
      Constant_Name : String_Access;
      --  Name of constant to be defined
 
      Constant_Type : String_Access;
      --  Type of constant (case of Kind = C)
 
      Value_Len     : Natural := 0;
      --  Length of text representation of constant's value
 
      Text_Value    : String_Access;
      --  Value for CNS / C constant
 
      Int_Value     : Int_Value_Type;
      --  Value for CND constant
 
      Comment       : String_Access;
      --  Additional descriptive comment for constant, or free-form text (TXT)
   end record;
 
   package Asm_Infos is new GNAT.Table
     (Table_Component_Type => Asm_Info,
      Table_Index_Type     => Integer,
      Table_Low_Bound      => 1,
      Table_Initial        => 100,
      Table_Increment      => 10);
 
   Max_Constant_Name_Len  : Natural := 0;
   Max_Constant_Value_Len : Natural := 0;
   Max_Constant_Type_Len  : Natural := 0;
   --  Lengths of longest name and longest value
 
   type Language is (Lang_Ada, Lang_C);
 
   procedure Output_Info
     (Lang       : Language;
      OFile      : Sfile;
      Info_Index : Integer);
   --  Output information from the indicated asm info line
 
   procedure Parse_Asm_Line (Line : String);
   --  Parse one information line from the assembly source
 
   function Contains_Template_Name (S : String) return Boolean;
   --  True if S contains Tmpl_Name, possibly with different casing
 
   function Spaces (Count : Integer) return String;
   --  If Count is positive, return a string of Count spaces, else return an
   --  empty string.
 
   ----------------------------
   -- Contains_Template_Name --
   ----------------------------
 
   function Contains_Template_Name (S : String) return Boolean is
   begin
      if Index (Source => To_Lower (S), Pattern => Tmpl_Name) > 0 then
         return True;
      else
         return False;
      end if;
   end Contains_Template_Name;
 
   -----------------
   -- Output_Info --
   -----------------
 
   procedure Output_Info
     (Lang       : Language;
      OFile      : Sfile;
      Info_Index : Integer)
   is
      Info : Asm_Info renames Asm_Infos.Table (Info_Index);
 
      procedure Put (S : String);
      --  Write S to OFile
 
      ---------
      -- Put --
      ---------
 
      procedure Put (S : String) is
      begin
         Put (OFile, S);
      end Put;
 
   begin
      if Info.Kind /= TXT then
         --  TXT case is handled by the common code below
 
         case Lang is
            when Lang_Ada =>
               Put ("   " & Info.Constant_Name.all);
               Put (Spaces (Max_Constant_Name_Len
                              - Info.Constant_Name'Length));
 
               if Info.Kind in Named_Number then
                  Put (" : constant := ");
               else
                  Put (" : constant " & Info.Constant_Type.all);
                  Put (Spaces (Max_Constant_Type_Len
                                 - Info.Constant_Type'Length));
                  Put (" := ");
               end if;
 
            when Lang_C =>
               Put ("#define " & Info.Constant_Name.all & " ");
               Put (Spaces (Max_Constant_Name_Len
                              - Info.Constant_Name'Length));
         end case;
 
         if Info.Kind = CND then
            if not Info.Int_Value.Positive then
               Put ("-");
            end if;
            Put (Trim (Info.Int_Value.Abs_Value'Img, Side => Left));
         else
            declare
               Is_String : constant Boolean :=
                             Info.Kind = C
                               and then Info.Constant_Type.all = "String";
            begin
               if Is_String then
                  Put ("""");
               end if;
               Put (Info.Text_Value.all);
               if Is_String then
                  Put ("""");
               end if;
            end;
         end if;
 
         if Lang = Lang_Ada then
            Put (";");
 
            if Info.Comment'Length > 0 then
               Put (Spaces (Max_Constant_Value_Len - Info.Value_Len));
               Put (" --  ");
            end if;
         end if;
      end if;
 
      if Lang = Lang_Ada then
         Put (Info.Comment.all);
      end if;
 
      New_Line (OFile);
   end Output_Info;
 
   --------------------
   -- Parse_Asm_Line --
   --------------------
 
   procedure Parse_Asm_Line (Line : String) is
      Index1, Index2 : Integer := Line'First;
 
      function Field_Alloc return String_Access;
      --  Allocate and return a copy of Line (Index1 .. Index2 - 1)
 
      procedure Find_Colon (Index : in out Integer);
      --  Increment Index until the next colon in Line
 
      function Parse_Int (S : String) return Int_Value_Type;
      --  Parse a decimal number, preceded by an optional '$' or '#' character,
      --  and return its value.
 
      -----------------
      -- Field_Alloc --
      -----------------
 
      function Field_Alloc return String_Access is
      begin
         return new String'(Line (Index1 .. Index2 - 1));
      end Field_Alloc;
 
      ----------------
      -- Find_Colon --
      ----------------
 
      procedure Find_Colon (Index : in out Integer) is
      begin
         loop
            Index := Index + 1;
            exit when Index > Line'Last or else Line (Index) = ':';
         end loop;
      end Find_Colon;
 
      ---------------
      -- Parse_Int --
      ---------------
 
      function Parse_Int (S : String) return Int_Value_Type is
         First    : Integer := S'First;
         Positive : Boolean;
      begin
         --  On some platforms, immediate integer values are prefixed with
         --  a $ or # character in assembly output.
 
         if S (First) = '$' or else S (First) = '#' then
            First := First + 1;
         end if;
 
         if S (First) = '-' then
            Positive := False;
            First    := First + 1;
         else
            Positive := True;
         end if;
 
         return (Positive  => Positive,
                 Abs_Value => Long_Unsigned'Value (S (First .. S'Last)));
 
      exception
         when E : others =>
            Put_Line (Standard_Error, "can't parse decimal value: " & S);
            raise;
      end Parse_Int;
 
   --  Start of processing for Parse_Asm_Line
 
   begin
      Find_Colon (Index2);
 
      declare
         Info : Asm_Info (Kind => Asm_Info_Kind'Value
                                    (Line (Line'First .. Index2 - 1)));
      begin
         Index1 := Index2 + 1;
         Find_Colon (Index2);
 
         Info.Line_Number :=
           Integer (Parse_Int (Line (Index1 .. Index2 - 1)).Abs_Value);
 
         case Info.Kind is
            when CND | CNS | C =>
               Index1 := Index2 + 1;
               Find_Colon (Index2);
 
               Info.Constant_Name := Field_Alloc;
               if Info.Constant_Name'Length > Max_Constant_Name_Len then
                  Max_Constant_Name_Len := Info.Constant_Name'Length;
               end if;
 
               Index1 := Index2 + 1;
               Find_Colon (Index2);
 
               if Info.Kind = C then
                  Info.Constant_Type := Field_Alloc;
                  if Info.Constant_Type'Length > Max_Constant_Type_Len then
                     Max_Constant_Type_Len := Info.Constant_Type'Length;
                  end if;
 
                  Index1 := Index2 + 1;
                  Find_Colon (Index2);
               end if;
 
               if Info.Kind = CND then
                  Info.Int_Value := Parse_Int (Line (Index1 .. Index2 - 1));
                  Info.Value_Len := Index2 - Index1 - 1;
 
               else
                  Info.Text_Value := Field_Alloc;
                  Info.Value_Len  := Info.Text_Value'Length;
               end if;
 
            when others =>
               null;
         end case;
 
         Index1 := Index2 + 1;
         Index2 := Line'Last + 1;
         Info.Comment := Field_Alloc;
 
         if Info.Kind = TXT then
            Info.Text_Value := Info.Comment;
 
         --  Update Max_Constant_Value_Len, but only if this constant has a
         --  comment (else the value is allowed to be longer).
 
         elsif Info.Comment'Length > 0 then
            if Info.Value_Len > Max_Constant_Value_Len then
               Max_Constant_Value_Len := Info.Value_Len;
            end if;
         end if;
 
         Asm_Infos.Append (Info);
      end;
   exception
      when E : others =>
         Put_Line (Standard_Error,
           "can't parse " & Line);
         Put_Line (Standard_Error,
           "exception raised: " & Exception_Information (E));
   end Parse_Asm_Line;
 
   ------------
   -- Spaces --
   ------------
 
   function Spaces (Count : Integer) return String is
   begin
      if Count <= 0 then
         return "";
      else
         return (1 .. Count => ' ');
      end if;
   end Spaces;
 
   --  Local declarations
 
   --  Input files
 
   Tmpl_File_Name : constant String := Tmpl_Name & ".i";
   Asm_File_Name  : constant String := Tmpl_Name & ".s";
 
   --  Output files
 
   Ada_File_Name  : constant String := Unit_Name & ".ads";
   C_File_Name    : constant String := Unit_Name & ".h";
 
   Asm_File  : Ada.Text_IO.File_Type;
   Tmpl_File : Ada.Text_IO.File_Type;
   Ada_OFile : Sfile;
   C_OFile   : Sfile;
 
   Line : String (1 .. 256);
   Last : Integer;
   --  Line being processed
 
   Current_Line : Integer;
   Current_Info : Integer;
   In_Comment   : Boolean;
   In_Template  : Boolean;
 
--  Start of processing for XOSCons
 
begin
   --  Load values from assembly file
 
   Open (Asm_File, In_File, Asm_File_Name);
 
   while not End_Of_File (Asm_File) loop
      Get_Line (Asm_File, Line, Last);
      if Last > 2 and then Line (1 .. 2) = "->" then
         Parse_Asm_Line (Line (3 .. Last));
      end if;
   end loop;
 
   Close (Asm_File);
 
   --  Load C template and output definitions
 
   Open   (Tmpl_File, In_File,  Tmpl_File_Name);
   Create (Ada_OFile, Out_File, Ada_File_Name);
   Create (C_OFile,   Out_File, C_File_Name);
 
   Current_Line := 0;
   Current_Info := Asm_Infos.First;
   In_Comment   := False;
 
   while not End_Of_File (Tmpl_File) loop
      <<Get_One_Line>>
      Get_Line (Tmpl_File, Line, Last);
 
      if Last >= 2 and then Line (1 .. 2) = "# " then
         declare
            Index : Integer := 3;
         begin
            while Index <= Last and then Line (Index) in '0' .. '9' loop
               Index := Index + 1;
            end loop;
 
            if Contains_Template_Name (Line (Index + 1 .. Last)) then
               Current_Line := Integer'Value (Line (3 .. Index - 1));
               In_Template  := True;
               goto Get_One_Line;
            else
               In_Template := False;
            end if;
         end;
 
      elsif In_Template then
         if In_Comment then
            if Line (1 .. Last) = "*/" then
               Put_Line (C_OFile, Line (1 .. Last));
               In_Comment := False;
            else
               Put_Line (Ada_OFile, Line (1 .. Last));
               Put_Line (C_OFile, Line (1 .. Last));
            end if;
 
         elsif Line (1 .. Last) = "/*" then
            Put_Line (C_OFile, Line (1 .. Last));
            In_Comment := True;
 
         elsif Asm_Infos.Table (Current_Info).Line_Number = Current_Line then
            Output_Info (Lang_Ada, Ada_OFile, Current_Info);
            Output_Info (Lang_C,   C_OFile,   Current_Info);
            Current_Info := Current_Info + 1;
         end if;
 
         Current_Line := Current_Line + 1;
      end if;
   end loop;
 
   Close (Tmpl_File);
 
end XOSCons;