gnoga_2.1.2_5f127c56/deps/zanyblue/src/text/zanyblue-text-format_parser.adb

--  -*- coding: utf-8 -*-
--
--  ZanyBlue, an Ada library and framework for finite element analysis.
--
--  Copyright (c) 2012, 2016, Michael Rohan <mrohan@zanyblue.com>
--  All rights reserved.
--
--  Redistribution and use in source and binary forms, with or without
--  modification, are permitted provided that the following conditions
--  are met:
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--    * Redistributions of source code must retain the above copyright
--      notice, this list of conditions and the following disclaimer.
--
--    * Redistributions in binary form must reproduce the above copyright
--      notice, this list of conditions and the following disclaimer in the
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--      be used to endorse or promote products derived from this software
--      without specific prior written permission.
--
--  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
--  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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--  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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--  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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--  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
--  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
--

--
--  Implementation of the format parsing function.
--

with Ada.Exceptions;
with Ada.Strings.Wide_Wide_Maps;
with UXStrings.Conversions;

package body ZanyBlue.Text.Format_Parser is

   use Ada.Exceptions;
   use Ada.Strings.Wide_Wide_Maps;

   Zero_Offset : constant := Unicode_Character'Pos ('0');
   Align_Set   : constant Wide_Wide_Character_Set := To_Set ("><=^");
   Sign_Set    : constant Wide_Wide_Character_Set := To_Set ("+- ");
   Type_Set    : constant Wide_Wide_Character_Set := To_Set ("bcdeEfFgGnoxX%");
   Number_Set  : constant Wide_Wide_Character_Set := To_Set ("0123456789");

   Current_Maximum_Field_Width : Positive := 100;

   function Make_Filler
     (Fill   : Unicode_Character;
      Length : Natural)
      return String;
   --  Construct a string of the given length composed of the given character.

   function In_Set
     (Format   : String;
      Position : Positive;
      Set      : Wide_Wide_Character_Set)
      return Boolean;
   --  Check if the Format character at the given position is with in
   --  the given set.  The Position might be beyond the end of the string
   --  in which case False is returned.

   procedure Parse_Base
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type);
   --  Parse the optional numeric base specifier, the '#' character.

   procedure Parse_Data_Type
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type);
   --  Parse the optional data type specifier, one of 'b', 'c', 'd', ...

   procedure Parse_Fill_Align
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type);
   --  Parse the optional alignment character ('<', '>', ...) and optional
   --  fill character.

   procedure Parse_Sign
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type);
   --  Parse the optional sign specifier, '+', '-', ' '

   procedure Parse_Zero_Fill
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type);
   --  Parse the optional numeric "fill with zero" character '0'

   procedure Parse_Width
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type);
   --  Parse the optional field width value (number).

   procedure Parse_Precision
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type);
   --  Parse the optional precision value (number).

   procedure Parse_Number
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Natural);
   --  General numeric parsing routine.

   -----------
   -- Align --
   -----------

   function Align
     (Value     : String;
      Fill      : Unicode_Character;
      Width     : Natural;
      Alignment : Align_Type;
      Prefix    : String := "")
      return String
   is

      Extra : constant Integer := Width - (Prefix.Length + Value.Length);

   begin
      if Extra <= 0 then
         --  No padding needed, just return the value
         return Prefix & Value;
      end if;
      case Alignment is
         when None | Left =>
            return Prefix & Value & Make_Filler (Fill, Extra);
         when Right =>
            return Make_Filler (Fill, Extra) & Prefix & Value;
         when Numeric =>
            return Prefix & Make_Filler (Fill, Extra) & Value;
         when Center =>
            return
              Make_Filler (Fill, Extra / 2 + Extra rem 2) & Prefix & Value &
              Make_Filler (Fill, Extra / 2);
      end case;
   end Align;

   ------------
   -- In_Set --
   ------------

   function In_Set
     (Format   : String;
      Position : Positive;
      Set      : Wide_Wide_Character_Set)
      return Boolean
   is
   begin
      return Position <= Format.Last and then Is_In (Format (Position), Set);
   end In_Set;

   -----------------
   -- Make_Filler --
   -----------------

   function Make_Filler
     (Fill   : Unicode_Character;
      Length : Natural)
      return String
   is
      Result : constant String := Length * Fill;
   begin
      return Result;
   end Make_Filler;

   -------------------------
   -- Maximum_Field_Width --
   -------------------------

   function Maximum_Field_Width return Positive is
   begin
      return Current_Maximum_Field_Width;
   end Maximum_Field_Width;

   -------------------------
   -- Maximum_Field_Width --
   -------------------------

   procedure Maximum_Field_Width (Value : Positive) is
   begin
      Current_Maximum_Field_Width := Value;
   end Maximum_Field_Width;

   -----------
   -- Parse --
   -----------

   function Parse
     (Format : String;
      Locale : Locale_Type)
      return Format_Type
   is
      pragma Unreferenced (Locale);
      Result   : Format_Type;
      Position : Positive := Format.First;
   begin
      Parse_Fill_Align (Format, Position, Result);
      Parse_Sign (Format, Position, Result);
      Parse_Base (Format, Position, Result);
      Parse_Zero_Fill (Format, Position, Result);
      Parse_Width (Format, Position, Result);
      Parse_Precision (Format, Position, Result);
      Parse_Data_Type (Format, Position, Result);
      if Position <= Format.Last then
         Raise_Exception
           (Invalid_Format'Identity,
            Message =>
              To_Latin_1
                (Format.Slice (Position, Format.Last), Substitute => '?'));
      end if;
      if Result.Width > Current_Maximum_Field_Width then
         Raise_Exception
           (Field_Too_Wide_Error'Identity,
            Message => Natural'Image (Result.Width));
      end if;
      return Result;
   end Parse;

   ----------------
   -- Parse_Base --
   ----------------

   procedure Parse_Base
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type)
   is
   begin
      if Position <= Format.Last and then Format (Position) = '#' then
         Result.Include_Base := True;
         Position            := Position + 1;
      end if;
   end Parse_Base;

   ---------------------
   -- Parse_Data_Type --
   ---------------------

   procedure Parse_Data_Type
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type)
   is
   begin
      if In_Set (Format, Position, Type_Set) then
         case Format (Position) is
            when 'b' =>
               Result.Data := 'b';
            when 'c' =>
               Result.Data := 'c';
            when 'd' =>
               Result.Data := 'd';
            when 'e' =>
               Result.Data := 'e';
            when 'E' =>
               Result.Data := 'E';
            when 'f' =>
               Result.Data := 'f';
            when 'F' =>
               Result.Data := 'F';
            when 'g' =>
               Result.Data := 'g';
            when 'G' =>
               Result.Data := 'G';
            when 'n' =>
               Result.Data := 'n';
            when 'o' =>
               Result.Data := 'o';
            when 'x' =>
               Result.Data := 'x';
            when 'X' =>
               Result.Data := 'X';
            when '%' =>
               Result.Data := '%';
            when others =>
               raise Internal_Error;
         end case;
         Position := Position + 1;
      end if;
   end Parse_Data_Type;

   ----------------------
   -- Parse_Fill_Align --
   ----------------------

   procedure Parse_Fill_Align
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type)
   is
      Have_Align_Character : Boolean := False;
      Align_Character      : Unicode_Character;
   begin
      if In_Set (Format, Position + 1, Align_Set) then
         Result.Fill          := Format (Position);
         Result.Fill_Defined  := True;
         Align_Character      := Format (Position + 1);
         Have_Align_Character := True;
         Position             := Position + 2;
      elsif In_Set (Format, Position, Align_Set) then
         Align_Character      := Format (Position);
         Have_Align_Character := True;
         Position             := Position + 1;
      end if;
      if Have_Align_Character then
         case Align_Character is
            when '<' =>
               Result.Align := Left;
            when '>' =>
               Result.Align := Right;
            when '=' =>
               Result.Align := Numeric;
            when '^' =>
               Result.Align := Center;
            when others =>
               raise Internal_Error;
         end case;
      end if;
   end Parse_Fill_Align;

   ------------------
   -- Parse_Number --
   ------------------

   procedure Parse_Number
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Natural)
   is
      Digit : Natural;
   begin
      while In_Set (Format, Position, Number_Set) loop
         Digit    := Unicode_Character'Pos (Format (Position)) - Zero_Offset;
         Result   := 10 * Result + Digit;
         Position := Position + 1;
      end loop;
   end Parse_Number;

   ---------------------
   -- Parse_Precision --
   ---------------------

   procedure Parse_Precision
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type)
   is
   begin
      Result.Precision_Defined :=
        Position <= Format.Last and then Format (Position) = '.';
      if Result.Precision_Defined then
         Position := Position + 1;
         Parse_Number (Format, Position, Result.Precision);
      end if;
   end Parse_Precision;

   ----------------
   -- Parse_Sign --
   ----------------

   procedure Parse_Sign
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type)
   is
   begin
      if In_Set (Format, Position, Sign_Set) then
         case Format (Position) is
            when '+' =>
               Result.Sign := Plus;
            when '-' =>
               Result.Sign := Minus;
            when ' ' =>
               Result.Sign := Space;
            when others =>
               raise Internal_Error;
         end case;
         Position := Position + 1;
      end if;
   end Parse_Sign;

   -----------------
   -- Parse_Width --
   -----------------

   procedure Parse_Width
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type)
   is
   begin
      Parse_Number (Format, Position, Result.Width);
   end Parse_Width;

   ---------------------
   -- Parse_Zero_Fill --
   ---------------------

   procedure Parse_Zero_Fill
     (Format   :        String;
      Position : in out Positive;
      Result   : in out Format_Type)
   is
   begin
      if Position <= Format.Last and then Format (Position) = '0' then
         --  Don't set Fill to '0' here as the default is to use the locale
         --  '0' character.  If the user also specified a fill character
         --  then that will be used instead.
         Result.Align := Numeric;
         Position     := Position + 1;
      end if;
   end Parse_Zero_Fill;

   ---------------
   -- To_String --
   ---------------

   function To_String
     (Format : Format_Type)
      return String
   is
      function Image is new UXStrings.Conversions.Scalar_Image (Align_Type);
      function Image is new UXStrings.Conversions.Scalar_Image (Sign_Type);
      function Image is new UXStrings.Conversions.Scalar_Image (Boolean);
      function Image is new UXStrings.Conversions.Scalar_Image (Natural);
      function Image is new UXStrings.Conversions.Scalar_Image (Data_Type);
   begin
      return
        "['" & Format.Fill & "', " & Image (Format.Align) & ", " &
        Image (Format.Sign) & ", " & Image (Format.Include_Base) & ", " &
        Image (Format.Width) & ", " & Image (Format.Precision_Defined) & ", " &
        Image (Format.Precision) & ", " & Image (Format.Data) & "]";
   end To_String;

end ZanyBlue.Text.Format_Parser;