--  GHDL Run Time (GRT) - 'value subprograms.
--  Copyright (C) 2002 - 2016 Tristan Gingold
--
--  This program is free software: you can redistribute it and/or modify
--  it under the terms of the GNU General Public License as published by
--  the Free Software Foundation, either version 2 of the License, or
--  (at your option) any later version.
--
--  This program is distributed in the hope that it will be useful,
--  but WITHOUT 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
--  along with this program.  If not, see <gnu.org/licenses>.
--
--  As a special exception, if other files instantiate generics from this
--  unit, or you link this unit with other files to produce an executable,
--  this unit does not by itself cause the resulting executable to be
--  covered by the GNU General Public License. This exception does not
--  however invalidate any other reasons why the executable file might be
--  covered by the GNU Public License.
with Grt.Errors; use Grt.Errors;
with Grt.Rtis_Utils;
with Grt.Strings; use Grt.Strings;
with Grt.To_Strings; use Grt.To_Strings;

package body Grt.Values is
   procedure Remove_Whitespaces (S     : Std_String_Basep;
                                 Len   : in out Ghdl_Index_Type;
                                 Pos   : in out Ghdl_Index_Type) is
   begin
      Grt.To_Strings.Remove_Whitespaces (S, Len, Pos);
      if Pos = Len then
         Error_E ("'value: empty string");
      end if;
   end Remove_Whitespaces;

   --  Return TRUE iff user string S (POS .. LEN - 1) is equal to REF.
   --  Comparaison is case insensitive, but REF must be lowercase (REF is
   --  supposed to come from an RTI).
   function String_Match (S : Std_String_Basep;
                          Pos : Ghdl_Index_Type;
                          Len : Ghdl_Index_Type;
                          Ref : Ghdl_C_String) return Boolean
   is
      Is_Char : constant Boolean := S (Pos) = ''';
      P : Ghdl_Index_Type;
      C_Ref, C_S : Character;
   begin
      P := 0;
      loop
         C_Ref := Ref (Natural (P + 1));
         if Pos + P = Len then
            --  End of string.
            return C_Ref = ASCII.NUL;
         end if;
         C_S := S (Pos + P);
         if not Is_Char then
            C_S := To_Lower (C_S);
         end if;
         if C_S /= C_Ref or else C_Ref = ASCII.NUL then
            return False;
         end if;
         P := P + 1;
      end loop;
   end String_Match;

   --  Return the value of STR for enumerated type RTI.
   function Value_Enum
     (S : Std_String_Basep; Len : Ghdl_Index_Type; Rti : Ghdl_Rti_Access)
      return Ghdl_Index_Type
   is
      Enum_Rti : constant Ghdl_Rtin_Type_Enum_Acc :=
        To_Ghdl_Rtin_Type_Enum_Acc (Rti);
      Pos : Ghdl_Index_Type;
      L : Ghdl_Index_Type;
   begin
      Pos := 0;
      L := Len;
      Remove_Whitespaces (S, L, Pos);

      for I in 0 .. Enum_Rti.Nbr - 1 loop
         if String_Match (S, Pos, L, Enum_Rti.Names (I)) then
            return I;
         end if;
      end loop;
      Error_S ("'value: '");
      Diag_C_Std (S (Pos .. L - 1));
      Diag_C ("' not in enumeration '");
      Diag_C (Enum_Rti.Name);
      Error_E ("'");
   end Value_Enum;

   function Ghdl_Value_Enum (Str : Std_String_Ptr; Rti : Ghdl_Rti_Access)
      return Ghdl_Index_Type is
   begin
      return Value_Enum (Str.Base, Str.Bounds.Dim_1.Length, Rti);
   end Ghdl_Value_Enum;

   function Ghdl_Value_B1 (Str : Std_String_Ptr; Rti : Ghdl_Rti_Access)
      return Ghdl_B1
   is
   begin
      return Ghdl_B1'Val (Ghdl_Value_Enum (Str, Rti));
   end Ghdl_Value_B1;

   function Ghdl_Value_E8 (Str : Std_String_Ptr; Rti : Ghdl_Rti_Access)
      return Ghdl_E8
   is
   begin
      return Ghdl_E8'Val (Ghdl_Value_Enum (Str, Rti));
   end Ghdl_Value_E8;

   function Ghdl_Value_E32 (Str : Std_String_Ptr; Rti : Ghdl_Rti_Access)
      return Ghdl_E32
   is
   begin
      return Ghdl_E32'Val (Ghdl_Value_Enum (Str, Rti));
   end Ghdl_Value_E32;

   procedure Value_Error (Status : Value_Status_Error);
   pragma No_Return (Value_Error);

   procedure Value_Error (Status : Value_Status_Error) is
   begin
      case Status is
         when Value_Err_No_Digit =>
            Error_E ("'value: missing digit");
         when Value_Err_Underscore =>
            Error_E ("'value: incorrect underscore");
         when Value_Err_Bad_Base =>
            Error_E ("'value: bad base");
         when Value_Err_Bad_Digit =>
            Error_E ("'value: digit expected");
         when Value_Err_Bad_End_Sign =>
            Error_E ("'value: incorrect or missing sign number");
         when Value_Err_Bad_Exponent =>
            Error_E ("'value: negativ exponent not allowed");
         when Value_Err_Trailing_Chars =>
            Error_E ("'value: trailing characters after blank");
      end case;
   end Value_Error;

   function Value_I64
     (S : Std_String_Basep; Len : Ghdl_Index_Type; Init_Pos : Ghdl_Index_Type)
     return Ghdl_I64
   is
      Res : Value_I64_Result;
   begin
      Res := Value_I64 (S, Len, Init_Pos);
      case Res.Status is
         when Value_Ok =>
            return Res.Val;
         when Value_Err_No_Digit =>
            Error_E ("'value: missing digit");
         when Value_Err_Underscore =>
            Error_E ("'value: incorrect underscore");
         when Value_Err_Bad_Base =>
            Error_E ("'value: bad base");
         when Value_Err_Bad_Digit =>
            Error_E ("'value: digit expected");
         when Value_Err_Bad_End_Sign =>
            Error_E ("'value: incorrect or missing sign number");
         when Value_Err_Bad_Exponent =>
            Error_E ("'value: negativ exponent not allowed");
         when Value_Err_Trailing_Chars =>
            Error_E ("'value: trailing characters after blank");
      end case;
   end Value_I64;

   function Ghdl_Value_I64 (Str : Std_String_Ptr) return Ghdl_I64
   is
      S : constant Std_String_Basep := Str.Base;
      Len : Ghdl_Index_Type := Str.Bounds.Dim_1.Length;
      Pos : Ghdl_Index_Type := 0;
   begin
      --  LRM 14.1
      --  Leading [and trailing] whitespace is allowed and ignored.
      --
      --  GHDL: allow several leading whitespace.
      Remove_Whitespaces (S, Len, Pos);

      return Value_I64 (S, Len, Pos);
   end Ghdl_Value_I64;

   function Ghdl_Value_I32 (Str : Std_String_Ptr) return Ghdl_I32
   is
   begin
      return Ghdl_I32 (Ghdl_Value_I64 (Str));
   end Ghdl_Value_I32;

   function Value_F64 (S : Std_String_Basep;
                       Len : Ghdl_Index_Type;
                       Init_Pos : Ghdl_Index_Type) return Ghdl_F64
   is
      Res : Value_F64_Result;
   begin
      Res := Value_F64 (S, Len, Init_Pos);

      if Res.Status = Value_Ok then
         return Res.Val;
      else
         Value_Error (Res.Status);
      end if;
   end Value_F64;

   -- From patch attached to https://gna.org/bugs/index.php?18352
   -- thanks to Christophe Curis https://gna.org/users/lobotomy
   function Ghdl_Value_F64 (Str : Std_String_Ptr) return Ghdl_F64
   is
      S   : constant Std_String_Basep := Str.Base;
      Len : Ghdl_Index_Type  := Str.Bounds.Dim_1.Length;
      Pos : Ghdl_Index_Type := 0;
   begin
      --  LRM 14.1
      --  Leading and trailing whitespace is allowed and ignored.
      --
      --  GHDL: allow several leading whitespace.
      Remove_Whitespaces (S, Len, Pos);

      return Value_F64 (S, Len, Pos);
   end Ghdl_Value_F64;

   function Ghdl_Value_Physical_Type (Str : Std_String_Ptr;
                                      Rti : Ghdl_Rti_Access)
                                     return Ghdl_I64
   is
      S        : constant Std_String_Basep := Str.Base;
      Len      : Ghdl_Index_Type := Str.Bounds.Dim_1.Length;
      Unit_Pos : Ghdl_Index_Type;
      Lit_Pos  : Ghdl_Index_Type;
      Lit_End  : Ghdl_Index_Type;

      Found_Real : Boolean;

      Phys_Rti : constant Ghdl_Rtin_Type_Physical_Acc :=
        To_Ghdl_Rtin_Type_Physical_Acc (Rti);
      Unit_Name : Ghdl_C_String;
      Multiple : Ghdl_Rti_Access;
      Mult     : Ghdl_I64;
   begin
      --  Remove trailing whitespaces.  FIXME: also called in physical_split.
      Lit_Pos := 0;
      Remove_Whitespaces (S, Len, Lit_Pos);

      --  Extract literal and unit
      Ghdl_Value_Physical_Split
        (S, Len, Found_Real, Lit_Pos, Lit_End, Unit_Pos);

      --  Find unit value
      Multiple := null;
      for i in 0 .. Phys_Rti.Nbr - 1 loop
         Unit_Name :=
           Rtis_Utils.Get_Physical_Unit_Name (Phys_Rti.Units (i));
         if String_Match (S, Unit_Pos, Len, Unit_Name) then
            Multiple := Phys_Rti.Units (i);
            exit;
         end if;
      end loop;
      if Multiple = null then
         Error_S ("'value: unit '");
         Diag_C_Std (S (Unit_Pos .. Len - 1));
         Diag_C ("' not in physical type '");
         Diag_C (Phys_Rti.Name);
         Error_E ("'");
      end if;

      Mult := Grt.Rtis_Utils.Get_Physical_Unit_Value (Multiple, Rti);

      if Lit_End = 0 then
         return Mult;
      else
         if Found_Real then
            return Ghdl_I64
              (Value_F64 (S, Lit_End, Lit_Pos) * Ghdl_F64 (Mult));
         else
            return Value_I64 (S, Lit_End, Lit_Pos) * Mult;
         end if;
      end if;
   end Ghdl_Value_Physical_Type;

   function Ghdl_Value_P64 (Str : Std_String_Ptr; Rti : Ghdl_Rti_Access)
      return Ghdl_I64
   is
   begin
      if Rti.Kind /= Ghdl_Rtik_Type_P64 then
         Error_E ("Physical_Type_64'value: incorrect RTI");
      end if;
      return Ghdl_Value_Physical_Type (Str, Rti);
   end Ghdl_Value_P64;

   function Ghdl_Value_P32 (Str : Std_String_Ptr; Rti : Ghdl_Rti_Access)
      return Ghdl_I32
   is
   begin
      if Rti.Kind /= Ghdl_Rtik_Type_P32 then
         Error_E ("Physical_Type_32'value: incorrect RTI");
      end if;
      return Ghdl_I32 (Ghdl_Value_Physical_Type (Str, Rti));
   end Ghdl_Value_P32;

end Grt.Values;