+++ /dev/null
-------------------------------------------------------------------------------
--- --
--- GNAT COMPILER COMPONENTS --
--- --
--- S Y S T E M . V A L _ L L U --
--- --
--- S p e c --
--- --
--- $Revision: 1.1.16.2 $
--- --
--- Copyright (C) 1992-1997 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 2, 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 COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
--- --
--- 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. --
--- --
--- GNAT was originally developed by the GNAT team at New York University. --
--- Extensive contributions were provided by Ada Core Technologies Inc. --
--- --
-------------------------------------------------------------------------------
-
-with System.Unsigned_Types; use System.Unsigned_Types;
-with System.Val_Util; use System.Val_Util;
-
-package body System.Val_LLU is
-
- -----------------------------
- -- Scan_Long_Long_Unsigned --
- -----------------------------
-
- function Scan_Long_Long_Unsigned
- (Str : String;
- Ptr : access Integer;
- Max : Integer)
- return Long_Long_Unsigned
- is
- P : Integer;
- -- Local copy of the pointer
-
- Uval : Long_Long_Unsigned;
- -- Accumulated unsigned integer result
-
- Expon : Integer;
- -- Exponent value
-
- Minus : Boolean := False;
- -- Set to True if minus sign is present, otherwise to False. Note that
- -- a minus sign is permissible for the singular case of -0, and in any
- -- case the pointer is left pointing past a negative integer literal.
-
- Overflow : Boolean := False;
- -- Set True if overflow is detected at any point
-
- Start : Positive;
- -- Save location of first non-blank character
-
- Base_Char : Character;
- -- Base character (# or :) in based case
-
- Base : Long_Long_Unsigned := 10;
- -- Base value (reset in based case)
-
- Digit : Long_Long_Unsigned;
- -- Digit value
-
- begin
- Scan_Sign (Str, Ptr, Max, Minus, Start);
-
- if Str (Ptr.all) not in '0' .. '9' then
- Ptr.all := Start;
- raise Constraint_Error;
- end if;
-
- P := Ptr.all;
- Uval := Character'Pos (Str (P)) - Character'Pos ('0');
- P := P + 1;
-
- -- Scan out digits of what is either the number or the base.
- -- In either case, we are definitely scanning out in base 10.
-
- declare
- Umax : constant := (Long_Long_Unsigned'Last - 9) / 10;
- -- Max value which cannot overflow on accumulating next digit
-
- Umax10 : constant := Long_Long_Unsigned'Last / 10;
- -- Numbers bigger than Umax10 overflow if multiplied by 10
-
- begin
- -- Loop through decimal digits
- loop
- exit when P > Max;
-
- Digit := Character'Pos (Str (P)) - Character'Pos ('0');
-
- -- Non-digit encountered
-
- if Digit > 9 then
- if Str (P) = '_' then
- Scan_Underscore (Str, P, Ptr, Max, False);
- else
- exit;
- end if;
-
- -- Accumulate result, checking for overflow
-
- else
- if Uval <= Umax then
- Uval := 10 * Uval + Digit;
-
- elsif Uval > Umax10 then
- Overflow := True;
-
- else
- Uval := 10 * Uval + Digit;
-
- if Uval < Umax10 then
- Overflow := True;
- end if;
- end if;
-
- P := P + 1;
- end if;
- end loop;
- end;
-
- Ptr.all := P;
-
- -- Deal with based case
-
- if P < Max and then (Str (P) = ':' or else Str (P) = '#') then
- Base_Char := Str (P);
- P := P + 1;
- Base := Uval;
- Uval := 0;
-
- -- Check base value. Overflow is set True if we find a bad base, or
- -- a digit that is out of range of the base. That way, we scan out
- -- the numeral that is still syntactically correct, though illegal.
- -- We use a safe base of 16 for this scan, to avoid zero divide.
-
- if Base not in 2 .. 16 then
- Overflow := True;
- Base := 16;
- end if;
-
- -- Scan out based integer
-
- declare
- Umax : constant Long_Long_Unsigned :=
- (Long_Long_Unsigned'Last - Base + 1) / Base;
- -- Max value which cannot overflow on accumulating next digit
-
- UmaxB : constant Long_Long_Unsigned :=
- Long_Long_Unsigned'Last / Base;
- -- Numbers bigger than UmaxB overflow if multiplied by base
-
- begin
- -- Loop to scan out based integer value
-
- loop
- -- We require a digit at this stage
-
- if Str (P) in '0' .. '9' then
- Digit := Character'Pos (Str (P)) - Character'Pos ('0');
-
- elsif Str (P) in 'A' .. 'F' then
- Digit :=
- Character'Pos (Str (P)) - (Character'Pos ('A') - 10);
-
- elsif Str (P) in 'a' .. 'f' then
- Digit :=
- Character'Pos (Str (P)) - (Character'Pos ('a') - 10);
-
- -- If we don't have a digit, then this is not a based number
- -- after all, so we use the value we scanned out as the base
- -- (now in Base), and the pointer to the base character was
- -- already stored in Ptr.all.
-
- else
- Uval := Base;
- exit;
- end if;
-
- -- If digit is too large, just signal overflow and continue.
- -- The idea here is to keep scanning as long as the input is
- -- syntactically valid, even if we have detected overflow
-
- if Digit >= Base then
- Overflow := True;
-
- -- Here we accumulate the value, checking overflow
-
- elsif Uval <= Umax then
- Uval := Base * Uval + Digit;
-
- elsif Uval > UmaxB then
- Overflow := True;
-
- else
- Uval := Base * Uval + Digit;
-
- if Uval < UmaxB then
- Overflow := True;
- end if;
- end if;
-
- -- If at end of string with no base char, not a based number
- -- but we signal Constraint_Error and set the pointer past
- -- the end of the field, since this is what the ACVC tests
- -- seem to require, see CE3704N, line 204.
-
- P := P + 1;
-
- if P > Max then
- Ptr.all := P;
- raise Constraint_Error;
- end if;
-
- -- If terminating base character, we are done with loop
-
- if Str (P) = Base_Char then
- Ptr.all := P + 1;
- exit;
-
- -- Deal with underscore
-
- elsif Str (P) = '_' then
- Scan_Underscore (Str, P, Ptr, Max, True);
- end if;
-
- end loop;
- end;
- end if;
-
- -- Come here with scanned unsigned value in Uval. The only remaining
- -- required step is to deal with exponent if one is present.
-
- Expon := Scan_Exponent (Str, Ptr, Max);
-
- if Expon /= 0 and then Uval /= 0 then
-
- -- For non-zero value, scale by exponent value. No need to do this
- -- efficiently, since use of exponent in integer literals is rare,
- -- and in any case the exponent cannot be very large.
-
- declare
- UmaxB : constant Long_Long_Unsigned :=
- Long_Long_Unsigned'Last / Base;
- -- Numbers bigger than UmaxB overflow if multiplied by base
-
- begin
- for J in 1 .. Expon loop
- if Uval > UmaxB then
- Overflow := True;
- exit;
- end if;
-
- Uval := Uval * Base;
- end loop;
- end;
- end if;
-
- -- Return result, dealing with sign and overflow
-
- if Overflow or else (Minus and then Uval /= 0) then
- raise Constraint_Error;
- else
- return Uval;
- end if;
- end Scan_Long_Long_Unsigned;
-
- ------------------------------
- -- Value_Long_Long_Unsigned --
- ------------------------------
-
- function Value_Long_Long_Unsigned
- (Str : String)
- return Long_Long_Unsigned
- is
- V : Long_Long_Unsigned;
- P : aliased Integer := Str'First;
-
- begin
- V := Scan_Long_Long_Unsigned (Str, P'Access, Str'Last);
- Scan_Trailing_Blanks (Str, P);
- return V;
-
- end Value_Long_Long_Unsigned;
-
-end System.Val_LLU;
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