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Diffstat (limited to 'gcc/ada/s-valuns.adb')
| -rw-r--r-- | gcc/ada/s-valuns.adb | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/gcc/ada/s-valuns.adb b/gcc/ada/s-valuns.adb new file mode 100644 index 00000000000..f3f552f9502 --- /dev/null +++ b/gcc/ada/s-valuns.adb @@ -0,0 +1,298 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S Y S T E M . V A L _ U N S -- +-- -- +-- B o d y -- +-- -- +-- $Revision: 1.13 $ -- +-- -- +-- 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. -- +-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +with System.Unsigned_Types; use System.Unsigned_Types; +with System.Val_Util; use System.Val_Util; + +package body System.Val_Uns is + + ------------------- + -- Scan_Unsigned -- + ------------------- + + function Scan_Unsigned + (Str : String; + Ptr : access Integer; + Max : Integer) + return Unsigned + is + P : Integer; + -- Local copy of the pointer + + Uval : 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 : Unsigned := 10; + -- Base value (reset in based case) + + Digit : 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 := (Unsigned'Last - 9) / 10; + -- Max value which cannot overflow on accumulating next digit + + Umax10 : constant := 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 Unsigned := (Unsigned'Last - Base + 1) / Base; + -- Max value which cannot overflow on accumulating next digit + + UmaxB : constant Unsigned := 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 Unsigned := 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_Unsigned; + + -------------------- + -- Value_Unsigned -- + -------------------- + + function Value_Unsigned (Str : String) return Unsigned is + V : Unsigned; + P : aliased Integer := Str'First; + + begin + V := Scan_Unsigned (Str, P'Access, Str'Last); + Scan_Trailing_Blanks (Str, P); + return V; + + end Value_Unsigned; + +end System.Val_Uns; |