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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . V A L _ U T I L --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2006, 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, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, 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.Case_Util; use System.Case_Util;
package body System.Val_Util is
----------------------
-- Normalize_String --
----------------------
procedure Normalize_String
(S : in out String;
F, L : out Integer)
is
begin
F := S'First;
L := S'Last;
-- Scan for leading spaces
while F <= L and then S (F) = ' ' loop
F := F + 1;
end loop;
-- Check for case when the string contained no characters
if F > L then
raise Constraint_Error;
end if;
-- Scan for trailing spaces
while S (L) = ' ' loop
L := L - 1;
end loop;
-- Except in the case of a character literal, convert to upper case
if S (F) /= ''' then
for J in F .. L loop
S (J) := To_Upper (S (J));
end loop;
end if;
end Normalize_String;
-------------------
-- Scan_Exponent --
-------------------
function Scan_Exponent
(Str : String;
Ptr : not null access Integer;
Max : Integer;
Real : Boolean := False) return Integer
is
P : Natural := Ptr.all;
M : Boolean;
X : Integer;
begin
if P >= Max
or else (Str (P) /= 'E' and then Str (P) /= 'e')
then
return 0;
end if;
-- We have an E/e, see if sign follows
P := P + 1;
if Str (P) = '+' then
P := P + 1;
if P > Max then
return 0;
else
M := False;
end if;
elsif Str (P) = '-' then
P := P + 1;
if P > Max or else not Real then
return 0;
else
M := True;
end if;
else
M := False;
end if;
if Str (P) not in '0' .. '9' then
return 0;
end if;
-- Scan out the exponent value as an unsigned integer. Values larger
-- than (Integer'Last / 10) are simply considered large enough here.
-- This assumption is correct for all machines we know of (e.g. in
-- the case of 16 bit integers it allows exponents up to 3276, which
-- is large enough for the largest floating types in base 2.)
X := 0;
loop
if X < (Integer'Last / 10) then
X := X * 10 + (Character'Pos (Str (P)) - Character'Pos ('0'));
end if;
P := P + 1;
exit when P > Max;
if Str (P) = '_' then
Scan_Underscore (Str, P, Ptr, Max, False);
else
exit when Str (P) not in '0' .. '9';
end if;
end loop;
if M then
X := -X;
end if;
Ptr.all := P;
return X;
end Scan_Exponent;
--------------------
-- Scan_Plus_Sign --
--------------------
procedure Scan_Plus_Sign
(Str : String;
Ptr : not null access Integer;
Max : Integer;
Start : out Positive)
is
P : Natural := Ptr.all;
begin
if P > Max then
raise Constraint_Error;
end if;
-- Scan past initial blanks
while Str (P) = ' ' loop
P := P + 1;
if P > Max then
Ptr.all := P;
raise Constraint_Error;
end if;
end loop;
Start := P;
-- Skip past an initial plus sign
if Str (P) = '+' then
P := P + 1;
if P > Max then
Ptr.all := Start;
raise Constraint_Error;
end if;
end if;
Ptr.all := P;
end Scan_Plus_Sign;
---------------
-- Scan_Sign --
---------------
procedure Scan_Sign
(Str : String;
Ptr : not null access Integer;
Max : Integer;
Minus : out Boolean;
Start : out Positive)
is
P : Natural := Ptr.all;
begin
-- Deal with case of null string (all blanks!). As per spec, we
-- raise constraint error, with Ptr unchanged, and thus > Max.
if P > Max then
raise Constraint_Error;
end if;
-- Scan past initial blanks
while Str (P) = ' ' loop
P := P + 1;
if P > Max then
Ptr.all := P;
raise Constraint_Error;
end if;
end loop;
Start := P;
-- Remember an initial minus sign
if Str (P) = '-' then
Minus := True;
P := P + 1;
if P > Max then
Ptr.all := Start;
raise Constraint_Error;
end if;
-- Skip past an initial plus sign
elsif Str (P) = '+' then
Minus := False;
P := P + 1;
if P > Max then
Ptr.all := Start;
raise Constraint_Error;
end if;
else
Minus := False;
end if;
Ptr.all := P;
end Scan_Sign;
--------------------------
-- Scan_Trailing_Blanks --
--------------------------
procedure Scan_Trailing_Blanks (Str : String; P : Positive) is
begin
for J in P .. Str'Last loop
if Str (J) /= ' ' then
raise Constraint_Error;
end if;
end loop;
end Scan_Trailing_Blanks;
---------------------
-- Scan_Underscore --
---------------------
procedure Scan_Underscore
(Str : String;
P : in out Natural;
Ptr : not null access Integer;
Max : Integer;
Ext : Boolean)
is
C : Character;
begin
P := P + 1;
-- If underscore is at the end of string, then this is an error and
-- we raise Constraint_Error, leaving the pointer past the undescore.
-- This seems a bit strange. It means e,g, that if the field is:
-- 345_
-- that Constraint_Error is raised. You might think that the RM in
-- this case would scan out the 345 as a valid integer, leaving the
-- pointer at the underscore, but the ACVC suite clearly requires
-- an error in this situation (see for example CE3704M).
if P > Max then
Ptr.all := P;
raise Constraint_Error;
end if;
-- Similarly, if no digit follows the underscore raise an error. This
-- also catches the case of double underscore which is also an error.
C := Str (P);
if C in '0' .. '9'
or else
(Ext and then (C in 'A' .. 'F' or else C in 'a' .. 'f'))
then
return;
else
Ptr.all := P;
raise Constraint_Error;
end if;
end Scan_Underscore;
end System.Val_Util;
|
