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Wrap

Text File | 1995-10-17 | 7.5 KB | 283 lines

------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S Y S T E M . V A L _ U T I L -- -- -- -- B o d y -- -- -- -- $Revision: 1.5 $ -- -- -- -- Copyright (c) 1992,1993,1994 NYU, All Rights Reserved -- -- -- -- The GNAT library is free software; you can redistribute it and/or modify -- -- it under terms of the GNU Library General Public License as published by -- -- the Free Software Foundation; either version 2, or (at your option) any -- -- later version. The GNAT library 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 -- -- Library General Public License for more details. You should have -- -- received a copy of the GNU Library General Public License along with -- -- the GNAT library; see the file COPYING.LIB. If not, write to the Free -- -- Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. -- -- -- ------------------------------------------------------------------------------ package body System.Val_Util is ---------------------- -- Normalize_String -- ---------------------- procedure Normalize_String (S : in out String; F, L : out Positive'Base) 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; if S (F) /= ''' then -- Upper case any lower case characters. -- This needs to be expanded to handle Latin-1 upper half ??? for J in F .. L loop if S (J) in 'a' .. 'z' then S (J) := Character'Val (Character'Pos (S (J)) - 32); end if; end loop; end if; end Normalize_String; --------------- -- Scan_Sign -- --------------- procedure Scan_Sign (Str : String; Ptr : access Positive'Base; Max : Positive'Base; Minus : out Boolean; Start : out Positive) is P : Natural := Ptr.all; begin -- Deal with case of null string (all blanks!). As per spec, we -- return with Ptr > Max (i.e. no change, since Ptr already > Max) if P > Max then return; 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_Exponent -- ------------------- function Scan_Exponent (Str : String; Ptr : access Positive'Base; Max : Positive'Base; 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')); P := P + 1; end if; 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_Trailing_Blanks -- -------------------------- procedure Scan_Trailing_Blanks (Str : String; P : Positive) is Max : constant Natural := Str'Last; begin for J in P .. Str'Last loop if Str (P) /= ' ' then raise Constraint_Error; end if; end loop; end Scan_Trailing_Blanks; --------------------- -- Scan_Underscore -- --------------------- procedure Scan_Underscore (Str : String; P : in out Natural; Ptr : 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;