------------------------------------------------------------------------------ -- -- -- GNAT RUNTIME COMPONENTS -- -- -- -- G N A T . S P E L L I N G _ C H E C K E R -- -- -- -- B o d y -- -- -- -- Copyright (C) 1998-2003 Ada Core Technologies, 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. -- -- -- ------------------------------------------------------------------------------ package body GNAT.Spelling_Checker is ------------------------ -- Is_Bad_Spelling_Of -- ------------------------ function Is_Bad_Spelling_Of (Found : String; Expect : String) return Boolean is FN : constant Natural := Found'Length; FF : constant Natural := Found'First; FL : constant Natural := Found'Last; EN : constant Natural := Expect'Length; EF : constant Natural := Expect'First; EL : constant Natural := Expect'Last; begin -- If both strings null, then we consider this a match, but if one -- is null and the other is not, then we definitely do not match if FN = 0 then return (EN = 0); elsif EN = 0 then return False; -- If first character does not match, then definitely not misspelling elsif Found (FF) /= Expect (EF) then return False; -- Not a bad spelling if both strings are 1-2 characters long elsif FN < 3 and then EN < 3 then return False; -- Lengths match. Execute loop to check for a single error, single -- transposition or exact match (we only fall through this loop if -- one of these three conditions is found). elsif FN = EN then for J in 1 .. FN - 2 loop if Expect (EF + J) /= Found (FF + J) then -- If both mismatched characters are digits, then we do -- not consider it a misspelling (e.g. B345 is not a -- misspelling of B346, it is something quite different) if Expect (EF + J) in '0' .. '9' and then Found (FF + J) in '0' .. '9' then return False; elsif Expect (EF + J + 1) = Found (FF + J + 1) and then Expect (EF + J + 2 .. EL) = Found (FF + J + 2 .. FL) then return True; elsif Expect (EF + J) = Found (FF + J + 1) and then Expect (EF + J + 1) = Found (FF + J) and then Expect (EF + J + 2 .. EL) = Found (FF + J + 2 .. FL) then return True; else return False; end if; end if; end loop; -- At last character. Test digit case as above, otherwise we -- have a match since at most this last character fails to match. if Expect (EL) in '0' .. '9' and then Found (FL) in '0' .. '9' and then Expect (EL) /= Found (FL) then return False; else return True; end if; -- Length is 1 too short. Execute loop to check for single deletion elsif FN = EN - 1 then for J in 1 .. FN - 1 loop if Found (FF + J) /= Expect (EF + J) then return Found (FF + J .. FL) = Expect (EF + J + 1 .. EL); end if; end loop; -- If we fall through then the last character was missing, which -- we consider to be a match (e.g. found xyz, expected xyza). return True; -- Length is 1 too long. Execute loop to check for single insertion elsif FN = EN + 1 then for J in 1 .. EN - 1 loop if Found (FF + J) /= Expect (EF + J) then return Found (FF + J + 1 .. FL) = Expect (EF + J .. EL); end if; end loop; -- If we fall through then the last character was an additional -- character, which is a match (e.g. found xyza, expected xyz). return True; -- Length is completely wrong else return False; end if; end Is_Bad_Spelling_Of; end GNAT.Spelling_Checker;