[thirdparty/gcc.git] / gcc / ada / s-strcom.adb

------------------------------------------------------------------------------
--                                                                          --
--                    GNAT RUN-TIME LIBRARY COMPONENTS                      --
--                                                                          --
--                S Y S T E M . S T R I N G _ C O M P A R E                 --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 2002-2009, 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 3,  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.                                     --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

pragma Warnings (Off);
pragma Compiler_Unit;
pragma Warnings (On);

with Ada.Unchecked_Conversion;

package body System.String_Compare is

   type Word is mod 2 ** 32;
   --  Used to process operands by words

   type Big_Words is array (Natural) of Word;
   type Big_Words_Ptr is access Big_Words;
   for Big_Words_Ptr'Storage_Size use 0;
   --  Array type used to access by words

   type Byte is mod 2 ** 8;
   --  Used to process operands by bytes

   type Big_Bytes is array (Natural) of Byte;
   type Big_Bytes_Ptr is access Big_Bytes;
   for Big_Bytes_Ptr'Storage_Size use 0;
   --  Array type used to access by bytes

   function To_Big_Words is new
     Ada.Unchecked_Conversion (System.Address, Big_Words_Ptr);

   function To_Big_Bytes is new
     Ada.Unchecked_Conversion (System.Address, Big_Bytes_Ptr);

   -----------------
   -- Str_Compare --
   -----------------

   function Str_Compare
     (Left      : System.Address;
      Right     : System.Address;
      Left_Len  : Natural;
      Right_Len : Natural) return Integer
   is
      Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);

   begin
      --  If operands are non-aligned, or length is too short, go by bytes

      if (((Left or Right) and 2#11#) /= 0) or else Compare_Len < 4 then
         return Str_Compare_Bytes (Left, Right, Left_Len, Right_Len);
      end if;

      --  Here we can go by words

      declare
         LeftP  : constant Big_Words_Ptr := To_Big_Words (Left);
         RightP : constant Big_Words_Ptr := To_Big_Words (Right);
         Clen4  : constant Natural       := Compare_Len / 4 - 1;
         Clen4F : constant Natural       := Clen4 * 4;

      begin
         for J in 0 .. Clen4 loop
            if LeftP (J) /= RightP (J) then
               return Str_Compare_Bytes
                        (Left  + Address (4 * J),
                         Right + Address (4 * J),
                         4, 4);
            end if;
         end loop;

         return Str_Compare_Bytes
                  (Left      + Address (Clen4F),
                   Right     + Address (Clen4F),
                   Left_Len  - Clen4F,
                   Right_Len - Clen4F);
      end;
   end Str_Compare;

   -----------------------
   -- Str_Compare_Bytes --
   -----------------------

   function Str_Compare_Bytes
     (Left      : System.Address;
      Right     : System.Address;
      Left_Len  : Natural;
      Right_Len : Natural) return Integer
   is
      Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);

      LeftP  : constant Big_Bytes_Ptr := To_Big_Bytes (Left);
      RightP : constant Big_Bytes_Ptr := To_Big_Bytes (Right);

   begin
      for J in 0 .. Compare_Len - 1 loop
         if LeftP (J) /= RightP (J) then
            if LeftP (J) > RightP (J) then
               return +1;
            else
               return -1;
            end if;
         end if;
      end loop;

      if Left_Len = Right_Len then
         return 0;
      elsif Left_Len > Right_Len then
         return +1;
      else
         return -1;
      end if;
   end Str_Compare_Bytes;

end System.String_Compare;
Commit	Line	Data
fbf5a39b AC	1	------------------------------------------------------------------------------
fbf5a39b AC	2	-- --
3084fecd	3	-- GNAT RUN-TIME LIBRARY COMPONENTS --
fbf5a39b AC	4	-- --
	5	-- S Y S T E M . S T R I N G _ C O M P A R E --
	6	-- --
3084fecd	7	-- B o d y --
fbf5a39b	8	-- --
748086b7	9	-- Copyright (C) 2002-2009, Free Software Foundation, Inc. --
fbf5a39b AC	10	-- --
	11	-- GNAT is free software; you can redistribute it and/or modify it under --
	12	-- terms of the GNU General Public License as published by the Free Soft- --
748086b7	13	-- ware Foundation; either version 3, or (at your option) any later ver- --
fbf5a39b AC	14	-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
fbf5a39b AC	15	-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
748086b7 JJ	16	-- or FITNESS FOR A PARTICULAR PURPOSE. --
	17	-- --
	18	-- As a special exception under Section 7 of GPL version 3, you are granted --
	19	-- additional permissions described in the GCC Runtime Library Exception, --
	20	-- version 3.1, as published by the Free Software Foundation. --
	21	-- --
	22	-- You should have received a copy of the GNU General Public License and --
	23	-- a copy of the GCC Runtime Library Exception along with this program; --
	24	-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
	25	-- <http://www.gnu.org/licenses/>. --
fbf5a39b AC	26	-- --
	27	-- GNAT was originally developed by the GNAT team at New York University. --
	28	-- Extensive contributions were provided by Ada Core Technologies Inc. --
	29	-- --
	30	------------------------------------------------------------------------------
	31
2d9ea47f RD	32	pragma Warnings (Off);
	33	pragma Compiler_Unit;
	34	pragma Warnings (On);
	35
cecaf88a	36	with Ada.Unchecked_Conversion;
fbf5a39b AC	37
	38	package body System.String_Compare is
	39
	40	type Word is mod 2 ** 32;
	41	-- Used to process operands by words
	42
	43	type Big_Words is array (Natural) of Word;
	44	type Big_Words_Ptr is access Big_Words;
a1e2130c	45	for Big_Words_Ptr'Storage_Size use 0;
fbf5a39b AC	46	-- Array type used to access by words
	47
	48	type Byte is mod 2 ** 8;
	49	-- Used to process operands by bytes
	50
	51	type Big_Bytes is array (Natural) of Byte;
	52	type Big_Bytes_Ptr is access Big_Bytes;
a1e2130c	53	for Big_Bytes_Ptr'Storage_Size use 0;
fbf5a39b AC	54	-- Array type used to access by bytes
	55
	56	function To_Big_Words is new
cecaf88a	57	Ada.Unchecked_Conversion (System.Address, Big_Words_Ptr);
fbf5a39b AC	58
fbf5a39b AC	59	function To_Big_Bytes is new
cecaf88a	60	Ada.Unchecked_Conversion (System.Address, Big_Bytes_Ptr);
fbf5a39b AC	61
	62	-----------------
	63	-- Str_Compare --
	64	-----------------
	65
	66	function Str_Compare
	67	(Left : System.Address;
	68	Right : System.Address;
	69	Left_Len : Natural;
2d9ea47f	70	Right_Len : Natural) return Integer
fbf5a39b AC	71	is
	72	Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);
	73
	74	begin
	75	-- If operands are non-aligned, or length is too short, go by bytes
	76
	77	if (((Left or Right) and 2#11#) /= 0) or else Compare_Len < 4 then
	78	return Str_Compare_Bytes (Left, Right, Left_Len, Right_Len);
	79	end if;
	80
	81	-- Here we can go by words
	82
	83	declare
	84	LeftP : constant Big_Words_Ptr := To_Big_Words (Left);
	85	RightP : constant Big_Words_Ptr := To_Big_Words (Right);
	86	Clen4 : constant Natural := Compare_Len / 4 - 1;
	87	Clen4F : constant Natural := Clen4 * 4;
	88
	89	begin
	90	for J in 0 .. Clen4 loop
	91	if LeftP (J) /= RightP (J) then
	92	return Str_Compare_Bytes
	93	(Left + Address (4 * J),
	94	Right + Address (4 * J),
	95	4, 4);
	96	end if;
	97	end loop;
	98
	99	return Str_Compare_Bytes
	100	(Left + Address (Clen4F),
	101	Right + Address (Clen4F),
	102	Left_Len - Clen4F,
	103	Right_Len - Clen4F);
	104	end;
	105	end Str_Compare;
	106
	107	-----------------------
	108	-- Str_Compare_Bytes --
	109	-----------------------
	110
	111	function Str_Compare_Bytes
	112	(Left : System.Address;
	113	Right : System.Address;
	114	Left_Len : Natural;
2d9ea47f	115	Right_Len : Natural) return Integer
fbf5a39b AC	116	is
	117	Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);
	118
	119	LeftP : constant Big_Bytes_Ptr := To_Big_Bytes (Left);
	120	RightP : constant Big_Bytes_Ptr := To_Big_Bytes (Right);
	121
	122	begin
	123	for J in 0 .. Compare_Len - 1 loop
	124	if LeftP (J) /= RightP (J) then
	125	if LeftP (J) > RightP (J) then
	126	return +1;
	127	else
	128	return -1;
	129	end if;
	130	end if;
	131	end loop;
	132
	133	if Left_Len = Right_Len then
	134	return 0;
	135	elsif Left_Len > Right_Len then
	136	return +1;
	137	else
	138	return -1;
	139	end if;
	140	end Str_Compare_Bytes;
	141
	142	end System.String_Compare;