1------------------------------------------------------------------------------ 2-- -- 3-- GNU ADA RUNTIME LIBRARY COMPONENTS -- 4-- -- 5-- S Y S T E M . C O M P A R E _ A R R A Y _ U N S I G N E D _ 8 -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 2002 Free Software Foundation, Inc. -- 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- -- 13-- ware Foundation; either version 2, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- 17-- for more details. You should have received a copy of the GNU General -- 18-- Public License distributed with GNAT; see file COPYING. If not, write -- 19-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- 20-- MA 02111-1307, USA. -- 21-- -- 22-- As a special exception, if other files instantiate generics from this -- 23-- unit, or you link this unit with other files to produce an executable, -- 24-- this unit does not by itself cause the resulting executable to be -- 25-- covered by the GNU General Public License. This exception does not -- 26-- however invalidate any other reasons why the executable file might be -- 27-- covered by the GNU Public License. -- 28-- -- 29-- GNAT was originally developed by the GNAT team at New York University. -- 30-- Extensive contributions were provided by Ada Core Technologies Inc. -- 31-- -- 32------------------------------------------------------------------------------ 33 34with Unchecked_Conversion; 35 36package body System.Compare_Array_Unsigned_8 is 37 38 type Word is mod 2 ** 32; 39 -- Used to process operands by words 40 41 type Big_Words is array (Natural) of Word; 42 type Big_Words_Ptr is access Big_Words; 43 -- Array type used to access by words 44 45 type Byte is mod 2 ** 8; 46 -- Used to process operands by bytes 47 48 type Big_Bytes is array (Natural) of Byte; 49 type Big_Bytes_Ptr is access Big_Bytes; 50 -- Array type used to access by bytes 51 52 function To_Big_Words is new 53 Unchecked_Conversion (System.Address, Big_Words_Ptr); 54 55 function To_Big_Bytes is new 56 Unchecked_Conversion (System.Address, Big_Bytes_Ptr); 57 58 ---------------------- 59 -- Compare_Array_U8 -- 60 ---------------------- 61 62 function Compare_Array_U8 63 (Left : System.Address; 64 Right : System.Address; 65 Left_Len : Natural; 66 Right_Len : Natural) 67 return Integer 68 is 69 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len); 70 71 begin 72 -- If operands are non-aligned, or length is too short, go by bytes 73 74 if (((Left or Right) and 2#11#) /= 0) or else Compare_Len < 4 then 75 return Compare_Array_U8_Unaligned (Left, Right, Left_Len, Right_Len); 76 end if; 77 78 -- Here we can go by words 79 80 declare 81 LeftP : constant Big_Words_Ptr := To_Big_Words (Left); 82 RightP : constant Big_Words_Ptr := To_Big_Words (Right); 83 Clen4 : constant Natural := Compare_Len / 4 - 1; 84 Clen4F : constant Natural := Clen4 * 4; 85 86 begin 87 for J in 0 .. Clen4 loop 88 if LeftP (J) /= RightP (J) then 89 return Compare_Array_U8_Unaligned 90 (Left + Address (4 * J), 91 Right + Address (4 * J), 92 4, 4); 93 end if; 94 end loop; 95 96 return Compare_Array_U8_Unaligned 97 (Left + Address (Clen4F), 98 Right + Address (Clen4F), 99 Left_Len - Clen4F, 100 Right_Len - Clen4F); 101 end; 102 end Compare_Array_U8; 103 104 -------------------------------- 105 -- Compare_Array_U8_Unaligned -- 106 -------------------------------- 107 108 function Compare_Array_U8_Unaligned 109 (Left : System.Address; 110 Right : System.Address; 111 Left_Len : Natural; 112 Right_Len : Natural) 113 return Integer 114 is 115 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len); 116 117 LeftP : constant Big_Bytes_Ptr := To_Big_Bytes (Left); 118 RightP : constant Big_Bytes_Ptr := To_Big_Bytes (Right); 119 120 begin 121 for J in 0 .. Compare_Len - 1 loop 122 if LeftP (J) /= RightP (J) then 123 if LeftP (J) > RightP (J) then 124 return +1; 125 else 126 return -1; 127 end if; 128 end if; 129 end loop; 130 131 if Left_Len = Right_Len then 132 return 0; 133 elsif Left_Len > Right_Len then 134 return +1; 135 else 136 return -1; 137 end if; 138 end Compare_Array_U8_Unaligned; 139 140end System.Compare_Array_Unsigned_8; 141