1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY COMPONENTS --
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 --
9 -- Copyright (C) 2002-2009, Free Software Foundation, Inc. --
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 3, 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. --
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. --
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/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 pragma Warnings (Off);
36 with System.Address_Operations; use System.Address_Operations;
38 with Ada.Unchecked_Conversion;
40 package body System.Compare_Array_Unsigned_8 is
42 type Word is mod 2 ** 32;
43 -- Used to process operands by words
45 type Big_Words is array (Natural) of Word;
46 type Big_Words_Ptr is access Big_Words;
47 for Big_Words_Ptr'Storage_Size use 0;
48 -- Array type used to access by words
50 type Byte is mod 2 ** 8;
51 -- Used to process operands by bytes
53 type Big_Bytes is array (Natural) of Byte;
54 type Big_Bytes_Ptr is access Big_Bytes;
55 for Big_Bytes_Ptr'Storage_Size use 0;
56 -- Array type used to access by bytes
58 function To_Big_Words is new
59 Ada.Unchecked_Conversion (System.Address, Big_Words_Ptr);
61 function To_Big_Bytes is new
62 Ada.Unchecked_Conversion (System.Address, Big_Bytes_Ptr);
64 ----------------------
65 -- Compare_Array_U8 --
66 ----------------------
68 function Compare_Array_U8
69 (Left : System.Address;
70 Right : System.Address;
72 Right_Len : Natural) return Integer
74 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);
77 -- If operands are non-aligned, or length is too short, go by bytes
79 if (ModA (OrA (Left, Right), 4) /= 0) or else Compare_Len < 4 then
80 return Compare_Array_U8_Unaligned (Left, Right, Left_Len, Right_Len);
83 -- Here we can go by words
86 LeftP : constant Big_Words_Ptr :=
88 RightP : constant Big_Words_Ptr :=
90 Words_To_Compare : constant Natural := Compare_Len / 4;
91 Bytes_Compared_As_Words : constant Natural := Words_To_Compare * 4;
94 for J in 0 .. Words_To_Compare - 1 loop
95 if LeftP (J) /= RightP (J) then
96 return Compare_Array_U8_Unaligned
97 (AddA (Left, Address (4 * J)),
98 AddA (Right, Address (4 * J)),
103 return Compare_Array_U8_Unaligned
104 (AddA (Left, Address (Bytes_Compared_As_Words)),
105 AddA (Right, Address (Bytes_Compared_As_Words)),
106 Left_Len - Bytes_Compared_As_Words,
107 Right_Len - Bytes_Compared_As_Words);
109 end Compare_Array_U8;
111 --------------------------------
112 -- Compare_Array_U8_Unaligned --
113 --------------------------------
115 function Compare_Array_U8_Unaligned
116 (Left : System.Address;
117 Right : System.Address;
119 Right_Len : Natural) return Integer
121 Compare_Len : constant Natural := Natural'Min (Left_Len, Right_Len);
123 LeftP : constant Big_Bytes_Ptr := To_Big_Bytes (Left);
124 RightP : constant Big_Bytes_Ptr := To_Big_Bytes (Right);
127 for J in 0 .. Compare_Len - 1 loop
128 if LeftP (J) /= RightP (J) then
129 if LeftP (J) > RightP (J) then
137 if Left_Len = Right_Len then
139 elsif Left_Len > Right_Len then
144 end Compare_Array_U8_Unaligned;
146 end System.Compare_Array_Unsigned_8;