diff options
author | Dan Albert <danalbert@google.com> | 2016-02-04 18:51:25 +0000 |
---|---|---|
committer | Gerrit Code Review <noreply-gerritcodereview@google.com> | 2016-02-04 18:51:25 +0000 |
commit | edbbe53c4ffa154a5f9ae3f89ba8105993d8800e (patch) | |
tree | 4cedb380a14027d9c4d1e531c2340c43cbd79175 /gcc-4.8.1/gcc/ada/g-crc32.ads | |
parent | a4ca82cac69c3147143d7b4b4d7cdeb5e02f20ef (diff) | |
parent | 3186be22b6598fbd467b126347d1c7f48ccb7f71 (diff) | |
download | toolchain_gcc-edbbe53c4ffa154a5f9ae3f89ba8105993d8800e.tar.gz toolchain_gcc-edbbe53c4ffa154a5f9ae3f89ba8105993d8800e.tar.bz2 toolchain_gcc-edbbe53c4ffa154a5f9ae3f89ba8105993d8800e.zip |
Merge "Check in a pristine copy of GCC 4.8.1."
Diffstat (limited to 'gcc-4.8.1/gcc/ada/g-crc32.ads')
-rw-r--r-- | gcc-4.8.1/gcc/ada/g-crc32.ads | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/gcc-4.8.1/gcc/ada/g-crc32.ads b/gcc-4.8.1/gcc/ada/g-crc32.ads new file mode 100644 index 000000000..61d37a346 --- /dev/null +++ b/gcc-4.8.1/gcc/ada/g-crc32.ads @@ -0,0 +1,111 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT LIBRARY COMPONENTS -- +-- -- +-- G N A T . C R C 3 2 -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 2004-2010, AdaCore -- +-- -- +-- 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. -- +-- -- +------------------------------------------------------------------------------ + +-- This package provides routines for computing a commonly used checksum +-- called CRC-32. This is a checksum based on treating the binary data +-- as a polynomial over a binary field, and the exact specifications of +-- the CRC-32 algorithm are as follows: + +-- Name : "CRC-32" +-- Width : 32 +-- Poly : 04C11DB7 +-- Init : FFFFFFFF +-- RefIn : True +-- RefOut : True +-- XorOut : FFFFFFFF +-- Check : CBF43926 + +-- Note that this is the algorithm used by PKZip, Ethernet and FDDI + +-- For more information about this algorithm see: + +-- ftp://ftp.rocksoft.com/papers/crc_v3.txt + +-- "A Painless Guide to CRC Error Detection Algorithms", Ross N. Williams + +-- "Computation of Cyclic Redundancy Checks via Table Look-Up", Communications +-- of the ACM, Vol. 31 No. 8, pp.1008-1013 Aug. 1988. Sarwate, D.V. + +with Ada.Streams; +with Interfaces; +with System.CRC32; + +package GNAT.CRC32 is + + subtype CRC32 is System.CRC32.CRC32; + -- Used to represent CRC32 values, which are 32 bit bit-strings + + procedure Initialize (C : out CRC32) + renames System.CRC32.Initialize; + -- Initialize CRC value by assigning the standard Init value (16#FFFF_FFFF) + + procedure Update + (C : in out CRC32; + Value : Character) + renames System.CRC32.Update; + -- Evolve CRC by including the contribution from Character'Pos (Value) + + procedure Update + (C : in out CRC32; + Value : String); + -- For each character in the Value string call above routine + + procedure Wide_Update + (C : in out CRC32; + Value : Wide_Character); + -- Evolve CRC by including the contribution from Wide_Character'Pos (Value) + -- with the bytes being included in the natural memory order. + + procedure Wide_Update + (C : in out CRC32; + Value : Wide_String); + -- For each character in the Value string call above routine + + procedure Update + (C : in out CRC32; + Value : Ada.Streams.Stream_Element); + -- Evolve CRC by including the contribution from Value + + procedure Update + (C : in out CRC32; + Value : Ada.Streams.Stream_Element_Array); + -- For each element in the Value array call above routine + + function Get_Value (C : CRC32) return Interfaces.Unsigned_32 + renames System.CRC32.Get_Value; + -- Get_Value computes the CRC32 value by performing an XOR with the + -- standard XorOut value (16#FFFF_FFFF). Note that this does not + -- change the value of C, so it may be used to retrieve intermediate + -- values of the CRC32 value during a sequence of Update calls. + + pragma Inline (Update); + pragma Inline (Wide_Update); +end GNAT.CRC32; |