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author | bosch <bosch@138bc75d-0d04-0410-961f-82ee72b054a4> | 2001-10-11 23:28:47 +0000 |
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committer | bosch <bosch@138bc75d-0d04-0410-961f-82ee72b054a4> | 2001-10-11 23:28:47 +0000 |
commit | 699d76d2a494aeb2233abbec7450eb8f28591412 (patch) | |
tree | 1eb5c3598cab3e28720f900ad0f6e3a309265f54 /gcc/ada/s-crc32.ads | |
parent | e38b11be1416a7104a780d673de4ad26417f1ed5 (diff) | |
download | gcc-699d76d2a494aeb2233abbec7450eb8f28591412.tar.gz |
* Makefile.in:
(GNAT_ADA_OBJS): add g-crc32.o, a-tags.o, a-stream.o
(GNATBIND_OBJS): add g-crc32.o, a-tags.o, a-stream.o
(GNATLS_RTL_OBJS): add g-crc32.o
(GNATMAKE_RTL_OBJS): add g-crc32.o
* ali-util.adb:
(CRC_Match): new function.
(Get_File_Checksum): renamed Get_File_CRC. Use the GNAT.CRC32 unit
instead of the previous simple checksum algorithm.
(Time_Stamp_Mismatch): use CRC_Match for comparison.
(Set_Source_Table): idem.
* ali-util.ads:
(Get_File_Checksum): renamed Get_File_CRC as now we compute CRC
instead of simple checksum.
(CRC_Match): new function.
(CRC_Error): new constant.
* ali.adb (Scan_ALI): rename variable Chk to CRC as we are handling
a CRC now and not a simple checksum. A CRC uses lower-case hex
letters, fixes ambiguity in parsing.
* ali.ads (Sdep_Record.Checksum): renamed Sdep_Record.CRC as this
is what this variable will store.
* bcheck.adb: Change reference to chechsum in comments by CRC.
(Check_Consistency): Rename Get_File_Checksum to Get_File_CRC.
rename All_Checksum_Match to All_CRC_Match. Change due to API
renaming since now GNAT does not use a simple checksum but a
CRC using GNAT.CRC32.
* gnatls.adb: Rename Checksum to CRC in many places, we use a CRC
now and not anymore a simple checksum.
* lib-load.adb: Use Source_CRC instead of Source_Checksum in many
places.
* lib-writ.adb (Write_ALI): Use Source_CRC instead of Source_Checksum.
* scans.adb:
(Restore_Scan_State): rename Checksum to CRC.
(Save_Scan_State): idem.
* scans.ads:
With GNAT.CRC32.
(Checksum): rename to CRC.
(Saved_Scan_State): Save_Checksum field renamed to Save_CRC
* scn-nlit.adb: Rename many Accumulate_Checksum to Update (from
GNAT.CRC32). Update copyright notice.
* scn-slit.adb: Rename many Accumulate_Checksum to Update (from
GNAT.CRC32). Update copyright notice.
* scn.adb:
(Accumulate_Checksum): removed.
(Update): new procedure. Add a wide-character into the CRC.
* sinput-l.adb:
(Complete_Source_File_Entry): use CRC32 instead of simple checksum.
(Load_File): fix initialization of S (change Source_Checksum to
Source_CRC)
* sinput-p.adb (Load_Project_File): rename Source_Checksum to
Source_CRC in S initialization.
* sinput.adb (Source_Checksum): renamed to Source_CRC.
* sinput.ads (Source_Checksum): renamed to Source_CRC.
Update comments for the CRC.
* types.adb (Hex): Use lowercase for the letter part.
* types.ads (Get_Hex_String): Returns the hexadecimal representation
for a word. This is currently used only for CRC. In previous version,
the checksum was using a representation with all letter being
upper-case. With the new implementation (using CRC) we do not remove
the 32th bit of the CRC, so we can have an upper-case starting letter
in the CRC. This is not possible to parse in Scan_ALI (ali.adb).
It is ambigous since the CRC was optional and could be followed by
options like EB, EE. So now this routines uses lower-case letter for
the hexadecimal representation. Strange enough only lower case letters
where checked in Scan_ALI (even if this was not a possible case).
* gnatvsn.ads (Library_Version): changed to 3.15a.
* s-crc32.ads: Initial version from GNAT.CRC32. This is the version
for the compiler.
* s-crc32.adb: Initial version from GNAT.CRC32. This is the version
for the compiler.
* ali-util.adb: Redo previous change to avoid using word CRC everywhere
Add 2001 to copyright notice
(Accumulate_Checksum): Modify to use System.CRC32.
* ali-util.ads: Redo changes of previous revision to continue to use
the word Checksum. Add 2001 to copyright notice.
* ali.adb: Undo some of previous changes, not needed.
Keep the change for lower case letters in the checksum.
* ali.ads: Undo previous change not needed.
* bcheck.adb: Undo most of previous change, not needed.
But do use Checksums_Match for checksum comparison.
* gnatls.adb: Undo most of previous change, not needed.
But do use Checksums_Match for comparing checksums.
* lib-load.adb: Undo previous change, not needed.
* lib-writ.adb: Undo previous change, not needed.
* lib-writ.ads: Document that checksums use lower case,
not upper case letters.
* scans.adb: Undo previous change, not needed
* scans.ads: Undo previous change, not needed.
* scn-nlit.adb: Undo previous changes, not needed.
* scn-slit.adb: Undo previous change, not needed. Fix header format.
* scn.adb:
(Accumulate_Checksum): Use System.CRC32.
(Initialize_Checksum): New procedure.
Remove other changes of previous revision.
* sinput-p.adb: Undo previous change, not needed.
* sinput.adb: Undo previous change, not needed.
* sinput-l.adb: Undo previous change, not needed.
* sinput.ads: Undo previous change, not needed. Keep only comment
on new checksum algorithm
* Makefile.in: Add s-crc32 as needed, remove g-crc32.
Also remove a-tags and a-stream from GNAT sources.
* ali.adb (Scan_ALI): fix typo introduce in latest check-in.
* Makefile.in (GNATRTL_NONTASKING_OBJS): Add g-crc32.o.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@46206 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/ada/s-crc32.ads')
-rw-r--r-- | gcc/ada/s-crc32.ads | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/gcc/ada/s-crc32.ads b/gcc/ada/s-crc32.ads new file mode 100644 index 00000000000..07ad1b552f3 --- /dev/null +++ b/gcc/ada/s-crc32.ads @@ -0,0 +1,84 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT LIBRARY COMPONENTS -- +-- -- +-- S Y S T E M . C R C 3 2 -- +-- -- +-- S p e c -- +-- -- +-- $Revision$ +-- -- +-- Copyright (C) 2001 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 is maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +-- 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 Interfaces; + +package System.CRC32 is + + type CRC32 is new Interfaces.Unsigned_32; + -- Used to represent CRC32 values, which are 32 bit bit-strings + + procedure Initialize (C : out CRC32); + pragma Inline (Initialize); + -- Initialize CRC value by assigning the standard Init value (16#FFFF_FFFF) + + procedure Update + (C : in out CRC32; + Value : Character); + pragma Inline (Update); + -- Evolve CRC by including the contribution from Character'Pos (Value) + + function Get_Value (C : CRC32) return Interfaces.Unsigned_32; + pragma Inline (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. + +end System.CRC32; |