93 lines
2.9 KiB
ObjectPascal
93 lines
2.9 KiB
ObjectPascal
{ rxCRC unit
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Copyright (C) 2005-2017 Lagunov Aleksey alexs@yandex.ru and Lazarus team
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original conception from rx library for Delphi (c)
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This library is free software; you can redistribute it and/or modify it
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under the terms of the GNU Library General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at your
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option) any later version with the following modification:
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent modules,and
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to copy and distribute the resulting executable under terms of your choice,
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provided that you also meet, for each linked independent module, the terms
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and conditions of the license of that module. An independent module is a
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module which is not derived from or based on this library. If you modify
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this library, you may extend this exception to your version of the library,
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but you are not obligated to do so. If you do not wish to do so, delete this
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exception statement from your version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
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for more details.
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You should have received a copy of the GNU Library General Public License
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along with this library; if not, write to the Free Software Foundation,
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Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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}
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unit rxCRC;
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{$mode objfpc}{$H+}
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interface
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uses
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Classes, SysUtils;
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function rxCRC8(Buffer:String;Polynom,Initial:Cardinal):Cardinal; overload;
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function rxCRC8(Buffer:PByteArray; BufferLen:Cardinal; Polynom,Initial:Cardinal):Cardinal; overload;
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implementation
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{autor - hansotten
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http://forum.lazarus.freepascal.org/index.php?topic=31532.msg202338#msg202338
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}
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function rxCRC8(Buffer:String;Polynom,Initial:Cardinal):Cardinal;
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var
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i,j : Integer;
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begin
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{ Result:=Initial;
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for i:=1 to Length(Buffer) do
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begin
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Result:=Result xor Ord(buffer[i]);
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for j:=0 to 7 do
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begin
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if (Result and $80)<>0 then
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Result:=(Result shl 1) xor Polynom
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else
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Result:=Result shl 1;
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end;
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end;
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Result:=Result and $ff;}
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if Length(Buffer) > 0 then
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Result:=rxCRC8(@Buffer[1], Length(Buffer), Polynom, Initial)
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else
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Result:=Initial;
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end;
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function rxCRC8(Buffer: PByteArray; BufferLen: Cardinal; Polynom, Initial: Cardinal
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): Cardinal;
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var
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i,j : Integer;
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begin
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Result:=Initial;
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for i:=0 to BufferLen-1 do
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begin
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Result:=Result xor Buffer^[i];
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for j:=0 to 7 do
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begin
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if (Result and $80)<>0 then
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Result:=(Result shl 1) xor Polynom
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else
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Result:=Result shl 1;
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end;
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end;
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Result:=Result and $ff;
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end;
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end.
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