分享一篇CRC校验码生成的源代码
分享一篇CRC校验的源代码，主要是改写别人的，原来是C语言写的，我把它改为 Pascal版本了
详见我的空间文件地址：http://www.cnblogs.com/tangqs/archive/2011/12/08/2280255.html
里面有源代码下载，这里没办法全部贴出来，我只贴了一部分。
这个对做硬件通信有些帮助，可能会用到。里面的CRC有很多种。
{ /*********************************************************************\ * * * Library : lib_crc * * File : lib_crc.c * * Author : Lammert Bies 1999-2008 * * E-mail : info@lammertbies.nl * * Language : ANSI C * * * * * * Description * * =========== * * * * The file lib_crc.c contains the private and public func- * * tions used for the calculation of CRC-16, CRC-CCITT and * * CRC-32 cyclic redundancy values. * /*********************************************************************\ // 以上为本程序的原始作者信息，我将改为 pascal 版本。 // 网址程序请参见：http://www.lammertbies.nl/comm/info/crc-calculation.html}unit Unit_CRC;interfaceuses SysUtils, StrUtils; function Calcu_crc_16(const initialCRC: Word; const DataStr: string): Word; function Calcu_crc_sick(const DataStr: string): Word; function Calcu_crc_ccitt(const initialCRC: Word; const DataStr: string): Word; function Calcu_crc_kermit(const DataStr: string): Word; function Calcu_crc_dnp(const DataStr: string): Word; // 福建省能源计量数据采集系统数据传输协议 DB 35/987-2010 中约定CRC计算方法 function Calcu_crc_DB35(const DataStr: string): Word; function Calcu_crc_32(const DataStr: string): LongWord; function OriginalCalcuCRC_16(const DataStr: string): Word; function OriginalCalcuCRC_CCITT(const DataStr: string): Word; function FormatHexData(var AHexStr: string): Boolean; function ConvHexToString(const AHexStr: string): string;implementationType TcrcArr = array [0..255] of Word; TcrcArrDW = array [0..255] of LongWord;const P_16: Word = $A001; P_CCITT: Word = $1021; P_DNP: Word = $A6BC; P_KERMIT: Word = $8408; P_SICK: Word = $8005; P_32: LongWord = $EDB88320;var crc_tab16, crc_tabccitt, crc_tabdnp, crc_tabkermit: TcrcArr; crc_tab32: TcrcArrDW;function Calcu_crc_16(const initialCRC: Word; const DataStr: string): Word;var i: integer; tmp, short_c, crc: Word; aByte: Byte;begin crc := initialCRC; for i := 1 to Length(DataStr) do begin aByte := ord(DataStr[i]); short_c := ($00ff and aByte); tmp := crc xor short_c; crc := (crc shr 8) xor crc_tab16[ tmp and $ff ]; end; result := crc;end;function Calcu_crc_sick(const DataStr: string): Word;var i: integer; short_c, short_p, crc, high_byte, low_byte: Word; aByte, prev_byte: Byte;begin crc := $0000; prev_byte := 0; for i := 1 to Length(DataStr) do begin aByte := ord(DataStr[i]); short_c := ($00ff and aByte); short_p := ($00ff and prev_byte) shl 8; if (crc and $8000) = $8000 then crc := (crc shl 1) xor P_SICK else crc := (crc shl 1); crc := crc and $FFFF; crc := crc xor (short_c or short_p); prev_byte := aByte; end; low_byte := (crc and $ff00) shr 8; high_byte := (crc and $00ff) shl 8; result := low_byte or high_byte;end;function Calcu_crc_ccitt(const initialCRC: Word; const DataStr: string): Word;var i: integer; tmp, short_c, crc: Word; aByte: Byte;begin crc := initialCRC; for i := 1 to Length(DataStr) do begin aByte := ord(DataStr[i]); short_c := ($00ff and aByte); tmp := (crc shr 8) xor short_c; crc := (crc shl 8) xor crc_tabccitt[tmp]; end; result := crc;end;function Calcu_crc_kermit(const DataStr: string): Word;var i: integer; tmp, short_c, crc, high_byte, low_byte: Word; aByte: Byte;begin crc := $0000; for i := 1 to Length(DataStr) do begin aByte := ord(DataStr[i]); short_c := ($00ff and aByte); tmp := crc xor short_c; crc := (crc shr 8) xor crc_tabkermit[ tmp and $ff ]; end; low_byte := (crc and $ff00) shr 8; high_byte := (crc and $00ff) shl 8; result := low_byte or high_byte;end;function Calcu_crc_dnp(const DataStr: string): Word;var i: integer; tmp, short_c, crc, high_byte, low_byte: Word; aByte: Byte;begin crc := $0000; for i := 1 to Length(DataStr) do begin aByte := ord(DataStr[i]); short_c := ($00ff and aByte); tmp := crc xor short_c; crc := (crc shr 8) xor crc_tabdnp[ tmp and $ff ]; end; crc := not crc; low_byte := (crc and $ff00) shr 8; high_byte := (crc and $00ff) shl 8; result := low_byte or high_byte;end;//....因代码无法全部复制，其他代码请访问我的博客，里面有下载地址// 地址：http://www.cnblogs.com/tangqs/archive/2011/12/08/2280255.html//......procedure init_crc32_tab();var i, j: integer; crc: longWord;begin for i := 0 to 255 do begin crc := i; for j := 0 to 7 do begin if (crc and $00000001) = 1 then crc := ( crc shr 1 ) xor P_32 else crc := crc shr 1; end; crc_tab32[i] := crc; end;end;function FormatHexData(var AHexStr: string): Boolean;var // 格式化16进制数，比如 A1 0 1 1B0 变为 A1 00 01 01 B0 str, tmpstr: string; hexDataErr: Boolean; i, j, s1: integer;begin result := false; hexDataErr := false; if AHexStr = '' then Exit; str := AHexStr; for i := 1 to Length(str) do // 检查16进制是否合法 begin if not (str[i] in ['0'..'9', 'A'..'F', ' ', ',']) then begin hexDataErr := true; break; end; if str[i] = ',' then str[i] := ' '; // 将间隔用的逗号统一用空格代替 end; if hexDataErr then Exit; str := trim(str); // 去掉首尾多余空格 if pos(' ', str) > 0 then begin i := 1; while (i <= Length(str)) do // 消除重复的空格 begin if (str[i] = ' ') and ((i + 1) <= Length(str)) then if str[i + 1] = ' ' then begin delete(str, i + 1, 1); Dec(i); end; Inc(i); end; i := 1; s1 := 1; while (i <= Length(str)) do // 将单个的16进制数补完整，比如 A 补为 0A begin if (str[i] = ' ') OR (i = Length(str)) then begin if s1 = 1 then tmpstr := midStr(str, s1, i - s1) else if i = Length(str) then tmpstr := midStr(str, s1 + 1, i - s1) // i = Length(str) 情况 else tmpstr := midStr(str, s1 + 1, i - s1 - 1); if (length(tmpstr) mod 2) <> 0 then begin if s1 <> 1 then insert('0', str, s1 + 1) else insert('0', str, s1); Inc(i); end; s1 := i; end; Inc(i); end; str := StringReplace(str, ' ', '', [rfReplaceAll]); end; if (Length(str) mod 2) <> 0 then str := '0' + str; tmpstr := ''; for i := 1 to Length(str) do begin if (i mod 2) = 0 then tmpstr := tmpstr + str[i] + ' ' else tmpstr := tmpstr + str[i]; end; AHexStr := Trim(tmpstr); result := true;end;function ConvHexToString(const AHexStr: string): string;var str, tmpStr: string; i: integer;begin result := ''; str := AHexStr; if FormatHexData(str) then begin str := StringReplace(str, ' ', '', [rfReplaceAll]); tmpStr := ''; i := 1; while (i < Length(str)) do begin tmpStr := tmpStr + Char(strToInt('$' + str[i] + str[i + 1])); // 转换为 ASCII 值 i := i + 2; end; result := tmpStr; end;end;initialization init_crc16_tab(); init_crcdnp_tab(); init_crckermit_tab(); init_crcccitt_tab(); init_crc32_tab();finalization //end.