CRC16校驗算法實現(xiàn)5頁

1、CRC16校驗算法實現(xiàn)（轉(zhuǎn)）循環(huán)冗余碼校驗英文名稱為Cyclical Redundancy Check，簡稱CRC。它是利用除法及余數(shù)的原理來作錯誤偵測（Error Detecting）的。實際應用時，發(fā)送裝置計算出CRC值并隨數(shù)據(jù)一同發(fā)送給接收裝置，接收裝置對收到的數(shù)據(jù)重新計算CRC并與收到的CRC相比較，若兩個CRC值不同，則說明數(shù)據(jù)通訊出現(xiàn)錯誤。根據(jù)應用環(huán)境與習慣的不同，CRC又可分為以下幾種標準：CRC-12碼；CRC-16碼；CRC-CCITT碼；CRC-32碼。CRC-12碼通常用來傳送6-bit字符串。CRC-16及CRC-CCITT碼則用是來傳送8-bit字符，其中CRC-16

2、為美國采用，而CRC-CCITT為歐洲國家所采用。CRC-32碼大都被采用在一種稱為Point-to-Point的同步傳輸中。下面著重是CRC-16檢驗碼的生成過程。CRC-16碼由兩個字節(jié)構成，在開始時CRC寄存器的每一位都預置為1，然后把CRC寄存器與8-bit的數(shù)據(jù)進行異或，之后對CRC寄存器從高到低進行移位，在最高位（MSB）的位置補零，而最低位（LSB，移位后已經(jīng)被移出CRC寄存器）如果為1，則把寄存器與預定義的多項式碼進行異或，否則如果 LSB為零，則無需進行異或。重復上述的由高至低的移位8次，第一個8-bit數(shù)據(jù)處理完畢，用此時CRC寄存器的值與下一個8-bit數(shù)據(jù)異或并進行如前

3、一個數(shù)據(jù)似的8次移位。所有的字符處理完成后CRC寄存器內(nèi)的值即為最終的CRC值。下面為CRC16的計算過程，其中生成多項式為:X16+X15+X2+1：1設置CRC寄存器，并給其賦值FFFF(hex)。2將數(shù)據(jù)的第一個8-bit字符與16位CRC寄存器的低8位進行異或，并把結果存入CRC寄存器。3CRC寄存器向右移一位，MSB補零，移出并檢查LSB。4如果LSB為0，重復第三步；若LSB為1，CRC寄存器與生成多項式碼相異或。5重復第3與第4步直到8次移位全部完成。此時一個8-bit數(shù)據(jù)處理完畢。6重復第2至第5步直到所有數(shù)據(jù)全部處理完成。7最終CRC寄存器的內(nèi)容即為CRC值。校驗碼實現(xiàn)編寫C

4、RC校驗程序有兩種辦法：一種為計算法，一種為查表法。下面是查表法的C語言實現(xiàn)：校驗碼算法程序?qū)崿F(xiàn)樣例（C語言）：/ Test.cpp : Defines the entry point for the console application.#include stdafx.hstatic unsigned char auchCRCHi=0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0

5、x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x00,

6、0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,0x00, 0xC1, 0x81, 0x40,

7、 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81

8、, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,0x01, 0xC0, 0x80, 0x41, 0x01, 0xC

9、0, 0x80, 0x41, 0x00, 0xC1,0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,0x80, 0x41, 0x00, 0xC1, 0x81, 0x40;static unsigned char auchCRCLo=0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,0x07, 0xC7, 0x05, 0xC5, 0xC4, 0

10、x04, 0xCC, 0x0C, 0x0D, 0xCD,0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30,

11、0x31, 0xF1, 0x33, 0xF3,0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27,

12、 0xE7, 0xE6, 0x26,0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA

13、, 0xBE, 0x7E,0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9

14、B, 0x5B,0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,0x43, 0x83, 0x41, 0x81, 0x80, 0x40;unsigned short CRC16(unsigned char* puchMsg, unsigned short usDataLen)unsigned c

15、har uchCRCHi = 0xFF ;unsigned char uchCRCLo = 0xFF ;unsigned char uIndex ;while (usDataLen-)uIndex = uchCRCHi *puchMsg+;uchCRCHi = uchCRCLo auchCRCHiuIndex;uchCRCLo = auchCRCLouIndex;return (uchCRCHi 8 | uchCRCLo) ;void main(int argc, char* argv)unsigned char src21=1,2,3,6,3,4,2,3,4,2,9,8,7,3,6,5,2,

16、8,9,3,5;unsigned short code = CRC16(src,21);printf(the result is %d/n,code);以下是Delphi實現(xiàn)的代碼unit CRC16;interfaceusesWindows, SysUtils;function CRC(a_strPuchMsg:string):LongWord;implementationconstct_ArrayCRCHi: array0.255 of LongWord=($00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0,$80, $41, $00, $C1

17、, $81, $40, $01, $C0, $80, $41,$00, $C1, $81, $40, $00, $C1, $81, $40, $01, $C0,$80, $41, $01, $C0, $80, $41, $00, $C1, $81, $40,$00, $C1, $81, $40, $01, $C0, $80, $41, $00, $C1,$81, $40, $01, $C0, $80, $41, $01, $C0, $80, $41,$00, $C1, $81, $40, $01, $C0, $80, $41, $00, $C1,$81, $40, $00, $C1, $81,

18、 $40, $01, $C0, $80, $41,$00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0,$80, $41, $00, $C1, $81, $40, $00, $C1, $81, $40,$01, $C0, $80, $41, $01, $C0, $80, $41, $00, $C1,$81, $40, $01, $C0, $80, $41, $00, $C1, $81, $40,$00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0,$80, $41, $00, $C1, $81, $40,

19、$00, $C1, $81, $40,$01, $C0, $80, $41, $00, $C1, $81, $40, $01, $C0,$80, $41, $01, $C0, $80, $41, $00, $C1, $81, $40,$00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0,$80, $41, $00, $C1, $81, $40, $01, $C0, $80, $41,$00, $C1, $81, $40, $00, $C1, $81, $40, $01, $C0,$80, $41, $00, $C1, $81, $40, $01, $

20、C0, $80, $41,$01, $C0, $80, $41, $00, $C1, $81, $40, $01, $C0,$80, $41, $00, $C1, $81, $40, $00, $C1, $81, $40,$01, $C0, $80, $41, $01, $C0, $80, $41, $00, $C1,$81, $40, $00, $C1, $81, $40, $01, $C0, $80, $41,$00, $C1, $81, $40, $01, $C0, $80, $41, $01, $C0,$80, $41, $00, $C1, $81, $40);ct_ArrayCRCL

21、o:array0.255 of LongWord=($00, $C0, $C1, $01, $C3, $03, $02, $C2, $C6, $06,$07, $C7, $05, $C5, $C4, $04, $CC, $0C, $0D, $CD,$0F, $CF, $CE, $0E, $0A, $CA, $CB, $0B, $C9, $09,$08, $C8, $D8, $18, $19, $D9, $1B, $DB, $DA, $1A,$1E, $DE, $DF, $1F, $DD, $1D, $1C, $DC, $14, $D4,$D5, $15, $D7, $17, $16, $D6,

22、 $D2, $12, $13, $D3,$11, $D1, $D0, $10, $F0, $30, $31, $F1, $33, $F3,$F2, $32, $36, $F6, $F7, $37, $F5, $35, $34, $F4,$3C, $FC, $FD, $3D, $FF, $3F, $3E, $FE, $FA, $3A,$3B, $FB, $39, $F9, $F8, $38, $28, $E8, $E9, $29,$EB, $2B, $2A, $EA, $EE, $2E, $2F, $EF, $2D, $ED,$EC, $2C, $E4, $24, $25, $E5, $27,

23、$E7, $E6, $26,$22, $E2, $E3, $23, $E1, $21, $20, $E0, $A0, $60,$61, $A1, $63, $A3, $A2, $62, $66, $A6, $A7, $67,$A5, $65, $64, $A4, $6C, $AC, $AD, $6D, $AF, $6F,$6E, $AE, $AA, $6A, $6B, $AB, $69, $A9, $A8, $68,$78, $B8, $B9, $79, $BB, $7B, $7A, $BA, $BE, $7E,$7F, $BF, $7D, $BD, $BC, $7C, $B4, $74, $7