1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
|
#include "lib_crc.h"
/*******************************************************************\
* *
* 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. *
* *
* *
* Dependencies *
* ============ *
* *
* lib_crc.h CRC definitions and prototypes *
* *
* *
* Modification history *
* ==================== *
* *
* Date Version Comment *
* *
* 2008-04-20 1.16 Added CRC-CCITT calculation for Kermit *
* *
* 2007-04-01 1.15 Added CRC16 calculation for Modbus *
* *
* 2007-03-28 1.14 Added CRC16 routine for Sick devices *
* *
* 2005-12-17 1.13 Added CRC-CCITT with initial 0x1D0F *
* *
* 2005-05-14 1.12 Added CRC-CCITT with start value 0 *
* *
* 2005-02-05 1.11 Fixed bug in CRC-DNP routine *
* *
* 2005-02-04 1.10 Added CRC-DNP routines *
* *
* 1999-02-21 1.01 Added FALSE and TRUE mnemonics *
* *
* 1999-01-22 1.00 Initial source *
* *
\*******************************************************************/
/*******************************************************************\
* *
* #define P_xxxx *
* *
* The CRC's are computed using polynomials. The coefficients *
* for the algorithms are defined by the following constants. *
* *
\*******************************************************************/
#define P_16 0xA001
#define P_32 0xEDB88320L
#define P_CCITT 0x1021
#define P_DNP 0xA6BC
#define P_KERMIT 0x8408
#define P_SICK 0x8005
/*******************************************************************\
* *
* static int crc_tab...init *
* static unsigned ... crc_tab...[] *
* *
* The algorithms use tables with precalculated values. This *
* speeds up the calculation dramaticaly. The first time the *
* CRC function is called, the table for that specific calcu- *
* lation is set up. The ...init variables are used to deter- *
* mine if the initialization has taken place. The calculated *
* values are stored in the crc_tab... arrays. *
* *
* The variables are declared static. This makes them invisi- *
* ble for other modules of the program. *
* *
\*******************************************************************/
static int crc_tab16_init = FALSE;
static int crc_tab32_init = FALSE;
static int crc_tabccitt_init = FALSE;
static int crc_tabdnp_init = FALSE;
static int crc_tabkermit_init = FALSE;
static unsigned short crc_tab16[256];
static unsigned long crc_tab32[256];
static unsigned short crc_tabccitt[256];
static unsigned short crc_tabdnp[256];
static unsigned short crc_tabkermit[256];
/*******************************************************************\
* *
* static void init_crc...tab(); *
* *
* Three local functions are used to initialize the tables *
* with values for the algorithm. *
* *
\*******************************************************************/
static void init_crc16_tab( void );
static void init_crc32_tab( void );
static void init_crcccitt_tab( void );
static void init_crcdnp_tab( void );
static void init_crckermit_tab( void );
/*******************************************************************\
* *
* unsigned short update_crc_ccitt( unsigned long crc, char c ); *
* *
* The function update_crc_ccitt calculates a new CRC-CCITT *
* value based on the previous value of the CRC and the next *
* byte of the data to be checked. *
* *
\*******************************************************************/
unsigned short update_crc_ccitt( unsigned short crc, char c ) {
unsigned short tmp, short_c;
short_c = 0x00ff & (unsigned short) c;
if ( ! crc_tabccitt_init ) init_crcccitt_tab();
tmp = (crc >> 8) ^ short_c;
crc = (crc << 8) ^ crc_tabccitt[tmp];
return crc;
} /* update_crc_ccitt */
/*******************************************************************\
* *
* unsigned short update_crc_sick( *
* unsigned long crc, char c, char prev_byte ); *
* *
* The function update_crc_sick calculates a new CRC-SICK *
* value based on the previous value of the CRC and the next *
* byte of the data to be checked. *
* *
\*******************************************************************/
unsigned short update_crc_sick( unsigned short crc, char c, char prev_byte ) {
unsigned short short_c, short_p;
short_c = 0x00ff & (unsigned short) c;
short_p = ( 0x00ff & (unsigned short) prev_byte ) << 8;
if ( crc & 0x8000 ) crc = ( crc << 1 ) ^ P_SICK;
else crc = crc << 1;
crc &= 0xffff;
crc ^= ( short_c | short_p );
return crc;
} /* update_crc_sick */
/*******************************************************************\
* *
* unsigned short update_crc_16( unsigned short crc, char c ); *
* *
* The function update_crc_16 calculates a new CRC-16 value *
* based on the previous value of the CRC and the next byte *
* of the data to be checked. *
* *
\*******************************************************************/
unsigned short update_crc_16( unsigned short crc, char c ) {
unsigned short tmp, short_c;
short_c = 0x00ff & (unsigned short) c;
if ( ! crc_tab16_init ) init_crc16_tab();
tmp = crc ^ short_c;
crc = (crc >> 8) ^ crc_tab16[ tmp & 0xff ];
return crc;
} /* update_crc_16 */
/*******************************************************************\
* *
* unsigned short update_crc_kermit( unsigned short crc, char c ); *
* *
* The function update_crc_kermit calculates a new CRC value *
* based on the previous value of the CRC and the next byte *
* of the data to be checked. *
* *
\*******************************************************************/
unsigned short update_crc_kermit( unsigned short crc, char c ) {
unsigned short tmp, short_c;
short_c = 0x00ff & (unsigned short) c;
if ( ! crc_tabkermit_init ) init_crckermit_tab();
tmp = crc ^ short_c;
crc = (crc >> 8) ^ crc_tabkermit[ tmp & 0xff ];
return crc;
} /* update_crc_kermit */
/*******************************************************************\
* *
* unsigned short update_crc_dnp( unsigned short crc, char c ); *
* *
* The function update_crc_dnp calculates a new CRC-DNP value *
* based on the previous value of the CRC and the next byte *
* of the data to be checked. *
* *
\*******************************************************************/
unsigned short update_crc_dnp( unsigned short crc, char c ) {
unsigned short tmp, short_c;
short_c = 0x00ff & (unsigned short) c;
if ( ! crc_tabdnp_init ) init_crcdnp_tab();
tmp = crc ^ short_c;
crc = (crc >> 8) ^ crc_tabdnp[ tmp & 0xff ];
return crc;
} /* update_crc_dnp */
/*******************************************************************\
* *
* unsigned long update_crc_32( unsigned long crc, char c ); *
* *
* The function update_crc_32 calculates a new CRC-32 value *
* based on the previous value of the CRC and the next byte *
* of the data to be checked. *
* *
\*******************************************************************/
unsigned long update_crc_32( unsigned long crc, char c ) {
unsigned long tmp, long_c;
long_c = 0x000000ffL & (unsigned long) c;
if ( ! crc_tab32_init ) init_crc32_tab();
tmp = crc ^ long_c;
crc = (crc >> 8) ^ crc_tab32[ tmp & 0xff ];
return crc;
} /* update_crc_32 */
/*******************************************************************\
* *
* static void init_crc16_tab( void ); *
* *
* The function init_crc16_tab() is used to fill the array *
* for calculation of the CRC-16 with values. *
* *
\*******************************************************************/
static void init_crc16_tab( void ) {
int i, j;
unsigned short crc, c;
for (i=0; i<256; i++) {
crc = 0;
c = (unsigned short) i;
for (j=0; j<8; j++) {
if ( (crc ^ c) & 0x0001 ) crc = ( crc >> 1 ) ^ P_16;
else crc = crc >> 1;
c = c >> 1;
}
crc_tab16[i] = crc;
}
crc_tab16_init = TRUE;
} /* init_crc16_tab */
/*******************************************************************\
* *
* static void init_crckermit_tab( void ); *
* *
* The function init_crckermit_tab() is used to fill the array *
* for calculation of the CRC Kermit with values. *
* *
\*******************************************************************/
static void init_crckermit_tab( void ) {
int i, j;
unsigned short crc, c;
for (i=0; i<256; i++) {
crc = 0;
c = (unsigned short) i;
for (j=0; j<8; j++) {
if ( (crc ^ c) & 0x0001 ) crc = ( crc >> 1 ) ^ P_KERMIT;
else crc = crc >> 1;
c = c >> 1;
}
crc_tabkermit[i] = crc;
}
crc_tabkermit_init = TRUE;
} /* init_crckermit_tab */
/*******************************************************************\
* *
* static void init_crcdnp_tab( void ); *
* *
* The function init_crcdnp_tab() is used to fill the array *
* for calculation of the CRC-DNP with values. *
* *
\*******************************************************************/
static void init_crcdnp_tab( void ) {
int i, j;
unsigned short crc, c;
for (i=0; i<256; i++) {
crc = 0;
c = (unsigned short) i;
for (j=0; j<8; j++) {
if ( (crc ^ c) & 0x0001 ) crc = ( crc >> 1 ) ^ P_DNP;
else crc = crc >> 1;
c = c >> 1;
}
crc_tabdnp[i] = crc;
}
crc_tabdnp_init = TRUE;
} /* init_crcdnp_tab */
/*******************************************************************\
* *
* static void init_crc32_tab( void ); *
* *
* The function init_crc32_tab() is used to fill the array *
* for calculation of the CRC-32 with values. *
* *
\*******************************************************************/
static void init_crc32_tab( void ) {
int i, j;
unsigned long crc;
for (i=0; i<256; i++) {
crc = (unsigned long) i;
for (j=0; j<8; j++) {
if ( crc & 0x00000001L ) crc = ( crc >> 1 ) ^ P_32;
else crc = crc >> 1;
}
crc_tab32[i] = crc;
}
crc_tab32_init = TRUE;
} /* init_crc32_tab */
/*******************************************************************\
* *
* static void init_crcccitt_tab( void ); *
* *
* The function init_crcccitt_tab() is used to fill the array *
* for calculation of the CRC-CCITT with values. *
* *
\*******************************************************************/
static void init_crcccitt_tab( void ) {
int i, j;
unsigned short crc, c;
for (i=0; i<256; i++) {
crc = 0;
c = ((unsigned short) i) << 8;
for (j=0; j<8; j++) {
if ( (crc ^ c) & 0x8000 ) crc = ( crc << 1 ) ^ P_CCITT;
else crc = crc << 1;
c = c << 1;
}
crc_tabccitt[i] = crc;
}
crc_tabccitt_init = TRUE;
} /* init_crcccitt_tab */
|
