1 /****************************************************************************
2 * RRDtool 1.0.28 Copyright Tobias Oetiker, 1997 - 2002
3 ****************************************************************************
4 * rrd_rpncalc.c RPN calculator functions
5 ****************************************************************************/
7 #include "rrd_tool.h"
8 #include "rrd_rpncalc.h"
9 #include <limits.h>
11 short addop2str(enum op_en op, enum op_en op_type, char *op_str,
12 char **result_str, unsigned short *offset);
13 int tzoffset(time_t); /* used to implement LTIME */
15 short rpn_compact(rpnp_t *rpnp, rpn_cdefds_t **rpnc, short *count)
16 {
17 short i;
18 *count = 0;
19 /* count the number of rpn nodes */
20 while(rpnp[*count].op != OP_END) (*count)++;
21 if (++(*count) > DS_CDEF_MAX_RPN_NODES) {
22 rrd_set_error("Maximum %d RPN nodes permitted",
23 DS_CDEF_MAX_RPN_NODES);
24 return -1;
25 }
27 /* allocate memory */
28 *rpnc = (rpn_cdefds_t *) calloc(*count,sizeof(rpn_cdefds_t));
29 for (i = 0; rpnp[i].op != OP_END; i++)
30 {
31 (*rpnc)[i].op = (char) rpnp[i].op;
32 if (rpnp[i].op == OP_NUMBER) {
33 /* rpnp.val is a double, rpnc.val is a short */
34 double temp = floor(rpnp[i].val);
35 if (temp < SHRT_MIN || temp > SHRT_MAX) {
36 rrd_set_error(
37 "constants must be integers in the interval (%d, %d)",
38 SHRT_MIN, SHRT_MAX);
39 free(*rpnc);
40 return -1;
41 }
42 (*rpnc)[i].val = (short) temp;
43 } else if (rpnp[i].op == OP_VARIABLE) {
44 (*rpnc)[i].val = (short) rpnp[i].ptr;
45 }
46 }
47 /* terminate the sequence */
48 (*rpnc)[(*count) - 1].op = OP_END;
49 return 0;
50 }
52 rpnp_t * rpn_expand(rpn_cdefds_t *rpnc)
53 {
54 short i;
55 rpnp_t *rpnp;
57 /* DS_CDEF_MAX_RPN_NODES is small, so at the expense of some wasted
58 * memory we avoid any reallocs */
59 rpnp = (rpnp_t *) calloc(DS_CDEF_MAX_RPN_NODES,sizeof(rpnp_t));
60 if (rpnp == NULL) return NULL;
61 for (i = 0; rpnc[i].op != OP_END; ++i)
62 {
63 rpnp[i].op = (long) rpnc[i].op;
64 if (rpnp[i].op == OP_NUMBER) {
65 rpnp[i].val = (double) rpnc[i].val;
66 } else if (rpnp[i].op == OP_VARIABLE) {
67 rpnp[i].ptr = (long) rpnc[i].val;
68 }
69 }
70 /* terminate the sequence */
71 rpnp[i].op = OP_END;
72 return rpnp;
73 }
75 /* rpn_compact2str: convert a compact sequence of RPN operator nodes back
76 * into a CDEF string. This function is used by rrd_dump.
77 * arguments:
78 * rpnc: an array of compact RPN operator nodes
79 * ds_def: a pointer to the data source definition section of an RRD header
80 * for lookup of data source names by index
81 * str: out string, memory is allocated by the function, must be freed by the
82 * the caller */
83 void rpn_compact2str(rpn_cdefds_t *rpnc,ds_def_t *ds_def,char **str)
84 {
85 unsigned short i,offset = 0;
86 char buffer[7]; /* short as a string */
88 for (i = 0; rpnc[i].op != OP_END; i++)
89 {
90 if (i > 0) (*str)[offset++] = ',';
92 #define add_op(VV,VVV) \
93 if (addop2str(rpnc[i].op, VV, VVV, str, &offset) == 1) continue;
95 if (rpnc[i].op == OP_NUMBER) {
96 /* convert a short into a string */
97 #ifdef WIN32
98 _itoa(rpnc[i].val,buffer,10);
99 #else
100 sprintf(buffer,"%d",rpnc[i].val);
101 #endif
102 add_op(OP_NUMBER,buffer)
103 }
105 if (rpnc[i].op == OP_VARIABLE) {
106 char *ds_name = ds_def[rpnc[i].val].ds_nam;
107 add_op(OP_VARIABLE, ds_name)
108 }
109 #undef add_op
111 #define add_op(VV,VVV) \
112 if (addop2str(rpnc[i].op, VV, #VVV, str, &offset) == 1) continue;
114 add_op(OP_ADD,+)
115 add_op(OP_SUB,-)
116 add_op(OP_MUL,*)
117 add_op(OP_DIV,/)
118 add_op(OP_MOD,%)
119 add_op(OP_SIN,SIN)
120 add_op(OP_COS,COS)
121 add_op(OP_LOG,LOG)
122 add_op(OP_FLOOR,FLOOR)
123 add_op(OP_CEIL,CEIL)
124 add_op(OP_EXP,EXP)
125 add_op(OP_DUP,DUP)
126 add_op(OP_EXC,EXC)
127 add_op(OP_POP,POP)
128 add_op(OP_LT,LT)
129 add_op(OP_LE,LE)
130 add_op(OP_GT,GT)
131 add_op(OP_GE,GE)
132 add_op(OP_EQ,EQ)
133 add_op(OP_IF,IF)
134 add_op(OP_MIN,MIN)
135 add_op(OP_MAX,MAX)
136 add_op(OP_LIMIT,LIMIT)
137 add_op(OP_UNKN,UNKN)
138 add_op(OP_UN,UN)
139 add_op(OP_NEGINF,NEGINF)
140 add_op(OP_NE,NE)
141 add_op(OP_PREV,PREV)
142 add_op(OP_INF,INF)
143 add_op(OP_ISINF,ISINF)
144 add_op(OP_NOW,NOW)
145 add_op(OP_LTIME,LTIME)
146 add_op(OP_TIME,TIME)
148 #undef add_op
149 }
150 (*str)[offset] = '\0';
152 }
154 short addop2str(enum op_en op, enum op_en op_type, char *op_str,
155 char **result_str, unsigned short *offset)
156 {
157 if (op == op_type) {
158 short op_len;
159 op_len = strlen(op_str);
160 *result_str = (char *) rrd_realloc(*result_str,
161 (op_len + 1 + *offset)*sizeof(char));
162 if (*result_str == NULL) {
163 rrd_set_error("failed to alloc memory in addop2str");
164 return -1;
165 }
166 strncpy(&((*result_str)[*offset]),op_str,op_len);
167 *offset += op_len;
168 return 1;
169 }
170 return 0;
171 }
173 void parseCDEF_DS(char *def,rrd_t *rrd, int ds_idx)
174 {
175 rpnp_t *rpnp = NULL;
176 rpn_cdefds_t *rpnc = NULL;
177 short count, i;
179 rpnp = rpn_parse((void*) rrd, def, &lookup_DS);
180 if (rpnp == NULL) {
181 rrd_set_error("failed to parse computed data source %s", def);
182 return;
183 }
184 /* Check for OP nodes not permitted in COMPUTE DS.
185 * Moved this check from within rpn_compact() because it really is
186 * COMPUTE DS specific. This is less efficient, but creation doesn't
187 * occur too often. */
188 for (i = 0; rpnp[i].op != OP_END; i++) {
189 if (rpnp[i].op == OP_TIME || rpnp[i].op == OP_LTIME ||
190 rpnp[i].op == OP_PREV)
191 {
192 rrd_set_error(
193 "operators time, ltime and prev not supported with DS COMPUTE");
194 free(rpnp);
195 return;
196 }
197 }
198 if (rpn_compact(rpnp,&rpnc,&count) == -1) {
199 free(rpnp);
200 return;
201 }
202 /* copy the compact rpn representation over the ds_def par array */
203 memcpy((void*) &(rrd -> ds_def[ds_idx].par[DS_cdef]),
204 (void*) rpnc, count*sizeof(rpn_cdefds_t));
205 free(rpnp);
206 free(rpnc);
207 }
209 /* lookup a data source name in the rrd struct and return the index,
210 * should use ds_match() here except:
211 * (1) need a void * pointer to the rrd
212 * (2) error handling is left to the caller
213 */
214 long lookup_DS(void *rrd_vptr,char *ds_name)
215 {
216 int i;
217 rrd_t *rrd;
219 rrd = (rrd_t *) rrd_vptr;
221 for (i = 0; i < rrd -> stat_head -> ds_cnt; ++i)
222 {
223 if(strcmp(ds_name,rrd -> ds_def[i].ds_nam) == 0)
224 return i;
225 }
226 /* the caller handles a bad data source name in the rpn string */
227 return -1;
228 }
230 /* rpn_parse : parse a string and generate a rpnp array; modified
231 * str2rpn() originally included in rrd_graph.c
232 * arguments:
233 * key_hash: a transparent argument passed to lookup(); conceptually this
234 * is a hash object for lookup of a numeric key given a variable name
235 * expr: the string RPN expression, including variable names
236 * lookup(): a function that retrieves a numeric key given a variable name
237 */
238 rpnp_t *
239 rpn_parse(void *key_hash,char *expr,long (*lookup)(void *,char*)){
240 int pos=0;
241 long steps=-1;
242 rpnp_t *rpnp;
243 char vname[30];
245 rpnp=NULL;
247 while(*expr){
248 if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2)*
249 sizeof(rpnp_t)))==NULL){
250 return NULL;
251 }
253 else if((sscanf(expr,"%lf%n",&rpnp[steps].val,&pos) == 1) && (expr[pos] == ',')){
254 rpnp[steps].op = OP_NUMBER;
255 expr+=pos;
256 }
258 #define match_op(VV,VVV) \
259 else if (strncmp(expr, #VVV, strlen(#VVV))==0){ \
260 rpnp[steps].op = VV; \
261 expr+=strlen(#VVV); \
262 }
264 match_op(OP_ADD,+)
265 match_op(OP_SUB,-)
266 match_op(OP_MUL,*)
267 match_op(OP_DIV,/)
268 match_op(OP_MOD,%)
269 match_op(OP_SIN,SIN)
270 match_op(OP_COS,COS)
271 match_op(OP_LOG,LOG)
272 match_op(OP_FLOOR,FLOOR)
273 match_op(OP_CEIL,CEIL)
274 match_op(OP_EXP,EXP)
275 match_op(OP_DUP,DUP)
276 match_op(OP_EXC,EXC)
277 match_op(OP_POP,POP)
278 match_op(OP_LT,LT)
279 match_op(OP_LE,LE)
280 match_op(OP_GT,GT)
281 match_op(OP_GE,GE)
282 match_op(OP_EQ,EQ)
283 match_op(OP_IF,IF)
284 match_op(OP_MIN,MIN)
285 match_op(OP_MAX,MAX)
286 match_op(OP_LIMIT,LIMIT)
287 /* order is important here ! .. match longest first */
288 match_op(OP_UNKN,UNKN)
289 match_op(OP_UN,UN)
290 match_op(OP_NEGINF,NEGINF)
291 match_op(OP_NE,NE)
292 match_op(OP_PREV,PREV)
293 match_op(OP_INF,INF)
294 match_op(OP_ISINF,ISINF)
295 match_op(OP_NOW,NOW)
296 match_op(OP_LTIME,LTIME)
297 match_op(OP_TIME,TIME)
299 #undef match_op
302 else if ((sscanf(expr,"%29[_A-Za-z0-9]%n",
303 vname,&pos) == 1)
304 && ((rpnp[steps].ptr = (*lookup)(key_hash,vname)) != -1)){
305 rpnp[steps].op = OP_VARIABLE;
306 expr+=pos;
307 }
309 else {
310 free(rpnp);
311 return NULL;
312 }
313 if (*expr == 0)
314 break;
315 if (*expr == ',')
316 expr++;
317 else {
318 free(rpnp);
319 return NULL;
320 }
321 }
322 rpnp[steps+1].op = OP_END;
323 return rpnp;
324 }
326 void
327 rpnstack_init(rpnstack_t *rpnstack)
328 {
329 rpnstack -> s = NULL;
330 rpnstack -> dc_stacksize = 0;
331 rpnstack -> dc_stackblock = 100;
332 }
334 void
335 rpnstack_free(rpnstack_t *rpnstack)
336 {
337 if (rpnstack -> s != NULL)
338 free(rpnstack -> s);
339 rpnstack -> dc_stacksize = 0;
340 }
342 /* rpn_calc: run the RPN calculator; also performs variable substitution;
343 * moved and modified from data_calc() originally included in rrd_graph.c
344 * arguments:
345 * rpnp : an array of RPN operators (including variable references)
346 * rpnstack : the initialized stack
347 * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
348 * is advanced by rpnp.ds_cnt; used only for variable substitution
349 * output : an array of output values; OP_PREV assumes this array contains
350 * the "previous" value at index position output_idx-1; the definition of
351 * "previous" depends on the calling environment
352 * output_idx : an index into the output array in which to store the output
353 * of the RPN calculator
354 * returns: -1 if the computation failed (also calls rrd_set_error)
355 * 0 on success
356 */
357 short
358 rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx,
359 rrd_value_t *output, int output_idx)
360 {
361 int rpi;
362 long stptr = -1;
364 /* process each op from the rpn in turn */
365 for (rpi=0; rpnp[rpi].op != OP_END; rpi++){
366 /* allocate or grow the stack */
367 if (stptr + 5 > rpnstack -> dc_stacksize){
368 /* could move this to a separate function */
369 rpnstack -> dc_stacksize += rpnstack -> dc_stackblock;
370 rpnstack -> s = rrd_realloc(rpnstack -> s,
371 (rpnstack -> dc_stacksize)*sizeof(*(rpnstack -> s)));
372 if (rpnstack -> s == NULL){
373 rrd_set_error("RPN stack overflow");
374 return -1;
375 }
376 }
378 #define stackunderflow(MINSIZE) \
379 if(stptr<MINSIZE){ \
380 rrd_set_error("RPN stack underflow"); \
381 return -1; \
382 }
384 switch (rpnp[rpi].op){
385 case OP_NUMBER:
386 rpnstack -> s[++stptr] = rpnp[rpi].val;
387 break;
388 case OP_VARIABLE:
389 /* Sanity check: VDEFs shouldn't make it here */
390 if (rpnp[rpi].ds_cnt == 0) {
391 rrd_set_error("VDEF made it into rpn_calc... aborting");
392 return -1;
393 } else {
394 /* make sure we pull the correct value from
395 * the *.data array. Adjust the pointer into
396 * the array acordingly. Advance the ptr one
397 * row in the rra (skip over non-relevant
398 * data sources)
399 */
400 rpnstack -> s[++stptr] = *(rpnp[rpi].data);
401 if (data_idx % rpnp[rpi].step == 0){
402 rpnp[rpi].data += rpnp[rpi].ds_cnt;
403 }
404 }
405 break;
406 case OP_PREV:
407 if ((output_idx-1) <= 0) {
408 rpnstack -> s[++stptr] = DNAN;
409 } else {
410 rpnstack -> s[++stptr] = output[output_idx-1];
411 }
412 break;
413 case OP_UNKN:
414 rpnstack -> s[++stptr] = DNAN;
415 break;
416 case OP_INF:
417 rpnstack -> s[++stptr] = DINF;
418 break;
419 case OP_NEGINF:
420 rpnstack -> s[++stptr] = -DINF;
421 break;
422 case OP_NOW:
423 rpnstack -> s[++stptr] = (double)time(NULL);
424 break;
425 case OP_TIME:
426 /* HACK: this relies on the data_idx being the time,
427 ** which the within-function scope is unaware of */
428 rpnstack -> s[++stptr] = (double) data_idx;
429 break;
430 case OP_LTIME:
431 rpnstack -> s[++stptr] =
432 (double) tzoffset(data_idx) + (double)data_idx;
433 break;
434 case OP_ADD:
435 stackunderflow(1);
436 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1]
437 + rpnstack -> s[stptr];
438 stptr--;
439 break;
440 case OP_SUB:
441 stackunderflow(1);
442 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1]
443 - rpnstack -> s[stptr];
444 stptr--;
445 break;
446 case OP_MUL:
447 stackunderflow(1);
448 rpnstack -> s[stptr-1] = (rpnstack -> s[stptr-1])
449 * (rpnstack -> s[stptr]);
450 stptr--;
451 break;
452 case OP_DIV:
453 stackunderflow(1);
454 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1]
455 / rpnstack -> s[stptr];
456 stptr--;
457 break;
458 case OP_MOD:
459 stackunderflow(1);
460 rpnstack -> s[stptr-1]= fmod( rpnstack -> s[stptr-1]
461 ,rpnstack -> s[stptr]);
462 stptr--;
463 break;
464 case OP_SIN:
465 stackunderflow(0);
466 rpnstack -> s[stptr] = sin(rpnstack -> s[stptr]);
467 break;
468 case OP_COS:
469 stackunderflow(0);
470 rpnstack -> s[stptr] = cos(rpnstack -> s[stptr]);
471 break;
472 case OP_CEIL:
473 stackunderflow(0);
474 rpnstack -> s[stptr] = ceil(rpnstack -> s[stptr]);
475 break;
476 case OP_FLOOR:
477 stackunderflow(0);
478 rpnstack -> s[stptr] = floor(rpnstack -> s[stptr]);
479 break;
480 case OP_LOG:
481 stackunderflow(0);
482 rpnstack -> s[stptr] = log(rpnstack -> s[stptr]);
483 break;
484 case OP_DUP:
485 stackunderflow(0);
486 rpnstack -> s[stptr+1] = rpnstack -> s[stptr];
487 stptr++;
488 break;
489 case OP_POP:
490 stackunderflow(0);
491 stptr--;
492 break;
493 case OP_EXC:
494 stackunderflow(1);
495 {
496 double dummy;
497 dummy = rpnstack -> s[stptr] ;
498 rpnstack -> s[stptr] = rpnstack -> s[stptr-1];
499 rpnstack -> s[stptr-1] = dummy;
500 }
501 break;
502 case OP_EXP:
503 stackunderflow(0);
504 rpnstack -> s[stptr] = exp(rpnstack -> s[stptr]);
505 break;
506 case OP_LT:
507 stackunderflow(1);
508 if (isnan(rpnstack -> s[stptr-1]))
509 ;
510 else if (isnan(rpnstack -> s[stptr]))
511 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
512 else
513 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <
514 rpnstack -> s[stptr] ? 1.0 : 0.0;
515 stptr--;
516 break;
517 case OP_LE:
518 stackunderflow(1);
519 if (isnan(rpnstack -> s[stptr-1]))
520 ;
521 else if (isnan(rpnstack -> s[stptr]))
522 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
523 else
524 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <=
525 rpnstack -> s[stptr] ? 1.0 : 0.0;
526 stptr--;
527 break;
528 case OP_GT:
529 stackunderflow(1);
530 if (isnan(rpnstack -> s[stptr-1]))
531 ;
532 else if (isnan(rpnstack -> s[stptr]))
533 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
534 else
535 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >
536 rpnstack -> s[stptr] ? 1.0 : 0.0;
537 stptr--;
538 break;
539 case OP_GE:
540 stackunderflow(1);
541 if (isnan(rpnstack -> s[stptr-1]))
542 ;
543 else if (isnan(rpnstack -> s[stptr]))
544 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
545 else
546 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >=
547 rpnstack -> s[stptr] ? 1.0 : 0.0;
548 stptr--;
549 break;
550 case OP_NE:
551 stackunderflow(1);
552 if (isnan(rpnstack -> s[stptr-1]))
553 ;
554 else if (isnan(rpnstack -> s[stptr]))
555 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
556 else
557 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
558 rpnstack -> s[stptr] ? 0.0 : 1.0;
559 stptr--;
560 break;
561 case OP_EQ:
562 stackunderflow(1);
563 if (isnan(rpnstack -> s[stptr-1]))
564 ;
565 else if (isnan(rpnstack -> s[stptr]))
566 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
567 else
568 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
569 rpnstack -> s[stptr] ? 1.0 : 0.0;
570 stptr--;
571 break;
572 case OP_IF:
573 stackunderflow(2);
574 rpnstack->s[stptr-2] = rpnstack->s[stptr-2] != 0.0 ?
575 rpnstack->s[stptr-1] : rpnstack->s[stptr];
576 stptr--;
577 stptr--;
578 break;
579 case OP_MIN:
580 stackunderflow(1);
581 if (isnan(rpnstack->s[stptr-1]))
582 ;
583 else if (isnan(rpnstack->s[stptr]))
584 rpnstack->s[stptr-1] = rpnstack->s[stptr];
585 else if (rpnstack->s[stptr-1] > rpnstack->s[stptr])
586 rpnstack->s[stptr-1] = rpnstack->s[stptr];
587 stptr--;
588 break;
589 case OP_MAX:
590 stackunderflow(1);
591 if (isnan(rpnstack->s[stptr-1]))
592 ;
593 else if (isnan(rpnstack->s[stptr]))
594 rpnstack->s[stptr-1] = rpnstack->s[stptr];
595 else if (rpnstack->s[stptr-1] < rpnstack->s[stptr])
596 rpnstack->s[stptr-1] = rpnstack->s[stptr];
597 stptr--;
598 break;
599 case OP_LIMIT:
600 stackunderflow(2);
601 if (isnan(rpnstack->s[stptr-2]))
602 ;
603 else if (isnan(rpnstack->s[stptr-1]))
604 rpnstack->s[stptr-2] = rpnstack->s[stptr-1];
605 else if (isnan(rpnstack->s[stptr]))
606 rpnstack->s[stptr-2] = rpnstack->s[stptr];
607 else if (rpnstack->s[stptr-2] < rpnstack->s[stptr-1])
608 rpnstack->s[stptr-2] = DNAN;
609 else if (rpnstack->s[stptr-2] > rpnstack->s[stptr])
610 rpnstack->s[stptr-2] = DNAN;
611 stptr-=2;
612 break;
613 case OP_UN:
614 stackunderflow(0);
615 rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
616 break;
617 case OP_ISINF:
618 stackunderflow(0);
619 rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
620 break;
621 case OP_END:
622 break;
623 }
624 #undef stackunderflow
625 }
626 if(stptr!=0){
627 rrd_set_error("RPN final stack size != 1");
628 return -1;
629 }
631 output[output_idx] = rpnstack->s[0];
632 return 0;
633 }
635 /* figure out what the local timezone offset for any point in
636 time was. Return it in seconds */
637 int
638 tzoffset( time_t now ){
639 int gm_sec, gm_min, gm_hour, gm_yday, gm_year,
640 l_sec, l_min, l_hour, l_yday, l_year;
641 struct tm *t;
642 int off;
643 t = gmtime(&now);
644 gm_sec = t->tm_sec;
645 gm_min = t->tm_min;
646 gm_hour = t->tm_hour;
647 gm_yday = t->tm_yday;
648 gm_year = t->tm_year;
649 t = localtime(&now);
650 l_sec = t->tm_sec;
651 l_min = t->tm_min;
652 l_hour = t->tm_hour;
653 l_yday = t->tm_yday;
654 l_year = t->tm_year;
655 off = (l_sec-gm_sec)+(l_min-gm_min)*60+(l_hour-gm_hour)*3600;
656 if ( l_yday > gm_yday || l_year > gm_year){
657 off += 24*3600;
658 } else if ( l_yday < gm_yday || l_year < gm_year){
659 off -= 24*3600;
660 }
661 return off;
662 }