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 rpnp[i].op == OP_PREV_OTHER) {
45 (*rpnc)[i].val = (short) rpnp[i].ptr;
46 }
47 }
48 /* terminate the sequence */
49 (*rpnc)[(*count) - 1].op = OP_END;
50 return 0;
51 }
53 rpnp_t * rpn_expand(rpn_cdefds_t *rpnc)
54 {
55 short i;
56 rpnp_t *rpnp;
58 /* DS_CDEF_MAX_RPN_NODES is small, so at the expense of some wasted
59 * memory we avoid any reallocs */
60 rpnp = (rpnp_t *) calloc(DS_CDEF_MAX_RPN_NODES,sizeof(rpnp_t));
61 if (rpnp == NULL) return NULL;
62 for (i = 0; rpnc[i].op != OP_END; ++i)
63 {
64 rpnp[i].op = (long) rpnc[i].op;
65 if (rpnp[i].op == OP_NUMBER) {
66 rpnp[i].val = (double) rpnc[i].val;
67 } else if (rpnp[i].op == OP_VARIABLE ||
68 rpnp[i].op == OP_PREV_OTHER) {
69 rpnp[i].ptr = (long) rpnc[i].val;
70 }
71 }
72 /* terminate the sequence */
73 rpnp[i].op = OP_END;
74 return rpnp;
75 }
77 /* rpn_compact2str: convert a compact sequence of RPN operator nodes back
78 * into a CDEF string. This function is used by rrd_dump.
79 * arguments:
80 * rpnc: an array of compact RPN operator nodes
81 * ds_def: a pointer to the data source definition section of an RRD header
82 * for lookup of data source names by index
83 * str: out string, memory is allocated by the function, must be freed by the
84 * the caller */
85 void rpn_compact2str(rpn_cdefds_t *rpnc,ds_def_t *ds_def,char **str)
86 {
87 unsigned short i,offset = 0;
88 char buffer[7]; /* short as a string */
90 for (i = 0; rpnc[i].op != OP_END; i++)
91 {
92 if (i > 0) (*str)[offset++] = ',';
94 #define add_op(VV,VVV) \
95 if (addop2str(rpnc[i].op, VV, VVV, str, &offset) == 1) continue;
97 if (rpnc[i].op == OP_NUMBER) {
98 /* convert a short into a string */
99 #ifdef WIN32
100 _itoa(rpnc[i].val,buffer,10);
101 #else
102 sprintf(buffer,"%d",rpnc[i].val);
103 #endif
104 add_op(OP_NUMBER,buffer)
105 }
107 if (rpnc[i].op == OP_VARIABLE) {
108 char *ds_name = ds_def[rpnc[i].val].ds_nam;
109 add_op(OP_VARIABLE, ds_name)
110 }
112 if (rpnc[i].op == OP_PREV_OTHER) {
113 char *ds_name = ds_def[rpnc[i].val].ds_nam;
114 add_op(OP_VARIABLE, ds_name)
115 }
117 #undef add_op
119 #define add_op(VV,VVV) \
120 if (addop2str(rpnc[i].op, VV, #VVV, str, &offset) == 1) continue;
122 add_op(OP_ADD,+)
123 add_op(OP_SUB,-)
124 add_op(OP_MUL,*)
125 add_op(OP_DIV,/)
126 add_op(OP_MOD,%)
127 add_op(OP_SIN,SIN)
128 add_op(OP_COS,COS)
129 add_op(OP_LOG,LOG)
130 add_op(OP_FLOOR,FLOOR)
131 add_op(OP_CEIL,CEIL)
132 add_op(OP_EXP,EXP)
133 add_op(OP_DUP,DUP)
134 add_op(OP_EXC,EXC)
135 add_op(OP_POP,POP)
136 add_op(OP_LT,LT)
137 add_op(OP_LE,LE)
138 add_op(OP_GT,GT)
139 add_op(OP_GE,GE)
140 add_op(OP_EQ,EQ)
141 add_op(OP_IF,IF)
142 add_op(OP_MIN,MIN)
143 add_op(OP_MAX,MAX)
144 add_op(OP_LIMIT,LIMIT)
145 add_op(OP_UNKN,UNKN)
146 add_op(OP_UN,UN)
147 add_op(OP_NEGINF,NEGINF)
148 add_op(OP_NE,NE)
149 add_op(OP_PREV,PREV)
150 add_op(OP_INF,INF)
151 add_op(OP_ISINF,ISINF)
152 add_op(OP_NOW,NOW)
153 add_op(OP_LTIME,LTIME)
154 add_op(OP_TIME,TIME)
156 #undef add_op
157 }
158 (*str)[offset] = '\0';
160 }
162 short addop2str(enum op_en op, enum op_en op_type, char *op_str,
163 char **result_str, unsigned short *offset)
164 {
165 if (op == op_type) {
166 short op_len;
167 op_len = strlen(op_str);
168 *result_str = (char *) rrd_realloc(*result_str,
169 (op_len + 1 + *offset)*sizeof(char));
170 if (*result_str == NULL) {
171 rrd_set_error("failed to alloc memory in addop2str");
172 return -1;
173 }
174 strncpy(&((*result_str)[*offset]),op_str,op_len);
175 *offset += op_len;
176 return 1;
177 }
178 return 0;
179 }
181 void parseCDEF_DS(char *def,rrd_t *rrd, int ds_idx)
182 {
183 rpnp_t *rpnp = NULL;
184 rpn_cdefds_t *rpnc = NULL;
185 short count, i;
187 rpnp = rpn_parse((void*) rrd, def, &lookup_DS);
188 if (rpnp == NULL) {
189 rrd_set_error("failed to parse computed data source %s", def);
190 return;
191 }
192 /* Check for OP nodes not permitted in COMPUTE DS.
193 * Moved this check from within rpn_compact() because it really is
194 * COMPUTE DS specific. This is less efficient, but creation doesn't
195 * occur too often. */
196 for (i = 0; rpnp[i].op != OP_END; i++) {
197 if (rpnp[i].op == OP_TIME || rpnp[i].op == OP_LTIME ||
198 rpnp[i].op == OP_PREV)
199 {
200 rrd_set_error(
201 "operators time, ltime and prev not supported with DS COMPUTE");
202 free(rpnp);
203 return;
204 }
205 }
206 if (rpn_compact(rpnp,&rpnc,&count) == -1) {
207 free(rpnp);
208 return;
209 }
210 /* copy the compact rpn representation over the ds_def par array */
211 memcpy((void*) &(rrd -> ds_def[ds_idx].par[DS_cdef]),
212 (void*) rpnc, count*sizeof(rpn_cdefds_t));
213 free(rpnp);
214 free(rpnc);
215 }
217 /* lookup a data source name in the rrd struct and return the index,
218 * should use ds_match() here except:
219 * (1) need a void * pointer to the rrd
220 * (2) error handling is left to the caller
221 */
222 long lookup_DS(void *rrd_vptr,char *ds_name)
223 {
224 int i;
225 rrd_t *rrd;
227 rrd = (rrd_t *) rrd_vptr;
229 for (i = 0; i < rrd -> stat_head -> ds_cnt; ++i)
230 {
231 if(strcmp(ds_name,rrd -> ds_def[i].ds_nam) == 0)
232 return i;
233 }
234 /* the caller handles a bad data source name in the rpn string */
235 return -1;
236 }
238 /* rpn_parse : parse a string and generate a rpnp array; modified
239 * str2rpn() originally included in rrd_graph.c
240 * arguments:
241 * key_hash: a transparent argument passed to lookup(); conceptually this
242 * is a hash object for lookup of a numeric key given a variable name
243 * expr: the string RPN expression, including variable names
244 * lookup(): a function that retrieves a numeric key given a variable name
245 */
246 rpnp_t *
247 rpn_parse(void *key_hash,char *expr,long (*lookup)(void *,char*)){
248 int pos=0;
249 long steps=-1;
250 rpnp_t *rpnp;
251 char vname[30];
253 rpnp=NULL;
255 while(*expr){
256 if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2)*
257 sizeof(rpnp_t)))==NULL){
258 return NULL;
259 }
261 else if((sscanf(expr,"%lf%n",&rpnp[steps].val,&pos) == 1) && (expr[pos] == ',')){
262 rpnp[steps].op = OP_NUMBER;
263 expr+=pos;
264 }
266 #define match_op(VV,VVV) \
267 else if (strncmp(expr, #VVV, strlen(#VVV))==0){ \
268 rpnp[steps].op = VV; \
269 expr+=strlen(#VVV); \
270 }
273 #define match_op_param(VV,VVV) \
274 else if (sscanf(expr, #VVV "(" DEF_NAM_FMT ")",vname) == 1) { \
275 int length = 0; \
276 if ((length = strlen(#VVV)+strlen(vname)+2, \
277 expr[length] == ',' || expr[length] == '\0') ) { \
278 rpnp[steps].op = VV; \
279 rpnp[steps].ptr = (*lookup)(key_hash,vname); \
280 if (rpnp[steps].ptr < 0) { \
281 free(rpnp); \
282 return NULL; \
283 } else expr+=length; \
284 } \
285 }
287 match_op(OP_ADD,+)
288 match_op(OP_SUB,-)
289 match_op(OP_MUL,*)
290 match_op(OP_DIV,/)
291 match_op(OP_MOD,%)
292 match_op(OP_SIN,SIN)
293 match_op(OP_COS,COS)
294 match_op(OP_LOG,LOG)
295 match_op(OP_FLOOR,FLOOR)
296 match_op(OP_CEIL,CEIL)
297 match_op(OP_EXP,EXP)
298 match_op(OP_DUP,DUP)
299 match_op(OP_EXC,EXC)
300 match_op(OP_POP,POP)
301 match_op(OP_LT,LT)
302 match_op(OP_LE,LE)
303 match_op(OP_GT,GT)
304 match_op(OP_GE,GE)
305 match_op(OP_EQ,EQ)
306 match_op(OP_IF,IF)
307 match_op(OP_MIN,MIN)
308 match_op(OP_MAX,MAX)
309 match_op(OP_LIMIT,LIMIT)
310 /* order is important here ! .. match longest first */
311 match_op(OP_UNKN,UNKN)
312 match_op(OP_UN,UN)
313 match_op(OP_NEGINF,NEGINF)
314 match_op(OP_NE,NE)
315 match_op_param(OP_PREV_OTHER,PREV)
316 match_op(OP_PREV,PREV)
317 match_op(OP_INF,INF)
318 match_op(OP_ISINF,ISINF)
319 match_op(OP_NOW,NOW)
320 match_op(OP_LTIME,LTIME)
321 match_op(OP_TIME,TIME)
323 #undef match_op
326 else if ((sscanf(expr,"%29[_A-Za-z0-9]%n",
327 vname,&pos) == 1)
328 && ((rpnp[steps].ptr = (*lookup)(key_hash,vname)) != -1)){
329 rpnp[steps].op = OP_VARIABLE;
330 expr+=pos;
331 }
333 else {
334 free(rpnp);
335 return NULL;
336 }
337 if (*expr == 0)
338 break;
339 if (*expr == ',')
340 expr++;
341 else {
342 free(rpnp);
343 return NULL;
344 }
345 }
346 rpnp[steps+1].op = OP_END;
347 return rpnp;
348 }
350 void
351 rpnstack_init(rpnstack_t *rpnstack)
352 {
353 rpnstack -> s = NULL;
354 rpnstack -> dc_stacksize = 0;
355 rpnstack -> dc_stackblock = 100;
356 }
358 void
359 rpnstack_free(rpnstack_t *rpnstack)
360 {
361 if (rpnstack -> s != NULL)
362 free(rpnstack -> s);
363 rpnstack -> dc_stacksize = 0;
364 }
366 /* rpn_calc: run the RPN calculator; also performs variable substitution;
367 * moved and modified from data_calc() originally included in rrd_graph.c
368 * arguments:
369 * rpnp : an array of RPN operators (including variable references)
370 * rpnstack : the initialized stack
371 * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
372 * is advanced by rpnp.ds_cnt; used only for variable substitution
373 * output : an array of output values; OP_PREV assumes this array contains
374 * the "previous" value at index position output_idx-1; the definition of
375 * "previous" depends on the calling environment
376 * output_idx : an index into the output array in which to store the output
377 * of the RPN calculator
378 * returns: -1 if the computation failed (also calls rrd_set_error)
379 * 0 on success
380 */
381 short
382 rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx,
383 rrd_value_t *output, int output_idx)
384 {
385 int rpi;
386 long stptr = -1;
388 /* process each op from the rpn in turn */
389 for (rpi=0; rpnp[rpi].op != OP_END; rpi++){
390 /* allocate or grow the stack */
391 if (stptr + 5 > rpnstack -> dc_stacksize){
392 /* could move this to a separate function */
393 rpnstack -> dc_stacksize += rpnstack -> dc_stackblock;
394 rpnstack -> s = rrd_realloc(rpnstack -> s,
395 (rpnstack -> dc_stacksize)*sizeof(*(rpnstack -> s)));
396 if (rpnstack -> s == NULL){
397 rrd_set_error("RPN stack overflow");
398 return -1;
399 }
400 }
402 #define stackunderflow(MINSIZE) \
403 if(stptr<MINSIZE){ \
404 rrd_set_error("RPN stack underflow"); \
405 return -1; \
406 }
408 switch (rpnp[rpi].op){
409 case OP_NUMBER:
410 rpnstack -> s[++stptr] = rpnp[rpi].val;
411 break;
412 case OP_VARIABLE:
413 /* Sanity check: VDEFs shouldn't make it here */
414 if (rpnp[rpi].ds_cnt == 0) {
415 rrd_set_error("VDEF made it into rpn_calc... aborting");
416 return -1;
417 } else {
418 /* make sure we pull the correct value from
419 * the *.data array. Adjust the pointer into
420 * the array acordingly. Advance the ptr one
421 * row in the rra (skip over non-relevant
422 * data sources)
423 */
424 rpnstack -> s[++stptr] = *(rpnp[rpi].data);
425 if (data_idx % rpnp[rpi].step == 0){
426 rpnp[rpi].data += rpnp[rpi].ds_cnt;
427 }
428 }
429 break;
430 case OP_PREV:
431 if ((output_idx-1) <= 0) {
432 rpnstack -> s[++stptr] = DNAN;
433 } else {
434 rpnstack -> s[++stptr] = output[output_idx-1];
435 }
436 break;
437 case OP_PREV_OTHER:
438 if ((output_idx-1) <= 0) {
439 rpnstack -> s[++stptr] = DNAN;
440 } else {
441 rpnstack -> s[++stptr] = rpnp[rpnp[rpi].ptr].data[output_idx-1];
442 }
443 break;
444 case OP_UNKN:
445 rpnstack -> s[++stptr] = DNAN;
446 break;
447 case OP_INF:
448 rpnstack -> s[++stptr] = DINF;
449 break;
450 case OP_NEGINF:
451 rpnstack -> s[++stptr] = -DINF;
452 break;
453 case OP_NOW:
454 rpnstack -> s[++stptr] = (double)time(NULL);
455 break;
456 case OP_TIME:
457 /* HACK: this relies on the data_idx being the time,
458 ** which the within-function scope is unaware of */
459 rpnstack -> s[++stptr] = (double) data_idx;
460 break;
461 case OP_LTIME:
462 rpnstack -> s[++stptr] =
463 (double) tzoffset(data_idx) + (double)data_idx;
464 break;
465 case OP_ADD:
466 stackunderflow(1);
467 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1]
468 + rpnstack -> s[stptr];
469 stptr--;
470 break;
471 case OP_SUB:
472 stackunderflow(1);
473 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1]
474 - rpnstack -> s[stptr];
475 stptr--;
476 break;
477 case OP_MUL:
478 stackunderflow(1);
479 rpnstack -> s[stptr-1] = (rpnstack -> s[stptr-1])
480 * (rpnstack -> s[stptr]);
481 stptr--;
482 break;
483 case OP_DIV:
484 stackunderflow(1);
485 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1]
486 / rpnstack -> s[stptr];
487 stptr--;
488 break;
489 case OP_MOD:
490 stackunderflow(1);
491 rpnstack -> s[stptr-1]= fmod( rpnstack -> s[stptr-1]
492 ,rpnstack -> s[stptr]);
493 stptr--;
494 break;
495 case OP_SIN:
496 stackunderflow(0);
497 rpnstack -> s[stptr] = sin(rpnstack -> s[stptr]);
498 break;
499 case OP_COS:
500 stackunderflow(0);
501 rpnstack -> s[stptr] = cos(rpnstack -> s[stptr]);
502 break;
503 case OP_CEIL:
504 stackunderflow(0);
505 rpnstack -> s[stptr] = ceil(rpnstack -> s[stptr]);
506 break;
507 case OP_FLOOR:
508 stackunderflow(0);
509 rpnstack -> s[stptr] = floor(rpnstack -> s[stptr]);
510 break;
511 case OP_LOG:
512 stackunderflow(0);
513 rpnstack -> s[stptr] = log(rpnstack -> s[stptr]);
514 break;
515 case OP_DUP:
516 stackunderflow(0);
517 rpnstack -> s[stptr+1] = rpnstack -> s[stptr];
518 stptr++;
519 break;
520 case OP_POP:
521 stackunderflow(0);
522 stptr--;
523 break;
524 case OP_EXC:
525 stackunderflow(1);
526 {
527 double dummy;
528 dummy = rpnstack -> s[stptr] ;
529 rpnstack -> s[stptr] = rpnstack -> s[stptr-1];
530 rpnstack -> s[stptr-1] = dummy;
531 }
532 break;
533 case OP_EXP:
534 stackunderflow(0);
535 rpnstack -> s[stptr] = exp(rpnstack -> s[stptr]);
536 break;
537 case OP_LT:
538 stackunderflow(1);
539 if (isnan(rpnstack -> s[stptr-1]))
540 ;
541 else if (isnan(rpnstack -> s[stptr]))
542 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
543 else
544 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <
545 rpnstack -> s[stptr] ? 1.0 : 0.0;
546 stptr--;
547 break;
548 case OP_LE:
549 stackunderflow(1);
550 if (isnan(rpnstack -> s[stptr-1]))
551 ;
552 else if (isnan(rpnstack -> s[stptr]))
553 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
554 else
555 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <=
556 rpnstack -> s[stptr] ? 1.0 : 0.0;
557 stptr--;
558 break;
559 case OP_GT:
560 stackunderflow(1);
561 if (isnan(rpnstack -> s[stptr-1]))
562 ;
563 else if (isnan(rpnstack -> s[stptr]))
564 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
565 else
566 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >
567 rpnstack -> s[stptr] ? 1.0 : 0.0;
568 stptr--;
569 break;
570 case OP_GE:
571 stackunderflow(1);
572 if (isnan(rpnstack -> s[stptr-1]))
573 ;
574 else if (isnan(rpnstack -> s[stptr]))
575 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
576 else
577 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >=
578 rpnstack -> s[stptr] ? 1.0 : 0.0;
579 stptr--;
580 break;
581 case OP_NE:
582 stackunderflow(1);
583 if (isnan(rpnstack -> s[stptr-1]))
584 ;
585 else if (isnan(rpnstack -> s[stptr]))
586 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
587 else
588 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
589 rpnstack -> s[stptr] ? 0.0 : 1.0;
590 stptr--;
591 break;
592 case OP_EQ:
593 stackunderflow(1);
594 if (isnan(rpnstack -> s[stptr-1]))
595 ;
596 else if (isnan(rpnstack -> s[stptr]))
597 rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
598 else
599 rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
600 rpnstack -> s[stptr] ? 1.0 : 0.0;
601 stptr--;
602 break;
603 case OP_IF:
604 stackunderflow(2);
605 rpnstack->s[stptr-2] = rpnstack->s[stptr-2] != 0.0 ?
606 rpnstack->s[stptr-1] : rpnstack->s[stptr];
607 stptr--;
608 stptr--;
609 break;
610 case OP_MIN:
611 stackunderflow(1);
612 if (isnan(rpnstack->s[stptr-1]))
613 ;
614 else if (isnan(rpnstack->s[stptr]))
615 rpnstack->s[stptr-1] = rpnstack->s[stptr];
616 else if (rpnstack->s[stptr-1] > rpnstack->s[stptr])
617 rpnstack->s[stptr-1] = rpnstack->s[stptr];
618 stptr--;
619 break;
620 case OP_MAX:
621 stackunderflow(1);
622 if (isnan(rpnstack->s[stptr-1]))
623 ;
624 else if (isnan(rpnstack->s[stptr]))
625 rpnstack->s[stptr-1] = rpnstack->s[stptr];
626 else if (rpnstack->s[stptr-1] < rpnstack->s[stptr])
627 rpnstack->s[stptr-1] = rpnstack->s[stptr];
628 stptr--;
629 break;
630 case OP_LIMIT:
631 stackunderflow(2);
632 if (isnan(rpnstack->s[stptr-2]))
633 ;
634 else if (isnan(rpnstack->s[stptr-1]))
635 rpnstack->s[stptr-2] = rpnstack->s[stptr-1];
636 else if (isnan(rpnstack->s[stptr]))
637 rpnstack->s[stptr-2] = rpnstack->s[stptr];
638 else if (rpnstack->s[stptr-2] < rpnstack->s[stptr-1])
639 rpnstack->s[stptr-2] = DNAN;
640 else if (rpnstack->s[stptr-2] > rpnstack->s[stptr])
641 rpnstack->s[stptr-2] = DNAN;
642 stptr-=2;
643 break;
644 case OP_UN:
645 stackunderflow(0);
646 rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
647 break;
648 case OP_ISINF:
649 stackunderflow(0);
650 rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
651 break;
652 case OP_END:
653 break;
654 }
655 #undef stackunderflow
656 }
657 if(stptr!=0){
658 rrd_set_error("RPN final stack size != 1");
659 return -1;
660 }
662 output[output_idx] = rpnstack->s[0];
663 return 0;
664 }
666 /* figure out what the local timezone offset for any point in
667 time was. Return it in seconds */
668 int
669 tzoffset( time_t now ){
670 int gm_sec, gm_min, gm_hour, gm_yday, gm_year,
671 l_sec, l_min, l_hour, l_yday, l_year;
672 struct tm *t;
673 int off;
674 t = gmtime(&now);
675 gm_sec = t->tm_sec;
676 gm_min = t->tm_min;
677 gm_hour = t->tm_hour;
678 gm_yday = t->tm_yday;
679 gm_year = t->tm_year;
680 t = localtime(&now);
681 l_sec = t->tm_sec;
682 l_min = t->tm_min;
683 l_hour = t->tm_hour;
684 l_yday = t->tm_yday;
685 l_year = t->tm_year;
686 off = (l_sec-gm_sec)+(l_min-gm_min)*60+(l_hour-gm_hour)*3600;
687 if ( l_yday > gm_yday || l_year > gm_year){
688 off += 24*3600;
689 } else if ( l_yday < gm_yday || l_year < gm_year){
690 off -= 24*3600;
691 }
692 return off;
693 }