src/rrd_rpncalc.c

   1 /****************************************************************************
   2  * RRDtool 1.4.3  Copyright by Tobi Oetiker, 1997-2010
   3  ****************************************************************************
   4  * rrd_rpncalc.c  RPN calculator functions
   5  ****************************************************************************/
   6
   7 #include <limits.h>
   8 #include <locale.h>
   9 #include <stdlib.h>
  10
  11 #include "rrd_tool.h"
  12 #include "rrd_rpncalc.h"
  13 // #include "rrd_graph.h"
  14
  15 short     addop2str(
  16     enum op_en op,
  17     enum op_en op_type,
  18     char *op_str,
  19     char **result_str,
  20     unsigned short *offset);
  21 int       tzoffset(
  22     time_t);            /* used to implement LTIME */
  23
  24 short rpn_compact(
  25     rpnp_t *rpnp,
  26     rpn_cdefds_t **rpnc,
  27     short *count)
  28 {
  29     short     i;
  30
  31     *count = 0;
  32     /* count the number of rpn nodes */
  33     while (rpnp[*count].op != OP_END)
  34         (*count)++;
  35     if (++(*count) > DS_CDEF_MAX_RPN_NODES) {
  36         rrd_set_error("Maximum %d RPN nodes permitted. Got %d RPN nodes at present.",
  37                       DS_CDEF_MAX_RPN_NODES-1,(*count)-1);
  38         return -1;
  39     }
  40
  41     /* allocate memory */
  42     *rpnc = (rpn_cdefds_t *) calloc(*count, sizeof(rpn_cdefds_t));
  43     for (i = 0; rpnp[i].op != OP_END; i++) {
  44         (*rpnc)[i].op = (char) rpnp[i].op;
  45         if (rpnp[i].op == OP_NUMBER) {
  46             /* rpnp.val is a double, rpnc.val is a short */
  47             double    temp = floor(rpnp[i].val);
  48
  49             if (temp < SHRT_MIN || temp > SHRT_MAX) {
  50                 rrd_set_error
  51                     ("constants must be integers in the interval (%d, %d)",
  52                      SHRT_MIN, SHRT_MAX);
  53                 free(*rpnc);
  54                 return -1;
  55             }
  56             (*rpnc)[i].val = (short) temp;
  57         } else if (rpnp[i].op == OP_VARIABLE || rpnp[i].op == OP_PREV_OTHER) {
  58             (*rpnc)[i].val = (short) rpnp[i].ptr;
  59         }
  60     }
  61     /* terminate the sequence */
  62     (*rpnc)[(*count) - 1].op = OP_END;
  63     return 0;
  64 }
  65
  66 rpnp_t   *rpn_expand(
  67     rpn_cdefds_t *rpnc)
  68 {
  69     short     i;
  70     rpnp_t   *rpnp;
  71
  72     /* DS_CDEF_MAX_RPN_NODES is small, so at the expense of some wasted
  73      * memory we avoid any reallocs */
  74     rpnp = (rpnp_t *) calloc(DS_CDEF_MAX_RPN_NODES, sizeof(rpnp_t));
  75     if (rpnp == NULL) {
  76         rrd_set_error("failed allocating rpnp array");
  77         return NULL;
  78     }
  79     for (i = 0; rpnc[i].op != OP_END; ++i) {
  80         rpnp[i].op = (enum op_en)rpnc[i].op;
  81         if (rpnp[i].op == OP_NUMBER) {
  82             rpnp[i].val = (double) rpnc[i].val;
  83         } else if (rpnp[i].op == OP_VARIABLE || rpnp[i].op == OP_PREV_OTHER) {
  84             rpnp[i].ptr = (long) rpnc[i].val;
  85         }
  86     }
  87     /* terminate the sequence */
  88     rpnp[i].op = OP_END;
  89     return rpnp;
  90 }
  91
  92 /* rpn_compact2str: convert a compact sequence of RPN operator nodes back
  93  * into a CDEF string. This function is used by rrd_dump.
  94  * arguments:
  95  *  rpnc: an array of compact RPN operator nodes
  96  *  ds_def: a pointer to the data source definition section of an RRD header
  97  *   for lookup of data source names by index
  98  *  str: out string, memory is allocated by the function, must be freed by the
  99  *   the caller */
 100 void rpn_compact2str(
 101     rpn_cdefds_t *rpnc,
 102     ds_def_t *ds_def,
 103     char **str)
 104 {
 105     unsigned short i, offset = 0;
 106     char      buffer[7];    /* short as a string */
 107
 108     for (i = 0; rpnc[i].op != OP_END; i++) {
 109         if (i > 0)
 110             (*str)[offset++] = ',';
 111
 112 #define add_op(VV,VVV) \
 113           if (addop2str((enum op_en)(rpnc[i].op), VV, VVV, str, &offset) == 1) continue;
 114
 115         if (rpnc[i].op == OP_NUMBER) {
 116             /* convert a short into a string */
 117 #if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)
 118             _itoa(rpnc[i].val, buffer, 10);
 119 #else
 120             sprintf(buffer, "%d", rpnc[i].val);
 121 #endif
 122             add_op(OP_NUMBER, buffer)
 123         }
 124
 125         if (rpnc[i].op == OP_VARIABLE) {
 126             char     *ds_name = ds_def[rpnc[i].val].ds_nam;
 127
 128             add_op(OP_VARIABLE, ds_name)
 129         }
 130
 131         if (rpnc[i].op == OP_PREV_OTHER) {
 132             char     *ds_name = ds_def[rpnc[i].val].ds_nam;
 133
 134             add_op(OP_VARIABLE, ds_name)
 135         }
 136 #undef add_op
 137
 138 #define add_op(VV,VVV) \
 139           if (addop2str((enum op_en)rpnc[i].op, VV, #VVV, str, &offset) == 1) continue;
 140
 141         add_op(OP_ADD, +)
 142             add_op(OP_SUB, -)
 143             add_op(OP_MUL, *)
 144             add_op(OP_DIV, /)
 145             add_op(OP_MOD, %)
 146             add_op(OP_SIN, SIN)
 147             add_op(OP_COS, COS)
 148             add_op(OP_LOG, LOG)
 149             add_op(OP_FLOOR, FLOOR)
 150             add_op(OP_CEIL, CEIL)
 151             add_op(OP_EXP, EXP)
 152             add_op(OP_DUP, DUP)
 153             add_op(OP_EXC, EXC)
 154             add_op(OP_POP, POP)
 155             add_op(OP_LT, LT)
 156             add_op(OP_LE, LE)
 157             add_op(OP_GT, GT)
 158             add_op(OP_GE, GE)
 159             add_op(OP_EQ, EQ)
 160             add_op(OP_IF, IF)
 161             add_op(OP_MIN, MIN)
 162             add_op(OP_MAX, MAX)
 163             add_op(OP_LIMIT, LIMIT)
 164             add_op(OP_UNKN, UNKN)
 165             add_op(OP_UN, UN)
 166             add_op(OP_NEGINF, NEGINF)
 167             add_op(OP_NE, NE)
 168             add_op(OP_PREV, PREV)
 169             add_op(OP_INF, INF)
 170             add_op(OP_ISINF, ISINF)
 171             add_op(OP_NOW, NOW)
 172             add_op(OP_LTIME, LTIME)
 173             add_op(OP_TIME, TIME)
 174             add_op(OP_ATAN2, ATAN2)
 175             add_op(OP_ATAN, ATAN)
 176             add_op(OP_SQRT, SQRT)
 177             add_op(OP_SORT, SORT)
 178             add_op(OP_REV, REV)
 179             add_op(OP_TREND, TREND)
 180             add_op(OP_TRENDNAN, TRENDNAN)
 181             add_op(OP_PREDICT, PREDICT)
 182             add_op(OP_PREDICTSIGMA, PREDICTSIGMA)
 183             add_op(OP_RAD2DEG, RAD2DEG)
 184             add_op(OP_DEG2RAD, DEG2RAD)
 185             add_op(OP_AVG, AVG)
 186             add_op(OP_ABS, ABS)
 187             add_op(OP_ADDNAN, ADDNAN)
 188 #undef add_op
 189     }
 190     (*str)[offset] = '\0';
 191
 192 }
 193
 194 short addop2str(
 195     enum op_en op,
 196     enum op_en op_type,
 197     char *op_str,
 198     char **result_str,
 199     unsigned short *offset)
 200 {
 201     if (op == op_type) {
 202         short     op_len;
 203
 204         op_len = strlen(op_str);
 205         *result_str = (char *) rrd_realloc(*result_str,
 206                                            (op_len + 1 +
 207                                             *offset) * sizeof(char));
 208         if (*result_str == NULL) {
 209             rrd_set_error("failed to alloc memory in addop2str");
 210             return -1;
 211         }
 212         strncpy(&((*result_str)[*offset]), op_str, op_len);
 213         *offset += op_len;
 214         return 1;
 215     }
 216     return 0;
 217 }
 218
 219 void parseCDEF_DS(
 220     const char *def,
 221     rrd_t *rrd,
 222     int ds_idx)
 223 {
 224     rpnp_t   *rpnp = NULL;
 225     rpn_cdefds_t *rpnc = NULL;
 226     short     count, i;
 227
 228     rpnp = rpn_parse((void *) rrd, def, &lookup_DS);
 229     if (rpnp == NULL) {
 230         rrd_set_error("failed to parse computed data source");
 231         return;
 232     }
 233     /* Check for OP nodes not permitted in COMPUTE DS.
 234      * Moved this check from within rpn_compact() because it really is
 235      * COMPUTE DS specific. This is less efficient, but creation doesn't
 236      * occur too often. */
 237     for (i = 0; rpnp[i].op != OP_END; i++) {
 238         if (rpnp[i].op == OP_TIME || rpnp[i].op == OP_LTIME ||
 239             rpnp[i].op == OP_PREV || rpnp[i].op == OP_COUNT ||
 240             rpnp[i].op == OP_TREND || rpnp[i].op == OP_TRENDNAN ||
 241             rpnp[i].op == OP_PREDICT || rpnp[i].op ==  OP_PREDICTSIGMA ) {
 242             rrd_set_error
 243                 ("operators TIME, LTIME, PREV COUNT TREND TRENDNAN PREDICT PREDICTSIGMA are not supported with DS COMPUTE");
 244             free(rpnp);
 245             return;
 246         }
 247     }
 248     if (rpn_compact(rpnp, &rpnc, &count) == -1) {
 249         free(rpnp);
 250         return;
 251     }
 252     /* copy the compact rpn representation over the ds_def par array */
 253     memcpy((void *) &(rrd->ds_def[ds_idx].par[DS_cdef]),
 254            (void *) rpnc, count * sizeof(rpn_cdefds_t));
 255     free(rpnp);
 256     free(rpnc);
 257 }
 258
 259 /* lookup a data source name in the rrd struct and return the index,
 260  * should use ds_match() here except:
 261  * (1) need a void * pointer to the rrd
 262  * (2) error handling is left to the caller
 263  */
 264 long lookup_DS(
 265     void *rrd_vptr,
 266     char *ds_name)
 267 {
 268     unsigned int i;
 269     rrd_t    *rrd;
 270
 271     rrd = (rrd_t *) rrd_vptr;
 272
 273     for (i = 0; i < rrd->stat_head->ds_cnt; ++i) {
 274         if (strcmp(ds_name, rrd->ds_def[i].ds_nam) == 0)
 275             return i;
 276     }
 277     /* the caller handles a bad data source name in the rpn string */
 278     return -1;
 279 }
 280
 281 /* rpn_parse : parse a string and generate a rpnp array; modified
 282  * str2rpn() originally included in rrd_graph.c
 283  * arguments:
 284  * key_hash: a transparent argument passed to lookup(); conceptually this
 285  *    is a hash object for lookup of a numeric key given a variable name
 286  * expr: the string RPN expression, including variable names
 287  * lookup(): a function that retrieves a numeric key given a variable name
 288  */
 289 rpnp_t   *rpn_parse(
 290     void *key_hash,
 291     const char *const expr_const,
 292     long      (*lookup) (void *,
 293                          char *))
 294 {
 295     int       pos = 0;
 296     char     *expr;
 297     long      steps = -1;
 298     rpnp_t   *rpnp;
 299     char      vname[MAX_VNAME_LEN + 10];
 300     char     *old_locale;
 301
 302     old_locale = setlocale(LC_NUMERIC, NULL);
 303     setlocale(LC_NUMERIC, "C");
 304
 305     rpnp = NULL;
 306     expr = (char *) expr_const;
 307
 308     while (*expr) {
 309         if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2) *
 310                                            sizeof(rpnp_t))) == NULL) {
 311             setlocale(LC_NUMERIC, old_locale);
 312             return NULL;
 313         }
 314
 315         else if ((sscanf(expr, "%lf%n", &rpnp[steps].val, &pos) == 1)
 316                  && (expr[pos] == ',')) {
 317             rpnp[steps].op = OP_NUMBER;
 318             expr += pos;
 319         }
 320 #define match_op(VV,VVV) \
 321         else if (strncmp(expr, #VVV, strlen(#VVV))==0 && ( expr[strlen(#VVV)] == ',' || expr[strlen(#VVV)] == '\0' )){ \
 322             rpnp[steps].op = VV; \
 323             expr+=strlen(#VVV); \
 324         }
 325
 326 #define match_op_param(VV,VVV) \
 327         else if (sscanf(expr, #VVV "(" DEF_NAM_FMT ")",vname) == 1) { \
 328           int length = 0; \
 329           if ((length = strlen(#VVV)+strlen(vname)+2, \
 330               expr[length] == ',' || expr[length] == '\0') ) { \
 331              rpnp[steps].op = VV; \
 332              rpnp[steps].ptr = (*lookup)(key_hash,vname); \
 333              if (rpnp[steps].ptr < 0) { \
 334                            free(rpnp); \
 335                            return NULL; \
 336                          } else expr+=length; \
 337           } \
 338         }
 339
 340         match_op(OP_ADD, +)
 341             match_op(OP_SUB, -)
 342             match_op(OP_MUL, *)
 343             match_op(OP_DIV, /)
 344             match_op(OP_MOD, %)
 345             match_op(OP_SIN, SIN)
 346             match_op(OP_COS, COS)
 347             match_op(OP_LOG, LOG)
 348             match_op(OP_FLOOR, FLOOR)
 349             match_op(OP_CEIL, CEIL)
 350             match_op(OP_EXP, EXP)
 351             match_op(OP_DUP, DUP)
 352             match_op(OP_EXC, EXC)
 353             match_op(OP_POP, POP)
 354             match_op(OP_LTIME, LTIME)
 355             match_op(OP_LT, LT)
 356             match_op(OP_LE, LE)
 357             match_op(OP_GT, GT)
 358             match_op(OP_GE, GE)
 359             match_op(OP_EQ, EQ)
 360             match_op(OP_IF, IF)
 361             match_op(OP_MIN, MIN)
 362             match_op(OP_MAX, MAX)
 363             match_op(OP_LIMIT, LIMIT)
 364             /* order is important here ! .. match longest first */
 365             match_op(OP_UNKN, UNKN)
 366             match_op(OP_UN, UN)
 367             match_op(OP_NEGINF, NEGINF)
 368             match_op(OP_NE, NE)
 369             match_op(OP_COUNT, COUNT)
 370             match_op_param(OP_PREV_OTHER, PREV)
 371             match_op(OP_PREV, PREV)
 372             match_op(OP_INF, INF)
 373             match_op(OP_ISINF, ISINF)
 374             match_op(OP_NOW, NOW)
 375             match_op(OP_TIME, TIME)
 376             match_op(OP_ATAN2, ATAN2)
 377             match_op(OP_ATAN, ATAN)
 378             match_op(OP_SQRT, SQRT)
 379             match_op(OP_SORT, SORT)
 380             match_op(OP_REV, REV)
 381             match_op(OP_TREND, TREND)
 382             match_op(OP_TRENDNAN, TRENDNAN)
 383             match_op(OP_PREDICT, PREDICT)
 384             match_op(OP_PREDICTSIGMA, PREDICTSIGMA)
 385             match_op(OP_RAD2DEG, RAD2DEG)
 386             match_op(OP_DEG2RAD, DEG2RAD)
 387             match_op(OP_AVG, AVG)
 388             match_op(OP_ABS, ABS)
 389             match_op(OP_ADDNAN, ADDNAN)
 390 #undef match_op
 391             else if ((sscanf(expr, DEF_NAM_FMT "%n", vname, &pos) == 1)
 392                      && ((rpnp[steps].ptr = (*lookup) (key_hash, vname)) !=
 393                          -1)) {
 394             rpnp[steps].op = OP_VARIABLE;
 395             expr += pos;
 396         }
 397
 398         else {
 399             setlocale(LC_NUMERIC, old_locale);
 400             free(rpnp);
 401             return NULL;
 402         }
 403
 404         if (*expr == 0)
 405             break;
 406         if (*expr == ',')
 407             expr++;
 408         else {
 409             setlocale(LC_NUMERIC, old_locale);
 410             free(rpnp);
 411             return NULL;
 412         }
 413     }
 414     rpnp[steps + 1].op = OP_END;
 415     setlocale(LC_NUMERIC, old_locale);
 416     return rpnp;
 417 }
 418
 419 void rpnstack_init(
 420     rpnstack_t *rpnstack)
 421 {
 422     rpnstack->s = NULL;
 423     rpnstack->dc_stacksize = 0;
 424     rpnstack->dc_stackblock = 100;
 425 }
 426
 427 void rpnstack_free(
 428     rpnstack_t *rpnstack)
 429 {
 430     if (rpnstack->s != NULL)
 431         free(rpnstack->s);
 432     rpnstack->dc_stacksize = 0;
 433 }
 434
 435 static int rpn_compare_double(
 436     const void *x,
 437     const void *y)
 438 {
 439     double    diff = *((const double *) x) - *((const double *) y);
 440
 441     return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
 442 }
 443
 444 /* rpn_calc: run the RPN calculator; also performs variable substitution;
 445  * moved and modified from data_calc() originally included in rrd_graph.c
 446  * arguments:
 447  * rpnp : an array of RPN operators (including variable references)
 448  * rpnstack : the initialized stack
 449  * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
 450  *   is advanced by rpnp.ds_cnt; used only for variable substitution
 451  * output : an array of output values; OP_PREV assumes this array contains
 452  *   the "previous" value at index position output_idx-1; the definition of
 453  *   "previous" depends on the calling environment
 454  * output_idx : an index into the output array in which to store the output
 455  *   of the RPN calculator
 456  * returns: -1 if the computation failed (also calls rrd_set_error)
 457  *           0 on success
 458  */
 459 short rpn_calc(
 460     rpnp_t *rpnp,
 461     rpnstack_t *rpnstack,
 462     long data_idx,
 463     rrd_value_t *output,
 464     int output_idx)
 465 {
 466     int       rpi;
 467     long      stptr = -1;
 468
 469     /* process each op from the rpn in turn */
 470     for (rpi = 0; rpnp[rpi].op != OP_END; rpi++) {
 471         /* allocate or grow the stack */
 472         if (stptr + 5 > rpnstack->dc_stacksize) {
 473             /* could move this to a separate function */
 474             rpnstack->dc_stacksize += rpnstack->dc_stackblock;
 475             rpnstack->s = (double*)rrd_realloc(rpnstack->s,
 476                                       (rpnstack->dc_stacksize) *
 477                                       sizeof(*(rpnstack->s)));
 478             if (rpnstack->s == NULL) {
 479                 rrd_set_error("RPN stack overflow");
 480                 return -1;
 481             }
 482         }
 483 #define stackunderflow(MINSIZE)                         \
 484         if(stptr<MINSIZE){                              \
 485             rrd_set_error("RPN stack underflow");       \
 486             return -1;                                  \
 487         }
 488
 489         switch (rpnp[rpi].op) {
 490         case OP_NUMBER:
 491             rpnstack->s[++stptr] = rpnp[rpi].val;
 492             break;
 493         case OP_VARIABLE:
 494         case OP_PREV_OTHER:
 495             /* Sanity check: VDEFs shouldn't make it here */
 496             if (rpnp[rpi].ds_cnt == 0) {
 497                 rrd_set_error("VDEF made it into rpn_calc... aborting");
 498                 return -1;
 499             } else {
 500                 /* make sure we pull the correct value from
 501                  * the *.data array. Adjust the pointer into
 502                  * the array acordingly. Advance the ptr one
 503                  * row in the rra (skip over non-relevant
 504                  * data sources)
 505                  */
 506                 if (rpnp[rpi].op == OP_VARIABLE) {
 507                     rpnstack->s[++stptr] = *(rpnp[rpi].data);
 508                 } else {
 509                     if ((output_idx) <= 0) {
 510                         rpnstack->s[++stptr] = DNAN;
 511                     } else {
 512                         rpnstack->s[++stptr] =
 513                             *(rpnp[rpi].data - rpnp[rpi].ds_cnt);
 514                     }
 515
 516                 }
 517                 if (data_idx % rpnp[rpi].step == 0) {
 518                     rpnp[rpi].data += rpnp[rpi].ds_cnt;
 519                 }
 520             }
 521             break;
 522         case OP_COUNT:
 523             rpnstack->s[++stptr] = (output_idx + 1);    /* Note: Counter starts at 1 */
 524             break;
 525         case OP_PREV:
 526             if ((output_idx) <= 0) {
 527                 rpnstack->s[++stptr] = DNAN;
 528             } else {
 529                 rpnstack->s[++stptr] = output[output_idx - 1];
 530             }
 531             break;
 532         case OP_UNKN:
 533             rpnstack->s[++stptr] = DNAN;
 534             break;
 535         case OP_INF:
 536             rpnstack->s[++stptr] = DINF;
 537             break;
 538         case OP_NEGINF:
 539             rpnstack->s[++stptr] = -DINF;
 540             break;
 541         case OP_NOW:
 542             rpnstack->s[++stptr] = (double) time(NULL);
 543             break;
 544         case OP_TIME:
 545             /* HACK: this relies on the data_idx being the time,
 546              ** which the within-function scope is unaware of */
 547             rpnstack->s[++stptr] = (double) data_idx;
 548             break;
 549         case OP_LTIME:
 550             rpnstack->s[++stptr] =
 551                 (double) tzoffset(data_idx) + (double) data_idx;
 552             break;
 553         case OP_ADD:
 554             stackunderflow(1);
 555             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 556                 + rpnstack->s[stptr];
 557             stptr--;
 558             break;
 559         case OP_ADDNAN:
 560             stackunderflow(1);
 561             if (isnan(rpnstack->s[stptr - 1])) {
 562                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 563             } else if (isnan(rpnstack->s[stptr])) {
 564                 /* NOOP */
 565                 /* rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]; */
 566             } else {
 567                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 568                     + rpnstack->s[stptr];
 569             }
 570
 571             stptr--;
 572             break;
 573         case OP_SUB:
 574             stackunderflow(1);
 575             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 576                 - rpnstack->s[stptr];
 577             stptr--;
 578             break;
 579         case OP_MUL:
 580             stackunderflow(1);
 581             rpnstack->s[stptr - 1] = (rpnstack->s[stptr - 1])
 582                 * (rpnstack->s[stptr]);
 583             stptr--;
 584             break;
 585         case OP_DIV:
 586             stackunderflow(1);
 587             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 588                 / rpnstack->s[stptr];
 589             stptr--;
 590             break;
 591         case OP_MOD:
 592             stackunderflow(1);
 593             rpnstack->s[stptr - 1] = fmod(rpnstack->s[stptr - 1]
 594                                           , rpnstack->s[stptr]);
 595             stptr--;
 596             break;
 597         case OP_SIN:
 598             stackunderflow(0);
 599             rpnstack->s[stptr] = sin(rpnstack->s[stptr]);
 600             break;
 601         case OP_ATAN:
 602             stackunderflow(0);
 603             rpnstack->s[stptr] = atan(rpnstack->s[stptr]);
 604             break;
 605         case OP_RAD2DEG:
 606             stackunderflow(0);
 607             rpnstack->s[stptr] = 57.29577951 * rpnstack->s[stptr];
 608             break;
 609         case OP_DEG2RAD:
 610             stackunderflow(0);
 611             rpnstack->s[stptr] = 0.0174532952 * rpnstack->s[stptr];
 612             break;
 613         case OP_ATAN2:
 614             stackunderflow(1);
 615             rpnstack->s[stptr - 1] = atan2(rpnstack->s[stptr - 1],
 616                                            rpnstack->s[stptr]);
 617             stptr--;
 618             break;
 619         case OP_COS:
 620             stackunderflow(0);
 621             rpnstack->s[stptr] = cos(rpnstack->s[stptr]);
 622             break;
 623         case OP_CEIL:
 624             stackunderflow(0);
 625             rpnstack->s[stptr] = ceil(rpnstack->s[stptr]);
 626             break;
 627         case OP_FLOOR:
 628             stackunderflow(0);
 629             rpnstack->s[stptr] = floor(rpnstack->s[stptr]);
 630             break;
 631         case OP_LOG:
 632             stackunderflow(0);
 633             rpnstack->s[stptr] = log(rpnstack->s[stptr]);
 634             break;
 635         case OP_DUP:
 636             stackunderflow(0);
 637             rpnstack->s[stptr + 1] = rpnstack->s[stptr];
 638             stptr++;
 639             break;
 640         case OP_POP:
 641             stackunderflow(0);
 642             stptr--;
 643             break;
 644         case OP_EXC:
 645             stackunderflow(1);
 646             {
 647                 double    dummy;
 648
 649                 dummy = rpnstack->s[stptr];
 650                 rpnstack->s[stptr] = rpnstack->s[stptr - 1];
 651                 rpnstack->s[stptr - 1] = dummy;
 652             }
 653             break;
 654         case OP_EXP:
 655             stackunderflow(0);
 656             rpnstack->s[stptr] = exp(rpnstack->s[stptr]);
 657             break;
 658         case OP_LT:
 659             stackunderflow(1);
 660             if (isnan(rpnstack->s[stptr - 1]));
 661             else if (isnan(rpnstack->s[stptr]))
 662                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 663             else
 664                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] <
 665                     rpnstack->s[stptr] ? 1.0 : 0.0;
 666             stptr--;
 667             break;
 668         case OP_LE:
 669             stackunderflow(1);
 670             if (isnan(rpnstack->s[stptr - 1]));
 671             else if (isnan(rpnstack->s[stptr]))
 672                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 673             else
 674                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] <=
 675                     rpnstack->s[stptr] ? 1.0 : 0.0;
 676             stptr--;
 677             break;
 678         case OP_GT:
 679             stackunderflow(1);
 680             if (isnan(rpnstack->s[stptr - 1]));
 681             else if (isnan(rpnstack->s[stptr]))
 682                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 683             else
 684                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] >
 685                     rpnstack->s[stptr] ? 1.0 : 0.0;
 686             stptr--;
 687             break;
 688         case OP_GE:
 689             stackunderflow(1);
 690             if (isnan(rpnstack->s[stptr - 1]));
 691             else if (isnan(rpnstack->s[stptr]))
 692                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 693             else
 694                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] >=
 695                     rpnstack->s[stptr] ? 1.0 : 0.0;
 696             stptr--;
 697             break;
 698         case OP_NE:
 699             stackunderflow(1);
 700             if (isnan(rpnstack->s[stptr - 1]));
 701             else if (isnan(rpnstack->s[stptr]))
 702                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 703             else
 704                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] ==
 705                     rpnstack->s[stptr] ? 0.0 : 1.0;
 706             stptr--;
 707             break;
 708         case OP_EQ:
 709             stackunderflow(1);
 710             if (isnan(rpnstack->s[stptr - 1]));
 711             else if (isnan(rpnstack->s[stptr]))
 712                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 713             else
 714                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] ==
 715                     rpnstack->s[stptr] ? 1.0 : 0.0;
 716             stptr--;
 717             break;
 718         case OP_IF:
 719             stackunderflow(2);
 720             rpnstack->s[stptr - 2] = (isnan(rpnstack->s[stptr - 2])
 721                                       || rpnstack->s[stptr - 2] ==
 722                                       0.0) ? rpnstack->s[stptr] : rpnstack->
 723                 s[stptr - 1];
 724             stptr--;
 725             stptr--;
 726             break;
 727         case OP_MIN:
 728             stackunderflow(1);
 729             if (isnan(rpnstack->s[stptr - 1]));
 730             else if (isnan(rpnstack->s[stptr]))
 731                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 732             else if (rpnstack->s[stptr - 1] > rpnstack->s[stptr])
 733                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 734             stptr--;
 735             break;
 736         case OP_MAX:
 737             stackunderflow(1);
 738             if (isnan(rpnstack->s[stptr - 1]));
 739             else if (isnan(rpnstack->s[stptr]))
 740                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 741             else if (rpnstack->s[stptr - 1] < rpnstack->s[stptr])
 742                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 743             stptr--;
 744             break;
 745         case OP_LIMIT:
 746             stackunderflow(2);
 747             if (isnan(rpnstack->s[stptr - 2]));
 748             else if (isnan(rpnstack->s[stptr - 1]))
 749                 rpnstack->s[stptr - 2] = rpnstack->s[stptr - 1];
 750             else if (isnan(rpnstack->s[stptr]))
 751                 rpnstack->s[stptr - 2] = rpnstack->s[stptr];
 752             else if (rpnstack->s[stptr - 2] < rpnstack->s[stptr - 1])
 753                 rpnstack->s[stptr - 2] = DNAN;
 754             else if (rpnstack->s[stptr - 2] > rpnstack->s[stptr])
 755                 rpnstack->s[stptr - 2] = DNAN;
 756             stptr -= 2;
 757             break;
 758         case OP_UN:
 759             stackunderflow(0);
 760             rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
 761             break;
 762         case OP_ISINF:
 763             stackunderflow(0);
 764             rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
 765             break;
 766         case OP_SQRT:
 767             stackunderflow(0);
 768             rpnstack->s[stptr] = sqrt(rpnstack->s[stptr]);
 769             break;
 770         case OP_SORT:
 771             stackunderflow(0);
 772             {
 773                 int       spn = (int) rpnstack->s[stptr--];
 774
 775                 stackunderflow(spn - 1);
 776                 qsort(rpnstack->s + stptr - spn + 1, spn, sizeof(double),
 777                       rpn_compare_double);
 778             }
 779             break;
 780         case OP_REV:
 781             stackunderflow(0);
 782             {
 783                 int       spn = (int) rpnstack->s[stptr--];
 784                 double   *p, *q;
 785
 786                 stackunderflow(spn - 1);
 787
 788                 p = rpnstack->s + stptr - spn + 1;
 789                 q = rpnstack->s + stptr;
 790                 while (p < q) {
 791                     double    x = *q;
 792
 793                     *q-- = *p;
 794                     *p++ = x;
 795                 }
 796             }
 797             break;
 798         case OP_PREDICT:
 799         case OP_PREDICTSIGMA:
 800             stackunderflow(2);
 801             {
 802                 /* the local averaging window (similar to trend, but better here, as we get better statistics thru numbers)*/
 803                 int   locstepsize = rpnstack->s[--stptr];
 804                 /* the number of shifts and range-checking*/
 805                 int     shifts = rpnstack->s[--stptr];
 806                 stackunderflow(shifts);
 807                 // handle negative shifts special
 808                 if (shifts<0) {
 809                     stptr--;
 810                 } else {
 811                     stptr-=shifts;
 812                 }
 813                 /* the real calculation */
 814                 double val=DNAN;
 815                 /* the info on the datasource */
 816                 time_t  dsstep = (time_t) rpnp[rpi - 1].step;
 817                 int    dscount = rpnp[rpi - 1].ds_cnt;
 818                 int   locstep = (int)ceil((float)locstepsize/(float)dsstep);
 819
 820                 /* the sums */
 821                 double    sum = 0;
 822                 double    sum2 = 0;
 823                 int       count = 0;
 824                 /* now loop for each position */
 825                 int doshifts=shifts;
 826                 if (shifts<0) { doshifts=-shifts; }
 827                 for(int loop=0;loop<doshifts;loop++) {
 828                     /* calculate shift step */
 829                     int shiftstep=1;
 830                     if (shifts<0) {
 831                         shiftstep = loop*rpnstack->s[stptr];
 832                     } else {
 833                         shiftstep = rpnstack->s[stptr+loop];
 834                     }
 835                     if(shiftstep <0) {
 836                         rrd_set_error("negative shift step not allowed: %i",shiftstep);
 837                         return -1;
 838                     }
 839                     shiftstep=(int)ceil((float)shiftstep/(float)dsstep);
 840                     /* loop all local shifts */
 841                     for(int i=0;i<=locstep;i++) {
 842                         /* now calculate offset into data-array - relative to output_idx*/
 843                         int offset=shiftstep+i;
 844                         /* and process if we have index 0 of above */
 845                         if ((offset>=0)&&(offset<output_idx)) {
 846                             /* get the value */
 847                             val =rpnp[rpi - 1].data[-dscount * offset];
 848                             /* and handle the non NAN case only*/
 849                             if (! isnan(val)) {
 850                                 sum+=val;
 851                                 sum2+=val*val;
 852                                 count++;
 853                             }
 854                         }
 855                     }
 856                 }
 857                 /* do the final calculations */
 858                 val=DNAN;
 859                 if (rpnp[rpi].op == OP_PREDICT) {  /* the average */
 860                     if (count>0) {
 861                         val = sum/(double)count;
 862                     }
 863                 } else {
 864                     if (count>1) { /* the sigma case */
 865                         val=count*sum2-sum*sum;
 866                         if (val<0) {
 867                             val=DNAN;
 868                         } else {
 869                             val=sqrt(val/((float)count*((float)count-1.0)));
 870                         }
 871                     }
 872                 }
 873                 rpnstack->s[stptr] = val;
 874             }
 875             break;
 876         case OP_TREND:
 877         case OP_TRENDNAN:
 878             stackunderflow(1);
 879             if ((rpi < 2) || (rpnp[rpi - 2].op != OP_VARIABLE)) {
 880                 rrd_set_error("malformed trend arguments");
 881                 return -1;
 882             } else {
 883                 time_t    dur = (time_t) rpnstack->s[stptr];
 884                 time_t    step = (time_t) rpnp[rpi - 2].step;
 885
 886                 if (output_idx + 1 >= (int) ceil((float) dur / (float) step)) {
 887                     int       ignorenan = (rpnp[rpi].op == OP_TREND);
 888                     double    accum = 0.0;
 889                     int       i = 0;
 890                     int       count = 0;
 891
 892                     do {
 893                         double    val =
 894                             rpnp[rpi - 2].data[rpnp[rpi - 2].ds_cnt * i--];
 895                         if (ignorenan || !isnan(val)) {
 896                             accum += val;
 897                             ++count;
 898                         }
 899
 900                         dur -= step;
 901                     } while (dur > 0);
 902
 903                     rpnstack->s[--stptr] =
 904                         (count == 0) ? DNAN : (accum / count);
 905                 } else
 906                     rpnstack->s[--stptr] = DNAN;
 907             }
 908             break;
 909         case OP_AVG:
 910             stackunderflow(0);
 911             {
 912                 int       i = (int) rpnstack->s[stptr--];
 913                 double    sum = 0;
 914                 int       count = 0;
 915
 916                 stackunderflow(i - 1);
 917                 while (i > 0) {
 918                     double    val = rpnstack->s[stptr--];
 919
 920                     i--;
 921                     if (isnan(val)) {
 922                         continue;
 923                     }
 924                     count++;
 925                     sum += val;
 926                 }
 927                 /* now push the result back on stack */
 928                 if (count > 0) {
 929                     rpnstack->s[++stptr] = sum / count;
 930                 } else {
 931                     rpnstack->s[++stptr] = DNAN;
 932                 }
 933             }
 934             break;
 935         case OP_ABS:
 936             stackunderflow(0);
 937             rpnstack->s[stptr] = fabs(rpnstack->s[stptr]);
 938             break;
 939         case OP_END:
 940             break;
 941         }
 942 #undef stackunderflow
 943     }
 944     if (stptr != 0) {
 945         rrd_set_error("RPN final stack size != 1");
 946         return -1;
 947     }
 948
 949     output[output_idx] = rpnstack->s[0];
 950     return 0;
 951 }
 952
 953 /* figure out what the local timezone offset for any point in
 954    time was. Return it in seconds */
 955 int tzoffset(
 956     time_t now)
 957 {
 958     int       gm_sec, gm_min, gm_hour, gm_yday, gm_year,
 959         l_sec, l_min, l_hour, l_yday, l_year;
 960     struct tm t;
 961     int       off;
 962
 963     gmtime_r(&now, &t);
 964     gm_sec = t.tm_sec;
 965     gm_min = t.tm_min;
 966     gm_hour = t.tm_hour;
 967     gm_yday = t.tm_yday;
 968     gm_year = t.tm_year;
 969     localtime_r(&now, &t);
 970     l_sec = t.tm_sec;
 971     l_min = t.tm_min;
 972     l_hour = t.tm_hour;
 973     l_yday = t.tm_yday;
 974     l_year = t.tm_year;
 975     off =
 976         (l_sec - gm_sec) + (l_min - gm_min) * 60 + (l_hour - gm_hour) * 3600;
 977     if (l_yday > gm_yday || l_year > gm_year) {
 978         off += 24 * 3600;
 979     } else if (l_yday < gm_yday || l_year < gm_year) {
 980         off -= 24 * 3600;
 981     }
 982     return off;
 983 }