src/rrd_rpncalc.c

   1 /****************************************************************************
   2  * RRDtool 1.3.2  Copyright by Tobi Oetiker, 1997-2008
   3  ****************************************************************************
   4  * rrd_rpncalc.c  RPN calculator functions
   5  ****************************************************************************/
   6
   7 #include "rrd_tool.h"
   8 #include "rrd_rpncalc.h"
   9 // #include "rrd_graph.h"
  10 #include <limits.h>
  11 #include <locale.h>
  12
  13 short     addop2str(
  14     enum op_en op,
  15     enum op_en op_type,
  16     char *op_str,
  17     char **result_str,
  18     unsigned short *offset);
  19 int       tzoffset(
  20     time_t);            /* used to implement LTIME */
  21
  22 short rpn_compact(
  23     rpnp_t *rpnp,
  24     rpn_cdefds_t **rpnc,
  25     short *count)
  26 {
  27     short     i;
  28
  29     *count = 0;
  30     /* count the number of rpn nodes */
  31     while (rpnp[*count].op != OP_END)
  32         (*count)++;
  33     if (++(*count) > DS_CDEF_MAX_RPN_NODES) {
  34         rrd_set_error("Maximum %d RPN nodes permitted",
  35                       DS_CDEF_MAX_RPN_NODES);
  36         return -1;
  37     }
  38
  39     /* allocate memory */
  40     *rpnc = (rpn_cdefds_t *) calloc(*count, sizeof(rpn_cdefds_t));
  41     for (i = 0; rpnp[i].op != OP_END; i++) {
  42         (*rpnc)[i].op = (char) rpnp[i].op;
  43         if (rpnp[i].op == OP_NUMBER) {
  44             /* rpnp.val is a double, rpnc.val is a short */
  45             double    temp = floor(rpnp[i].val);
  46
  47             if (temp < SHRT_MIN || temp > SHRT_MAX) {
  48                 rrd_set_error
  49                     ("constants must be integers in the interval (%d, %d)",
  50                      SHRT_MIN, SHRT_MAX);
  51                 free(*rpnc);
  52                 return -1;
  53             }
  54             (*rpnc)[i].val = (short) temp;
  55         } else if (rpnp[i].op == OP_VARIABLE || rpnp[i].op == OP_PREV_OTHER) {
  56             (*rpnc)[i].val = (short) rpnp[i].ptr;
  57         }
  58     }
  59     /* terminate the sequence */
  60     (*rpnc)[(*count) - 1].op = OP_END;
  61     return 0;
  62 }
  63
  64 rpnp_t   *rpn_expand(
  65     rpn_cdefds_t *rpnc)
  66 {
  67     short     i;
  68     rpnp_t   *rpnp;
  69
  70     /* DS_CDEF_MAX_RPN_NODES is small, so at the expense of some wasted
  71      * memory we avoid any reallocs */
  72     rpnp = (rpnp_t *) calloc(DS_CDEF_MAX_RPN_NODES, sizeof(rpnp_t));
  73     if (rpnp == NULL)
  74         return NULL;
  75     for (i = 0; rpnc[i].op != OP_END; ++i) {
  76         rpnp[i].op = (long) rpnc[i].op;
  77         if (rpnp[i].op == OP_NUMBER) {
  78             rpnp[i].val = (double) rpnc[i].val;
  79         } else if (rpnp[i].op == OP_VARIABLE || rpnp[i].op == OP_PREV_OTHER) {
  80             rpnp[i].ptr = (long) rpnc[i].val;
  81         }
  82     }
  83     /* terminate the sequence */
  84     rpnp[i].op = OP_END;
  85     return rpnp;
  86 }
  87
  88 /* rpn_compact2str: convert a compact sequence of RPN operator nodes back
  89  * into a CDEF string. This function is used by rrd_dump.
  90  * arguments:
  91  *  rpnc: an array of compact RPN operator nodes
  92  *  ds_def: a pointer to the data source definition section of an RRD header
  93  *   for lookup of data source names by index
  94  *  str: out string, memory is allocated by the function, must be freed by the
  95  *   the caller */
  96 void rpn_compact2str(
  97     rpn_cdefds_t *rpnc,
  98     ds_def_t *ds_def,
  99     char **str)
 100 {
 101     unsigned short i, offset = 0;
 102     char      buffer[7];    /* short as a string */
 103
 104     for (i = 0; rpnc[i].op != OP_END; i++) {
 105         if (i > 0)
 106             (*str)[offset++] = ',';
 107
 108 #define add_op(VV,VVV) \
 109           if (addop2str(rpnc[i].op, VV, VVV, str, &offset) == 1) continue;
 110
 111         if (rpnc[i].op == OP_NUMBER) {
 112             /* convert a short into a string */
 113 #if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)
 114             _itoa(rpnc[i].val, buffer, 10);
 115 #else
 116             sprintf(buffer, "%d", rpnc[i].val);
 117 #endif
 118             add_op(OP_NUMBER, buffer)
 119         }
 120
 121         if (rpnc[i].op == OP_VARIABLE) {
 122             char     *ds_name = ds_def[rpnc[i].val].ds_nam;
 123
 124             add_op(OP_VARIABLE, ds_name)
 125         }
 126
 127         if (rpnc[i].op == OP_PREV_OTHER) {
 128             char     *ds_name = ds_def[rpnc[i].val].ds_nam;
 129
 130             add_op(OP_VARIABLE, ds_name)
 131         }
 132 #undef add_op
 133
 134 #define add_op(VV,VVV) \
 135           if (addop2str(rpnc[i].op, VV, #VVV, str, &offset) == 1) continue;
 136
 137         add_op(OP_ADD, +)
 138             add_op(OP_SUB, -)
 139             add_op(OP_MUL, *)
 140             add_op(OP_DIV, /)
 141             add_op(OP_MOD, %)
 142             add_op(OP_SIN, SIN)
 143             add_op(OP_COS, COS)
 144             add_op(OP_LOG, LOG)
 145             add_op(OP_FLOOR, FLOOR)
 146             add_op(OP_CEIL, CEIL)
 147             add_op(OP_EXP, EXP)
 148             add_op(OP_DUP, DUP)
 149             add_op(OP_EXC, EXC)
 150             add_op(OP_POP, POP)
 151             add_op(OP_LT, LT)
 152             add_op(OP_LE, LE)
 153             add_op(OP_GT, GT)
 154             add_op(OP_GE, GE)
 155             add_op(OP_EQ, EQ)
 156             add_op(OP_IF, IF)
 157             add_op(OP_MIN, MIN)
 158             add_op(OP_MAX, MAX)
 159             add_op(OP_LIMIT, LIMIT)
 160             add_op(OP_UNKN, UNKN)
 161             add_op(OP_UN, UN)
 162             add_op(OP_NEGINF, NEGINF)
 163             add_op(OP_NE, NE)
 164             add_op(OP_PREV, PREV)
 165             add_op(OP_INF, INF)
 166             add_op(OP_ISINF, ISINF)
 167             add_op(OP_NOW, NOW)
 168             add_op(OP_LTIME, LTIME)
 169             add_op(OP_TIME, TIME)
 170             add_op(OP_ATAN2, ATAN2)
 171             add_op(OP_ATAN, ATAN)
 172             add_op(OP_SQRT, SQRT)
 173             add_op(OP_SORT, SORT)
 174             add_op(OP_REV, REV)
 175             add_op(OP_TREND, TREND)
 176             add_op(OP_TRENDNAN, TRENDNAN)
 177             add_op(OP_PREDICT, PREDICT)
 178             add_op(OP_PREDICTSIGMA, PREDICTSIGMA)
 179             add_op(OP_RAD2DEG, RAD2DEG)
 180             add_op(OP_DEG2RAD, DEG2RAD)
 181             add_op(OP_AVG, AVG)
 182             add_op(OP_ABS, ABS)
 183             add_op(OP_ADDNAN, ADDNAN)
 184 #undef add_op
 185     }
 186     (*str)[offset] = '\0';
 187
 188 }
 189
 190 short addop2str(
 191     enum op_en op,
 192     enum op_en op_type,
 193     char *op_str,
 194     char **result_str,
 195     unsigned short *offset)
 196 {
 197     if (op == op_type) {
 198         short     op_len;
 199
 200         op_len = strlen(op_str);
 201         *result_str = (char *) rrd_realloc(*result_str,
 202                                            (op_len + 1 +
 203                                             *offset) * sizeof(char));
 204         if (*result_str == NULL) {
 205             rrd_set_error("failed to alloc memory in addop2str");
 206             return -1;
 207         }
 208         strncpy(&((*result_str)[*offset]), op_str, op_len);
 209         *offset += op_len;
 210         return 1;
 211     }
 212     return 0;
 213 }
 214
 215 void parseCDEF_DS(
 216     const char *def,
 217     rrd_t *rrd,
 218     int ds_idx)
 219 {
 220     rpnp_t   *rpnp = NULL;
 221     rpn_cdefds_t *rpnc = NULL;
 222     short     count, i;
 223
 224     rpnp = rpn_parse((void *) rrd, def, &lookup_DS);
 225     if (rpnp == NULL) {
 226         rrd_set_error("failed to parse computed data source");
 227         return;
 228     }
 229     /* Check for OP nodes not permitted in COMPUTE DS.
 230      * Moved this check from within rpn_compact() because it really is
 231      * COMPUTE DS specific. This is less efficient, but creation doesn't
 232      * occur too often. */
 233     for (i = 0; rpnp[i].op != OP_END; i++) {
 234         if (rpnp[i].op == OP_TIME || rpnp[i].op == OP_LTIME ||
 235             rpnp[i].op == OP_PREV || rpnp[i].op == OP_COUNT) {
 236             rrd_set_error
 237                 ("operators time, ltime, prev and count not supported with DS COMPUTE");
 238             free(rpnp);
 239             return;
 240         }
 241     }
 242     if (rpn_compact(rpnp, &rpnc, &count) == -1) {
 243         free(rpnp);
 244         return;
 245     }
 246     /* copy the compact rpn representation over the ds_def par array */
 247     memcpy((void *) &(rrd->ds_def[ds_idx].par[DS_cdef]),
 248            (void *) rpnc, count * sizeof(rpn_cdefds_t));
 249     free(rpnp);
 250     free(rpnc);
 251 }
 252
 253 /* lookup a data source name in the rrd struct and return the index,
 254  * should use ds_match() here except:
 255  * (1) need a void * pointer to the rrd
 256  * (2) error handling is left to the caller
 257  */
 258 long lookup_DS(
 259     void *rrd_vptr,
 260     char *ds_name)
 261 {
 262     unsigned int i;
 263     rrd_t    *rrd;
 264
 265     rrd = (rrd_t *) rrd_vptr;
 266
 267     for (i = 0; i < rrd->stat_head->ds_cnt; ++i) {
 268         if (strcmp(ds_name, rrd->ds_def[i].ds_nam) == 0)
 269             return i;
 270     }
 271     /* the caller handles a bad data source name in the rpn string */
 272     return -1;
 273 }
 274
 275 /* rpn_parse : parse a string and generate a rpnp array; modified
 276  * str2rpn() originally included in rrd_graph.c
 277  * arguments:
 278  * key_hash: a transparent argument passed to lookup(); conceptually this
 279  *    is a hash object for lookup of a numeric key given a variable name
 280  * expr: the string RPN expression, including variable names
 281  * lookup(): a function that retrieves a numeric key given a variable name
 282  */
 283 rpnp_t   *rpn_parse(
 284     void *key_hash,
 285     const char *const expr_const,
 286     long      (*lookup) (void *,
 287                          char *))
 288 {
 289     int       pos = 0;
 290     char     *expr;
 291     long      steps = -1;
 292     rpnp_t   *rpnp;
 293     char      vname[MAX_VNAME_LEN + 10];
 294     char     *old_locale;
 295
 296     old_locale = setlocale(LC_NUMERIC, "C");
 297
 298     rpnp = NULL;
 299     expr = (char *) expr_const;
 300
 301     while (*expr) {
 302         if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2) *
 303                                            sizeof(rpnp_t))) == NULL) {
 304             setlocale(LC_NUMERIC, old_locale);
 305             return NULL;
 306         }
 307
 308         else if ((sscanf(expr, "%lf%n", &rpnp[steps].val, &pos) == 1)
 309                  && (expr[pos] == ',')) {
 310             rpnp[steps].op = OP_NUMBER;
 311             expr += pos;
 312         }
 313 #define match_op(VV,VVV) \
 314         else if (strncmp(expr, #VVV, strlen(#VVV))==0 && ( expr[strlen(#VVV)] == ',' || expr[strlen(#VVV)] == '\0' )){ \
 315             rpnp[steps].op = VV; \
 316             expr+=strlen(#VVV); \
 317         }
 318
 319 #define match_op_param(VV,VVV) \
 320         else if (sscanf(expr, #VVV "(" DEF_NAM_FMT ")",vname) == 1) { \
 321           int length = 0; \
 322           if ((length = strlen(#VVV)+strlen(vname)+2, \
 323               expr[length] == ',' || expr[length] == '\0') ) { \
 324              rpnp[steps].op = VV; \
 325              rpnp[steps].ptr = (*lookup)(key_hash,vname); \
 326              if (rpnp[steps].ptr < 0) { \
 327                            free(rpnp); \
 328                            return NULL; \
 329                          } else expr+=length; \
 330           } \
 331         }
 332
 333         match_op(OP_ADD, +)
 334             match_op(OP_SUB, -)
 335             match_op(OP_MUL, *)
 336             match_op(OP_DIV, /)
 337             match_op(OP_MOD, %)
 338             match_op(OP_SIN, SIN)
 339             match_op(OP_COS, COS)
 340             match_op(OP_LOG, LOG)
 341             match_op(OP_FLOOR, FLOOR)
 342             match_op(OP_CEIL, CEIL)
 343             match_op(OP_EXP, EXP)
 344             match_op(OP_DUP, DUP)
 345             match_op(OP_EXC, EXC)
 346             match_op(OP_POP, POP)
 347             match_op(OP_LTIME, LTIME)
 348             match_op(OP_LT, LT)
 349             match_op(OP_LE, LE)
 350             match_op(OP_GT, GT)
 351             match_op(OP_GE, GE)
 352             match_op(OP_EQ, EQ)
 353             match_op(OP_IF, IF)
 354             match_op(OP_MIN, MIN)
 355             match_op(OP_MAX, MAX)
 356             match_op(OP_LIMIT, LIMIT)
 357             /* order is important here ! .. match longest first */
 358             match_op(OP_UNKN, UNKN)
 359             match_op(OP_UN, UN)
 360             match_op(OP_NEGINF, NEGINF)
 361             match_op(OP_NE, NE)
 362             match_op(OP_COUNT, COUNT)
 363             match_op_param(OP_PREV_OTHER, PREV)
 364             match_op(OP_PREV, PREV)
 365             match_op(OP_INF, INF)
 366             match_op(OP_ISINF, ISINF)
 367             match_op(OP_NOW, NOW)
 368             match_op(OP_TIME, TIME)
 369             match_op(OP_ATAN2, ATAN2)
 370             match_op(OP_ATAN, ATAN)
 371             match_op(OP_SQRT, SQRT)
 372             match_op(OP_SORT, SORT)
 373             match_op(OP_REV, REV)
 374             match_op(OP_TREND, TREND)
 375             match_op(OP_TRENDNAN, TRENDNAN)
 376             match_op(OP_PREDICT, PREDICT)
 377             match_op(OP_PREDICTSIGMA, PREDICTSIGMA)
 378             match_op(OP_RAD2DEG, RAD2DEG)
 379             match_op(OP_DEG2RAD, DEG2RAD)
 380             match_op(OP_AVG, AVG)
 381             match_op(OP_ABS, ABS)
 382             match_op(OP_ADDNAN, ADDNAN)
 383 #undef match_op
 384             else if ((sscanf(expr, DEF_NAM_FMT "%n", vname, &pos) == 1)
 385                      && ((rpnp[steps].ptr = (*lookup) (key_hash, vname)) !=
 386                          -1)) {
 387             rpnp[steps].op = OP_VARIABLE;
 388             expr += pos;
 389         }
 390
 391         else {
 392             setlocale(LC_NUMERIC, old_locale);
 393             free(rpnp);
 394             return NULL;
 395         }
 396
 397         if (*expr == 0)
 398             break;
 399         if (*expr == ',')
 400             expr++;
 401         else {
 402             setlocale(LC_NUMERIC, old_locale);
 403             free(rpnp);
 404             return NULL;
 405         }
 406     }
 407     rpnp[steps + 1].op = OP_END;
 408     setlocale(LC_NUMERIC, old_locale);
 409     return rpnp;
 410 }
 411
 412 void rpnstack_init(
 413     rpnstack_t *rpnstack)
 414 {
 415     rpnstack->s = NULL;
 416     rpnstack->dc_stacksize = 0;
 417     rpnstack->dc_stackblock = 100;
 418 }
 419
 420 void rpnstack_free(
 421     rpnstack_t *rpnstack)
 422 {
 423     if (rpnstack->s != NULL)
 424         free(rpnstack->s);
 425     rpnstack->dc_stacksize = 0;
 426 }
 427
 428 static int rpn_compare_double(
 429     const void *x,
 430     const void *y)
 431 {
 432     double    diff = *((const double *) x) - *((const double *) y);
 433
 434     return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
 435 }
 436
 437 /* rpn_calc: run the RPN calculator; also performs variable substitution;
 438  * moved and modified from data_calc() originally included in rrd_graph.c
 439  * arguments:
 440  * rpnp : an array of RPN operators (including variable references)
 441  * rpnstack : the initialized stack
 442  * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
 443  *   is advanced by rpnp.ds_cnt; used only for variable substitution
 444  * output : an array of output values; OP_PREV assumes this array contains
 445  *   the "previous" value at index position output_idx-1; the definition of
 446  *   "previous" depends on the calling environment
 447  * output_idx : an index into the output array in which to store the output
 448  *   of the RPN calculator
 449  * returns: -1 if the computation failed (also calls rrd_set_error)
 450  *           0 on success
 451  */
 452 short rpn_calc(
 453     rpnp_t *rpnp,
 454     rpnstack_t *rpnstack,
 455     long data_idx,
 456     rrd_value_t *output,
 457     int output_idx)
 458 {
 459     int       rpi;
 460     long      stptr = -1;
 461
 462     /* process each op from the rpn in turn */
 463     for (rpi = 0; rpnp[rpi].op != OP_END; rpi++) {
 464         /* allocate or grow the stack */
 465         if (stptr + 5 > rpnstack->dc_stacksize) {
 466             /* could move this to a separate function */
 467             rpnstack->dc_stacksize += rpnstack->dc_stackblock;
 468             rpnstack->s = rrd_realloc(rpnstack->s,
 469                                       (rpnstack->dc_stacksize) *
 470                                       sizeof(*(rpnstack->s)));
 471             if (rpnstack->s == NULL) {
 472                 rrd_set_error("RPN stack overflow");
 473                 return -1;
 474             }
 475         }
 476 #define stackunderflow(MINSIZE)                         \
 477         if(stptr<MINSIZE){                              \
 478             rrd_set_error("RPN stack underflow");       \
 479             return -1;                                  \
 480         }
 481
 482         switch (rpnp[rpi].op) {
 483         case OP_NUMBER:
 484             rpnstack->s[++stptr] = rpnp[rpi].val;
 485             break;
 486         case OP_VARIABLE:
 487         case OP_PREV_OTHER:
 488             /* Sanity check: VDEFs shouldn't make it here */
 489             if (rpnp[rpi].ds_cnt == 0) {
 490                 rrd_set_error("VDEF made it into rpn_calc... aborting");
 491                 return -1;
 492             } else {
 493                 /* make sure we pull the correct value from
 494                  * the *.data array. Adjust the pointer into
 495                  * the array acordingly. Advance the ptr one
 496                  * row in the rra (skip over non-relevant
 497                  * data sources)
 498                  */
 499                 if (rpnp[rpi].op == OP_VARIABLE) {
 500                     rpnstack->s[++stptr] = *(rpnp[rpi].data);
 501                 } else {
 502                     if ((output_idx) <= 0) {
 503                         rpnstack->s[++stptr] = DNAN;
 504                     } else {
 505                         rpnstack->s[++stptr] =
 506                             *(rpnp[rpi].data - rpnp[rpi].ds_cnt);
 507                     }
 508
 509                 }
 510                 if (data_idx % rpnp[rpi].step == 0) {
 511                     rpnp[rpi].data += rpnp[rpi].ds_cnt;
 512                 }
 513             }
 514             break;
 515         case OP_COUNT:
 516             rpnstack->s[++stptr] = (output_idx + 1);    /* Note: Counter starts at 1 */
 517             break;
 518         case OP_PREV:
 519             if ((output_idx) <= 0) {
 520                 rpnstack->s[++stptr] = DNAN;
 521             } else {
 522                 rpnstack->s[++stptr] = output[output_idx - 1];
 523             }
 524             break;
 525         case OP_UNKN:
 526             rpnstack->s[++stptr] = DNAN;
 527             break;
 528         case OP_INF:
 529             rpnstack->s[++stptr] = DINF;
 530             break;
 531         case OP_NEGINF:
 532             rpnstack->s[++stptr] = -DINF;
 533             break;
 534         case OP_NOW:
 535             rpnstack->s[++stptr] = (double) time(NULL);
 536             break;
 537         case OP_TIME:
 538             /* HACK: this relies on the data_idx being the time,
 539              ** which the within-function scope is unaware of */
 540             rpnstack->s[++stptr] = (double) data_idx;
 541             break;
 542         case OP_LTIME:
 543             rpnstack->s[++stptr] =
 544                 (double) tzoffset(data_idx) + (double) data_idx;
 545             break;
 546         case OP_ADD:
 547             stackunderflow(1);
 548             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 549                 + rpnstack->s[stptr];
 550             stptr--;
 551             break;
 552         case OP_ADDNAN:
 553             stackunderflow(1);
 554             if (isnan(rpnstack->s[stptr - 1])) {
 555                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 556             } else if (isnan(rpnstack->s[stptr])) {
 557                 /* NOOP */
 558                 /* rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]; */
 559             } else {
 560                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 561                     + rpnstack->s[stptr];
 562             }
 563
 564             stptr--;
 565             break;
 566         case OP_SUB:
 567             stackunderflow(1);
 568             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 569                 - rpnstack->s[stptr];
 570             stptr--;
 571             break;
 572         case OP_MUL:
 573             stackunderflow(1);
 574             rpnstack->s[stptr - 1] = (rpnstack->s[stptr - 1])
 575                 * (rpnstack->s[stptr]);
 576             stptr--;
 577             break;
 578         case OP_DIV:
 579             stackunderflow(1);
 580             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 581                 / rpnstack->s[stptr];
 582             stptr--;
 583             break;
 584         case OP_MOD:
 585             stackunderflow(1);
 586             rpnstack->s[stptr - 1] = fmod(rpnstack->s[stptr - 1]
 587                                           , rpnstack->s[stptr]);
 588             stptr--;
 589             break;
 590         case OP_SIN:
 591             stackunderflow(0);
 592             rpnstack->s[stptr] = sin(rpnstack->s[stptr]);
 593             break;
 594         case OP_ATAN:
 595             stackunderflow(0);
 596             rpnstack->s[stptr] = atan(rpnstack->s[stptr]);
 597             break;
 598         case OP_RAD2DEG:
 599             stackunderflow(0);
 600             rpnstack->s[stptr] = 57.29577951 * rpnstack->s[stptr];
 601             break;
 602         case OP_DEG2RAD:
 603             stackunderflow(0);
 604             rpnstack->s[stptr] = 0.0174532952 * rpnstack->s[stptr];
 605             break;
 606         case OP_ATAN2:
 607             stackunderflow(1);
 608             rpnstack->s[stptr - 1] = atan2(rpnstack->s[stptr - 1],
 609                                            rpnstack->s[stptr]);
 610             stptr--;
 611             break;
 612         case OP_COS:
 613             stackunderflow(0);
 614             rpnstack->s[stptr] = cos(rpnstack->s[stptr]);
 615             break;
 616         case OP_CEIL:
 617             stackunderflow(0);
 618             rpnstack->s[stptr] = ceil(rpnstack->s[stptr]);
 619             break;
 620         case OP_FLOOR:
 621             stackunderflow(0);
 622             rpnstack->s[stptr] = floor(rpnstack->s[stptr]);
 623             break;
 624         case OP_LOG:
 625             stackunderflow(0);
 626             rpnstack->s[stptr] = log(rpnstack->s[stptr]);
 627             break;
 628         case OP_DUP:
 629             stackunderflow(0);
 630             rpnstack->s[stptr + 1] = rpnstack->s[stptr];
 631             stptr++;
 632             break;
 633         case OP_POP:
 634             stackunderflow(0);
 635             stptr--;
 636             break;
 637         case OP_EXC:
 638             stackunderflow(1);
 639             {
 640                 double    dummy;
 641
 642                 dummy = rpnstack->s[stptr];
 643                 rpnstack->s[stptr] = rpnstack->s[stptr - 1];
 644                 rpnstack->s[stptr - 1] = dummy;
 645             }
 646             break;
 647         case OP_EXP:
 648             stackunderflow(0);
 649             rpnstack->s[stptr] = exp(rpnstack->s[stptr]);
 650             break;
 651         case OP_LT:
 652             stackunderflow(1);
 653             if (isnan(rpnstack->s[stptr - 1]));
 654             else if (isnan(rpnstack->s[stptr]))
 655                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 656             else
 657                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] <
 658                     rpnstack->s[stptr] ? 1.0 : 0.0;
 659             stptr--;
 660             break;
 661         case OP_LE:
 662             stackunderflow(1);
 663             if (isnan(rpnstack->s[stptr - 1]));
 664             else if (isnan(rpnstack->s[stptr]))
 665                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 666             else
 667                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] <=
 668                     rpnstack->s[stptr] ? 1.0 : 0.0;
 669             stptr--;
 670             break;
 671         case OP_GT:
 672             stackunderflow(1);
 673             if (isnan(rpnstack->s[stptr - 1]));
 674             else if (isnan(rpnstack->s[stptr]))
 675                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 676             else
 677                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] >
 678                     rpnstack->s[stptr] ? 1.0 : 0.0;
 679             stptr--;
 680             break;
 681         case OP_GE:
 682             stackunderflow(1);
 683             if (isnan(rpnstack->s[stptr - 1]));
 684             else if (isnan(rpnstack->s[stptr]))
 685                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 686             else
 687                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] >=
 688                     rpnstack->s[stptr] ? 1.0 : 0.0;
 689             stptr--;
 690             break;
 691         case OP_NE:
 692             stackunderflow(1);
 693             if (isnan(rpnstack->s[stptr - 1]));
 694             else if (isnan(rpnstack->s[stptr]))
 695                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 696             else
 697                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] ==
 698                     rpnstack->s[stptr] ? 0.0 : 1.0;
 699             stptr--;
 700             break;
 701         case OP_EQ:
 702             stackunderflow(1);
 703             if (isnan(rpnstack->s[stptr - 1]));
 704             else if (isnan(rpnstack->s[stptr]))
 705                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 706             else
 707                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] ==
 708                     rpnstack->s[stptr] ? 1.0 : 0.0;
 709             stptr--;
 710             break;
 711         case OP_IF:
 712             stackunderflow(2);
 713             rpnstack->s[stptr - 2] = (isnan(rpnstack->s[stptr - 2])
 714                                       || rpnstack->s[stptr - 2] ==
 715                                       0.0) ? rpnstack->s[stptr] : rpnstack->
 716                 s[stptr - 1];
 717             stptr--;
 718             stptr--;
 719             break;
 720         case OP_MIN:
 721             stackunderflow(1);
 722             if (isnan(rpnstack->s[stptr - 1]));
 723             else if (isnan(rpnstack->s[stptr]))
 724                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 725             else if (rpnstack->s[stptr - 1] > rpnstack->s[stptr])
 726                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 727             stptr--;
 728             break;
 729         case OP_MAX:
 730             stackunderflow(1);
 731             if (isnan(rpnstack->s[stptr - 1]));
 732             else if (isnan(rpnstack->s[stptr]))
 733                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 734             else if (rpnstack->s[stptr - 1] < rpnstack->s[stptr])
 735                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 736             stptr--;
 737             break;
 738         case OP_LIMIT:
 739             stackunderflow(2);
 740             if (isnan(rpnstack->s[stptr - 2]));
 741             else if (isnan(rpnstack->s[stptr - 1]))
 742                 rpnstack->s[stptr - 2] = rpnstack->s[stptr - 1];
 743             else if (isnan(rpnstack->s[stptr]))
 744                 rpnstack->s[stptr - 2] = rpnstack->s[stptr];
 745             else if (rpnstack->s[stptr - 2] < rpnstack->s[stptr - 1])
 746                 rpnstack->s[stptr - 2] = DNAN;
 747             else if (rpnstack->s[stptr - 2] > rpnstack->s[stptr])
 748                 rpnstack->s[stptr - 2] = DNAN;
 749             stptr -= 2;
 750             break;
 751         case OP_UN:
 752             stackunderflow(0);
 753             rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
 754             break;
 755         case OP_ISINF:
 756             stackunderflow(0);
 757             rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
 758             break;
 759         case OP_SQRT:
 760             stackunderflow(0);
 761             rpnstack->s[stptr] = sqrt(rpnstack->s[stptr]);
 762             break;
 763         case OP_SORT:
 764             stackunderflow(0);
 765             {
 766                 int       spn = (int) rpnstack->s[stptr--];
 767
 768                 stackunderflow(spn - 1);
 769                 qsort(rpnstack->s + stptr - spn + 1, spn, sizeof(double),
 770                       rpn_compare_double);
 771             }
 772             break;
 773         case OP_REV:
 774             stackunderflow(0);
 775             {
 776                 int       spn = (int) rpnstack->s[stptr--];
 777                 double   *p, *q;
 778
 779                 stackunderflow(spn - 1);
 780
 781                 p = rpnstack->s + stptr - spn + 1;
 782                 q = rpnstack->s + stptr;
 783                 while (p < q) {
 784                     double    x = *q;
 785
 786                     *q-- = *p;
 787                     *p++ = x;
 788                 }
 789             }
 790             break;
 791         case OP_PREDICT:
 792         case OP_PREDICTSIGMA:
 793             stackunderflow(2);
 794             {
 795                 /* the local averaging window (similar to trend, but better here, as we get better statistics thru numbers)*/
 796                 int   locstepsize = rpnstack->s[--stptr];
 797                 /* the number of shifts and range-checking*/
 798                 int     shifts = rpnstack->s[--stptr];
 799                 stackunderflow(shifts);
 800                 // handle negative shifts special
 801                 if (shifts<0) {
 802                     stptr--;
 803                 } else {
 804                     stptr-=shifts;
 805                 }
 806                 /* the real calculation */
 807                 double val=DNAN;
 808                 /* the info on the datasource */
 809                 time_t  dsstep = (time_t) rpnp[rpi - 1].step;
 810                 int    dscount = rpnp[rpi - 1].ds_cnt;
 811                 int   locstep = (int)ceil((float)locstepsize/(float)dsstep);
 812
 813                 /* the sums */
 814                 double    sum = 0;
 815                 double    sum2 = 0;
 816                 int       count = 0;
 817                 /* now loop for each position */
 818                 int doshifts=shifts;
 819                 if (shifts<0) { doshifts=-shifts; }
 820                 for(int loop=0;loop<doshifts;loop++) {
 821                     /* calculate shift step */
 822                     int shiftstep=1;
 823                     if (shifts<0) {
 824                         shiftstep = loop*rpnstack->s[stptr];
 825                     } else {
 826                         shiftstep = rpnstack->s[stptr+loop];
 827                     }
 828                     if(shiftstep <0) {
 829                         rrd_set_error("negative shift step not allowed: %i",shiftstep);
 830                         return -1;
 831                     }
 832                     shiftstep=(int)ceil((float)shiftstep/(float)dsstep);
 833                     /* loop all local shifts */
 834                     for(int i=0;i<=locstep;i++) {
 835                         /* now calculate offset into data-array - relative to output_idx*/
 836                         int offset=shiftstep+i;
 837                         /* and process if we have index 0 of above */
 838                         if ((offset>=0)&&(offset<output_idx)) {
 839                             /* get the value */
 840                             val =rpnp[rpi - 1].data[-dscount * offset];
 841                             /* and handle the non NAN case only*/
 842                             if (! isnan(val)) {
 843                                 sum+=val;
 844                                 sum2+=val*val;
 845                                 count++;
 846                             }
 847                         }
 848                     }
 849                 }
 850                 /* do the final calculations */
 851                 val=DNAN;
 852                 if (rpnp[rpi].op == OP_PREDICT) {  /* the average */
 853                     if (count>0) {
 854                         val = sum/(double)count;
 855                     }
 856                 } else {
 857                     if (count>1) { /* the sigma case */
 858                         val=count*sum2-sum*sum;
 859                         if (val<0) {
 860                             val=DNAN;
 861                         } else {
 862                             val=sqrt(val/((float)count*((float)count-1.0)));
 863                         }
 864                     }
 865                 }
 866                 rpnstack->s[stptr] = val;
 867             }
 868             break;
 869         case OP_TREND:
 870         case OP_TRENDNAN:
 871             stackunderflow(1);
 872             if ((rpi < 2) || (rpnp[rpi - 2].op != OP_VARIABLE)) {
 873                 rrd_set_error("malformed trend arguments");
 874                 return -1;
 875             } else {
 876                 time_t    dur = (time_t) rpnstack->s[stptr];
 877                 time_t    step = (time_t) rpnp[rpi - 2].step;
 878
 879                 if (output_idx > (int) ceil((float) dur / (float) step)) {
 880                     int       ignorenan = (rpnp[rpi].op == OP_TREND);
 881                     double    accum = 0.0;
 882                     int       i = 0;
 883                     int       count = 0;
 884
 885                     do {
 886                         double    val =
 887                             rpnp[rpi - 2].data[rpnp[rpi - 2].ds_cnt * i--];
 888                         if (ignorenan || !isnan(val)) {
 889                             accum += val;
 890                             ++count;
 891                         }
 892
 893                         dur -= step;
 894                     } while (dur > 0);
 895
 896                     rpnstack->s[--stptr] =
 897                         (count == 0) ? DNAN : (accum / count);
 898                 } else
 899                     rpnstack->s[--stptr] = DNAN;
 900             }
 901             break;
 902         case OP_AVG:
 903             stackunderflow(0);
 904             {
 905                 int       i = (int) rpnstack->s[stptr--];
 906                 double    sum = 0;
 907                 int       count = 0;
 908
 909                 stackunderflow(i - 1);
 910                 while (i > 0) {
 911                     double    val = rpnstack->s[stptr--];
 912
 913                     i--;
 914                     if (isnan(val)) {
 915                         continue;
 916                     }
 917                     count++;
 918                     sum += val;
 919                 }
 920                 /* now push the result back on stack */
 921                 if (count > 0) {
 922                     rpnstack->s[++stptr] = sum / count;
 923                 } else {
 924                     rpnstack->s[++stptr] = DNAN;
 925                 }
 926             }
 927             break;
 928         case OP_ABS:
 929             stackunderflow(0);
 930             rpnstack->s[stptr] = fabs(rpnstack->s[stptr]);
 931             break;
 932         case OP_END:
 933             break;
 934         }
 935 #undef stackunderflow
 936     }
 937     if (stptr != 0) {
 938         rrd_set_error("RPN final stack size != 1");
 939         return -1;
 940     }
 941
 942     output[output_idx] = rpnstack->s[0];
 943     return 0;
 944 }
 945
 946 /* figure out what the local timezone offset for any point in
 947    time was. Return it in seconds */
 948 int tzoffset(
 949     time_t now)
 950 {
 951     int       gm_sec, gm_min, gm_hour, gm_yday, gm_year,
 952         l_sec, l_min, l_hour, l_yday, l_year;
 953     struct tm t;
 954     int       off;
 955
 956     gmtime_r(&now, &t);
 957     gm_sec = t.tm_sec;
 958     gm_min = t.tm_min;
 959     gm_hour = t.tm_hour;
 960     gm_yday = t.tm_yday;
 961     gm_year = t.tm_year;
 962     localtime_r(&now, &t);
 963     l_sec = t.tm_sec;
 964     l_min = t.tm_min;
 965     l_hour = t.tm_hour;
 966     l_yday = t.tm_yday;
 967     l_year = t.tm_year;
 968     off =
 969         (l_sec - gm_sec) + (l_min - gm_min) * 60 + (l_hour - gm_hour) * 3600;
 970     if (l_yday > gm_yday || l_year > gm_year) {
 971         off += 24 * 3600;
 972     } else if (l_yday < gm_yday || l_year < gm_year) {
 973         off -= 24 * 3600;
 974     }
 975     return off;
 976 }