src/rrd_rpncalc.c

   1 /****************************************************************************
   2  * RRDtool 1.4.8  Copyright by Tobi Oetiker, 1997-2013
   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                            rrd_set_error("variable '%s' not found",vname);\
 335                            free(rpnp); \
 336                            return NULL; \
 337                          } else expr+=length; \
 338           } \
 339         }
 340
 341         match_op(OP_ADD, +)
 342             match_op(OP_SUB, -)
 343             match_op(OP_MUL, *)
 344             match_op(OP_DIV, /)
 345             match_op(OP_MOD, %)
 346             match_op(OP_SIN, SIN)
 347             match_op(OP_COS, COS)
 348             match_op(OP_LOG, LOG)
 349             match_op(OP_FLOOR, FLOOR)
 350             match_op(OP_CEIL, CEIL)
 351             match_op(OP_EXP, EXP)
 352             match_op(OP_DUP, DUP)
 353             match_op(OP_EXC, EXC)
 354             match_op(OP_POP, POP)
 355             match_op(OP_LTIME, LTIME)
 356             match_op(OP_LT, LT)
 357             match_op(OP_LE, LE)
 358             match_op(OP_GT, GT)
 359             match_op(OP_GE, GE)
 360             match_op(OP_EQ, EQ)
 361             match_op(OP_IF, IF)
 362             match_op(OP_MIN, MIN)
 363             match_op(OP_MAX, MAX)
 364             match_op(OP_LIMIT, LIMIT)
 365             /* order is important here ! .. match longest first */
 366             match_op(OP_UNKN, UNKN)
 367             match_op(OP_UN, UN)
 368             match_op(OP_NEGINF, NEGINF)
 369             match_op(OP_NE, NE)
 370             match_op(OP_COUNT, COUNT)
 371             match_op_param(OP_PREV_OTHER, PREV)
 372             match_op(OP_PREV, PREV)
 373             match_op(OP_INF, INF)
 374             match_op(OP_ISINF, ISINF)
 375             match_op(OP_NOW, NOW)
 376             match_op(OP_TIME, TIME)
 377             match_op(OP_ATAN2, ATAN2)
 378             match_op(OP_ATAN, ATAN)
 379             match_op(OP_SQRT, SQRT)
 380             match_op(OP_SORT, SORT)
 381             match_op(OP_REV, REV)
 382             match_op(OP_TREND, TREND)
 383             match_op(OP_TRENDNAN, TRENDNAN)
 384             match_op(OP_PREDICT, PREDICT)
 385             match_op(OP_PREDICTSIGMA, PREDICTSIGMA)
 386             match_op(OP_RAD2DEG, RAD2DEG)
 387             match_op(OP_DEG2RAD, DEG2RAD)
 388             match_op(OP_AVG, AVG)
 389             match_op(OP_ABS, ABS)
 390             match_op(OP_ADDNAN, ADDNAN)
 391 #undef match_op
 392             else if ((sscanf(expr, DEF_NAM_FMT "%n", vname, &pos) == 1)
 393                      && ((rpnp[steps].ptr = (*lookup) (key_hash, vname)) !=
 394                          -1)) {
 395             rpnp[steps].op = OP_VARIABLE;
 396             expr += pos;
 397         }
 398
 399         else {
 400             rrd_set_error("don't undestand '%s'",expr);
 401             setlocale(LC_NUMERIC, old_locale);
 402             free(rpnp);
 403             return NULL;
 404         }
 405
 406         if (*expr == 0)
 407             break;
 408         if (*expr == ',')
 409             expr++;
 410         else {
 411             setlocale(LC_NUMERIC, old_locale);
 412             free(rpnp);
 413             return NULL;
 414         }
 415     }
 416     rpnp[steps + 1].op = OP_END;
 417     setlocale(LC_NUMERIC, old_locale);
 418     return rpnp;
 419 }
 420
 421 void rpnstack_init(
 422     rpnstack_t *rpnstack)
 423 {
 424     rpnstack->s = NULL;
 425     rpnstack->dc_stacksize = 0;
 426     rpnstack->dc_stackblock = 100;
 427 }
 428
 429 void rpnstack_free(
 430     rpnstack_t *rpnstack)
 431 {
 432     if (rpnstack->s != NULL)
 433         free(rpnstack->s);
 434     rpnstack->dc_stacksize = 0;
 435 }
 436
 437 static int rpn_compare_double(
 438     const void *x,
 439     const void *y)
 440 {
 441     double    diff = *((const double *) x) - *((const double *) y);
 442
 443     return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
 444 }
 445
 446 /* rpn_calc: run the RPN calculator; also performs variable substitution;
 447  * moved and modified from data_calc() originally included in rrd_graph.c
 448  * arguments:
 449  * rpnp : an array of RPN operators (including variable references)
 450  * rpnstack : the initialized stack
 451  * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
 452  *   is advanced by rpnp.ds_cnt; used only for variable substitution
 453  * output : an array of output values; OP_PREV assumes this array contains
 454  *   the "previous" value at index position output_idx-1; the definition of
 455  *   "previous" depends on the calling environment
 456  * output_idx : an index into the output array in which to store the output
 457  *   of the RPN calculator
 458  * returns: -1 if the computation failed (also calls rrd_set_error)
 459  *           0 on success
 460  */
 461 short rpn_calc(
 462     rpnp_t *rpnp,
 463     rpnstack_t *rpnstack,
 464     long data_idx,
 465     rrd_value_t *output,
 466     int output_idx)
 467 {
 468     int       rpi;
 469     long      stptr = -1;
 470
 471     /* process each op from the rpn in turn */
 472     for (rpi = 0; rpnp[rpi].op != OP_END; rpi++) {
 473         /* allocate or grow the stack */
 474         if (stptr + 5 > rpnstack->dc_stacksize) {
 475             /* could move this to a separate function */
 476             rpnstack->dc_stacksize += rpnstack->dc_stackblock;
 477             rpnstack->s = (double*)rrd_realloc(rpnstack->s,
 478                                       (rpnstack->dc_stacksize) *
 479                                       sizeof(*(rpnstack->s)));
 480             if (rpnstack->s == NULL) {
 481                 rrd_set_error("RPN stack overflow");
 482                 return -1;
 483             }
 484         }
 485 #define stackunderflow(MINSIZE)                         \
 486         if(stptr<MINSIZE){                              \
 487             rrd_set_error("RPN stack underflow");       \
 488             return -1;                                  \
 489         }
 490
 491         switch (rpnp[rpi].op) {
 492         case OP_NUMBER:
 493             rpnstack->s[++stptr] = rpnp[rpi].val;
 494             break;
 495         case OP_VARIABLE:
 496         case OP_PREV_OTHER:
 497             /* Sanity check: VDEFs shouldn't make it here */
 498             if (rpnp[rpi].ds_cnt == 0) {
 499                 rrd_set_error("VDEF made it into rpn_calc... aborting");
 500                 return -1;
 501             } else {
 502                 /* make sure we pull the correct value from
 503                  * the *.data array. Adjust the pointer into
 504                  * the array acordingly. Advance the ptr one
 505                  * row in the rra (skip over non-relevant
 506                  * data sources)
 507                  */
 508                 if (rpnp[rpi].op == OP_VARIABLE) {
 509                     rpnstack->s[++stptr] = *(rpnp[rpi].data);
 510                 } else {
 511                     if ((output_idx) <= 0) {
 512                         rpnstack->s[++stptr] = DNAN;
 513                     } else {
 514                         rpnstack->s[++stptr] =
 515                             *(rpnp[rpi].data - rpnp[rpi].ds_cnt);
 516                     }
 517
 518                 }
 519                 if (data_idx % rpnp[rpi].step == 0) {
 520                     rpnp[rpi].data += rpnp[rpi].ds_cnt;
 521                 }
 522             }
 523             break;
 524         case OP_COUNT:
 525             rpnstack->s[++stptr] = (output_idx + 1);    /* Note: Counter starts at 1 */
 526             break;
 527         case OP_PREV:
 528             if ((output_idx) <= 0) {
 529                 rpnstack->s[++stptr] = DNAN;
 530             } else {
 531                 rpnstack->s[++stptr] = output[output_idx - 1];
 532             }
 533             break;
 534         case OP_UNKN:
 535             rpnstack->s[++stptr] = DNAN;
 536             break;
 537         case OP_INF:
 538             rpnstack->s[++stptr] = DINF;
 539             break;
 540         case OP_NEGINF:
 541             rpnstack->s[++stptr] = -DINF;
 542             break;
 543         case OP_NOW:
 544             rpnstack->s[++stptr] = (double) time(NULL);
 545             break;
 546         case OP_TIME:
 547             /* HACK: this relies on the data_idx being the time,
 548              ** which the within-function scope is unaware of */
 549             rpnstack->s[++stptr] = (double) data_idx;
 550             break;
 551         case OP_LTIME:
 552             rpnstack->s[++stptr] =
 553                 (double) tzoffset(data_idx) + (double) data_idx;
 554             break;
 555         case OP_ADD:
 556             stackunderflow(1);
 557             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 558                 + rpnstack->s[stptr];
 559             stptr--;
 560             break;
 561         case OP_ADDNAN:
 562             stackunderflow(1);
 563             if (isnan(rpnstack->s[stptr - 1])) {
 564                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 565             } else if (isnan(rpnstack->s[stptr])) {
 566                 /* NOOP */
 567                 /* rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]; */
 568             } else {
 569                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 570                     + rpnstack->s[stptr];
 571             }
 572
 573             stptr--;
 574             break;
 575         case OP_SUB:
 576             stackunderflow(1);
 577             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 578                 - rpnstack->s[stptr];
 579             stptr--;
 580             break;
 581         case OP_MUL:
 582             stackunderflow(1);
 583             rpnstack->s[stptr - 1] = (rpnstack->s[stptr - 1])
 584                 * (rpnstack->s[stptr]);
 585             stptr--;
 586             break;
 587         case OP_DIV:
 588             stackunderflow(1);
 589             rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1]
 590                 / rpnstack->s[stptr];
 591             stptr--;
 592             break;
 593         case OP_MOD:
 594             stackunderflow(1);
 595             rpnstack->s[stptr - 1] = fmod(rpnstack->s[stptr - 1]
 596                                           , rpnstack->s[stptr]);
 597             stptr--;
 598             break;
 599         case OP_SIN:
 600             stackunderflow(0);
 601             rpnstack->s[stptr] = sin(rpnstack->s[stptr]);
 602             break;
 603         case OP_ATAN:
 604             stackunderflow(0);
 605             rpnstack->s[stptr] = atan(rpnstack->s[stptr]);
 606             break;
 607         case OP_RAD2DEG:
 608             stackunderflow(0);
 609             rpnstack->s[stptr] = 57.29577951 * rpnstack->s[stptr];
 610             break;
 611         case OP_DEG2RAD:
 612             stackunderflow(0);
 613             rpnstack->s[stptr] = 0.0174532952 * rpnstack->s[stptr];
 614             break;
 615         case OP_ATAN2:
 616             stackunderflow(1);
 617             rpnstack->s[stptr - 1] = atan2(rpnstack->s[stptr - 1],
 618                                            rpnstack->s[stptr]);
 619             stptr--;
 620             break;
 621         case OP_COS:
 622             stackunderflow(0);
 623             rpnstack->s[stptr] = cos(rpnstack->s[stptr]);
 624             break;
 625         case OP_CEIL:
 626             stackunderflow(0);
 627             rpnstack->s[stptr] = ceil(rpnstack->s[stptr]);
 628             break;
 629         case OP_FLOOR:
 630             stackunderflow(0);
 631             rpnstack->s[stptr] = floor(rpnstack->s[stptr]);
 632             break;
 633         case OP_LOG:
 634             stackunderflow(0);
 635             rpnstack->s[stptr] = log(rpnstack->s[stptr]);
 636             break;
 637         case OP_DUP:
 638             stackunderflow(0);
 639             rpnstack->s[stptr + 1] = rpnstack->s[stptr];
 640             stptr++;
 641             break;
 642         case OP_POP:
 643             stackunderflow(0);
 644             stptr--;
 645             break;
 646         case OP_EXC:
 647             stackunderflow(1);
 648             {
 649                 double    dummy;
 650
 651                 dummy = rpnstack->s[stptr];
 652                 rpnstack->s[stptr] = rpnstack->s[stptr - 1];
 653                 rpnstack->s[stptr - 1] = dummy;
 654             }
 655             break;
 656         case OP_EXP:
 657             stackunderflow(0);
 658             rpnstack->s[stptr] = exp(rpnstack->s[stptr]);
 659             break;
 660         case OP_LT:
 661             stackunderflow(1);
 662             if (isnan(rpnstack->s[stptr - 1]));
 663             else if (isnan(rpnstack->s[stptr]))
 664                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 665             else
 666                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] <
 667                     rpnstack->s[stptr] ? 1.0 : 0.0;
 668             stptr--;
 669             break;
 670         case OP_LE:
 671             stackunderflow(1);
 672             if (isnan(rpnstack->s[stptr - 1]));
 673             else if (isnan(rpnstack->s[stptr]))
 674                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 675             else
 676                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] <=
 677                     rpnstack->s[stptr] ? 1.0 : 0.0;
 678             stptr--;
 679             break;
 680         case OP_GT:
 681             stackunderflow(1);
 682             if (isnan(rpnstack->s[stptr - 1]));
 683             else if (isnan(rpnstack->s[stptr]))
 684                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 685             else
 686                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] >
 687                     rpnstack->s[stptr] ? 1.0 : 0.0;
 688             stptr--;
 689             break;
 690         case OP_GE:
 691             stackunderflow(1);
 692             if (isnan(rpnstack->s[stptr - 1]));
 693             else if (isnan(rpnstack->s[stptr]))
 694                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 695             else
 696                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] >=
 697                     rpnstack->s[stptr] ? 1.0 : 0.0;
 698             stptr--;
 699             break;
 700         case OP_NE:
 701             stackunderflow(1);
 702             if (isnan(rpnstack->s[stptr - 1]));
 703             else if (isnan(rpnstack->s[stptr]))
 704                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 705             else
 706                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] ==
 707                     rpnstack->s[stptr] ? 0.0 : 1.0;
 708             stptr--;
 709             break;
 710         case OP_EQ:
 711             stackunderflow(1);
 712             if (isnan(rpnstack->s[stptr - 1]));
 713             else if (isnan(rpnstack->s[stptr]))
 714                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 715             else
 716                 rpnstack->s[stptr - 1] = rpnstack->s[stptr - 1] ==
 717                     rpnstack->s[stptr] ? 1.0 : 0.0;
 718             stptr--;
 719             break;
 720         case OP_IF:
 721             stackunderflow(2);
 722             rpnstack->s[stptr - 2] = (isnan(rpnstack->s[stptr - 2])
 723                                       || rpnstack->s[stptr - 2] ==
 724                                       0.0) ? rpnstack->s[stptr] : rpnstack->
 725                 s[stptr - 1];
 726             stptr--;
 727             stptr--;
 728             break;
 729         case OP_MIN:
 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_MAX:
 739             stackunderflow(1);
 740             if (isnan(rpnstack->s[stptr - 1]));
 741             else if (isnan(rpnstack->s[stptr]))
 742                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 743             else if (rpnstack->s[stptr - 1] < rpnstack->s[stptr])
 744                 rpnstack->s[stptr - 1] = rpnstack->s[stptr];
 745             stptr--;
 746             break;
 747         case OP_LIMIT:
 748             stackunderflow(2);
 749             if (isnan(rpnstack->s[stptr - 2]));
 750             else if (isnan(rpnstack->s[stptr - 1]))
 751                 rpnstack->s[stptr - 2] = rpnstack->s[stptr - 1];
 752             else if (isnan(rpnstack->s[stptr]))
 753                 rpnstack->s[stptr - 2] = rpnstack->s[stptr];
 754             else if (rpnstack->s[stptr - 2] < rpnstack->s[stptr - 1])
 755                 rpnstack->s[stptr - 2] = DNAN;
 756             else if (rpnstack->s[stptr - 2] > rpnstack->s[stptr])
 757                 rpnstack->s[stptr - 2] = DNAN;
 758             stptr -= 2;
 759             break;
 760         case OP_UN:
 761             stackunderflow(0);
 762             rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
 763             break;
 764         case OP_ISINF:
 765             stackunderflow(0);
 766             rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
 767             break;
 768         case OP_SQRT:
 769             stackunderflow(0);
 770             rpnstack->s[stptr] = sqrt(rpnstack->s[stptr]);
 771             break;
 772         case OP_SORT:
 773             stackunderflow(0);
 774             {
 775                 int       spn = (int) rpnstack->s[stptr--];
 776
 777                 stackunderflow(spn - 1);
 778                 qsort(rpnstack->s + stptr - spn + 1, spn, sizeof(double),
 779                       rpn_compare_double);
 780             }
 781             break;
 782         case OP_REV:
 783             stackunderflow(0);
 784             {
 785                 int       spn = (int) rpnstack->s[stptr--];
 786                 double   *p, *q;
 787
 788                 stackunderflow(spn - 1);
 789
 790                 p = rpnstack->s + stptr - spn + 1;
 791                 q = rpnstack->s + stptr;
 792                 while (p < q) {
 793                     double    x = *q;
 794
 795                     *q-- = *p;
 796                     *p++ = x;
 797                 }
 798             }
 799             break;
 800         case OP_PREDICT:
 801         case OP_PREDICTSIGMA:
 802             stackunderflow(2);
 803             {
 804                 /* the local averaging window (similar to trend, but better here, as we get better statistics thru numbers)*/
 805                 int   locstepsize = rpnstack->s[--stptr];
 806                 /* the number of shifts and range-checking*/
 807                 int     shifts = rpnstack->s[--stptr];
 808                 stackunderflow(shifts);
 809                 // handle negative shifts special
 810                 if (shifts<0) {
 811                     stptr--;
 812                 } else {
 813                     stptr-=shifts;
 814                 }
 815                 /* the real calculation */
 816                 double val=DNAN;
 817                 /* the info on the datasource */
 818                 time_t  dsstep = (time_t) rpnp[rpi - 1].step;
 819                 int    dscount = rpnp[rpi - 1].ds_cnt;
 820                 int   locstep = (int)ceil((float)locstepsize/(float)dsstep);
 821
 822                 /* the sums */
 823                 double    sum = 0;
 824                 double    sum2 = 0;
 825                 int       count = 0;
 826                 /* now loop for each position */
 827                 int doshifts=shifts;
 828                 if (shifts<0) { doshifts=-shifts; }
 829                 for(int loop=0;loop<doshifts;loop++) {
 830                     /* calculate shift step */
 831                     int shiftstep=1;
 832                     if (shifts<0) {
 833                         shiftstep = loop*rpnstack->s[stptr];
 834                     } else {
 835                         shiftstep = rpnstack->s[stptr+loop];
 836                     }
 837                     if(shiftstep <0) {
 838                         rrd_set_error("negative shift step not allowed: %i",shiftstep);
 839                         return -1;
 840                     }
 841                     shiftstep=(int)ceil((float)shiftstep/(float)dsstep);
 842                     /* loop all local shifts */
 843                     for(int i=0;i<=locstep;i++) {
 844                         /* now calculate offset into data-array - relative to output_idx*/
 845                         int offset=shiftstep+i;
 846                         /* and process if we have index 0 of above */
 847                         if ((offset>=0)&&(offset<output_idx)) {
 848                             /* get the value */
 849                             val =rpnp[rpi - 1].data[-dscount * offset];
 850                             /* and handle the non NAN case only*/
 851                             if (! isnan(val)) {
 852                                 sum+=val;
 853                                 sum2+=val*val;
 854                                 count++;
 855                             }
 856                         }
 857                     }
 858                 }
 859                 /* do the final calculations */
 860                 val=DNAN;
 861                 if (rpnp[rpi].op == OP_PREDICT) {  /* the average */
 862                     if (count>0) {
 863                         val = sum/(double)count;
 864                     }
 865                 } else {
 866                     if (count>1) { /* the sigma case */
 867                         val=count*sum2-sum*sum;
 868                         if (val<0) {
 869                             val=DNAN;
 870                         } else {
 871                             val=sqrt(val/((float)count*((float)count-1.0)));
 872                         }
 873                     }
 874                 }
 875                 rpnstack->s[stptr] = val;
 876             }
 877             break;
 878         case OP_TREND:
 879         case OP_TRENDNAN:
 880             stackunderflow(1);
 881             if ((rpi < 2) || (rpnp[rpi - 2].op != OP_VARIABLE)) {
 882                 rrd_set_error("malformed trend arguments");
 883                 return -1;
 884             } else {
 885                 time_t    dur = (time_t) rpnstack->s[stptr];
 886                 time_t    step = (time_t) rpnp[rpi - 2].step;
 887
 888                 if (output_idx + 1 >= (int) ceil((float) dur / (float) step)) {
 889                     int       ignorenan = (rpnp[rpi].op == OP_TREND);
 890                     double    accum = 0.0;
 891                     int       i = -1; /* pick the current entries, not the next one
 892                                          as the data pointer has already been forwarded
 893                                          when the OP_VARIABLE was processed */
 894                     int       count = 0;
 895
 896                     do {
 897                         double    val =
 898                             rpnp[rpi - 2].data[rpnp[rpi - 2].ds_cnt * i--];
 899                         if (ignorenan || !isnan(val)) {
 900                             accum += val;
 901                             ++count;
 902                         }
 903
 904                         dur -= step;
 905                     } while (dur > 0);
 906
 907                     rpnstack->s[--stptr] =
 908                         (count == 0) ? DNAN : (accum / count);
 909                 } else
 910                     rpnstack->s[--stptr] = DNAN;
 911             }
 912             break;
 913         case OP_AVG:
 914             stackunderflow(0);
 915             {
 916                 int       i = (int) rpnstack->s[stptr--];
 917                 double    sum = 0;
 918                 int       count = 0;
 919
 920                 stackunderflow(i - 1);
 921                 while (i > 0) {
 922                     double    val = rpnstack->s[stptr--];
 923
 924                     i--;
 925                     if (isnan(val)) {
 926                         continue;
 927                     }
 928                     count++;
 929                     sum += val;
 930                 }
 931                 /* now push the result back on stack */
 932                 if (count > 0) {
 933                     rpnstack->s[++stptr] = sum / count;
 934                 } else {
 935                     rpnstack->s[++stptr] = DNAN;
 936                 }
 937             }
 938             break;
 939         case OP_ABS:
 940             stackunderflow(0);
 941             rpnstack->s[stptr] = fabs(rpnstack->s[stptr]);
 942             break;
 943         case OP_END:
 944             break;
 945         }
 946 #undef stackunderflow
 947     }
 948     if (stptr != 0) {
 949         rrd_set_error("RPN final stack size != 1");
 950         return -1;
 951     }
 952
 953     output[output_idx] = rpnstack->s[0];
 954     return 0;
 955 }
 956
 957 /* figure out what the local timezone offset for any point in
 958    time was. Return it in seconds */
 959 int tzoffset(
 960     time_t now)
 961 {
 962     int       gm_sec, gm_min, gm_hour, gm_yday, gm_year,
 963         l_sec, l_min, l_hour, l_yday, l_year;
 964     struct tm t;
 965     int       off;
 966
 967     gmtime_r(&now, &t);
 968     gm_sec = t.tm_sec;
 969     gm_min = t.tm_min;
 970     gm_hour = t.tm_hour;
 971     gm_yday = t.tm_yday;
 972     gm_year = t.tm_year;
 973     localtime_r(&now, &t);
 974     l_sec = t.tm_sec;
 975     l_min = t.tm_min;
 976     l_hour = t.tm_hour;
 977     l_yday = t.tm_yday;
 978     l_year = t.tm_year;
 979     off =
 980         (l_sec - gm_sec) + (l_min - gm_min) * 60 + (l_hour - gm_hour) * 3600;
 981     if (l_yday > gm_yday || l_year > gm_year) {
 982         off += 24 * 3600;
 983     } else if (l_yday < gm_yday || l_year < gm_year) {
 984         off -= 24 * 3600;
 985     }
 986     return off;
 987 }