src/rrd_rpncalc.c

   1 /****************************************************************************
   2  * RRDtool 1.2.19  Copyright by Tobi Oetiker, 1997-2007
   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
  12 short addop2str(enum op_en op, enum op_en op_type, char *op_str,
  13             char **result_str, unsigned short *offset);
  14 int tzoffset(time_t); /* used to implement LTIME */
  15
  16 short rpn_compact(rpnp_t *rpnp, rpn_cdefds_t **rpnc, short *count)
  17 {
  18     short i;
  19     *count = 0;
  20     /* count the number of rpn nodes */
  21     while(rpnp[*count].op != OP_END) (*count)++;
  22     if (++(*count) > DS_CDEF_MAX_RPN_NODES) {
  23         rrd_set_error("Maximum %d RPN nodes permitted",
  24                       DS_CDEF_MAX_RPN_NODES);
  25         return -1;
  26     }
  27
  28     /* allocate memory */
  29     *rpnc = (rpn_cdefds_t *) calloc(*count,sizeof(rpn_cdefds_t));
  30     for (i = 0; rpnp[i].op != OP_END; i++)
  31     {
  32         (*rpnc)[i].op = (char) rpnp[i].op;
  33         if (rpnp[i].op == OP_NUMBER) {
  34             /* rpnp.val is a double, rpnc.val is a short */
  35             double temp = floor(rpnp[i].val);
  36             if (temp < SHRT_MIN || temp > SHRT_MAX) {
  37                 rrd_set_error(
  38                     "constants must be integers in the interval (%d, %d)",
  39                     SHRT_MIN, SHRT_MAX);
  40                 free(*rpnc);
  41                 return -1;
  42             }
  43             (*rpnc)[i].val = (short) temp;
  44           } else if (rpnp[i].op == OP_VARIABLE ||
  45                                  rpnp[i].op == OP_PREV_OTHER) {
  46             (*rpnc)[i].val = (short) rpnp[i].ptr;
  47         }
  48     }
  49     /* terminate the sequence */
  50     (*rpnc)[(*count) - 1].op = OP_END;
  51     return 0;
  52 }
  53
  54 rpnp_t * rpn_expand(rpn_cdefds_t *rpnc)
  55 {
  56     short i;
  57     rpnp_t *rpnp;
  58
  59     /* DS_CDEF_MAX_RPN_NODES is small, so at the expense of some wasted
  60      * memory we avoid any reallocs */
  61     rpnp = (rpnp_t *) calloc(DS_CDEF_MAX_RPN_NODES,sizeof(rpnp_t));
  62     if (rpnp == NULL) return NULL;
  63     for (i = 0; rpnc[i].op != OP_END; ++i)
  64     {
  65         rpnp[i].op = (long) rpnc[i].op;
  66         if (rpnp[i].op == OP_NUMBER) {
  67             rpnp[i].val = (double) rpnc[i].val;
  68           } else if (rpnp[i].op == OP_VARIABLE ||
  69                                  rpnp[i].op == OP_PREV_OTHER) {
  70             rpnp[i].ptr = (long) rpnc[i].val;
  71         }
  72     }
  73     /* terminate the sequence */
  74     rpnp[i].op = OP_END;
  75     return rpnp;
  76 }
  77
  78 /* rpn_compact2str: convert a compact sequence of RPN operator nodes back
  79  * into a CDEF string. This function is used by rrd_dump.
  80  * arguments:
  81  *  rpnc: an array of compact RPN operator nodes
  82  *  ds_def: a pointer to the data source definition section of an RRD header
  83  *   for lookup of data source names by index
  84  *  str: out string, memory is allocated by the function, must be freed by the
  85  *   the caller */
  86 void rpn_compact2str(rpn_cdefds_t *rpnc,ds_def_t *ds_def,char **str)
  87 {
  88     unsigned short i,offset = 0;
  89     char buffer[7]; /* short as a string */
  90
  91     for (i = 0; rpnc[i].op != OP_END; i++)
  92     {
  93         if (i > 0) (*str)[offset++] = ',';
  94
  95 #define add_op(VV,VVV) \
  96           if (addop2str(rpnc[i].op, VV, VVV, str, &offset) == 1) continue;
  97
  98         if (rpnc[i].op == OP_NUMBER) {
  99             /* convert a short into a string */
 100 #if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)
 101             _itoa(rpnc[i].val,buffer,10);
 102 #else
 103             sprintf(buffer,"%d",rpnc[i].val);
 104 #endif
 105             add_op(OP_NUMBER,buffer)
 106                 }
 107
 108         if (rpnc[i].op == OP_VARIABLE) {
 109             char *ds_name = ds_def[rpnc[i].val].ds_nam;
 110             add_op(OP_VARIABLE, ds_name)
 111                 }
 112
 113           if (rpnc[i].op == OP_PREV_OTHER) {
 114                 char *ds_name = ds_def[rpnc[i].val].ds_nam;
 115                 add_op(OP_VARIABLE, ds_name)
 116           }
 117
 118 #undef add_op
 119
 120 #define add_op(VV,VVV) \
 121           if (addop2str(rpnc[i].op, VV, #VVV, str, &offset) == 1) continue;
 122
 123           add_op(OP_ADD,+)
 124           add_op(OP_SUB,-)
 125           add_op(OP_MUL,*)
 126           add_op(OP_DIV,/)
 127           add_op(OP_MOD,%)
 128           add_op(OP_SIN,SIN)
 129           add_op(OP_COS,COS)
 130           add_op(OP_LOG,LOG)
 131           add_op(OP_FLOOR,FLOOR)
 132           add_op(OP_CEIL,CEIL)
 133           add_op(OP_EXP,EXP)
 134           add_op(OP_DUP,DUP)
 135           add_op(OP_EXC,EXC)
 136           add_op(OP_POP,POP)
 137           add_op(OP_LT,LT)
 138           add_op(OP_LE,LE)
 139           add_op(OP_GT,GT)
 140           add_op(OP_GE,GE)
 141           add_op(OP_EQ,EQ)
 142           add_op(OP_IF,IF)
 143           add_op(OP_MIN,MIN)
 144           add_op(OP_MAX,MAX)
 145           add_op(OP_LIMIT,LIMIT)
 146           add_op(OP_UNKN,UNKN)
 147           add_op(OP_UN,UN)
 148           add_op(OP_NEGINF,NEGINF)
 149           add_op(OP_NE,NE)
 150           add_op(OP_PREV,PREV)
 151           add_op(OP_INF,INF)
 152           add_op(OP_ISINF,ISINF)
 153           add_op(OP_NOW,NOW)
 154           add_op(OP_LTIME,LTIME)
 155           add_op(OP_TIME,TIME)
 156          add_op(OP_ATAN2,ATAN2)
 157           add_op(OP_ATAN,ATAN)
 158           add_op(OP_SQRT,SQRT)
 159           add_op(OP_SORT,SORT)
 160           add_op(OP_REV,REV)
 161           add_op(OP_TREND,TREND)
 162          add_op(OP_RAD2DEG,RAD2DEG)
 163          add_op(OP_DEG2RAD,DEG2RAD)
 164          add_op(OP_AVG,AVG)
 165 #undef add_op
 166               }
 167     (*str)[offset] = '\0';
 168
 169 }
 170
 171 short addop2str(enum op_en op, enum op_en op_type, char *op_str,
 172                 char **result_str, unsigned short *offset)
 173 {
 174     if (op == op_type) {
 175         short op_len;
 176         op_len = strlen(op_str);
 177         *result_str =  (char *) rrd_realloc(*result_str,
 178                                             (op_len + 1 + *offset)*sizeof(char));
 179         if (*result_str == NULL) {
 180             rrd_set_error("failed to alloc memory in addop2str");
 181             return -1;
 182         }
 183         strncpy(&((*result_str)[*offset]),op_str,op_len);
 184         *offset += op_len;
 185         return 1;
 186     }
 187     return 0;
 188 }
 189
 190 void parseCDEF_DS(char *def,rrd_t *rrd, int ds_idx)
 191 {
 192     rpnp_t *rpnp = NULL;
 193     rpn_cdefds_t *rpnc = NULL;
 194     short count, i;
 195
 196     rpnp = rpn_parse((void*) rrd, def, &lookup_DS);
 197     if (rpnp == NULL) {
 198         rrd_set_error("failed to parse computed data source");
 199         return;
 200     }
 201     /* Check for OP nodes not permitted in COMPUTE DS.
 202      * Moved this check from within rpn_compact() because it really is
 203      * COMPUTE DS specific. This is less efficient, but creation doesn't
 204      * occur too often. */
 205     for (i = 0; rpnp[i].op != OP_END; i++) {
 206         if (rpnp[i].op == OP_TIME || rpnp[i].op == OP_LTIME ||
 207             rpnp[i].op == OP_PREV || rpnp[i].op == OP_COUNT)
 208         {
 209             rrd_set_error(
 210                 "operators time, ltime, prev and count not supported with DS COMPUTE");
 211             free(rpnp);
 212             return;
 213         }
 214     }
 215     if (rpn_compact(rpnp,&rpnc,&count) == -1) {
 216         free(rpnp);
 217         return;
 218     }
 219     /* copy the compact rpn representation over the ds_def par array */
 220     memcpy((void*) &(rrd -> ds_def[ds_idx].par[DS_cdef]),
 221            (void*) rpnc, count*sizeof(rpn_cdefds_t));
 222     free(rpnp);
 223     free(rpnc);
 224 }
 225
 226 /* lookup a data source name in the rrd struct and return the index,
 227  * should use ds_match() here except:
 228  * (1) need a void * pointer to the rrd
 229  * (2) error handling is left to the caller
 230  */
 231 long lookup_DS(void *rrd_vptr,char *ds_name)
 232 {
 233     unsigned int i;
 234     rrd_t *rrd;
 235
 236     rrd = (rrd_t *) rrd_vptr;
 237
 238     for (i = 0; i < rrd -> stat_head -> ds_cnt; ++i)
 239     {
 240         if(strcmp(ds_name,rrd -> ds_def[i].ds_nam) == 0)
 241             return i;
 242     }
 243     /* the caller handles a bad data source name in the rpn string */
 244     return -1;
 245 }
 246
 247 /* rpn_parse : parse a string and generate a rpnp array; modified
 248  * str2rpn() originally included in rrd_graph.c
 249  * arguments:
 250  * key_hash: a transparent argument passed to lookup(); conceptually this
 251  *    is a hash object for lookup of a numeric key given a variable name
 252  * expr: the string RPN expression, including variable names
 253  * lookup(): a function that retrieves a numeric key given a variable name
 254  */
 255 rpnp_t *
 256 rpn_parse(void *key_hash,const char *const expr_const,long (*lookup)(void *,char*)){
 257     int pos=0;
 258     char *expr;
 259     long steps=-1;
 260     rpnp_t  *rpnp;
 261     char vname[MAX_VNAME_LEN+10];
 262
 263     rpnp=NULL;
 264     expr=(char *)expr_const;
 265
 266     while(*expr){
 267         if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2)*
 268                                        sizeof(rpnp_t)))==NULL){
 269             return NULL;
 270         }
 271
 272         else if((sscanf(expr,"%lf%n",&rpnp[steps].val,&pos) == 1) && (expr[pos] == ',')){
 273             rpnp[steps].op = OP_NUMBER;
 274             expr+=pos;
 275         }
 276
 277 #define match_op(VV,VVV) \
 278         else if (strncmp(expr, #VVV, strlen(#VVV))==0 && ( expr[strlen(#VVV)] == ',' || expr[strlen(#VVV)] == '\0' )){ \
 279             rpnp[steps].op = VV; \
 280             expr+=strlen(#VVV); \
 281         }
 282
 283
 284 #define match_op_param(VV,VVV) \
 285         else if (sscanf(expr, #VVV "(" DEF_NAM_FMT ")",vname) == 1) { \
 286           int length = 0; \
 287           if ((length = strlen(#VVV)+strlen(vname)+2, \
 288               expr[length] == ',' || expr[length] == '\0') ) { \
 289              rpnp[steps].op = VV; \
 290              rpnp[steps].ptr = (*lookup)(key_hash,vname); \
 291              if (rpnp[steps].ptr < 0) { \
 292                            free(rpnp); \
 293                            return NULL; \
 294                          } else expr+=length; \
 295           } \
 296         }
 297
 298         match_op(OP_ADD,+)
 299         match_op(OP_SUB,-)
 300         match_op(OP_MUL,*)
 301         match_op(OP_DIV,/)
 302         match_op(OP_MOD,%)
 303         match_op(OP_SIN,SIN)
 304         match_op(OP_COS,COS)
 305         match_op(OP_LOG,LOG)
 306         match_op(OP_FLOOR,FLOOR)
 307         match_op(OP_CEIL,CEIL)
 308         match_op(OP_EXP,EXP)
 309         match_op(OP_DUP,DUP)
 310         match_op(OP_EXC,EXC)
 311         match_op(OP_POP,POP)
 312         match_op(OP_LTIME,LTIME)
 313         match_op(OP_LT,LT)
 314         match_op(OP_LE,LE)
 315         match_op(OP_GT,GT)
 316         match_op(OP_GE,GE)
 317         match_op(OP_EQ,EQ)
 318         match_op(OP_IF,IF)
 319         match_op(OP_MIN,MIN)
 320         match_op(OP_MAX,MAX)
 321         match_op(OP_LIMIT,LIMIT)
 322           /* order is important here ! .. match longest first */
 323         match_op(OP_UNKN,UNKN)
 324         match_op(OP_UN,UN)
 325         match_op(OP_NEGINF,NEGINF)
 326         match_op(OP_NE,NE)
 327         match_op(OP_COUNT,COUNT)
 328         match_op_param(OP_PREV_OTHER,PREV)
 329         match_op(OP_PREV,PREV)
 330         match_op(OP_INF,INF)
 331         match_op(OP_ISINF,ISINF)
 332         match_op(OP_NOW,NOW)
 333         match_op(OP_TIME,TIME)
 334        match_op(OP_ATAN2,ATAN2)
 335         match_op(OP_ATAN,ATAN)
 336         match_op(OP_SQRT,SQRT)
 337         match_op(OP_SORT,SORT)
 338         match_op(OP_REV,REV)
 339         match_op(OP_TREND,TREND)
 340        match_op(OP_RAD2DEG,RAD2DEG)
 341        match_op(OP_DEG2RAD,DEG2RAD)
 342        match_op(OP_AVG,AVG)
 343 #undef match_op
 344
 345
 346             else if ((sscanf(expr, DEF_NAM_FMT "%n",
 347                              vname,&pos) == 1)
 348                      && ((rpnp[steps].ptr = (*lookup)(key_hash,vname)) != -1)){
 349                 rpnp[steps].op = OP_VARIABLE;
 350                 expr+=pos;
 351             }
 352
 353         else {
 354             free(rpnp);
 355             return NULL;
 356         }
 357         if (*expr == 0)
 358             break;
 359         if (*expr == ',')
 360             expr++;
 361         else {
 362             free(rpnp);
 363             return NULL;
 364         }
 365     }
 366     rpnp[steps+1].op = OP_END;
 367     return rpnp;
 368 }
 369
 370 void
 371 rpnstack_init(rpnstack_t *rpnstack)
 372 {
 373     rpnstack -> s = NULL;
 374     rpnstack -> dc_stacksize = 0;
 375     rpnstack -> dc_stackblock = 100;
 376 }
 377
 378 void
 379 rpnstack_free(rpnstack_t *rpnstack)
 380 {
 381    if (rpnstack -> s != NULL)
 382           free(rpnstack -> s);
 383    rpnstack -> dc_stacksize = 0;
 384 }
 385
 386 static int
 387 rpn_compare_double(const void *x, const void *y)
 388 {
 389         double  diff = *((const double *)x) - *((const double *)y);
 390
 391         return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
 392 }
 393
 394 /* rpn_calc: run the RPN calculator; also performs variable substitution;
 395  * moved and modified from data_calc() originally included in rrd_graph.c
 396  * arguments:
 397  * rpnp : an array of RPN operators (including variable references)
 398  * rpnstack : the initialized stack
 399  * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
 400  *   is advanced by rpnp.ds_cnt; used only for variable substitution
 401  * output : an array of output values; OP_PREV assumes this array contains
 402  *   the "previous" value at index position output_idx-1; the definition of
 403  *   "previous" depends on the calling environment
 404  * output_idx : an index into the output array in which to store the output
 405  *   of the RPN calculator
 406  * returns: -1 if the computation failed (also calls rrd_set_error)
 407  *           0 on success
 408  */
 409 short
 410 rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx,
 411                 rrd_value_t *output, int output_idx)
 412 {
 413     int rpi;
 414     long stptr = -1;
 415
 416     /* process each op from the rpn in turn */
 417     for (rpi=0; rpnp[rpi].op != OP_END; rpi++){
 418         /* allocate or grow the stack */
 419         if (stptr + 5 > rpnstack -> dc_stacksize){
 420             /* could move this to a separate function */
 421             rpnstack -> dc_stacksize += rpnstack -> dc_stackblock;
 422             rpnstack -> s = rrd_realloc(rpnstack -> s,
 423                         (rpnstack -> dc_stacksize)*sizeof(*(rpnstack -> s)));
 424             if (rpnstack -> s == NULL){
 425                 rrd_set_error("RPN stack overflow");
 426                 return -1;
 427             }
 428         }
 429
 430 #define stackunderflow(MINSIZE)                         \
 431         if(stptr<MINSIZE){                              \
 432             rrd_set_error("RPN stack underflow");       \
 433             return -1;                                  \
 434         }
 435
 436         switch (rpnp[rpi].op){
 437             case OP_NUMBER:
 438                 rpnstack -> s[++stptr] = rpnp[rpi].val;
 439                 break;
 440             case OP_VARIABLE:
 441             case OP_PREV_OTHER:
 442             /* Sanity check: VDEFs shouldn't make it here */
 443                 if (rpnp[rpi].ds_cnt == 0) {
 444                     rrd_set_error("VDEF made it into rpn_calc... aborting");
 445                     return -1;
 446                 } else {
 447                     /* make sure we pull the correct value from
 448                      * the *.data array. Adjust the pointer into
 449                      * the array acordingly. Advance the ptr one
 450                      * row in the rra (skip over non-relevant
 451                      * data sources)
 452                      */
 453                     if (rpnp[rpi].op == OP_VARIABLE) {
 454                         rpnstack -> s[++stptr] =  *(rpnp[rpi].data);
 455                     } else {
 456                         if ((output_idx) <= 0) {
 457                             rpnstack -> s[++stptr] = DNAN;
 458                         } else {
 459                             rpnstack -> s[++stptr] =  *(rpnp[rpi].data-rpnp[rpi].ds_cnt);
 460                         }
 461
 462                     }
 463                     if (data_idx % rpnp[rpi].step == 0){
 464                         rpnp[rpi].data += rpnp[rpi].ds_cnt;
 465                     }
 466                 }
 467                 break;
 468             case OP_COUNT:
 469                 rpnstack -> s[++stptr] = (output_idx+1); /* Note: Counter starts at 1 */
 470                 break;
 471             case OP_PREV:
 472                 if ((output_idx) <= 0) {
 473                     rpnstack -> s[++stptr] = DNAN;
 474                 } else {
 475                     rpnstack -> s[++stptr] = output[output_idx-1];
 476                 }
 477                 break;
 478          case OP_UNKN:
 479                 rpnstack -> s[++stptr] = DNAN;
 480                 break;
 481             case OP_INF:
 482                 rpnstack -> s[++stptr] = DINF;
 483                 break;
 484             case OP_NEGINF:
 485                 rpnstack -> s[++stptr] = -DINF;
 486                 break;
 487             case OP_NOW:
 488                 rpnstack -> s[++stptr] = (double)time(NULL);
 489                 break;
 490             case OP_TIME:
 491                 /* HACK: this relies on the data_idx being the time,
 492                 ** which the within-function scope is unaware of */
 493                 rpnstack -> s[++stptr] = (double) data_idx;
 494                 break;
 495             case OP_LTIME:
 496                 rpnstack -> s[++stptr] =
 497                         (double) tzoffset(data_idx) + (double)data_idx;
 498                 break;
 499             case OP_ADD:
 500                 stackunderflow(1);
 501                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 502                                         + rpnstack -> s[stptr];
 503                 stptr--;
 504                 break;
 505             case OP_SUB:
 506                 stackunderflow(1);
 507                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 508                                         - rpnstack -> s[stptr];
 509                 stptr--;
 510                 break;
 511             case OP_MUL:
 512                 stackunderflow(1);
 513                 rpnstack -> s[stptr-1]  = (rpnstack -> s[stptr-1])
 514                                         * (rpnstack -> s[stptr]);
 515                 stptr--;
 516                 break;
 517             case OP_DIV:
 518                 stackunderflow(1);
 519                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 520                                         / rpnstack -> s[stptr];
 521                 stptr--;
 522                 break;
 523             case OP_MOD:
 524                 stackunderflow(1);
 525                 rpnstack -> s[stptr-1]= fmod(   rpnstack -> s[stptr-1]
 526                                                 ,rpnstack -> s[stptr]);
 527                 stptr--;
 528                 break;
 529             case OP_SIN:
 530                 stackunderflow(0);
 531                 rpnstack -> s[stptr] = sin(rpnstack -> s[stptr]);
 532                 break;
 533             case OP_ATAN:
 534                 stackunderflow(0);
 535                 rpnstack -> s[stptr] = atan(rpnstack -> s[stptr]);
 536                 break;
 537            case OP_RAD2DEG:
 538                stackunderflow(0);
 539                rpnstack -> s[stptr] = 57.29577951 * rpnstack -> s[stptr];
 540                break;
 541            case OP_DEG2RAD:
 542                stackunderflow(0);
 543                rpnstack -> s[stptr] = 0.0174532952 * rpnstack -> s[stptr];
 544                break;
 545            case OP_ATAN2:
 546                stackunderflow(1);
 547                rpnstack -> s[stptr-1]= atan2(
 548                                rpnstack -> s[stptr-1],
 549                                rpnstack -> s[stptr]);
 550                stptr--;
 551                break;
 552             case OP_COS:
 553                 stackunderflow(0);
 554                 rpnstack -> s[stptr] = cos(rpnstack -> s[stptr]);
 555                 break;
 556             case OP_CEIL:
 557                 stackunderflow(0);
 558                 rpnstack -> s[stptr] = ceil(rpnstack -> s[stptr]);
 559                 break;
 560             case OP_FLOOR:
 561                 stackunderflow(0);
 562                 rpnstack -> s[stptr] = floor(rpnstack -> s[stptr]);
 563                 break;
 564             case OP_LOG:
 565                 stackunderflow(0);
 566                 rpnstack -> s[stptr] = log(rpnstack -> s[stptr]);
 567                 break;
 568             case OP_DUP:
 569                 stackunderflow(0);
 570                 rpnstack -> s[stptr+1] = rpnstack -> s[stptr];
 571                 stptr++;
 572                 break;
 573             case OP_POP:
 574                 stackunderflow(0);
 575                 stptr--;
 576                 break;
 577             case OP_EXC:
 578                 stackunderflow(1);
 579                 {
 580                     double dummy;
 581                     dummy = rpnstack -> s[stptr] ;
 582                     rpnstack -> s[stptr] = rpnstack -> s[stptr-1];
 583                     rpnstack -> s[stptr-1] = dummy;
 584                 }
 585                 break;
 586             case OP_EXP:
 587                 stackunderflow(0);
 588                 rpnstack -> s[stptr] = exp(rpnstack -> s[stptr]);
 589                 break;
 590             case OP_LT:
 591                 stackunderflow(1);
 592                 if (isnan(rpnstack -> s[stptr-1]))
 593                     ;
 594                 else if (isnan(rpnstack -> s[stptr]))
 595                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 596                 else
 597                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <
 598                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 599                 stptr--;
 600                 break;
 601             case OP_LE:
 602                 stackunderflow(1);
 603                 if (isnan(rpnstack -> s[stptr-1]))
 604                     ;
 605                 else if (isnan(rpnstack -> s[stptr]))
 606                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 607                 else
 608                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <=
 609                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 610                 stptr--;
 611                 break;
 612             case OP_GT:
 613                 stackunderflow(1);
 614                 if (isnan(rpnstack -> s[stptr-1]))
 615                     ;
 616                 else if (isnan(rpnstack -> s[stptr]))
 617                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 618                 else
 619                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >
 620                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 621                 stptr--;
 622                 break;
 623             case OP_GE:
 624                 stackunderflow(1);
 625                 if (isnan(rpnstack -> s[stptr-1]))
 626                     ;
 627                 else if (isnan(rpnstack -> s[stptr]))
 628                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 629                 else
 630                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >=
 631                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 632                 stptr--;
 633                 break;
 634             case OP_NE:
 635                 stackunderflow(1);
 636                 if (isnan(rpnstack -> s[stptr-1]))
 637                     ;
 638                 else if (isnan(rpnstack -> s[stptr]))
 639                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 640                 else
 641                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
 642                                         rpnstack -> s[stptr] ? 0.0 : 1.0;
 643                 stptr--;
 644                 break;
 645             case OP_EQ:
 646                 stackunderflow(1);
 647                 if (isnan(rpnstack -> s[stptr-1]))
 648                     ;
 649                 else if (isnan(rpnstack -> s[stptr]))
 650                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 651                 else
 652                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
 653                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 654                 stptr--;
 655                 break;
 656             case OP_IF:
 657                 stackunderflow(2);
 658                 rpnstack->s[stptr-2] = rpnstack->s[stptr-2] != 0.0 ?
 659                                 rpnstack->s[stptr-1] : rpnstack->s[stptr];
 660                 stptr--;
 661                 stptr--;
 662                 break;
 663             case OP_MIN:
 664                 stackunderflow(1);
 665                 if (isnan(rpnstack->s[stptr-1]))
 666                     ;
 667                 else if (isnan(rpnstack->s[stptr]))
 668                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 669                 else if (rpnstack->s[stptr-1] > rpnstack->s[stptr])
 670                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 671                 stptr--;
 672                 break;
 673             case OP_MAX:
 674                 stackunderflow(1);
 675                 if (isnan(rpnstack->s[stptr-1]))
 676                ;
 677                 else if (isnan(rpnstack->s[stptr]))
 678                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 679                 else if (rpnstack->s[stptr-1] < rpnstack->s[stptr])
 680                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 681                 stptr--;
 682                 break;
 683             case OP_LIMIT:
 684                 stackunderflow(2);
 685                 if (isnan(rpnstack->s[stptr-2]))
 686                     ;
 687                 else if (isnan(rpnstack->s[stptr-1]))
 688                     rpnstack->s[stptr-2] = rpnstack->s[stptr-1];
 689                 else if (isnan(rpnstack->s[stptr]))
 690                     rpnstack->s[stptr-2] = rpnstack->s[stptr];
 691                 else if (rpnstack->s[stptr-2] < rpnstack->s[stptr-1])
 692                     rpnstack->s[stptr-2] = DNAN;
 693                 else if (rpnstack->s[stptr-2] > rpnstack->s[stptr])
 694                     rpnstack->s[stptr-2] = DNAN;
 695                 stptr-=2;
 696                 break;
 697             case OP_UN:
 698                 stackunderflow(0);
 699                 rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
 700                 break;
 701             case OP_ISINF:
 702                 stackunderflow(0);
 703                 rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
 704                 break;
 705             case OP_SQRT:
 706                 stackunderflow(0);
 707                 rpnstack -> s[stptr] = sqrt(rpnstack -> s[stptr]);
 708                 break;
 709             case OP_SORT:
 710                 stackunderflow(0);
 711                 {
 712                     int spn = (int)rpnstack -> s[stptr--];
 713
 714                     stackunderflow(spn-1);
 715                     qsort(rpnstack -> s + stptr-spn+1, spn, sizeof(double),
 716                           rpn_compare_double);
 717                 }
 718                 break;
 719             case OP_REV:
 720                 stackunderflow(0);
 721                 {
 722                     int spn = (int)rpnstack -> s[stptr--];
 723                     double *p, *q;
 724
 725                     stackunderflow(spn-1);
 726
 727                     p = rpnstack -> s + stptr-spn+1;
 728                     q = rpnstack -> s + stptr;
 729                     while (p < q) {
 730                             double      x = *q;
 731
 732                             *q-- = *p;
 733                             *p++ = x;
 734                     }
 735                 }
 736                 break;
 737             case OP_TREND:
 738                 stackunderflow(1);
 739                 if ((rpi < 2) || (rpnp[rpi-2].op != OP_VARIABLE)) {
 740                     rrd_set_error("malformed trend arguments");
 741                     return -1;
 742                 } else {
 743                     time_t dur = (time_t)rpnstack -> s[stptr];
 744                     time_t step = (time_t)rpnp[rpi-2].step;
 745
 746                     if (output_idx > (int)ceil((float)dur / (float)step)) {
 747                         double accum = 0.0;
 748                         int i = 0;
 749
 750                         do {
 751                             accum += rpnp[rpi-2].data[rpnp[rpi-2].ds_cnt * i--];
 752                             dur -= step;
 753                         } while (dur > 0);
 754
 755                         rpnstack -> s[--stptr] = (accum / -i);
 756                     } else
 757                         rpnstack -> s[--stptr] = DNAN;
 758                 }
 759                 break;
 760            case OP_AVG:
 761                stackunderflow(0);
 762                 {
 763                    int i=(int)rpnstack -> s[stptr--];
 764                    double sum=0;
 765                    int count=0;
 766                    stackunderflow(i-1);
 767                    while(i>0) {
 768                      double val=rpnstack -> s[stptr--];
 769                      i--;
 770                     if (isnan(val)) { continue; }
 771                      count++;
 772                      sum+=val;
 773                    }
 774                    // now push the result bavk on stack
 775                    if (count>0) {
 776                      rpnstack -> s[++stptr]=sum/count;
 777                    } else {
 778                      rpnstack -> s[++stptr]=DNAN;
 779                    }
 780                 }
 781                 break;
 782             case OP_END:
 783                 break;
 784        }
 785 #undef stackunderflow
 786    }
 787    if(stptr!=0){
 788        rrd_set_error("RPN final stack size != 1");
 789        return -1;
 790    }
 791
 792    output[output_idx] = rpnstack->s[0];
 793    return 0;
 794 }
 795
 796 /* figure out what the local timezone offset for any point in
 797    time was. Return it in seconds */
 798 int
 799 tzoffset( time_t now ){
 800     int gm_sec, gm_min, gm_hour, gm_yday, gm_year,
 801         l_sec, l_min, l_hour, l_yday, l_year;
 802     struct tm t;
 803     int off;
 804     gmtime_r(&now, &t);
 805     gm_sec = t.tm_sec;
 806     gm_min = t.tm_min;
 807     gm_hour = t.tm_hour;
 808     gm_yday = t.tm_yday;
 809     gm_year = t.tm_year;
 810     localtime_r(&now, &t);
 811     l_sec = t.tm_sec;
 812     l_min = t.tm_min;
 813     l_hour = t.tm_hour;
 814     l_yday = t.tm_yday;
 815     l_year = t.tm_year;
 816     off = (l_sec-gm_sec)+(l_min-gm_min)*60+(l_hour-gm_hour)*3600;
 817     if ( l_yday > gm_yday || l_year > gm_year){
 818         off += 24*3600;
 819     } else if ( l_yday < gm_yday || l_year < gm_year){
 820         off -= 24*3600;
 821     }
 822    return off;
 823 }
 824