src/rrd_rpncalc.c

   1 /****************************************************************************
   2  * RRDtool 1.0.28  Copyright Tobias Oetiker, 1997 - 2002
   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 #ifdef WIN32
 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_ATAN,ATAN)
 157           add_op(OP_SQRT,SQRT)
 158           add_op(OP_SORT,SORT)
 159           add_op(OP_REV,REV)
 160
 161 #undef add_op
 162               }
 163     (*str)[offset] = '\0';
 164
 165 }
 166
 167 short addop2str(enum op_en op, enum op_en op_type, char *op_str,
 168                 char **result_str, unsigned short *offset)
 169 {
 170     if (op == op_type) {
 171         short op_len;
 172         op_len = strlen(op_str);
 173         *result_str =  (char *) rrd_realloc(*result_str,
 174                                             (op_len + 1 + *offset)*sizeof(char));
 175         if (*result_str == NULL) {
 176             rrd_set_error("failed to alloc memory in addop2str");
 177             return -1;
 178         }
 179         strncpy(&((*result_str)[*offset]),op_str,op_len);
 180         *offset += op_len;
 181         return 1;
 182     }
 183     return 0;
 184 }
 185
 186 void parseCDEF_DS(char *def,rrd_t *rrd, int ds_idx)
 187 {
 188     rpnp_t *rpnp = NULL;
 189     rpn_cdefds_t *rpnc = NULL;
 190     short count, i;
 191
 192     rpnp = rpn_parse((void*) rrd, def, &lookup_DS);
 193     if (rpnp == NULL) {
 194         rrd_set_error("failed to parse computed data source %s", def);
 195         return;
 196     }
 197     /* Check for OP nodes not permitted in COMPUTE DS.
 198      * Moved this check from within rpn_compact() because it really is
 199      * COMPUTE DS specific. This is less efficient, but creation doesn't
 200      * occur too often. */
 201     for (i = 0; rpnp[i].op != OP_END; i++) {
 202         if (rpnp[i].op == OP_TIME || rpnp[i].op == OP_LTIME ||
 203             rpnp[i].op == OP_PREV || rpnp[i].op == OP_COUNT)
 204         {
 205             rrd_set_error(
 206                 "operators time, ltime, prev and count not supported with DS COMPUTE");
 207             free(rpnp);
 208             return;
 209         }
 210     }
 211     if (rpn_compact(rpnp,&rpnc,&count) == -1) {
 212         free(rpnp);
 213         return;
 214     }
 215     /* copy the compact rpn representation over the ds_def par array */
 216     memcpy((void*) &(rrd -> ds_def[ds_idx].par[DS_cdef]),
 217            (void*) rpnc, count*sizeof(rpn_cdefds_t));
 218     free(rpnp);
 219     free(rpnc);
 220 }
 221
 222 /* lookup a data source name in the rrd struct and return the index,
 223  * should use ds_match() here except:
 224  * (1) need a void * pointer to the rrd
 225  * (2) error handling is left to the caller
 226  */
 227 long lookup_DS(void *rrd_vptr,char *ds_name)
 228 {
 229     unsigned int i;
 230     rrd_t *rrd;
 231
 232     rrd = (rrd_t *) rrd_vptr;
 233
 234     for (i = 0; i < rrd -> stat_head -> ds_cnt; ++i)
 235     {
 236         if(strcmp(ds_name,rrd -> ds_def[i].ds_nam) == 0)
 237             return i;
 238     }
 239     /* the caller handles a bad data source name in the rpn string */
 240     return -1;
 241 }
 242
 243 /* rpn_parse : parse a string and generate a rpnp array; modified
 244  * str2rpn() originally included in rrd_graph.c
 245  * arguments:
 246  * key_hash: a transparent argument passed to lookup(); conceptually this
 247  *    is a hash object for lookup of a numeric key given a variable name
 248  * expr: the string RPN expression, including variable names
 249  * lookup(): a function that retrieves a numeric key given a variable name
 250  */
 251 rpnp_t *
 252 rpn_parse(void *key_hash,char *expr,long (*lookup)(void *,char*)){
 253     int pos=0;
 254     long steps=-1;
 255     rpnp_t  *rpnp;
 256     char vname[30];
 257
 258     rpnp=NULL;
 259
 260     while(*expr){
 261         if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2)*
 262                                        sizeof(rpnp_t)))==NULL){
 263             return NULL;
 264         }
 265
 266         else if((sscanf(expr,"%lf%n",&rpnp[steps].val,&pos) == 1) && (expr[pos] == ',')){
 267             rpnp[steps].op = OP_NUMBER;
 268             expr+=pos;
 269         }
 270
 271 #define match_op(VV,VVV) \
 272         else if (strncmp(expr, #VVV, strlen(#VVV))==0){ \
 273             rpnp[steps].op = VV; \
 274             expr+=strlen(#VVV); \
 275         }
 276
 277
 278 #define match_op_param(VV,VVV) \
 279         else if (sscanf(expr, #VVV "(" DEF_NAM_FMT ")",vname) == 1) { \
 280           int length = 0; \
 281           if ((length = strlen(#VVV)+strlen(vname)+2, \
 282               expr[length] == ',' || expr[length] == '\0') ) { \
 283              rpnp[steps].op = VV; \
 284              rpnp[steps].ptr = (*lookup)(key_hash,vname); \
 285              if (rpnp[steps].ptr < 0) { \
 286                            free(rpnp); \
 287                            return NULL; \
 288                          } else expr+=length; \
 289           } \
 290         }
 291
 292         match_op(OP_ADD,+)
 293         match_op(OP_SUB,-)
 294         match_op(OP_MUL,*)
 295         match_op(OP_DIV,/)
 296         match_op(OP_MOD,%)
 297         match_op(OP_SIN,SIN)
 298         match_op(OP_COS,COS)
 299         match_op(OP_LOG,LOG)
 300         match_op(OP_FLOOR,FLOOR)
 301         match_op(OP_CEIL,CEIL)
 302         match_op(OP_EXP,EXP)
 303         match_op(OP_DUP,DUP)
 304         match_op(OP_EXC,EXC)
 305         match_op(OP_POP,POP)
 306         match_op(OP_LTIME,LTIME)
 307         match_op(OP_LT,LT)
 308         match_op(OP_LE,LE)
 309         match_op(OP_GT,GT)
 310         match_op(OP_GE,GE)
 311         match_op(OP_EQ,EQ)
 312         match_op(OP_IF,IF)
 313         match_op(OP_MIN,MIN)
 314         match_op(OP_MAX,MAX)
 315         match_op(OP_LIMIT,LIMIT)
 316           /* order is important here ! .. match longest first */
 317         match_op(OP_UNKN,UNKN)
 318         match_op(OP_UN,UN)
 319         match_op(OP_NEGINF,NEGINF)
 320         match_op(OP_NE,NE)
 321         match_op(OP_COUNT,COUNT)
 322           match_op_param(OP_PREV_OTHER,PREV)
 323         match_op(OP_PREV,PREV)
 324         match_op(OP_INF,INF)
 325         match_op(OP_ISINF,ISINF)
 326         match_op(OP_NOW,NOW)
 327         match_op(OP_TIME,TIME)
 328         match_op(OP_ATAN,ATAN)
 329         match_op(OP_SQRT,SQRT)
 330         match_op(OP_SORT,SORT)
 331         match_op(OP_REV,REV)
 332 #undef match_op
 333
 334
 335             else if ((sscanf(expr, DEF_NAM_FMT "%n",
 336                              vname,&pos) == 1)
 337                      && ((rpnp[steps].ptr = (*lookup)(key_hash,vname)) != -1)){
 338                 rpnp[steps].op = OP_VARIABLE;
 339                 expr+=pos;
 340             }
 341
 342         else {
 343             free(rpnp);
 344             return NULL;
 345         }
 346         if (*expr == 0)
 347             break;
 348         if (*expr == ',')
 349             expr++;
 350         else {
 351             free(rpnp);
 352             return NULL;
 353         }
 354     }
 355     rpnp[steps+1].op = OP_END;
 356     return rpnp;
 357 }
 358
 359 void
 360 rpnstack_init(rpnstack_t *rpnstack)
 361 {
 362     rpnstack -> s = NULL;
 363     rpnstack -> dc_stacksize = 0;
 364     rpnstack -> dc_stackblock = 100;
 365 }
 366
 367 void
 368 rpnstack_free(rpnstack_t *rpnstack)
 369 {
 370    if (rpnstack -> s != NULL)
 371           free(rpnstack -> s);
 372    rpnstack -> dc_stacksize = 0;
 373 }
 374
 375 static int
 376 rpn_compare_double(const void *x, const void *y)
 377 {
 378         double  diff = *((const double *)x) - *((const double *)y);
 379
 380         return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
 381 }
 382
 383 /* rpn_calc: run the RPN calculator; also performs variable substitution;
 384  * moved and modified from data_calc() originally included in rrd_graph.c
 385  * arguments:
 386  * rpnp : an array of RPN operators (including variable references)
 387  * rpnstack : the initialized stack
 388  * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
 389  *   is advanced by rpnp.ds_cnt; used only for variable substitution
 390  * output : an array of output values; OP_PREV assumes this array contains
 391  *   the "previous" value at index position output_idx-1; the definition of
 392  *   "previous" depends on the calling environment
 393  * output_idx : an index into the output array in which to store the output
 394  *   of the RPN calculator
 395  * returns: -1 if the computation failed (also calls rrd_set_error)
 396  *           0 on success
 397  */
 398 short
 399 rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx,
 400                 rrd_value_t *output, int output_idx)
 401 {
 402     int rpi;
 403     long stptr = -1;
 404
 405     /* process each op from the rpn in turn */
 406     for (rpi=0; rpnp[rpi].op != OP_END; rpi++){
 407         /* allocate or grow the stack */
 408         if (stptr + 5 > rpnstack -> dc_stacksize){
 409             /* could move this to a separate function */
 410             rpnstack -> dc_stacksize += rpnstack -> dc_stackblock;
 411             rpnstack -> s = rrd_realloc(rpnstack -> s,
 412                         (rpnstack -> dc_stacksize)*sizeof(*(rpnstack -> s)));
 413             if (rpnstack -> s == NULL){
 414                 rrd_set_error("RPN stack overflow");
 415                 return -1;
 416             }
 417         }
 418
 419 #define stackunderflow(MINSIZE)                         \
 420         if(stptr<MINSIZE){                              \
 421             rrd_set_error("RPN stack underflow");       \
 422             return -1;                                  \
 423         }
 424
 425         switch (rpnp[rpi].op){
 426             case OP_NUMBER:
 427                 rpnstack -> s[++stptr] = rpnp[rpi].val;
 428                 break;
 429             case OP_VARIABLE:
 430                 /* Sanity check: VDEFs shouldn't make it here */
 431                 if (rpnp[rpi].ds_cnt == 0) {
 432                     rrd_set_error("VDEF made it into rpn_calc... aborting");
 433                     return -1;
 434                 } else {
 435                     /* make sure we pull the correct value from
 436                      * the *.data array. Adjust the pointer into
 437                      * the array acordingly. Advance the ptr one
 438                      * row in the rra (skip over non-relevant
 439                      * data sources)
 440                      */
 441                     rpnstack -> s[++stptr] =  *(rpnp[rpi].data);
 442                     if (data_idx % rpnp[rpi].step == 0){
 443                         rpnp[rpi].data += rpnp[rpi].ds_cnt;
 444                     }
 445                 }
 446                 break;
 447             case OP_COUNT:
 448                 rpnstack -> s[++stptr] = (output_idx+1); /* Note: Counter starts at 1 */
 449                 break;
 450             case OP_PREV:
 451                 if ((output_idx) <= 0) {
 452                     rpnstack -> s[++stptr] = DNAN;
 453                 } else {
 454                     rpnstack -> s[++stptr] = output[output_idx-1];
 455                 }
 456                 break;
 457         case OP_PREV_OTHER:
 458           if ((output_idx) <= 0) {
 459                 rpnstack -> s[++stptr] = DNAN;
 460           } else {
 461                 rpnstack -> s[++stptr] = rpnp[rpnp[rpi].ptr].data[output_idx-1];
 462           }
 463           break;
 464             case OP_UNKN:
 465                 rpnstack -> s[++stptr] = DNAN;
 466                 break;
 467             case OP_INF:
 468                 rpnstack -> s[++stptr] = DINF;
 469                 break;
 470             case OP_NEGINF:
 471                 rpnstack -> s[++stptr] = -DINF;
 472                 break;
 473             case OP_NOW:
 474                 rpnstack -> s[++stptr] = (double)time(NULL);
 475                 break;
 476             case OP_TIME:
 477                 /* HACK: this relies on the data_idx being the time,
 478                 ** which the within-function scope is unaware of */
 479                 rpnstack -> s[++stptr] = (double) data_idx;
 480                 break;
 481             case OP_LTIME:
 482                 rpnstack -> s[++stptr] =
 483                         (double) tzoffset(data_idx) + (double)data_idx;
 484                 break;
 485             case OP_ADD:
 486                 stackunderflow(1);
 487                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 488                                         + rpnstack -> s[stptr];
 489                 stptr--;
 490                 break;
 491             case OP_SUB:
 492                 stackunderflow(1);
 493                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 494                                         - rpnstack -> s[stptr];
 495                 stptr--;
 496                 break;
 497             case OP_MUL:
 498                 stackunderflow(1);
 499                 rpnstack -> s[stptr-1]  = (rpnstack -> s[stptr-1])
 500                                         * (rpnstack -> s[stptr]);
 501                 stptr--;
 502                 break;
 503             case OP_DIV:
 504                 stackunderflow(1);
 505                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 506                                         / rpnstack -> s[stptr];
 507                 stptr--;
 508                 break;
 509             case OP_MOD:
 510                 stackunderflow(1);
 511                 rpnstack -> s[stptr-1]= fmod(   rpnstack -> s[stptr-1]
 512                                                 ,rpnstack -> s[stptr]);
 513                 stptr--;
 514                 break;
 515             case OP_SIN:
 516                 stackunderflow(0);
 517                 rpnstack -> s[stptr] = sin(rpnstack -> s[stptr]);
 518                 break;
 519             case OP_ATAN:
 520                 stackunderflow(0);
 521                 rpnstack -> s[stptr] = atan(rpnstack -> s[stptr]);
 522                 break;
 523             case OP_COS:
 524                 stackunderflow(0);
 525                 rpnstack -> s[stptr] = cos(rpnstack -> s[stptr]);
 526                 break;
 527             case OP_CEIL:
 528                 stackunderflow(0);
 529                 rpnstack -> s[stptr] = ceil(rpnstack -> s[stptr]);
 530                 break;
 531             case OP_FLOOR:
 532                 stackunderflow(0);
 533                 rpnstack -> s[stptr] = floor(rpnstack -> s[stptr]);
 534                 break;
 535             case OP_LOG:
 536                 stackunderflow(0);
 537                 rpnstack -> s[stptr] = log(rpnstack -> s[stptr]);
 538                 break;
 539             case OP_DUP:
 540                 stackunderflow(0);
 541                 rpnstack -> s[stptr+1] = rpnstack -> s[stptr];
 542                 stptr++;
 543                 break;
 544             case OP_POP:
 545                 stackunderflow(0);
 546                 stptr--;
 547                 break;
 548             case OP_EXC:
 549                 stackunderflow(1);
 550                 {
 551                     double dummy;
 552                     dummy = rpnstack -> s[stptr] ;
 553                     rpnstack -> s[stptr] = rpnstack -> s[stptr-1];
 554                     rpnstack -> s[stptr-1] = dummy;
 555                 }
 556                 break;
 557             case OP_EXP:
 558                 stackunderflow(0);
 559                 rpnstack -> s[stptr] = exp(rpnstack -> s[stptr]);
 560                 break;
 561             case OP_LT:
 562                 stackunderflow(1);
 563                 if (isnan(rpnstack -> s[stptr-1]))
 564                     ;
 565                 else if (isnan(rpnstack -> s[stptr]))
 566                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 567                 else
 568                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <
 569                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 570                 stptr--;
 571                 break;
 572             case OP_LE:
 573                 stackunderflow(1);
 574                 if (isnan(rpnstack -> s[stptr-1]))
 575                     ;
 576                 else if (isnan(rpnstack -> s[stptr]))
 577                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 578                 else
 579                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <=
 580                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 581                 stptr--;
 582                 break;
 583             case OP_GT:
 584                 stackunderflow(1);
 585                 if (isnan(rpnstack -> s[stptr-1]))
 586                     ;
 587                 else if (isnan(rpnstack -> s[stptr]))
 588                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 589                 else
 590                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >
 591                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 592                 stptr--;
 593                 break;
 594             case OP_GE:
 595                 stackunderflow(1);
 596                 if (isnan(rpnstack -> s[stptr-1]))
 597                     ;
 598                 else if (isnan(rpnstack -> s[stptr]))
 599                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 600                 else
 601                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >=
 602                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 603                 stptr--;
 604                 break;
 605             case OP_NE:
 606                 stackunderflow(1);
 607                 if (isnan(rpnstack -> s[stptr-1]))
 608                     ;
 609                 else if (isnan(rpnstack -> s[stptr]))
 610                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 611                 else
 612                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
 613                                         rpnstack -> s[stptr] ? 0.0 : 1.0;
 614                 stptr--;
 615                 break;
 616             case OP_EQ:
 617                 stackunderflow(1);
 618                 if (isnan(rpnstack -> s[stptr-1]))
 619                     ;
 620                 else if (isnan(rpnstack -> s[stptr]))
 621                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 622                 else
 623                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
 624                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 625                 stptr--;
 626                 break;
 627             case OP_IF:
 628                 stackunderflow(2);
 629                 rpnstack->s[stptr-2] = rpnstack->s[stptr-2] != 0.0 ?
 630                                 rpnstack->s[stptr-1] : rpnstack->s[stptr];
 631                 stptr--;
 632                 stptr--;
 633                 break;
 634             case OP_MIN:
 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 if (rpnstack->s[stptr-1] > rpnstack->s[stptr])
 641                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 642                 stptr--;
 643                 break;
 644             case OP_MAX:
 645                 stackunderflow(1);
 646                 if (isnan(rpnstack->s[stptr-1]))
 647                ;
 648                 else if (isnan(rpnstack->s[stptr]))
 649                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 650                 else if (rpnstack->s[stptr-1] < rpnstack->s[stptr])
 651                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 652                 stptr--;
 653                 break;
 654             case OP_LIMIT:
 655                 stackunderflow(2);
 656                 if (isnan(rpnstack->s[stptr-2]))
 657                     ;
 658                 else if (isnan(rpnstack->s[stptr-1]))
 659                     rpnstack->s[stptr-2] = rpnstack->s[stptr-1];
 660                 else if (isnan(rpnstack->s[stptr]))
 661                     rpnstack->s[stptr-2] = rpnstack->s[stptr];
 662                 else if (rpnstack->s[stptr-2] < rpnstack->s[stptr-1])
 663                     rpnstack->s[stptr-2] = DNAN;
 664                 else if (rpnstack->s[stptr-2] > rpnstack->s[stptr])
 665                     rpnstack->s[stptr-2] = DNAN;
 666                 stptr-=2;
 667                 break;
 668             case OP_UN:
 669                 stackunderflow(0);
 670                 rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
 671                 break;
 672             case OP_ISINF:
 673                 stackunderflow(0);
 674                 rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
 675                 break;
 676             case OP_SQRT:
 677                 stackunderflow(0);
 678                 rpnstack -> s[stptr] = sqrt(rpnstack -> s[stptr]);
 679                 break;
 680             case OP_SORT:
 681                 stackunderflow(0);
 682                 {
 683                     int spn = (int)rpnstack -> s[stptr--];
 684
 685                     stackunderflow(spn-1);
 686                     qsort(rpnstack -> s + stptr-spn+1, spn, sizeof(double),
 687                           rpn_compare_double);
 688                 }
 689                 break;
 690             case OP_REV:
 691                 stackunderflow(0);
 692                 {
 693                     int spn = (int)rpnstack -> s[stptr--];
 694                     double *p, *q;
 695
 696                     stackunderflow(spn-1);
 697
 698                     p = rpnstack -> s + stptr-spn+1;
 699                     q = rpnstack -> s + stptr;
 700                     while (p < q) {
 701                             double      x = *q;
 702
 703                             *q-- = *p;
 704                             *p++ = x;
 705                     }
 706                 }
 707                 break;
 708             case OP_END:
 709                 break;
 710        }
 711 #undef stackunderflow
 712    }
 713    if(stptr!=0){
 714        rrd_set_error("RPN final stack size != 1");
 715        return -1;
 716    }
 717
 718    output[output_idx] = rpnstack->s[0];
 719    return 0;
 720 }
 721
 722 /* figure out what the local timezone offset for any point in
 723    time was. Return it in seconds */
 724 int
 725 tzoffset( time_t now ){
 726     int gm_sec, gm_min, gm_hour, gm_yday, gm_year,
 727         l_sec, l_min, l_hour, l_yday, l_year;
 728     struct tm t;
 729     int off;
 730     gmtime_r(&now, &t);
 731     gm_sec = t.tm_sec;
 732     gm_min = t.tm_min;
 733     gm_hour = t.tm_hour;
 734     gm_yday = t.tm_yday;
 735     gm_year = t.tm_year;
 736     localtime_r(&now, &t);
 737     l_sec = t.tm_sec;
 738     l_min = t.tm_min;
 739     l_hour = t.tm_hour;
 740     l_yday = t.tm_yday;
 741     l_year = t.tm_year;
 742     off = (l_sec-gm_sec)+(l_min-gm_min)*60+(l_hour-gm_hour)*3600;
 743     if ( l_yday > gm_yday || l_year > gm_year){
 744         off += 24*3600;
 745     } else if ( l_yday < gm_yday || l_year < gm_year){
 746         off -= 24*3600;
 747     }
 748    return off;
 749 }
 750