src/rrd_rpncalc.c

   1 /****************************************************************************
   2  * RRDtool 1.2.11  Copyright by Tobi Oetiker, 1997-2005
   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 #undef add_op
 165               }
 166     (*str)[offset] = '\0';
 167
 168 }
 169
 170 short addop2str(enum op_en op, enum op_en op_type, char *op_str,
 171                 char **result_str, unsigned short *offset)
 172 {
 173     if (op == op_type) {
 174         short op_len;
 175         op_len = strlen(op_str);
 176         *result_str =  (char *) rrd_realloc(*result_str,
 177                                             (op_len + 1 + *offset)*sizeof(char));
 178         if (*result_str == NULL) {
 179             rrd_set_error("failed to alloc memory in addop2str");
 180             return -1;
 181         }
 182         strncpy(&((*result_str)[*offset]),op_str,op_len);
 183         *offset += op_len;
 184         return 1;
 185     }
 186     return 0;
 187 }
 188
 189 void parseCDEF_DS(char *def,rrd_t *rrd, int ds_idx)
 190 {
 191     rpnp_t *rpnp = NULL;
 192     rpn_cdefds_t *rpnc = NULL;
 193     short count, i;
 194
 195     rpnp = rpn_parse((void*) rrd, def, &lookup_DS);
 196     if (rpnp == NULL) {
 197         rrd_set_error("failed to parse computed data source %s", def);
 198         return;
 199     }
 200     /* Check for OP nodes not permitted in COMPUTE DS.
 201      * Moved this check from within rpn_compact() because it really is
 202      * COMPUTE DS specific. This is less efficient, but creation doesn't
 203      * occur too often. */
 204     for (i = 0; rpnp[i].op != OP_END; i++) {
 205         if (rpnp[i].op == OP_TIME || rpnp[i].op == OP_LTIME ||
 206             rpnp[i].op == OP_PREV || rpnp[i].op == OP_COUNT)
 207         {
 208             rrd_set_error(
 209                 "operators time, ltime, prev and count not supported with DS COMPUTE");
 210             free(rpnp);
 211             return;
 212         }
 213     }
 214     if (rpn_compact(rpnp,&rpnc,&count) == -1) {
 215         free(rpnp);
 216         return;
 217     }
 218     /* copy the compact rpn representation over the ds_def par array */
 219     memcpy((void*) &(rrd -> ds_def[ds_idx].par[DS_cdef]),
 220            (void*) rpnc, count*sizeof(rpn_cdefds_t));
 221     free(rpnp);
 222     free(rpnc);
 223 }
 224
 225 /* lookup a data source name in the rrd struct and return the index,
 226  * should use ds_match() here except:
 227  * (1) need a void * pointer to the rrd
 228  * (2) error handling is left to the caller
 229  */
 230 long lookup_DS(void *rrd_vptr,char *ds_name)
 231 {
 232     unsigned int i;
 233     rrd_t *rrd;
 234
 235     rrd = (rrd_t *) rrd_vptr;
 236
 237     for (i = 0; i < rrd -> stat_head -> ds_cnt; ++i)
 238     {
 239         if(strcmp(ds_name,rrd -> ds_def[i].ds_nam) == 0)
 240             return i;
 241     }
 242     /* the caller handles a bad data source name in the rpn string */
 243     return -1;
 244 }
 245
 246 /* rpn_parse : parse a string and generate a rpnp array; modified
 247  * str2rpn() originally included in rrd_graph.c
 248  * arguments:
 249  * key_hash: a transparent argument passed to lookup(); conceptually this
 250  *    is a hash object for lookup of a numeric key given a variable name
 251  * expr: the string RPN expression, including variable names
 252  * lookup(): a function that retrieves a numeric key given a variable name
 253  */
 254 rpnp_t *
 255 rpn_parse(void *key_hash,char *expr,long (*lookup)(void *,char*)){
 256     int pos=0;
 257     long steps=-1;
 258     rpnp_t  *rpnp;
 259     char vname[30];
 260
 261     rpnp=NULL;
 262
 263     while(*expr){
 264         if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2)*
 265                                        sizeof(rpnp_t)))==NULL){
 266             return NULL;
 267         }
 268
 269         else if((sscanf(expr,"%lf%n",&rpnp[steps].val,&pos) == 1) && (expr[pos] == ',')){
 270             rpnp[steps].op = OP_NUMBER;
 271             expr+=pos;
 272         }
 273
 274 #define match_op(VV,VVV) \
 275         else if (strncmp(expr, #VVV, strlen(#VVV))==0){ \
 276             rpnp[steps].op = VV; \
 277             expr+=strlen(#VVV); \
 278         }
 279
 280
 281 #define match_op_param(VV,VVV) \
 282         else if (sscanf(expr, #VVV "(" DEF_NAM_FMT ")",vname) == 1) { \
 283           int length = 0; \
 284           if ((length = strlen(#VVV)+strlen(vname)+2, \
 285               expr[length] == ',' || expr[length] == '\0') ) { \
 286              rpnp[steps].op = VV; \
 287              rpnp[steps].ptr = (*lookup)(key_hash,vname); \
 288              if (rpnp[steps].ptr < 0) { \
 289                            free(rpnp); \
 290                            return NULL; \
 291                          } else expr+=length; \
 292           } \
 293         }
 294
 295         match_op(OP_ADD,+)
 296         match_op(OP_SUB,-)
 297         match_op(OP_MUL,*)
 298         match_op(OP_DIV,/)
 299         match_op(OP_MOD,%)
 300         match_op(OP_SIN,SIN)
 301         match_op(OP_COS,COS)
 302         match_op(OP_LOG,LOG)
 303         match_op(OP_FLOOR,FLOOR)
 304         match_op(OP_CEIL,CEIL)
 305         match_op(OP_EXP,EXP)
 306         match_op(OP_DUP,DUP)
 307         match_op(OP_EXC,EXC)
 308         match_op(OP_POP,POP)
 309         match_op(OP_LTIME,LTIME)
 310         match_op(OP_LT,LT)
 311         match_op(OP_LE,LE)
 312         match_op(OP_GT,GT)
 313         match_op(OP_GE,GE)
 314         match_op(OP_EQ,EQ)
 315         match_op(OP_IF,IF)
 316         match_op(OP_MIN,MIN)
 317         match_op(OP_MAX,MAX)
 318         match_op(OP_LIMIT,LIMIT)
 319           /* order is important here ! .. match longest first */
 320         match_op(OP_UNKN,UNKN)
 321         match_op(OP_UN,UN)
 322         match_op(OP_NEGINF,NEGINF)
 323         match_op(OP_NE,NE)
 324         match_op(OP_COUNT,COUNT)
 325         match_op_param(OP_PREV_OTHER,PREV)
 326         match_op(OP_PREV,PREV)
 327         match_op(OP_INF,INF)
 328         match_op(OP_ISINF,ISINF)
 329         match_op(OP_NOW,NOW)
 330         match_op(OP_TIME,TIME)
 331        match_op(OP_ATAN2,ATAN2)
 332         match_op(OP_ATAN,ATAN)
 333         match_op(OP_SQRT,SQRT)
 334         match_op(OP_SORT,SORT)
 335         match_op(OP_REV,REV)
 336         match_op(OP_TREND,TREND)
 337        match_op(OP_RAD2DEG,RAD2DEG)
 338        match_op(OP_DEG2RAD,DEG2RAD)
 339 #undef match_op
 340
 341
 342             else if ((sscanf(expr, DEF_NAM_FMT "%n",
 343                              vname,&pos) == 1)
 344                      && ((rpnp[steps].ptr = (*lookup)(key_hash,vname)) != -1)){
 345                 rpnp[steps].op = OP_VARIABLE;
 346                 expr+=pos;
 347             }
 348
 349         else {
 350             free(rpnp);
 351             return NULL;
 352         }
 353         if (*expr == 0)
 354             break;
 355         if (*expr == ',')
 356             expr++;
 357         else {
 358             free(rpnp);
 359             return NULL;
 360         }
 361     }
 362     rpnp[steps+1].op = OP_END;
 363     return rpnp;
 364 }
 365
 366 void
 367 rpnstack_init(rpnstack_t *rpnstack)
 368 {
 369     rpnstack -> s = NULL;
 370     rpnstack -> dc_stacksize = 0;
 371     rpnstack -> dc_stackblock = 100;
 372 }
 373
 374 void
 375 rpnstack_free(rpnstack_t *rpnstack)
 376 {
 377    if (rpnstack -> s != NULL)
 378           free(rpnstack -> s);
 379    rpnstack -> dc_stacksize = 0;
 380 }
 381
 382 static int
 383 rpn_compare_double(const void *x, const void *y)
 384 {
 385         double  diff = *((const double *)x) - *((const double *)y);
 386
 387         return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
 388 }
 389
 390 /* rpn_calc: run the RPN calculator; also performs variable substitution;
 391  * moved and modified from data_calc() originally included in rrd_graph.c
 392  * arguments:
 393  * rpnp : an array of RPN operators (including variable references)
 394  * rpnstack : the initialized stack
 395  * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
 396  *   is advanced by rpnp.ds_cnt; used only for variable substitution
 397  * output : an array of output values; OP_PREV assumes this array contains
 398  *   the "previous" value at index position output_idx-1; the definition of
 399  *   "previous" depends on the calling environment
 400  * output_idx : an index into the output array in which to store the output
 401  *   of the RPN calculator
 402  * returns: -1 if the computation failed (also calls rrd_set_error)
 403  *           0 on success
 404  */
 405 short
 406 rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx,
 407                 rrd_value_t *output, int output_idx)
 408 {
 409     int rpi;
 410     long stptr = -1;
 411
 412     /* process each op from the rpn in turn */
 413     for (rpi=0; rpnp[rpi].op != OP_END; rpi++){
 414         /* allocate or grow the stack */
 415         if (stptr + 5 > rpnstack -> dc_stacksize){
 416             /* could move this to a separate function */
 417             rpnstack -> dc_stacksize += rpnstack -> dc_stackblock;
 418             rpnstack -> s = rrd_realloc(rpnstack -> s,
 419                         (rpnstack -> dc_stacksize)*sizeof(*(rpnstack -> s)));
 420             if (rpnstack -> s == NULL){
 421                 rrd_set_error("RPN stack overflow");
 422                 return -1;
 423             }
 424         }
 425
 426 #define stackunderflow(MINSIZE)                         \
 427         if(stptr<MINSIZE){                              \
 428             rrd_set_error("RPN stack underflow");       \
 429             return -1;                                  \
 430         }
 431
 432         switch (rpnp[rpi].op){
 433             case OP_NUMBER:
 434                 rpnstack -> s[++stptr] = rpnp[rpi].val;
 435                 break;
 436             case OP_VARIABLE:
 437             case OP_PREV_OTHER:
 438             /* Sanity check: VDEFs shouldn't make it here */
 439                 if (rpnp[rpi].ds_cnt == 0) {
 440                     rrd_set_error("VDEF made it into rpn_calc... aborting");
 441                     return -1;
 442                 } else {
 443                     /* make sure we pull the correct value from
 444                      * the *.data array. Adjust the pointer into
 445                      * the array acordingly. Advance the ptr one
 446                      * row in the rra (skip over non-relevant
 447                      * data sources)
 448                      */
 449                     if (rpnp[rpi].op == OP_VARIABLE) {
 450                         rpnstack -> s[++stptr] =  *(rpnp[rpi].data);
 451                     } else {
 452                         if ((output_idx) <= 0) {
 453                             rpnstack -> s[++stptr] = DNAN;
 454                         } else {
 455                             rpnstack -> s[++stptr] =  *(rpnp[rpi].data-rpnp[rpi].ds_cnt);
 456                         }
 457
 458                     }
 459                     if (data_idx % rpnp[rpi].step == 0){
 460                         rpnp[rpi].data += rpnp[rpi].ds_cnt;
 461                     }
 462                 }
 463                 break;
 464             case OP_COUNT:
 465                 rpnstack -> s[++stptr] = (output_idx+1); /* Note: Counter starts at 1 */
 466                 break;
 467             case OP_PREV:
 468                 if ((output_idx) <= 0) {
 469                     rpnstack -> s[++stptr] = DNAN;
 470                 } else {
 471                     rpnstack -> s[++stptr] = output[output_idx-1];
 472                 }
 473                 break;
 474          case OP_UNKN:
 475                 rpnstack -> s[++stptr] = DNAN;
 476                 break;
 477             case OP_INF:
 478                 rpnstack -> s[++stptr] = DINF;
 479                 break;
 480             case OP_NEGINF:
 481                 rpnstack -> s[++stptr] = -DINF;
 482                 break;
 483             case OP_NOW:
 484                 rpnstack -> s[++stptr] = (double)time(NULL);
 485                 break;
 486             case OP_TIME:
 487                 /* HACK: this relies on the data_idx being the time,
 488                 ** which the within-function scope is unaware of */
 489                 rpnstack -> s[++stptr] = (double) data_idx;
 490                 break;
 491             case OP_LTIME:
 492                 rpnstack -> s[++stptr] =
 493                         (double) tzoffset(data_idx) + (double)data_idx;
 494                 break;
 495             case OP_ADD:
 496                 stackunderflow(1);
 497                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 498                                         + rpnstack -> s[stptr];
 499                 stptr--;
 500                 break;
 501             case OP_SUB:
 502                 stackunderflow(1);
 503                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 504                                         - rpnstack -> s[stptr];
 505                 stptr--;
 506                 break;
 507             case OP_MUL:
 508                 stackunderflow(1);
 509                 rpnstack -> s[stptr-1]  = (rpnstack -> s[stptr-1])
 510                                         * (rpnstack -> s[stptr]);
 511                 stptr--;
 512                 break;
 513             case OP_DIV:
 514                 stackunderflow(1);
 515                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 516                                         / rpnstack -> s[stptr];
 517                 stptr--;
 518                 break;
 519             case OP_MOD:
 520                 stackunderflow(1);
 521                 rpnstack -> s[stptr-1]= fmod(   rpnstack -> s[stptr-1]
 522                                                 ,rpnstack -> s[stptr]);
 523                 stptr--;
 524                 break;
 525             case OP_SIN:
 526                 stackunderflow(0);
 527                 rpnstack -> s[stptr] = sin(rpnstack -> s[stptr]);
 528                 break;
 529             case OP_ATAN:
 530                 stackunderflow(0);
 531                 rpnstack -> s[stptr] = atan(rpnstack -> s[stptr]);
 532                 break;
 533            case OP_RAD2DEG:
 534                stackunderflow(0);
 535                rpnstack -> s[stptr] = 57.29577951 * rpnstack -> s[stptr];
 536                break;
 537            case OP_DEG2RAD:
 538                stackunderflow(0);
 539                rpnstack -> s[stptr] = 0.0174532952 * rpnstack -> s[stptr];
 540                break;
 541            case OP_ATAN2:
 542                stackunderflow(1);
 543                rpnstack -> s[stptr-1]= atan2(
 544                                rpnstack -> s[stptr-1],
 545                                rpnstack -> s[stptr]);
 546                stptr--;
 547                break;
 548             case OP_COS:
 549                 stackunderflow(0);
 550                 rpnstack -> s[stptr] = cos(rpnstack -> s[stptr]);
 551                 break;
 552             case OP_CEIL:
 553                 stackunderflow(0);
 554                 rpnstack -> s[stptr] = ceil(rpnstack -> s[stptr]);
 555                 break;
 556             case OP_FLOOR:
 557                 stackunderflow(0);
 558                 rpnstack -> s[stptr] = floor(rpnstack -> s[stptr]);
 559                 break;
 560             case OP_LOG:
 561                 stackunderflow(0);
 562                 rpnstack -> s[stptr] = log(rpnstack -> s[stptr]);
 563                 break;
 564             case OP_DUP:
 565                 stackunderflow(0);
 566                 rpnstack -> s[stptr+1] = rpnstack -> s[stptr];
 567                 stptr++;
 568                 break;
 569             case OP_POP:
 570                 stackunderflow(0);
 571                 stptr--;
 572                 break;
 573             case OP_EXC:
 574                 stackunderflow(1);
 575                 {
 576                     double dummy;
 577                     dummy = rpnstack -> s[stptr] ;
 578                     rpnstack -> s[stptr] = rpnstack -> s[stptr-1];
 579                     rpnstack -> s[stptr-1] = dummy;
 580                 }
 581                 break;
 582             case OP_EXP:
 583                 stackunderflow(0);
 584                 rpnstack -> s[stptr] = exp(rpnstack -> s[stptr]);
 585                 break;
 586             case OP_LT:
 587                 stackunderflow(1);
 588                 if (isnan(rpnstack -> s[stptr-1]))
 589                     ;
 590                 else if (isnan(rpnstack -> s[stptr]))
 591                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 592                 else
 593                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <
 594                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 595                 stptr--;
 596                 break;
 597             case OP_LE:
 598                 stackunderflow(1);
 599                 if (isnan(rpnstack -> s[stptr-1]))
 600                     ;
 601                 else if (isnan(rpnstack -> s[stptr]))
 602                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 603                 else
 604                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <=
 605                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 606                 stptr--;
 607                 break;
 608             case OP_GT:
 609                 stackunderflow(1);
 610                 if (isnan(rpnstack -> s[stptr-1]))
 611                     ;
 612                 else if (isnan(rpnstack -> s[stptr]))
 613                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 614                 else
 615                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >
 616                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 617                 stptr--;
 618                 break;
 619             case OP_GE:
 620                 stackunderflow(1);
 621                 if (isnan(rpnstack -> s[stptr-1]))
 622                     ;
 623                 else if (isnan(rpnstack -> s[stptr]))
 624                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 625                 else
 626                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >=
 627                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 628                 stptr--;
 629                 break;
 630             case OP_NE:
 631                 stackunderflow(1);
 632                 if (isnan(rpnstack -> s[stptr-1]))
 633                     ;
 634                 else if (isnan(rpnstack -> s[stptr]))
 635                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 636                 else
 637                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
 638                                         rpnstack -> s[stptr] ? 0.0 : 1.0;
 639                 stptr--;
 640                 break;
 641             case OP_EQ:
 642                 stackunderflow(1);
 643                 if (isnan(rpnstack -> s[stptr-1]))
 644                     ;
 645                 else if (isnan(rpnstack -> s[stptr]))
 646                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 647                 else
 648                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
 649                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 650                 stptr--;
 651                 break;
 652             case OP_IF:
 653                 stackunderflow(2);
 654                 rpnstack->s[stptr-2] = rpnstack->s[stptr-2] != 0.0 ?
 655                                 rpnstack->s[stptr-1] : rpnstack->s[stptr];
 656                 stptr--;
 657                 stptr--;
 658                 break;
 659             case OP_MIN:
 660                 stackunderflow(1);
 661                 if (isnan(rpnstack->s[stptr-1]))
 662                     ;
 663                 else if (isnan(rpnstack->s[stptr]))
 664                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 665                 else if (rpnstack->s[stptr-1] > rpnstack->s[stptr])
 666                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 667                 stptr--;
 668                 break;
 669             case OP_MAX:
 670                 stackunderflow(1);
 671                 if (isnan(rpnstack->s[stptr-1]))
 672                ;
 673                 else if (isnan(rpnstack->s[stptr]))
 674                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 675                 else if (rpnstack->s[stptr-1] < rpnstack->s[stptr])
 676                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 677                 stptr--;
 678                 break;
 679             case OP_LIMIT:
 680                 stackunderflow(2);
 681                 if (isnan(rpnstack->s[stptr-2]))
 682                     ;
 683                 else if (isnan(rpnstack->s[stptr-1]))
 684                     rpnstack->s[stptr-2] = rpnstack->s[stptr-1];
 685                 else if (isnan(rpnstack->s[stptr]))
 686                     rpnstack->s[stptr-2] = rpnstack->s[stptr];
 687                 else if (rpnstack->s[stptr-2] < rpnstack->s[stptr-1])
 688                     rpnstack->s[stptr-2] = DNAN;
 689                 else if (rpnstack->s[stptr-2] > rpnstack->s[stptr])
 690                     rpnstack->s[stptr-2] = DNAN;
 691                 stptr-=2;
 692                 break;
 693             case OP_UN:
 694                 stackunderflow(0);
 695                 rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
 696                 break;
 697             case OP_ISINF:
 698                 stackunderflow(0);
 699                 rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
 700                 break;
 701             case OP_SQRT:
 702                 stackunderflow(0);
 703                 rpnstack -> s[stptr] = sqrt(rpnstack -> s[stptr]);
 704                 break;
 705             case OP_SORT:
 706                 stackunderflow(0);
 707                 {
 708                     int spn = (int)rpnstack -> s[stptr--];
 709
 710                     stackunderflow(spn-1);
 711                     qsort(rpnstack -> s + stptr-spn+1, spn, sizeof(double),
 712                           rpn_compare_double);
 713                 }
 714                 break;
 715             case OP_REV:
 716                 stackunderflow(0);
 717                 {
 718                     int spn = (int)rpnstack -> s[stptr--];
 719                     double *p, *q;
 720
 721                     stackunderflow(spn-1);
 722
 723                     p = rpnstack -> s + stptr-spn+1;
 724                     q = rpnstack -> s + stptr;
 725                     while (p < q) {
 726                             double      x = *q;
 727
 728                             *q-- = *p;
 729                             *p++ = x;
 730                     }
 731                 }
 732                 break;
 733             case OP_TREND:
 734                 stackunderflow(1);
 735                 if ((rpi < 2) || (rpnp[rpi-2].op != OP_VARIABLE)) {
 736                     rrd_set_error("malformed trend arguments");
 737                     return -1;
 738                 } else {
 739                     time_t dur = (time_t)rpnstack -> s[stptr];
 740                     time_t step = (time_t)rpnp[rpi-2].step;
 741
 742                     if (output_idx > (int)ceil((float)dur / (float)step)) {
 743                         double accum = 0.0;
 744                         int i = 0;
 745
 746                         do {
 747                             accum += rpnp[rpi-2].data[rpnp[rpi-2].ds_cnt * i--];
 748                             dur -= step;
 749                         } while (dur > 0);
 750
 751                         rpnstack -> s[--stptr] = (accum / -i);
 752                     } else
 753                         rpnstack -> s[--stptr] = DNAN;
 754                 }
 755                 break;
 756             case OP_END:
 757                 break;
 758        }
 759 #undef stackunderflow
 760    }
 761    if(stptr!=0){
 762        rrd_set_error("RPN final stack size != 1");
 763        return -1;
 764    }
 765
 766    output[output_idx] = rpnstack->s[0];
 767    return 0;
 768 }
 769
 770 /* figure out what the local timezone offset for any point in
 771    time was. Return it in seconds */
 772 int
 773 tzoffset( time_t now ){
 774     int gm_sec, gm_min, gm_hour, gm_yday, gm_year,
 775         l_sec, l_min, l_hour, l_yday, l_year;
 776     struct tm t;
 777     int off;
 778     gmtime_r(&now, &t);
 779     gm_sec = t.tm_sec;
 780     gm_min = t.tm_min;
 781     gm_hour = t.tm_hour;
 782     gm_yday = t.tm_yday;
 783     gm_year = t.tm_year;
 784     localtime_r(&now, &t);
 785     l_sec = t.tm_sec;
 786     l_min = t.tm_min;
 787     l_hour = t.tm_hour;
 788     l_yday = t.tm_yday;
 789     l_year = t.tm_year;
 790     off = (l_sec-gm_sec)+(l_min-gm_min)*60+(l_hour-gm_hour)*3600;
 791     if ( l_yday > gm_yday || l_year > gm_year){
 792         off += 24*3600;
 793     } else if ( l_yday < gm_yday || l_year < gm_year){
 794         off -= 24*3600;
 795     }
 796    return off;
 797 }
 798