program/src/rrd_rpncalc.c

   1 /****************************************************************************
   2  * RRDtool 1.2.28  Copyright by Tobi Oetiker, 1997-2008
   3  ****************************************************************************
   4  * rrd_rpncalc.c  RPN calculator functions
   5  ****************************************************************************/
   6
   7 #include "rrd_tool.h"
   8 #include "rrd_rpncalc.h"
   9 #include "rrd_graph.h"
  10 #include <limits.h>
  11
  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          add_op(OP_ABS,ABS)
 166 #undef add_op
 167               }
 168     (*str)[offset] = '\0';
 169
 170 }
 171
 172 short addop2str(enum op_en op, enum op_en op_type, char *op_str,
 173                 char **result_str, unsigned short *offset)
 174 {
 175     if (op == op_type) {
 176         short op_len;
 177         op_len = strlen(op_str);
 178         *result_str =  (char *) rrd_realloc(*result_str,
 179                                             (op_len + 1 + *offset)*sizeof(char));
 180         if (*result_str == NULL) {
 181             rrd_set_error("failed to alloc memory in addop2str");
 182             return -1;
 183         }
 184         strncpy(&((*result_str)[*offset]),op_str,op_len);
 185         *offset += op_len;
 186         return 1;
 187     }
 188     return 0;
 189 }
 190
 191 void parseCDEF_DS(const char *def,rrd_t *rrd, int ds_idx)
 192 {
 193     rpnp_t *rpnp = NULL;
 194     rpn_cdefds_t *rpnc = NULL;
 195     short count, i;
 196
 197     rpnp = rpn_parse((void*) rrd, def, &lookup_DS);
 198     if (rpnp == NULL) {
 199         rrd_set_error("failed to parse computed data source");
 200         return;
 201     }
 202     /* Check for OP nodes not permitted in COMPUTE DS.
 203      * Moved this check from within rpn_compact() because it really is
 204      * COMPUTE DS specific. This is less efficient, but creation doesn't
 205      * occur too often. */
 206     for (i = 0; rpnp[i].op != OP_END; i++) {
 207         if (rpnp[i].op == OP_TIME || rpnp[i].op == OP_LTIME ||
 208             rpnp[i].op == OP_PREV || rpnp[i].op == OP_COUNT)
 209         {
 210             rrd_set_error(
 211                 "operators time, ltime, prev and count not supported with DS COMPUTE");
 212             free(rpnp);
 213             return;
 214         }
 215     }
 216     if (rpn_compact(rpnp,&rpnc,&count) == -1) {
 217         free(rpnp);
 218         return;
 219     }
 220     /* copy the compact rpn representation over the ds_def par array */
 221     memcpy((void*) &(rrd -> ds_def[ds_idx].par[DS_cdef]),
 222            (void*) rpnc, count*sizeof(rpn_cdefds_t));
 223     free(rpnp);
 224     free(rpnc);
 225 }
 226
 227 /* lookup a data source name in the rrd struct and return the index,
 228  * should use ds_match() here except:
 229  * (1) need a void * pointer to the rrd
 230  * (2) error handling is left to the caller
 231  */
 232 long lookup_DS(void *rrd_vptr,char *ds_name)
 233 {
 234     unsigned int i;
 235     rrd_t *rrd;
 236
 237     rrd = (rrd_t *) rrd_vptr;
 238
 239     for (i = 0; i < rrd -> stat_head -> ds_cnt; ++i)
 240     {
 241         if(strcmp(ds_name,rrd -> ds_def[i].ds_nam) == 0)
 242             return i;
 243     }
 244     /* the caller handles a bad data source name in the rpn string */
 245     return -1;
 246 }
 247
 248 /* rpn_parse : parse a string and generate a rpnp array; modified
 249  * str2rpn() originally included in rrd_graph.c
 250  * arguments:
 251  * key_hash: a transparent argument passed to lookup(); conceptually this
 252  *    is a hash object for lookup of a numeric key given a variable name
 253  * expr: the string RPN expression, including variable names
 254  * lookup(): a function that retrieves a numeric key given a variable name
 255  */
 256 rpnp_t *
 257 rpn_parse(void *key_hash,const char *const expr_const,long (*lookup)(void *,char*)){
 258     int pos=0;
 259     char *expr;
 260     long steps=-1;
 261     rpnp_t  *rpnp;
 262     char vname[MAX_VNAME_LEN+10];
 263
 264     rpnp=NULL;
 265     expr=(char *)expr_const;
 266
 267     while(*expr){
 268         if ((rpnp = (rpnp_t *) rrd_realloc(rpnp, (++steps + 2)*
 269                                        sizeof(rpnp_t)))==NULL){
 270             return NULL;
 271         }
 272
 273         else if((sscanf(expr,"%lf%n",&rpnp[steps].val,&pos) == 1) && (expr[pos] == ',')){
 274             rpnp[steps].op = OP_NUMBER;
 275             expr+=pos;
 276         }
 277
 278 #define match_op(VV,VVV) \
 279         else if (strncmp(expr, #VVV, strlen(#VVV))==0 && ( expr[strlen(#VVV)] == ',' || expr[strlen(#VVV)] == '\0' )){ \
 280             rpnp[steps].op = VV; \
 281             expr+=strlen(#VVV); \
 282         }
 283
 284
 285 #define match_op_param(VV,VVV) \
 286         else if (sscanf(expr, #VVV "(" DEF_NAM_FMT ")",vname) == 1) { \
 287           int length = 0; \
 288           if ((length = strlen(#VVV)+strlen(vname)+2, \
 289               expr[length] == ',' || expr[length] == '\0') ) { \
 290              rpnp[steps].op = VV; \
 291              rpnp[steps].ptr = (*lookup)(key_hash,vname); \
 292              if (rpnp[steps].ptr < 0) { \
 293                            free(rpnp); \
 294                            return NULL; \
 295                          } else expr+=length; \
 296           } \
 297         }
 298
 299         match_op(OP_ADD,+)
 300         match_op(OP_SUB,-)
 301         match_op(OP_MUL,*)
 302         match_op(OP_DIV,/)
 303         match_op(OP_MOD,%)
 304         match_op(OP_SIN,SIN)
 305         match_op(OP_COS,COS)
 306         match_op(OP_LOG,LOG)
 307         match_op(OP_FLOOR,FLOOR)
 308         match_op(OP_CEIL,CEIL)
 309         match_op(OP_EXP,EXP)
 310         match_op(OP_DUP,DUP)
 311         match_op(OP_EXC,EXC)
 312         match_op(OP_POP,POP)
 313         match_op(OP_LTIME,LTIME)
 314         match_op(OP_LT,LT)
 315         match_op(OP_LE,LE)
 316         match_op(OP_GT,GT)
 317         match_op(OP_GE,GE)
 318         match_op(OP_EQ,EQ)
 319         match_op(OP_IF,IF)
 320         match_op(OP_MIN,MIN)
 321         match_op(OP_MAX,MAX)
 322         match_op(OP_LIMIT,LIMIT)
 323           /* order is important here ! .. match longest first */
 324         match_op(OP_UNKN,UNKN)
 325         match_op(OP_UN,UN)
 326         match_op(OP_NEGINF,NEGINF)
 327         match_op(OP_NE,NE)
 328         match_op(OP_COUNT,COUNT)
 329         match_op_param(OP_PREV_OTHER,PREV)
 330         match_op(OP_PREV,PREV)
 331         match_op(OP_INF,INF)
 332         match_op(OP_ISINF,ISINF)
 333         match_op(OP_NOW,NOW)
 334         match_op(OP_TIME,TIME)
 335        match_op(OP_ATAN2,ATAN2)
 336         match_op(OP_ATAN,ATAN)
 337         match_op(OP_SQRT,SQRT)
 338         match_op(OP_SORT,SORT)
 339         match_op(OP_REV,REV)
 340         match_op(OP_TREND,TREND)
 341        match_op(OP_RAD2DEG,RAD2DEG)
 342        match_op(OP_DEG2RAD,DEG2RAD)
 343        match_op(OP_AVG,AVG)
 344        match_op(OP_ABS,ABS)
 345 #undef match_op
 346
 347
 348             else if ((sscanf(expr, DEF_NAM_FMT "%n",
 349                              vname,&pos) == 1)
 350                      && ((rpnp[steps].ptr = (*lookup)(key_hash,vname)) != -1)){
 351                 rpnp[steps].op = OP_VARIABLE;
 352                 expr+=pos;
 353             }
 354
 355         else {
 356             free(rpnp);
 357             return NULL;
 358         }
 359         if (*expr == 0)
 360             break;
 361         if (*expr == ',')
 362             expr++;
 363         else {
 364             free(rpnp);
 365             return NULL;
 366         }
 367     }
 368     rpnp[steps+1].op = OP_END;
 369     return rpnp;
 370 }
 371
 372 void
 373 rpnstack_init(rpnstack_t *rpnstack)
 374 {
 375     rpnstack -> s = NULL;
 376     rpnstack -> dc_stacksize = 0;
 377     rpnstack -> dc_stackblock = 100;
 378 }
 379
 380 void
 381 rpnstack_free(rpnstack_t *rpnstack)
 382 {
 383    if (rpnstack -> s != NULL)
 384           free(rpnstack -> s);
 385    rpnstack -> dc_stacksize = 0;
 386 }
 387
 388 static int
 389 rpn_compare_double(const void *x, const void *y)
 390 {
 391         double  diff = *((const double *)x) - *((const double *)y);
 392
 393         return (diff < 0) ? -1 : (diff > 0) ? 1 : 0;
 394 }
 395
 396 /* rpn_calc: run the RPN calculator; also performs variable substitution;
 397  * moved and modified from data_calc() originally included in rrd_graph.c
 398  * arguments:
 399  * rpnp : an array of RPN operators (including variable references)
 400  * rpnstack : the initialized stack
 401  * data_idx : when data_idx is a multiple of rpnp.step, the rpnp.data pointer
 402  *   is advanced by rpnp.ds_cnt; used only for variable substitution
 403  * output : an array of output values; OP_PREV assumes this array contains
 404  *   the "previous" value at index position output_idx-1; the definition of
 405  *   "previous" depends on the calling environment
 406  * output_idx : an index into the output array in which to store the output
 407  *   of the RPN calculator
 408  * returns: -1 if the computation failed (also calls rrd_set_error)
 409  *           0 on success
 410  */
 411 short
 412 rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx,
 413                 rrd_value_t *output, int output_idx)
 414 {
 415     int rpi;
 416     long stptr = -1;
 417
 418     /* process each op from the rpn in turn */
 419     for (rpi=0; rpnp[rpi].op != OP_END; rpi++){
 420         /* allocate or grow the stack */
 421         if (stptr + 5 > rpnstack -> dc_stacksize){
 422             /* could move this to a separate function */
 423             rpnstack -> dc_stacksize += rpnstack -> dc_stackblock;
 424             rpnstack -> s = rrd_realloc(rpnstack -> s,
 425                         (rpnstack -> dc_stacksize)*sizeof(*(rpnstack -> s)));
 426             if (rpnstack -> s == NULL){
 427                 rrd_set_error("RPN stack overflow");
 428                 return -1;
 429             }
 430         }
 431
 432 #define stackunderflow(MINSIZE)                         \
 433         if(stptr<MINSIZE){                              \
 434             rrd_set_error("RPN stack underflow");       \
 435             return -1;                                  \
 436         }
 437
 438         switch (rpnp[rpi].op){
 439             case OP_NUMBER:
 440                 rpnstack -> s[++stptr] = rpnp[rpi].val;
 441                 break;
 442             case OP_VARIABLE:
 443             case OP_PREV_OTHER:
 444             /* Sanity check: VDEFs shouldn't make it here */
 445                 if (rpnp[rpi].ds_cnt == 0) {
 446                     rrd_set_error("VDEF made it into rpn_calc... aborting");
 447                     return -1;
 448                 } else {
 449                     /* make sure we pull the correct value from
 450                      * the *.data array. Adjust the pointer into
 451                      * the array acordingly. Advance the ptr one
 452                      * row in the rra (skip over non-relevant
 453                      * data sources)
 454                      */
 455                     if (rpnp[rpi].op == OP_VARIABLE) {
 456                         rpnstack -> s[++stptr] =  *(rpnp[rpi].data);
 457                     } else {
 458                         if ((output_idx) <= 0) {
 459                             rpnstack -> s[++stptr] = DNAN;
 460                         } else {
 461                             rpnstack -> s[++stptr] =  *(rpnp[rpi].data-rpnp[rpi].ds_cnt);
 462                         }
 463
 464                     }
 465                     if (data_idx % rpnp[rpi].step == 0){
 466                         rpnp[rpi].data += rpnp[rpi].ds_cnt;
 467                     }
 468                 }
 469                 break;
 470             case OP_COUNT:
 471                 rpnstack -> s[++stptr] = (output_idx+1); /* Note: Counter starts at 1 */
 472                 break;
 473             case OP_PREV:
 474                 if ((output_idx) <= 0) {
 475                     rpnstack -> s[++stptr] = DNAN;
 476                 } else {
 477                     rpnstack -> s[++stptr] = output[output_idx-1];
 478                 }
 479                 break;
 480          case OP_UNKN:
 481                 rpnstack -> s[++stptr] = DNAN;
 482                 break;
 483             case OP_INF:
 484                 rpnstack -> s[++stptr] = DINF;
 485                 break;
 486             case OP_NEGINF:
 487                 rpnstack -> s[++stptr] = -DINF;
 488                 break;
 489             case OP_NOW:
 490                 rpnstack -> s[++stptr] = (double)time(NULL);
 491                 break;
 492             case OP_TIME:
 493                 /* HACK: this relies on the data_idx being the time,
 494                 ** which the within-function scope is unaware of */
 495                 rpnstack -> s[++stptr] = (double) data_idx;
 496                 break;
 497             case OP_LTIME:
 498                 rpnstack -> s[++stptr] =
 499                         (double) tzoffset(data_idx) + (double)data_idx;
 500                 break;
 501             case OP_ADD:
 502                 stackunderflow(1);
 503                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 504                                         + rpnstack -> s[stptr];
 505                 stptr--;
 506                 break;
 507             case OP_SUB:
 508                 stackunderflow(1);
 509                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 510                                         - rpnstack -> s[stptr];
 511                 stptr--;
 512                 break;
 513             case OP_MUL:
 514                 stackunderflow(1);
 515                 rpnstack -> s[stptr-1]  = (rpnstack -> s[stptr-1])
 516                                         * (rpnstack -> s[stptr]);
 517                 stptr--;
 518                 break;
 519             case OP_DIV:
 520                 stackunderflow(1);
 521                 rpnstack -> s[stptr-1]  = rpnstack -> s[stptr-1]
 522                                         / rpnstack -> s[stptr];
 523                 stptr--;
 524                 break;
 525             case OP_MOD:
 526                 stackunderflow(1);
 527                 rpnstack -> s[stptr-1]= fmod(   rpnstack -> s[stptr-1]
 528                                                 ,rpnstack -> s[stptr]);
 529                 stptr--;
 530                 break;
 531             case OP_SIN:
 532                 stackunderflow(0);
 533                 rpnstack -> s[stptr] = sin(rpnstack -> s[stptr]);
 534                 break;
 535             case OP_ATAN:
 536                 stackunderflow(0);
 537                 rpnstack -> s[stptr] = atan(rpnstack -> s[stptr]);
 538                 break;
 539            case OP_RAD2DEG:
 540                stackunderflow(0);
 541                rpnstack -> s[stptr] = 57.29577951 * rpnstack -> s[stptr];
 542                break;
 543            case OP_DEG2RAD:
 544                stackunderflow(0);
 545                rpnstack -> s[stptr] = 0.0174532952 * rpnstack -> s[stptr];
 546                break;
 547            case OP_ATAN2:
 548                stackunderflow(1);
 549                rpnstack -> s[stptr-1]= atan2(
 550                                rpnstack -> s[stptr-1],
 551                                rpnstack -> s[stptr]);
 552                stptr--;
 553                break;
 554             case OP_COS:
 555                 stackunderflow(0);
 556                 rpnstack -> s[stptr] = cos(rpnstack -> s[stptr]);
 557                 break;
 558             case OP_CEIL:
 559                 stackunderflow(0);
 560                 rpnstack -> s[stptr] = ceil(rpnstack -> s[stptr]);
 561                 break;
 562             case OP_FLOOR:
 563                 stackunderflow(0);
 564                 rpnstack -> s[stptr] = floor(rpnstack -> s[stptr]);
 565                 break;
 566             case OP_LOG:
 567                 stackunderflow(0);
 568                 rpnstack -> s[stptr] = log(rpnstack -> s[stptr]);
 569                 break;
 570             case OP_DUP:
 571                 stackunderflow(0);
 572                 rpnstack -> s[stptr+1] = rpnstack -> s[stptr];
 573                 stptr++;
 574                 break;
 575             case OP_POP:
 576                 stackunderflow(0);
 577                 stptr--;
 578                 break;
 579             case OP_EXC:
 580                 stackunderflow(1);
 581                 {
 582                     double dummy;
 583                     dummy = rpnstack -> s[stptr] ;
 584                     rpnstack -> s[stptr] = rpnstack -> s[stptr-1];
 585                     rpnstack -> s[stptr-1] = dummy;
 586                 }
 587                 break;
 588             case OP_EXP:
 589                 stackunderflow(0);
 590                 rpnstack -> s[stptr] = exp(rpnstack -> s[stptr]);
 591                 break;
 592             case OP_LT:
 593                 stackunderflow(1);
 594                 if (isnan(rpnstack -> s[stptr-1]))
 595                     ;
 596                 else if (isnan(rpnstack -> s[stptr]))
 597                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 598                 else
 599                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <
 600                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 601                 stptr--;
 602                 break;
 603             case OP_LE:
 604                 stackunderflow(1);
 605                 if (isnan(rpnstack -> s[stptr-1]))
 606                     ;
 607                 else if (isnan(rpnstack -> s[stptr]))
 608                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 609                 else
 610                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] <=
 611                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 612                 stptr--;
 613                 break;
 614             case OP_GT:
 615                 stackunderflow(1);
 616                 if (isnan(rpnstack -> s[stptr-1]))
 617                     ;
 618                 else if (isnan(rpnstack -> s[stptr]))
 619                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 620                 else
 621                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >
 622                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 623                 stptr--;
 624                 break;
 625             case OP_GE:
 626                 stackunderflow(1);
 627                 if (isnan(rpnstack -> s[stptr-1]))
 628                     ;
 629                 else if (isnan(rpnstack -> s[stptr]))
 630                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 631                 else
 632                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] >=
 633                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 634                 stptr--;
 635                 break;
 636             case OP_NE:
 637                 stackunderflow(1);
 638                 if (isnan(rpnstack -> s[stptr-1]))
 639                     ;
 640                 else if (isnan(rpnstack -> s[stptr]))
 641                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 642                 else
 643                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
 644                                         rpnstack -> s[stptr] ? 0.0 : 1.0;
 645                 stptr--;
 646                 break;
 647             case OP_EQ:
 648                 stackunderflow(1);
 649                 if (isnan(rpnstack -> s[stptr-1]))
 650                     ;
 651                 else if (isnan(rpnstack -> s[stptr]))
 652                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr];
 653                 else
 654                     rpnstack -> s[stptr-1] = rpnstack -> s[stptr-1] ==
 655                                         rpnstack -> s[stptr] ? 1.0 : 0.0;
 656                 stptr--;
 657                 break;
 658             case OP_IF:
 659                 stackunderflow(2);
 660                 rpnstack->s[stptr-2] = rpnstack->s[stptr-2] != 0.0 ?
 661                                 rpnstack->s[stptr-1] : rpnstack->s[stptr];
 662                 stptr--;
 663                 stptr--;
 664                 break;
 665             case OP_MIN:
 666                 stackunderflow(1);
 667                 if (isnan(rpnstack->s[stptr-1]))
 668                     ;
 669                 else if (isnan(rpnstack->s[stptr]))
 670                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 671                 else if (rpnstack->s[stptr-1] > rpnstack->s[stptr])
 672                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 673                 stptr--;
 674                 break;
 675             case OP_MAX:
 676                 stackunderflow(1);
 677                 if (isnan(rpnstack->s[stptr-1]))
 678                ;
 679                 else if (isnan(rpnstack->s[stptr]))
 680                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 681                 else if (rpnstack->s[stptr-1] < rpnstack->s[stptr])
 682                     rpnstack->s[stptr-1] = rpnstack->s[stptr];
 683                 stptr--;
 684                 break;
 685             case OP_LIMIT:
 686                 stackunderflow(2);
 687                 if (isnan(rpnstack->s[stptr-2]))
 688                     ;
 689                 else if (isnan(rpnstack->s[stptr-1]))
 690                     rpnstack->s[stptr-2] = rpnstack->s[stptr-1];
 691                 else if (isnan(rpnstack->s[stptr]))
 692                     rpnstack->s[stptr-2] = rpnstack->s[stptr];
 693                 else if (rpnstack->s[stptr-2] < rpnstack->s[stptr-1])
 694                     rpnstack->s[stptr-2] = DNAN;
 695                 else if (rpnstack->s[stptr-2] > rpnstack->s[stptr])
 696                     rpnstack->s[stptr-2] = DNAN;
 697                 stptr-=2;
 698                 break;
 699             case OP_UN:
 700                 stackunderflow(0);
 701                 rpnstack->s[stptr] = isnan(rpnstack->s[stptr]) ? 1.0 : 0.0;
 702                 break;
 703             case OP_ISINF:
 704                 stackunderflow(0);
 705                 rpnstack->s[stptr] = isinf(rpnstack->s[stptr]) ? 1.0 : 0.0;
 706                 break;
 707             case OP_SQRT:
 708                 stackunderflow(0);
 709                 rpnstack -> s[stptr] = sqrt(rpnstack -> s[stptr]);
 710                 break;
 711             case OP_SORT:
 712                 stackunderflow(0);
 713                 {
 714                     int spn = (int)rpnstack -> s[stptr--];
 715
 716                     stackunderflow(spn-1);
 717                     qsort(rpnstack -> s + stptr-spn+1, spn, sizeof(double),
 718                           rpn_compare_double);
 719                 }
 720                 break;
 721             case OP_REV:
 722                 stackunderflow(0);
 723                 {
 724                     int spn = (int)rpnstack -> s[stptr--];
 725                     double *p, *q;
 726
 727                     stackunderflow(spn-1);
 728
 729                     p = rpnstack -> s + stptr-spn+1;
 730                     q = rpnstack -> s + stptr;
 731                     while (p < q) {
 732                             double      x = *q;
 733
 734                             *q-- = *p;
 735                             *p++ = x;
 736                     }
 737                 }
 738                 break;
 739             case OP_TREND:
 740                 stackunderflow(1);
 741                 if ((rpi < 2) || (rpnp[rpi-2].op != OP_VARIABLE)) {
 742                     rrd_set_error("malformed trend arguments");
 743                     return -1;
 744                 } else {
 745                     time_t dur = (time_t)rpnstack -> s[stptr];
 746                     time_t step = (time_t)rpnp[rpi-2].step;
 747
 748                     if (output_idx > (int)ceil((float)dur / (float)step)) {
 749                         double accum = 0.0;
 750                         int i = 0;
 751
 752                         do {
 753                             accum += rpnp[rpi-2].data[rpnp[rpi-2].ds_cnt * i--];
 754                             dur -= step;
 755                         } while (dur > 0);
 756
 757                         rpnstack -> s[--stptr] = (accum / -i);
 758                     } else
 759                         rpnstack -> s[--stptr] = DNAN;
 760                 }
 761                 break;
 762            case OP_AVG:
 763                stackunderflow(0);
 764                 {
 765                    int i=(int)rpnstack -> s[stptr--];
 766                    double sum=0;
 767                    int count=0;
 768                    stackunderflow(i-1);
 769                    while(i>0) {
 770                      double val=rpnstack -> s[stptr--];
 771                      i--;
 772                     if (isnan(val)) { continue; }
 773                      count++;
 774                      sum+=val;
 775                    }
 776                    /* now push the result back on stack */
 777                    if (count>0) {
 778                      rpnstack -> s[++stptr]=sum/count;
 779                    } else {
 780                      rpnstack -> s[++stptr]=DNAN;
 781                    }
 782                 }
 783                 break;
 784             case OP_ABS:
 785                 stackunderflow(0);
 786                 rpnstack -> s[stptr] = fabs(rpnstack -> s[stptr]);
 787                 break;
 788             case OP_END:
 789                 break;
 790        }
 791 #undef stackunderflow
 792    }
 793    if(stptr!=0){
 794        rrd_set_error("RPN final stack size != 1");
 795        return -1;
 796    }
 797
 798    output[output_idx] = rpnstack->s[0];
 799    return 0;
 800 }
 801
 802 /* figure out what the local timezone offset for any point in
 803    time was. Return it in seconds */
 804 int
 805 tzoffset( time_t now ){
 806     int gm_sec, gm_min, gm_hour, gm_yday, gm_year,
 807         l_sec, l_min, l_hour, l_yday, l_year;
 808     struct tm t;
 809     int off;
 810     gmtime_r(&now, &t);
 811     gm_sec = t.tm_sec;
 812     gm_min = t.tm_min;
 813     gm_hour = t.tm_hour;
 814     gm_yday = t.tm_yday;
 815     gm_year = t.tm_year;
 816     localtime_r(&now, &t);
 817     l_sec = t.tm_sec;
 818     l_min = t.tm_min;
 819     l_hour = t.tm_hour;
 820     l_yday = t.tm_yday;
 821     l_year = t.tm_year;
 822     off = (l_sec-gm_sec)+(l_min-gm_min)*60+(l_hour-gm_hour)*3600;
 823     if ( l_yday > gm_yday || l_year > gm_year){
 824         off += 24*3600;
 825     } else if ( l_yday < gm_yday || l_year < gm_year){
 826         off -= 24*3600;
 827     }
 828    return off;
 829 }
 830