contrib/intarray/_int_bool.c

   1 /*
   2  * $PostgreSQL:$
   3  */
   4 #include "postgres.h"
   5
   6 #include "utils/builtins.h"
   7
   8 #include "_int.h"
   9
  10 PG_FUNCTION_INFO_V1(bqarr_in);
  11 PG_FUNCTION_INFO_V1(bqarr_out);
  12 Datum           bqarr_in(PG_FUNCTION_ARGS);
  13 Datum           bqarr_out(PG_FUNCTION_ARGS);
  14
  15 PG_FUNCTION_INFO_V1(boolop);
  16 Datum           boolop(PG_FUNCTION_ARGS);
  17
  18 PG_FUNCTION_INFO_V1(rboolop);
  19 Datum           rboolop(PG_FUNCTION_ARGS);
  20
  21 PG_FUNCTION_INFO_V1(querytree);
  22 Datum           querytree(PG_FUNCTION_ARGS);
  23
  24
  25 #define END             0
  26 #define ERR             1
  27 #define VAL             2
  28 #define OPR             3
  29 #define OPEN    4
  30 #define CLOSE   5
  31
  32 /* parser's states */
  33 #define WAITOPERAND 1
  34 #define WAITENDOPERAND  2
  35 #define WAITOPERATOR    3
  36
  37 /*
  38  * node of query tree, also used
  39  * for storing polish notation in parser
  40  */
  41 typedef struct NODE
  42 {
  43         int4            type;
  44         int4            val;
  45         struct NODE *next;
  46 } NODE;
  47
  48 typedef struct
  49 {
  50         char       *buf;
  51         int4            state;
  52         int4            count;
  53         /* reverse polish notation in list (for temporary usage) */
  54         NODE       *str;
  55         /* number in str */
  56         int4            num;
  57 }       WORKSTATE;
  58
  59 /*
  60  * get token from query string
  61  */
  62 static int4
  63 gettoken(WORKSTATE * state, int4 *val)
  64 {
  65         char            nnn[16],
  66                            *curnnn;
  67
  68         *val = 0;                                       /* default result */
  69
  70         curnnn = nnn;
  71         while (1)
  72         {
  73                 switch (state->state)
  74                 {
  75                         case WAITOPERAND:
  76                                 curnnn = nnn;
  77                                 if ((*(state->buf) >= '0' && *(state->buf) <= '9') ||
  78                                         *(state->buf) == '-')
  79                                 {
  80                                         state->state = WAITENDOPERAND;
  81                                         *curnnn = *(state->buf);
  82                                         curnnn++;
  83                                 }
  84                                 else if (*(state->buf) == '!')
  85                                 {
  86                                         (state->buf)++;
  87                                         *val = (int4) '!';
  88                                         return OPR;
  89                                 }
  90                                 else if (*(state->buf) == '(')
  91                                 {
  92                                         state->count++;
  93                                         (state->buf)++;
  94                                         return OPEN;
  95                                 }
  96                                 else if (*(state->buf) != ' ')
  97                                         return ERR;
  98                                 break;
  99                         case WAITENDOPERAND:
 100                                 if (*(state->buf) >= '0' && *(state->buf) <= '9')
 101                                 {
 102                                         *curnnn = *(state->buf);
 103                                         curnnn++;
 104                                 }
 105                                 else
 106                                 {
 107                                         *curnnn = '\0';
 108                                         *val = (int4) atoi(nnn);
 109                                         state->state = WAITOPERATOR;
 110                                         return (state->count && *(state->buf) == '\0')
 111                                                 ? ERR : VAL;
 112                                 }
 113                                 break;
 114                         case WAITOPERATOR:
 115                                 if (*(state->buf) == '&' || *(state->buf) == '|')
 116                                 {
 117                                         state->state = WAITOPERAND;
 118                                         *val = (int4) *(state->buf);
 119                                         (state->buf)++;
 120                                         return OPR;
 121                                 }
 122                                 else if (*(state->buf) == ')')
 123                                 {
 124                                         (state->buf)++;
 125                                         state->count--;
 126                                         return (state->count < 0) ? ERR : CLOSE;
 127                                 }
 128                                 else if (*(state->buf) == '\0')
 129                                         return (state->count) ? ERR : END;
 130                                 else if (*(state->buf) != ' ')
 131                                         return ERR;
 132                                 break;
 133                         default:
 134                                 return ERR;
 135                                 break;
 136                 }
 137                 (state->buf)++;
 138         }
 139         return END;
 140 }
 141
 142 /*
 143  * push new one in polish notation reverse view
 144  */
 145 static void
 146 pushquery(WORKSTATE * state, int4 type, int4 val)
 147 {
 148         NODE       *tmp = (NODE *) palloc(sizeof(NODE));
 149
 150         tmp->type = type;
 151         tmp->val = val;
 152         tmp->next = state->str;
 153         state->str = tmp;
 154         state->num++;
 155 }
 156
 157 #define STACKDEPTH      16
 158
 159 /*
 160  * make polish notation of query
 161  */
 162 static int4
 163 makepol(WORKSTATE * state)
 164 {
 165         int4            val,
 166                                 type;
 167         int4            stack[STACKDEPTH];
 168         int4            lenstack = 0;
 169
 170         while ((type = gettoken(state, &val)) != END)
 171         {
 172                 switch (type)
 173                 {
 174                         case VAL:
 175                                 pushquery(state, type, val);
 176                                 while (lenstack && (stack[lenstack - 1] == (int4) '&' ||
 177                                                                         stack[lenstack - 1] == (int4) '!'))
 178                                 {
 179                                         lenstack--;
 180                                         pushquery(state, OPR, stack[lenstack]);
 181                                 }
 182                                 break;
 183                         case OPR:
 184                                 if (lenstack && val == (int4) '|')
 185                                         pushquery(state, OPR, val);
 186                                 else
 187                                 {
 188                                         if (lenstack == STACKDEPTH)
 189                                                 ereport(ERROR,
 190                                                                 (errcode(ERRCODE_STATEMENT_TOO_COMPLEX),
 191                                                                  errmsg("statement too complex")));
 192                                         stack[lenstack] = val;
 193                                         lenstack++;
 194                                 }
 195                                 break;
 196                         case OPEN:
 197                                 if (makepol(state) == ERR)
 198                                         return ERR;
 199                                 if (lenstack && (stack[lenstack - 1] == (int4) '&' ||
 200                                                                  stack[lenstack - 1] == (int4) '!'))
 201                                 {
 202                                         lenstack--;
 203                                         pushquery(state, OPR, stack[lenstack]);
 204                                 }
 205                                 break;
 206                         case CLOSE:
 207                                 while (lenstack)
 208                                 {
 209                                         lenstack--;
 210                                         pushquery(state, OPR, stack[lenstack]);
 211                                 };
 212                                 return END;
 213                                 break;
 214                         case ERR:
 215                         default:
 216                                 ereport(ERROR,
 217                                                 (errcode(ERRCODE_SYNTAX_ERROR),
 218                                                  errmsg("syntax error")));
 219                                 return ERR;
 220
 221                 }
 222         }
 223
 224         while (lenstack)
 225         {
 226                 lenstack--;
 227                 pushquery(state, OPR, stack[lenstack]);
 228         };
 229         return END;
 230 }
 231
 232 typedef struct
 233 {
 234         int4       *arrb;
 235         int4       *arre;
 236 } CHKVAL;
 237
 238 /*
 239  * is there value 'val' in array or not ?
 240  */
 241 static bool
 242 checkcondition_arr(void *checkval, ITEM * item)
 243 {
 244         int4       *StopLow = ((CHKVAL *) checkval)->arrb;
 245         int4       *StopHigh = ((CHKVAL *) checkval)->arre;
 246         int4       *StopMiddle;
 247
 248         /* Loop invariant: StopLow <= val < StopHigh */
 249
 250         while (StopLow < StopHigh)
 251         {
 252                 StopMiddle = StopLow + (StopHigh - StopLow) / 2;
 253                 if (*StopMiddle == item->val)
 254                         return (true);
 255                 else if (*StopMiddle < item->val)
 256                         StopLow = StopMiddle + 1;
 257                 else
 258                         StopHigh = StopMiddle;
 259         }
 260         return false;
 261 }
 262
 263 static bool
 264 checkcondition_bit(void *checkval, ITEM * item)
 265 {
 266         return GETBIT(checkval, HASHVAL(item->val));
 267 }
 268
 269 /*
 270  * check for boolean condition
 271  */
 272 static bool
 273 execute(ITEM * curitem, void *checkval, bool calcnot, bool (*chkcond) (void *checkval, ITEM * item))
 274 {
 275
 276         if (curitem->type == VAL)
 277                 return (*chkcond) (checkval, curitem);
 278         else if (curitem->val == (int4) '!')
 279         {
 280                 return (calcnot) ?
 281                         ((execute(curitem - 1, checkval, calcnot, chkcond)) ? false : true)
 282                         : true;
 283         }
 284         else if (curitem->val == (int4) '&')
 285         {
 286                 if (execute(curitem + curitem->left, checkval, calcnot, chkcond))
 287                         return execute(curitem - 1, checkval, calcnot, chkcond);
 288                 else
 289                         return false;
 290         }
 291         else
 292         {                                                       /* |-operator */
 293                 if (execute(curitem + curitem->left, checkval, calcnot, chkcond))
 294                         return true;
 295                 else
 296                         return execute(curitem - 1, checkval, calcnot, chkcond);
 297         }
 298         return false;
 299 }
 300
 301 /*
 302  * signconsistent & execconsistent called by *_consistent
 303  */
 304 bool
 305 signconsistent(QUERYTYPE * query, BITVEC sign, bool calcnot)
 306 {
 307         return execute(
 308                                    GETQUERY(query) + query->size - 1,
 309                                    (void *) sign, calcnot,
 310                                    checkcondition_bit
 311                 );
 312 }
 313
 314 bool
 315 execconsistent(QUERYTYPE * query, ArrayType *array, bool calcnot)
 316 {
 317         CHKVAL          chkval;
 318
 319         CHECKARRVALID(array);
 320         chkval.arrb = ARRPTR(array);
 321         chkval.arre = chkval.arrb + ARRNELEMS(array);
 322         return execute(
 323                                    GETQUERY(query) + query->size - 1,
 324                                    (void *) &chkval, calcnot,
 325                                    checkcondition_arr
 326                 );
 327 }
 328
 329 typedef struct
 330 {
 331         ITEM       *first;
 332         bool       *mapped_check;
 333 } GinChkVal;
 334
 335 static bool
 336 checkcondition_gin(void *checkval, ITEM * item)
 337 {
 338         GinChkVal  *gcv = (GinChkVal *) checkval;
 339
 340         return gcv->mapped_check[item - gcv->first];
 341 }
 342
 343 bool
 344 ginconsistent(QUERYTYPE * query, bool *check)
 345 {
 346         GinChkVal       gcv;
 347         ITEM       *items = GETQUERY(query);
 348         int                     i,
 349                                 j = 0;
 350
 351         if (query->size < 0)
 352                 return FALSE;
 353
 354         gcv.first = items;
 355         gcv.mapped_check = (bool *) palloc(sizeof(bool) * query->size);
 356         for (i = 0; i < query->size; i++)
 357                 if (items[i].type == VAL)
 358                         gcv.mapped_check[i] = check[j++];
 359
 360         return execute(
 361                                    GETQUERY(query) + query->size - 1,
 362                                    (void *) &gcv, true,
 363                                    checkcondition_gin
 364                 );
 365 }
 366
 367 /*
 368  * boolean operations
 369  */
 370 Datum
 371 rboolop(PG_FUNCTION_ARGS)
 372 {
 373         return DirectFunctionCall2(
 374                                                            boolop,
 375                                                            PG_GETARG_DATUM(1),
 376                                                            PG_GETARG_DATUM(0)
 377                 );
 378 }
 379
 380 Datum
 381 boolop(PG_FUNCTION_ARGS)
 382 {
 383         ArrayType  *val = (ArrayType *) PG_DETOAST_DATUM_COPY(PG_GETARG_POINTER(0));
 384         QUERYTYPE  *query = (QUERYTYPE *) PG_DETOAST_DATUM(PG_GETARG_POINTER(1));
 385         CHKVAL          chkval;
 386         bool            result;
 387
 388         CHECKARRVALID(val);
 389         if (ARRISVOID(val))
 390         {
 391                 pfree(val);
 392                 PG_FREE_IF_COPY(query, 1);
 393                 PG_RETURN_BOOL(false);
 394         }
 395
 396         PREPAREARR(val);
 397         chkval.arrb = ARRPTR(val);
 398         chkval.arre = chkval.arrb + ARRNELEMS(val);
 399         result = execute(
 400                                          GETQUERY(query) + query->size - 1,
 401                                          &chkval, true,
 402                                          checkcondition_arr
 403                 );
 404         pfree(val);
 405
 406         PG_FREE_IF_COPY(query, 1);
 407         PG_RETURN_BOOL(result);
 408 }
 409
 410 static void
 411 findoprnd(ITEM * ptr, int4 *pos)
 412 {
 413 #ifdef BS_DEBUG
 414         elog(DEBUG3, (ptr[*pos].type == OPR) ?
 415                  "%d  %c" : "%d  %d", *pos, ptr[*pos].val);
 416 #endif
 417         if (ptr[*pos].type == VAL)
 418         {
 419                 ptr[*pos].left = 0;
 420                 (*pos)--;
 421         }
 422         else if (ptr[*pos].val == (int4) '!')
 423         {
 424                 ptr[*pos].left = -1;
 425                 (*pos)--;
 426                 findoprnd(ptr, pos);
 427         }
 428         else
 429         {
 430                 ITEM       *curitem = &ptr[*pos];
 431                 int4            tmp = *pos;
 432
 433                 (*pos)--;
 434                 findoprnd(ptr, pos);
 435                 curitem->left = *pos - tmp;
 436                 findoprnd(ptr, pos);
 437         }
 438 }
 439
 440
 441 /*
 442  * input
 443  */
 444 Datum
 445 bqarr_in(PG_FUNCTION_ARGS)
 446 {
 447         char       *buf = (char *) PG_GETARG_POINTER(0);
 448         WORKSTATE       state;
 449         int4            i;
 450         QUERYTYPE  *query;
 451         int4            commonlen;
 452         ITEM       *ptr;
 453         NODE       *tmp;
 454         int4            pos = 0;
 455
 456 #ifdef BS_DEBUG
 457         StringInfoData pbuf;
 458 #endif
 459
 460         state.buf = buf;
 461         state.state = WAITOPERAND;
 462         state.count = 0;
 463         state.num = 0;
 464         state.str = NULL;
 465
 466         /* make polish notation (postfix, but in reverse order) */
 467         makepol(&state);
 468         if (!state.num)
 469                 ereport(ERROR,
 470                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 471                                  errmsg("empty query")));
 472
 473         commonlen = COMPUTESIZE(state.num);
 474         query = (QUERYTYPE *) palloc(commonlen);
 475         SET_VARSIZE(query, commonlen);
 476         query->size = state.num;
 477         ptr = GETQUERY(query);
 478
 479         for (i = state.num - 1; i >= 0; i--)
 480         {
 481                 ptr[i].type = state.str->type;
 482                 ptr[i].val = state.str->val;
 483                 tmp = state.str->next;
 484                 pfree(state.str);
 485                 state.str = tmp;
 486         }
 487
 488         pos = query->size - 1;
 489         findoprnd(ptr, &pos);
 490 #ifdef BS_DEBUG
 491         initStringInfo(&pbuf);
 492         for (i = 0; i < query->size; i++)
 493         {
 494                 if (ptr[i].type == OPR)
 495                         appendStringInfo(&pbuf, "%c(%d) ", ptr[i].val, ptr[i].left);
 496                 else
 497                         appendStringInfo(&pbuf, "%d ", ptr[i].val);
 498         }
 499         elog(DEBUG3, "POR: %s", pbuf.data);
 500         pfree(pbuf.data);
 501 #endif
 502
 503         PG_RETURN_POINTER(query);
 504 }
 505
 506
 507 /*
 508  * out function
 509  */
 510 typedef struct
 511 {
 512         ITEM       *curpol;
 513         char       *buf;
 514         char       *cur;
 515         int4            buflen;
 516 } INFIX;
 517
 518 #define RESIZEBUF(inf,addsize) while( ( (inf)->cur - (inf)->buf ) + (addsize) + 1 >= (inf)->buflen ) { \
 519         int4 len = inf->cur - inf->buf; \
 520         inf->buflen *= 2; \
 521         inf->buf = (char*) repalloc( (void*)inf->buf, inf->buflen ); \
 522         inf->cur = inf->buf + len; \
 523 }
 524
 525 static void
 526 infix(INFIX *in, bool first)
 527 {
 528         if (in->curpol->type == VAL)
 529         {
 530                 RESIZEBUF(in, 11);
 531                 sprintf(in->cur, "%d", in->curpol->val);
 532                 in->cur = strchr(in->cur, '\0');
 533                 in->curpol--;
 534         }
 535         else if (in->curpol->val == (int4) '!')
 536         {
 537                 bool            isopr = false;
 538
 539                 RESIZEBUF(in, 1);
 540                 *(in->cur) = '!';
 541                 in->cur++;
 542                 *(in->cur) = '\0';
 543                 in->curpol--;
 544                 if (in->curpol->type == OPR)
 545                 {
 546                         isopr = true;
 547                         RESIZEBUF(in, 2);
 548                         sprintf(in->cur, "( ");
 549                         in->cur = strchr(in->cur, '\0');
 550                 }
 551                 infix(in, isopr);
 552                 if (isopr)
 553                 {
 554                         RESIZEBUF(in, 2);
 555                         sprintf(in->cur, " )");
 556                         in->cur = strchr(in->cur, '\0');
 557                 }
 558         }
 559         else
 560         {
 561                 int4            op = in->curpol->val;
 562                 INFIX           nrm;
 563
 564                 in->curpol--;
 565                 if (op == (int4) '|' && !first)
 566                 {
 567                         RESIZEBUF(in, 2);
 568                         sprintf(in->cur, "( ");
 569                         in->cur = strchr(in->cur, '\0');
 570                 }
 571
 572                 nrm.curpol = in->curpol;
 573                 nrm.buflen = 16;
 574                 nrm.cur = nrm.buf = (char *) palloc(sizeof(char) * nrm.buflen);
 575
 576                 /* get right operand */
 577                 infix(&nrm, false);
 578
 579                 /* get & print left operand */
 580                 in->curpol = nrm.curpol;
 581                 infix(in, false);
 582
 583                 /* print operator & right operand */
 584                 RESIZEBUF(in, 3 + (nrm.cur - nrm.buf));
 585                 sprintf(in->cur, " %c %s", op, nrm.buf);
 586                 in->cur = strchr(in->cur, '\0');
 587                 pfree(nrm.buf);
 588
 589                 if (op == (int4) '|' && !first)
 590                 {
 591                         RESIZEBUF(in, 2);
 592                         sprintf(in->cur, " )");
 593                         in->cur = strchr(in->cur, '\0');
 594                 }
 595         }
 596 }
 597
 598
 599 Datum
 600 bqarr_out(PG_FUNCTION_ARGS)
 601 {
 602         QUERYTYPE  *query = (QUERYTYPE *) PG_DETOAST_DATUM(PG_GETARG_POINTER(0));
 603         INFIX           nrm;
 604
 605         if (query->size == 0)
 606                 ereport(ERROR,
 607                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 608                                  errmsg("empty query")));
 609
 610         nrm.curpol = GETQUERY(query) + query->size - 1;
 611         nrm.buflen = 32;
 612         nrm.cur = nrm.buf = (char *) palloc(sizeof(char) * nrm.buflen);
 613         *(nrm.cur) = '\0';
 614         infix(&nrm, true);
 615
 616         PG_FREE_IF_COPY(query, 0);
 617         PG_RETURN_POINTER(nrm.buf);
 618 }
 619
 620 static int4
 621 countdroptree(ITEM * q, int4 pos)
 622 {
 623         if (q[pos].type == VAL)
 624                 return 1;
 625         else if (q[pos].val == (int4) '!')
 626                 return 1 + countdroptree(q, pos - 1);
 627         else
 628                 return 1 + countdroptree(q, pos - 1) + countdroptree(q, pos + q[pos].left);
 629 }
 630
 631 /*
 632  * common algorithm:
 633  * result of all '!' will be = 'true', so
 634  * we can modify query tree for clearing
 635  */
 636 int4
 637 shorterquery(ITEM * q, int4 len)
 638 {
 639         int4            index,
 640                                 posnot,
 641                                 poscor;
 642         bool            notisleft = false;
 643         int4            drop,
 644                                 i;
 645
 646         /* out all '!' */
 647         do
 648         {
 649                 index = 0;
 650                 drop = 0;
 651                 /* find ! */
 652                 for (posnot = 0; posnot < len; posnot++)
 653                         if (q[posnot].type == OPR && q[posnot].val == (int4) '!')
 654                         {
 655                                 index = 1;
 656                                 break;
 657                         }
 658
 659                 if (posnot == len)
 660                         return len;
 661
 662                 /* last operator is ! */
 663                 if (posnot == len - 1)
 664                         return 0;
 665
 666                 /* find operator for this operand */
 667                 for (poscor = posnot + 1; poscor < len; poscor++)
 668                 {
 669                         if (q[poscor].type == OPR)
 670                         {
 671                                 if (poscor == posnot + 1)
 672                                 {
 673                                         notisleft = false;
 674                                         break;
 675                                 }
 676                                 else if (q[poscor].left + poscor == posnot)
 677                                 {
 678                                         notisleft = true;
 679                                         break;
 680                                 }
 681                         }
 682                 }
 683                 if (q[poscor].val == (int4) '!')
 684                 {
 685                         drop = countdroptree(q, poscor);
 686                         q[poscor - 1].type = VAL;
 687                         for (i = poscor + 1; i < len; i++)
 688                                 if (q[i].type == OPR && q[i].left + i <= poscor)
 689                                         q[i].left += drop - 2;
 690                         memcpy((void *) &q[poscor - drop + 1],
 691                                    (void *) &q[poscor - 1],
 692                                    sizeof(ITEM) * (len - (poscor - 1)));
 693                         len -= drop - 2;
 694                 }
 695                 else if (q[poscor].val == (int4) '|')
 696                 {
 697                         drop = countdroptree(q, poscor);
 698                         q[poscor - 1].type = VAL;
 699                         q[poscor].val = (int4) '!';
 700                         q[poscor].left = -1;
 701                         for (i = poscor + 1; i < len; i++)
 702                                 if (q[i].type == OPR && q[i].left + i < poscor)
 703                                         q[i].left += drop - 2;
 704                         memcpy((void *) &q[poscor - drop + 1],
 705                                    (void *) &q[poscor - 1],
 706                                    sizeof(ITEM) * (len - (poscor - 1)));
 707                         len -= drop - 2;
 708                 }
 709                 else
 710                 {                                               /* &-operator */
 711                         if (
 712                                 (notisleft && q[poscor - 1].type == OPR &&
 713                                  q[poscor - 1].val == (int4) '!') ||
 714                                 (!notisleft && q[poscor + q[poscor].left].type == OPR &&
 715                                  q[poscor + q[poscor].left].val == (int4) '!')
 716                                 )
 717                         {                                       /* drop subtree */
 718                                 drop = countdroptree(q, poscor);
 719                                 q[poscor - 1].type = VAL;
 720                                 q[poscor].val = (int4) '!';
 721                                 q[poscor].left = -1;
 722                                 for (i = poscor + 1; i < len; i++)
 723                                         if (q[i].type == OPR && q[i].left + i < poscor)
 724                                                 q[i].left += drop - 2;
 725                                 memcpy((void *) &q[poscor - drop + 1],
 726                                            (void *) &q[poscor - 1],
 727                                            sizeof(ITEM) * (len - (poscor - 1)));
 728                                 len -= drop - 2;
 729                         }
 730                         else
 731                         {                                       /* drop only operator */
 732                                 int4            subtreepos = (notisleft) ?
 733                                 poscor - 1 : poscor + q[poscor].left;
 734                                 int4            subtreelen = countdroptree(q, subtreepos);
 735
 736                                 drop = countdroptree(q, poscor);
 737                                 for (i = poscor + 1; i < len; i++)
 738                                         if (q[i].type == OPR && q[i].left + i < poscor)
 739                                                 q[i].left += drop - subtreelen;
 740                                 memcpy((void *) &q[subtreepos + 1],
 741                                            (void *) &q[poscor + 1],
 742                                            sizeof(ITEM) * (len - (poscor - 1)));
 743                                 memcpy((void *) &q[poscor - drop + 1],
 744                                            (void *) &q[subtreepos - subtreelen + 1],
 745                                            sizeof(ITEM) * (len - (drop - subtreelen)));
 746                                 len -= drop - subtreelen;
 747                         }
 748                 }
 749         } while (index);
 750         return len;
 751 }
 752
 753
 754 Datum
 755 querytree(PG_FUNCTION_ARGS)
 756 {
 757         QUERYTYPE  *query = (QUERYTYPE *) PG_DETOAST_DATUM(PG_GETARG_POINTER(0));
 758         INFIX           nrm;
 759         text       *res;
 760         ITEM       *q;
 761         int4            len;
 762
 763         if (query->size == 0)
 764                 ereport(ERROR,
 765                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 766                                  errmsg("empty query")));
 767
 768         q = (ITEM *) palloc(sizeof(ITEM) * query->size);
 769         memcpy((void *) q, GETQUERY(query), sizeof(ITEM) * query->size);
 770         len = shorterquery(q, query->size);
 771         PG_FREE_IF_COPY(query, 0);
 772
 773         if (len == 0)
 774         {
 775                 res = cstring_to_text("T");
 776         }
 777         else
 778         {
 779                 nrm.curpol = q + len - 1;
 780                 nrm.buflen = 32;
 781                 nrm.cur = nrm.buf = (char *) palloc(sizeof(char) * nrm.buflen);
 782                 *(nrm.cur) = '\0';
 783                 infix(&nrm, true);
 784                 res = cstring_to_text_with_len(nrm.buf, nrm.cur - nrm.buf);
 785         }
 786         pfree(q);
 787
 788         PG_RETURN_TEXT_P(res);
 789 }