parser.c

   1 #include <malloc.h>
   2 #include <math.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5
   6 #include "debug.h"
   7
   8 #include "parser.h"
   9
  10 /* global variables */
  11
  12 double answer = 0;
  13
  14 #define STORAGE_SIZE 10
  15 double storage[STORAGE_SIZE] = {0};
  16
  17 /* compare codes */
  18
  19 int codecmp (char *ref, char *str)
  20 {
  21     int sig;
  22
  23     while (*ref != '\0') {
  24         if (*ref == '\t') {
  25              sig = (*str == '.') ? -1 : ((*str >= '0') && (*str <= '9'));
  26         } else {
  27             sig = *str - *ref;
  28         }
  29         if (sig != 0) {
  30             return (sig > 0) ? 1 : -1;
  31         }
  32         str++;
  33         ref++;
  34     }
  35
  36     return 0;
  37 }
  38
  39 /* allocate new element */
  40
  41 element_t *newelement (func_t function, int nbops, int prio)
  42 {
  43     element_t *new = (element_t *) calloc (1, sizeof (element_t));
  44     if (new == NULL) {
  45         VERBOSE (ERROR, fprintf (stderr, "can't allocate memory\n"));
  46         return NULL;
  47     }
  48     new->func = function;
  49     new->nbops = nbops;
  50     new->prio = prio;
  51
  52     return new;
  53 }
  54
  55 /* desallocate element */
  56
  57 void delelement (element_t *root)
  58 {
  59     int i;
  60     if ((root != NULL) && (root != ERROR_OP)) {
  61         for (i = 0; i < root->nbops; i++) {
  62             if ((root->ops[i] != NULL) && (root->ops[i] != ERROR_OP)) {
  63                 delelement (root->ops[i]);
  64             }
  65         }
  66         free (root);
  67     }
  68 }
  69
  70 /* duplicate element */
  71
  72 element_t *dupelement (element_t *root)
  73 {
  74     element_t *tmp = NULL;
  75     int i;
  76
  77     if ((root == NULL) || (root == ERROR_OP)) {
  78         return root;
  79     }
  80     tmp = newelement (root->func, root->nbops, root->prio);
  81     if (tmp == NULL) {
  82         return ERROR_OP;
  83     }
  84     tmp->value = root->value;
  85     for (i = 0; i < root->nbops; i++) {
  86         tmp->ops[i] = dupelement (root->ops[i]);
  87         if (tmp->ops[i] == ERROR_OP) {
  88             delelement (tmp);
  89             return ERROR_OP;
  90         }
  91     }
  92     return tmp;
  93 }
  94
  95 /* functions */
  96
  97 #define NB_OPERATORS 14
  98 keyword_t operators[NB_OPERATORS] = {
  99     { "+\t", Add, 2, 1, 1},
 100     { "-\t", Sub, 2, 1, 1},
 101     { "*",   Mul, 2, 1, 2},
 102     { "/",   Div, 2, 1, 2},
 103     { "%",   Mod, 2, 1, 3},
 104     { "^",   Pow, 2, 1, 4},
 105     { "==",  Equal, 2, 2, -1},
 106     { "!=",  Diff, 2, 2, -1},
 107     { ">=",  Ge, 2, 2, -1},
 108     { "<=",  Le, 2, 2, -1},
 109     { ">",   Gt, 2, 1, -1},
 110     { "<",   Lt, 2, 1, -1},
 111     { "&",   And, 2, 1, -2},
 112     { "|",   Or, 2, 1, -2}
 113 };
 114
 115 #define NB_FUNCTIONS 17
 116 keyword_t functions[NB_FUNCTIONS] = {
 117     { "sqrt", Sqr, 1, 4, 5},
 118     { "pow",  Pow, 2, 3, 5},
 119     { "cos",  Cos, 1, 3, 5},
 120     { "sin",  Sin, 1, 3, 5},
 121     { "atan", Atan, 1, 4, 5},
 122     { "exp",  Exp, 1, 3, 5},
 123     { "log",  Log, 1, 3, 5},
 124     { "sto",  Store, 2, 3, 5},
 125     { "rcl",  Recall, 1, 3, 5},
 126     { "inc",  Inc, 1, 3, 5},
 127     { "dec",  Dec, 1, 3, 5},
 128     { "disp", Disp, 0, 4, 9},
 129     { "quit", Quit, 0, 4, 9},
 130     { "help", Help, 0, 4, 9},
 131     { "!",    Not, 1, 1, 6},
 132     { "cond", Cond, 3, 4, 5},
 133     { "whl",  While, 2, 3, 5}
 134 };
 135
 136 #define NB_CONSTANTS 3
 137 keyword_t constants[NB_CONSTANTS] = {
 138     { "ans", Ans, 0, 3, 5},
 139     { "e",   E, 0, 1, 5},
 140     { "pi",  Pi, 0, 2, 5}
 141 };
 142
 143 /* subparser function */
 144
 145 element_t *subparser (element_t **proot, char **pstr, func_t func, int nbops, int prio)
 146 {
 147     element_t *new = newelement (func, nbops, prio);
 148     if (new == NULL) {
 149         return ERROR_OP;
 150     }
 151     new->ops[0] = *proot;
 152     new->ops[1] = parser (*pstr, pstr, new->prio);
 153     if ((new->ops[1] == NULL) || ((new->ops[1] != ERROR_OP) && (new->ops[1]->prio == 9))) {
 154         delelement (new->ops[1]);
 155         new->ops[1] = ERROR_OP;
 156     }
 157     if (new->ops[1] == ERROR_OP) {
 158         delelement (new);
 159         *proot = NULL;
 160         return ERROR_OP;
 161     }
 162     *proot = newelement (Val, 1, 5);
 163     if (*proot == NULL) {
 164         delelement (new);
 165         return ERROR_OP;
 166     }
 167     (*proot)->ops[0] = new;
 168
 169     return *proot;
 170 }
 171
 172 /* parser function */
 173
 174 element_t *parser (char *str, char **next, int prio)
 175 {
 176     element_t *root = NULL;
 177     int i;
 178
 179     VERBOSE (DEBUG, fprintf (stdout, "Starting parsing\n"));
 180
 181     /* main loop */
 182     while (*str != '\0') {
 183         int found = 0;
 184         element_t *new = NULL;
 185         VERBOSE (INFO, fprintf (stdout, "Processing: %s\n", str));
 186
 187         /* skip spaces and tabs */
 188
 189         if ((*str == ' ') || (*str == '\t')) {
 190             str++;
 191             continue;
 192         }
 193
 194         /* check for open bracket */
 195
 196         if (*str == '(') {
 197             VERBOSE (DEBUG, fprintf (stdout, "start processing bracket\n"));
 198             if (root) {
 199                 do {
 200                     found = 0;
 201                     new = parser (str + 1, &str, 0);
 202                     if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 203                         delelement (new);
 204                         new = ERROR_OP;
 205                     }
 206                     if ((new == NULL) || (new == ERROR_OP)) {
 207                         delelement (root);
 208                         return ERROR_OP;
 209                     }
 210                     for (i = 0; i < root->nbops; i++) {
 211                         if (root->ops[i] == NULL) {
 212                             root->ops[i] = new;
 213                             found = 1;
 214                             break;
 215                         }
 216                     }
 217                     if (!found) {
 218                         delelement (new);
 219                         delelement (root);
 220                         return ERROR_OP;
 221                     }
 222                 } while (*str == ',');
 223             } else {
 224                 root = newelement (Val, 1, 5);
 225                 if (root == NULL) {
 226                     return ERROR_OP;
 227                 }
 228                 new = parser (str + 1, &str, 0);
 229                 if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 230                     delelement (new);
 231                     new = ERROR_OP;
 232                 }
 233                 if ((new == NULL) || (new == ERROR_OP) || (*str == ',')) {
 234                     delelement (new);
 235                     delelement (root);
 236                     return ERROR_OP;
 237                 }
 238                 root->ops[0] = new;
 239             }
 240             if (*str != ')') {
 241                 delelement (root);
 242                 return ERROR_OP;
 243             }
 244             str++;
 245             VERBOSE (DEBUG, fprintf (stdout, "stop processing bracket\n"));
 246             continue;
 247         }
 248
 249         /* check for closing bracket or koma */
 250
 251         if ((*str == ')') || (*str == ',')) {
 252             if (next != NULL) {
 253                 *next = str;
 254             }
 255             return root;
 256         }
 257
 258         /* look for operators */
 259
 260         for (i = 0; i < NB_OPERATORS; i++) {
 261             keyword_t *operator = operators + i;
 262             if (codecmp (operator->keyword, str) == 0) {
 263                 VERBOSE (DEBUG, fprintf (stdout, "start processing operator\n"));
 264                 if (root) {
 265                     if ((prio) && (prio > operator->prio)) {
 266                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 267                         *next = str;
 268                         return root;
 269                     }
 270                     str += operator->offset;
 271                     VERBOSE (INFO, fprintf (stdout, "Oper: %d\n", operator->func));
 272                     if (subparser (&root, &str, operator->func, operator->nbops, operator->prio) == ERROR_OP) {
 273                         delelement (root);
 274                         return ERROR_OP;
 275                     }
 276                 } else if (*str == '-') {
 277                     new = newelement (Sig, 1, 9);
 278                     if (new == NULL) {
 279                         return ERROR_OP;
 280                     }
 281                     root = new;
 282                 } else {
 283                     return ERROR_OP;
 284                 }
 285                 found = 1;
 286                 VERBOSE (DEBUG, fprintf (stdout, "stop processing operator\n"));
 287                 break;
 288             }
 289         }
 290         if (found) {
 291             continue;
 292         }
 293
 294         /* look for functions */
 295
 296         for (i = 0; i < NB_FUNCTIONS; i++) {
 297             keyword_t *function = functions + i;
 298             if (codecmp (function->keyword, str) == 0) {
 299                 VERBOSE (DEBUG, fprintf (stdout, "start processing function\n"));
 300                 if (root == NULL) {
 301                     VERBOSE (INFO, fprintf (stdout, "Func: %d\n", function->func));
 302                     new = newelement (function->func, function->nbops, function->prio);
 303                     if (new == NULL) {
 304                         return ERROR_OP;
 305                     }
 306                     root = new;
 307                 } else {
 308                     delelement (root);
 309                     return ERROR_OP;
 310                 }
 311                 str += function->offset;
 312                 found = 1;
 313                 VERBOSE (DEBUG, fprintf (stdout, "stop processing function\n"));
 314                 break;
 315             }
 316         }
 317         if (found) {
 318             continue;
 319         }
 320
 321         /* look for constant */
 322
 323         for (i = 0; i < NB_CONSTANTS; i++) {
 324             keyword_t *constant = constants + i;
 325             if (codecmp (constant->keyword, str) == 0) {
 326                 VERBOSE (DEBUG, fprintf (stdout, "start processing constant\n"));
 327                 if (root == NULL) {
 328                     VERBOSE (INFO, fprintf (stdout, "Const: %d\n", constant->func));
 329                     new = newelement (constant->func, constant->nbops, constant->prio);
 330                     if (new == NULL) {
 331                         return ERROR_OP;
 332                     }
 333                     root = new;
 334                 } else {
 335                     delelement (root);
 336                     return ERROR_OP;
 337                 }
 338                 str += constant->offset;
 339                 found = 1;
 340                 VERBOSE (DEBUG, fprintf (stdout, "stop processing constant\n"));
 341                 break;
 342             }
 343         }
 344         if (found) {
 345             continue;
 346         }
 347
 348         /* look for number */
 349
 350         if (((*str >= '0') && (*str <= '9')) ||
 351             (*str == '.') || (*str == '+') || (*str == '-')) {
 352             VERBOSE (DEBUG, fprintf (stdout, "start processing value\n"));
 353             char *pt;
 354             double value = strtod (str, &pt);
 355             VERBOSE (INFO, fprintf (stdout, "Value: %f\n", value));
 356             if (str != pt) {
 357                 if ((root == NULL) || (root->prio == 6)) {
 358                     new = newelement (Val, 1, 5);
 359                     if (new == NULL) {
 360                         return ERROR_OP;
 361                     }
 362                     new->value = value;
 363                     if (root == NULL) {
 364                         root = new;
 365                     } else {
 366                         for (i = 0; i < root->nbops; i++) {
 367                             if (root->ops[i] == NULL) {
 368                                 root->ops[i] = new;
 369                                 found = 1;
 370                                 break;
 371                             }
 372                         }
 373                         if (!found) {
 374                             delelement (new);
 375                             delelement (root);
 376                             return ERROR_OP;
 377                         }
 378                     }
 379                     str = pt;
 380                 } else if ((*str == '+') || (*str == '-')) {
 381                     if ((prio) && (prio > 1)) {
 382                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 383                         *next = str;
 384                         return root;
 385                     }
 386                     if (subparser (&root, &str, Add, 2, 1) == ERROR_OP) {
 387                         delelement (root);
 388                         return ERROR_OP;
 389                     }
 390                 } else {
 391                     delelement (root);
 392                     return ERROR_OP;
 393                 }
 394                 found = 1;
 395             }
 396             VERBOSE (DEBUG, fprintf (stdout, "stop processing value\n"));
 397         }
 398
 399         /* error */
 400
 401         if (!found) {
 402             delelement (root);
 403             return ERROR_OP;
 404         }
 405
 406     }
 407
 408     if (next != NULL) {
 409         *next = str;
 410     }
 411
 412     return root;
 413 }
 414
 415 /* print element tree */
 416
 417 void print_element (element_t *root, int level)
 418 {
 419     char *func = NULL;
 420     int i;
 421
 422     if ((root == NULL) || (root == ERROR_OP)) {
 423         return;
 424     }
 425
 426     for (i = 0; i < level; i++) {
 427         fprintf (stdout, " ");
 428     }
 429
 430     switch (root->func) {
 431     case Val: func = "Value"; break;
 432     case Sig: func = "Sign"; break;
 433     case Add: func = "Addition"; break;
 434     case Sub: func = "Subtraction"; break;
 435     case Mul: func = "Multiplication"; break;
 436     case Div: func = "Division"; break;
 437     case Mod: func = "Modulo"; break;
 438     case Pow: func = "Power"; break;
 439     case Sqr: func = "Square Root"; break;
 440     case Cos: func = "Cosine"; break;
 441     case Sin: func = "Sine"; break;
 442     case Atan: func = "Arc Tangent"; break;
 443     case Log: func = "Logarithm"; break;
 444     case Exp: func = "Exponantial"; break;
 445     case Store: func = "Store"; break;
 446     case Recall: func = "Recall"; break;
 447     case Inc: func = "Increase"; break;
 448     case Dec: func = "Decrease"; break;
 449     case Disp: func = "Display"; break;
 450     case Quit: func = "Quit"; break;
 451     case Help: func = "Help"; break;
 452     case Ans: func = "Ans"; break;
 453     case Pi: func = "Pi"; break;
 454     case E: func = "E"; break;
 455     case Equal: func = "Equal"; break;
 456     case Diff: func = "Different"; break;
 457     case Ge: func = "Greater or equal"; break;
 458     case Le: func = "Lesser or equal"; break;
 459     case Gt: func = "Greater"; break;
 460     case Lt: func = "Lesser"; break;
 461     case And: func = "And"; break;
 462     case Or: func = "Or"; break;
 463     case Not: func = "Not"; break;
 464     case Cond: func = "Condition"; break;
 465     case While: func = "While"; break;
 466     }
 467
 468     fprintf (stdout, "Function: %s\n", func);
 469
 470     if ((root->func == Val) && (root->ops[0] == NULL)) {
 471         for (i = 0; i < level; i++) {
 472             fprintf (stdout, " ");
 473         }
 474         fprintf (stdout, "value: %f\n", root->value);
 475     } else {
 476         for (i = 0; i < root->nbops; i++) {
 477             print_element (root->ops[i], level + 1);
 478         }
 479     }
 480 }
 481
 482 /* storage functions */
 483
 484 double store (int index, double value)
 485 {
 486     if ((index > 0) && (index <= STORAGE_SIZE)) {
 487         storage[index - 1] = value;
 488     } else {
 489         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 490     }
 491     return value;
 492 }
 493
 494 double recall (int index)
 495 {
 496     if ((index > 0) && (index <= STORAGE_SIZE)) {
 497         return storage[index - 1];
 498     } else {
 499         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 500     }
 501     return 0;
 502 }
 503
 504 double increase (int index)
 505 {
 506     if ((index > 0) && (index <= STORAGE_SIZE)) {
 507         return storage[index - 1]++;
 508     } else {
 509         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 510     }
 511     return 0;
 512 }
 513
 514 double decrease (int index)
 515 {
 516     if ((index > 0) && (index <= STORAGE_SIZE)) {
 517         return storage[index - 1]--;
 518     } else {
 519         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 520     }
 521     return 0;
 522 }
 523
 524 void display (void)
 525 {
 526     int i;
 527     fprintf (stdout, "storage:");
 528     for (i = 0; i < STORAGE_SIZE; i++) {
 529         fprintf (stdout, " %g", storage[i]);
 530     }
 531     fprintf (stdout, "\n");
 532 }
 533
 534 /* While do function */
 535
 536 double while_do (element_t *cond, element_t *action)
 537 {
 538     double ret = 0;
 539     element_t *temp = NULL;
 540
 541     VERBOSE (DEBUG, fprintf (stdout, "starting while loop\n"));
 542     if (cond == NULL) {
 543         return ret;
 544     }
 545     while (1) {
 546         VERBOSE (DEBUG, fprintf (stdout, "loop...\n"));
 547
 548         temp = dupelement (cond);
 549         if (!evaluate_element (temp, 0)) {
 550             break;
 551         }
 552         if (action) {
 553             temp = dupelement (action);
 554             ret = evaluate_element (temp, 0);
 555         }
 556     }
 557
 558     VERBOSE (DEBUG, fprintf (stdout, "ending while loop\n"));
 559
 560     return ret;
 561 }
 562
 563 /* quit function */
 564
 565 void quit (void)
 566 {
 567     fprintf (stdout, "bye\n");
 568     exit (0);
 569 }
 570
 571 /* help message */
 572
 573 void help (void)
 574 {
 575     fprintf (stdout, "calc is a simple calculator\n\n");
 576     fprintf (stdout, "supported operators:");
 577     fprintf (stdout, " + - * / %% ^\n");
 578     fprintf (stdout, "camparison operators:");
 579     fprintf (stdout, " == != >= <= > <\n");
 580     fprintf (stdout, "logical operators:");
 581     fprintf (stdout, " & | !\n");
 582     fprintf (stdout, "supported functions:");
 583     fprintf (stdout, " pow sqrt cos sin atan log exp\n");
 584     fprintf (stdout, "storage functions:");
 585     fprintf (stdout, " sto rcl inc dec\n");
 586     fprintf (stdout, "conditional functions:");
 587     fprintf (stdout, " cond\n");
 588     fprintf (stdout, "miscellaneous functions:");
 589     fprintf (stdout, " quit help\n");
 590     fprintf (stdout, "supported constants:");
 591     fprintf (stdout, " e pi\n");
 592 }
 593
 594 /* evaluate element tree */
 595
 596 #define MASK_SUB 0x1
 597 #define MASK_DIV 0x2
 598
 599 double evaluate_element (element_t *root, char mask)
 600 {
 601     double op0 = 0, op1 = 0;
 602     char nextmask = mask;
 603
 604     if ((root == NULL) || (root == ERROR_OP)) {
 605         VERBOSE (WARNING, fprintf (stdout, "error while evaluating\n"));
 606         return 0;
 607     }
 608
 609     /* mask to manage sub operator sub and div */
 610     switch (root->func) {
 611     case Add:
 612         nextmask &= ~MASK_SUB;
 613         nextmask &= ~MASK_DIV;
 614         break;
 615     case Sub:
 616         nextmask |= MASK_SUB;
 617         nextmask &= ~MASK_DIV;
 618         break;
 619     case Mul:
 620         nextmask &= ~MASK_DIV;
 621         break;
 622     case Div:
 623         nextmask |= MASK_DIV;
 624         break;
 625     default:
 626         nextmask = mask;
 627     }
 628
 629     switch (root->func) {
 630     case Val:
 631     case Sig:
 632         op0 = (root->ops[0]) ? evaluate_element (root->ops[0], nextmask) : root->value;
 633         break;
 634     case Add:
 635     case Sub:
 636     case Mul:
 637     case Div:
 638     case Mod:
 639     case Pow:
 640     case Store:
 641     case Equal:
 642     case Diff:
 643     case Ge:
 644     case Le:
 645     case Gt:
 646     case Lt:
 647     case And:
 648     case Or:
 649         if (root->ops[1]) {
 650             op1 = evaluate_element (root->ops[1], nextmask);
 651         } else if (root->func != Store) {
 652             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[1])\n"));
 653             return 0;
 654         }
 655         /* fallthrough */
 656     case Sqr:
 657     case Cos:
 658     case Sin:
 659     case Atan:
 660     case Log:
 661     case Exp:
 662     case Recall:
 663     case Inc:
 664     case Dec:
 665     case Not:
 666     case Cond:
 667         if (root->ops[0]) {
 668             op0 = evaluate_element (root->ops[0], 0);
 669         } else {
 670             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[0])\n"));
 671             return 0;
 672         }
 673         break;
 674     case Disp:
 675     case Quit:
 676     case Help:
 677     case Ans:
 678     case Pi:
 679     case E:
 680     case While:
 681         break;
 682     }
 683
 684     switch (root->func) {
 685     case Val: return op0;
 686     case Sig: return -op0;
 687     case Add: return ((mask & MASK_SUB) == 0) ? op0 + op1 : op0 - op1;
 688     case Sub: return ((mask & MASK_SUB) == 0) ? op0 - op1 : op0 + op1;
 689     case Mul: return ((mask & MASK_DIV) == 0) ? op0 * op1 : op0 / op1;
 690     case Div: return ((mask & MASK_DIV) == 0) ? op0 / op1 : op0 * op1;
 691     case Mod: return fmod (op0, op1);
 692     case Pow: return pow (op0, op1);
 693     case Sqr: return sqrt (op0);
 694     case Cos: return cos (op0);
 695     case Sin: return sin (op0);
 696     case Atan: return atan (op0);
 697     case Log: return log (op0);
 698     case Exp: return exp (op0);
 699     case Store: return store ((int)op0, (op1) ? op1 : answer);
 700     case Recall: return recall ((int)op0);
 701     case Inc: return increase ((int)op0);
 702     case Dec: return decrease ((int)op0);
 703     case Disp: display (); break;
 704     case Quit: quit (); break;
 705     case Help: help (); break;
 706     case Ans: return answer;
 707     case Pi: return M_PI;
 708     case E: return M_E;
 709     case Equal: return op0 == op1;
 710     case Diff: return op0 != op1;
 711     case Ge: return op0 >= op1;
 712     case Le: return op0 <= op1;
 713     case Gt: return op0 > op1;
 714     case Lt: return op0 < op1;
 715     case And: return (op0 != 0) && (op1 != 0);
 716     case Or: return (op0 != 0) || (op1 != 0);
 717     case Not: return (op0 == 0);
 718     case Cond:
 719         if ((op0) && (root->ops[1])) {
 720             return evaluate_element (root->ops[1], 0);
 721         } else if ((!op0) && (root->ops[2])) {
 722             return evaluate_element (root->ops[2], 0);
 723         } else {
 724             return 0;
 725         }
 726     case While: return while_do (root->ops[0], root->ops[1]);
 727     }
 728
 729     return 0;
 730 }
 731
 732 /* vim: set ts=4 sw=4 et: */