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