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 13
  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     { "disp", Disp, 0, 4, 9},
 102     { "quit", Quit, 0, 4, 9},
 103     { "help", Help, 0, 4, 9},
 104     { "!",    Not, 1, 1, 6}
 105 };
 106
 107 #define NB_CONSTANTS 3
 108 keyword_t constants[NB_CONSTANTS] = {
 109     { "ans", Ans, 0, 3, 5},
 110     { "e",   E, 0, 1, 5},
 111     { "pi",  Pi, 0, 2, 5}
 112 };
 113
 114 /* subparser function */
 115
 116 element_t *subparser (element_t **proot, char **pstr, func_t func, int nbops, int prio)
 117 {
 118     element_t *new = newelement (func, nbops, prio);
 119     if (new == NULL) {
 120         return ERROR_OP;
 121     }
 122     new->ops[0] = *proot;
 123     new->ops[1] = parser (*pstr, pstr, new->prio);
 124     if ((new->ops[1] == NULL) || ((new->ops[1] != ERROR_OP) && (new->ops[1]->prio == 9))) {
 125         delelement (new->ops[1]);
 126         new->ops[1] = ERROR_OP;
 127     }
 128     if (new->ops[1] == ERROR_OP) {
 129         delelement (new);
 130         *proot = NULL;
 131         return ERROR_OP;
 132     }
 133     *proot = newelement (Val, 1, 5);
 134     if (*proot == NULL) {
 135         delelement (new);
 136         return ERROR_OP;
 137     }
 138     (*proot)->ops[0] = new;
 139
 140     return *proot;
 141 }
 142
 143 /* parser function */
 144
 145 element_t *parser (char *str, char **next, int prio)
 146 {
 147     element_t *root = NULL;
 148     int i;
 149
 150     VERBOSE (DEBUG, fprintf (stdout, "Starting parsing\n"));
 151
 152     /* main loop */
 153     while (*str != '\0') {
 154         int found = 0;
 155         element_t *new = NULL;
 156         VERBOSE (INFO, fprintf (stdout, "Processing: %s\n", str));
 157
 158         /* skip spaces and tabs */
 159
 160         if ((*str == ' ') || (*str == '\t')) {
 161             str++;
 162             continue;
 163         }
 164
 165         /* check for open bracket */
 166
 167         if (*str == '(') {
 168             VERBOSE (DEBUG, fprintf (stdout, "start processing bracket\n"));
 169             if (root) {
 170                 do {
 171                     found = 0;
 172                     new = parser (str + 1, &str, 0);
 173                     if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 174                         delelement (new);
 175                         new = ERROR_OP;
 176                     }
 177                     if ((new == NULL) || (new == ERROR_OP)) {
 178                         delelement (root);
 179                         return ERROR_OP;
 180                     }
 181                     for (i = 0; i < root->nbops; i++) {
 182                         if (root->ops[i] == NULL) {
 183                             root->ops[i] = new;
 184                             found = 1;
 185                             break;
 186                         }
 187                     }
 188                     if (!found) {
 189                         delelement (new);
 190                         delelement (root);
 191                         return ERROR_OP;
 192                     }
 193                 } while (*str == ',');
 194             } else {
 195                 root = newelement (Val, 1, 5);
 196                 if (root == NULL) {
 197                     return ERROR_OP;
 198                 }
 199                 new = parser (str + 1, &str, 0);
 200                 if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 201                     delelement (new);
 202                     new = ERROR_OP;
 203                 }
 204                 if ((new == NULL) || (new == ERROR_OP) || (*str == ',')) {
 205                     delelement (new);
 206                     delelement (root);
 207                     return ERROR_OP;
 208                 }
 209                 root->ops[0] = new;
 210             }
 211             if (*str != ')') {
 212                 delelement (root);
 213                 return ERROR_OP;
 214             }
 215             str++;
 216             VERBOSE (DEBUG, fprintf (stdout, "stop processing bracket\n"));
 217             continue;
 218         }
 219
 220         /* check for closing bracket or koma */
 221
 222         if ((*str == ')') || (*str == ',')) {
 223             if (next != NULL) {
 224                 *next = str;
 225             }
 226             return root;
 227         }
 228
 229         /* look for operators */
 230
 231         for (i = 0; i < NB_OPERATORS; i++) {
 232             keyword_t *operator = operators + i;
 233             if (codecmp (operator->keyword, str) == 0) {
 234                 VERBOSE (DEBUG, fprintf (stdout, "start processing operator\n"));
 235                 if (root) {
 236                     if ((prio) && (prio > operator->prio)) {
 237                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 238                         *next = str;
 239                         return root;
 240                     }
 241                     str += operator->offset;
 242                     VERBOSE (INFO, fprintf (stdout, "Oper: %d\n", operator->func));
 243                     if (subparser (&root, &str, operator->func, operator->nbops, operator->prio) == ERROR_OP) {
 244                         delelement (root);
 245                         return ERROR_OP;
 246                     }
 247                 } else if (*str == '-') {
 248                     new = newelement (Sig, 1, 9);
 249                     if (new == NULL) {
 250                         return ERROR_OP;
 251                     }
 252                     root = new;
 253                 } else {
 254                     return ERROR_OP;
 255                 }
 256                 found = 1;
 257                 VERBOSE (DEBUG, fprintf (stdout, "stop processing operator\n"));
 258                 break;
 259             }
 260         }
 261         if (found) {
 262             continue;
 263         }
 264
 265         /* look for functions */
 266
 267         for (i = 0; i < NB_FUNCTIONS; i++) {
 268             keyword_t *function = functions + i;
 269             if (codecmp (function->keyword, str) == 0) {
 270                 VERBOSE (DEBUG, fprintf (stdout, "start processing function\n"));
 271                 if (root == NULL) {
 272                     VERBOSE (INFO, fprintf (stdout, "Func: %d\n", function->func));
 273                     new = newelement (function->func, function->nbops, function->prio);
 274                     if (new == NULL) {
 275                         return ERROR_OP;
 276                     }
 277                     root = new;
 278                 } else {
 279                     delelement (root);
 280                     return ERROR_OP;
 281                 }
 282                 str += function->offset;
 283                 found = 1;
 284                 VERBOSE (DEBUG, fprintf (stdout, "stop processing function\n"));
 285                 break;
 286             }
 287         }
 288         if (found) {
 289             continue;
 290         }
 291
 292         /* look for constant */
 293
 294         for (i = 0; i < NB_CONSTANTS; i++) {
 295             keyword_t *constant = constants + i;
 296             if (codecmp (constant->keyword, str) == 0) {
 297                 VERBOSE (DEBUG, fprintf (stdout, "start processing constant\n"));
 298                 if (root == NULL) {
 299                     VERBOSE (INFO, fprintf (stdout, "Const: %d\n", constant->func));
 300                     new = newelement (constant->func, constant->nbops, constant->prio);
 301                     if (new == NULL) {
 302                         return ERROR_OP;
 303                     }
 304                     root = new;
 305                 } else {
 306                     delelement (root);
 307                     return ERROR_OP;
 308                 }
 309                 str += constant->offset;
 310                 found = 1;
 311                 VERBOSE (DEBUG, fprintf (stdout, "stop processing constant\n"));
 312                 break;
 313             }
 314         }
 315         if (found) {
 316             continue;
 317         }
 318
 319         /* look for number */
 320
 321         if (((*str >= '0') && (*str <= '9')) ||
 322             (*str == '.') || (*str == '+') || (*str == '-')) {
 323             VERBOSE (DEBUG, fprintf (stdout, "start processing value\n"));
 324             char *pt;
 325             double value = strtod (str, &pt);
 326             VERBOSE (INFO, fprintf (stdout, "Value: %f\n", value));
 327             if (str != pt) {
 328                 if ((root == NULL) || (root->prio == 6)) {
 329                     new = newelement (Val, 1, 5);
 330                     if (new == NULL) {
 331                         return ERROR_OP;
 332                     }
 333                     new->value = value;
 334                     if (root == NULL) {
 335                         root = new;
 336                     } else {
 337                         for (i = 0; i < root->nbops; i++) {
 338                             if (root->ops[i] == NULL) {
 339                                 root->ops[i] = new;
 340                                 found = 1;
 341                                 break;
 342                             }
 343                         }
 344                         if (!found) {
 345                             delelement (new);
 346                             delelement (root);
 347                             return ERROR_OP;
 348                         }
 349                     }
 350                     str = pt;
 351                 } else if ((*str == '+') || (*str == '-')) {
 352                     if ((prio) && (prio > 1)) {
 353                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 354                         *next = str;
 355                         return root;
 356                     }
 357                     if (subparser (&root, &str, Add, 2, 1) == ERROR_OP) {
 358                         delelement (root);
 359                         return ERROR_OP;
 360                     }
 361                 } else {
 362                     delelement (root);
 363                     return ERROR_OP;
 364                 }
 365                 found = 1;
 366             }
 367             VERBOSE (DEBUG, fprintf (stdout, "stop processing value\n"));
 368         }
 369
 370         /* error */
 371
 372         if (!found) {
 373             delelement (root);
 374             return ERROR_OP;
 375         }
 376
 377     }
 378
 379     if (next != NULL) {
 380         *next = str;
 381     }
 382
 383     return root;
 384 }
 385
 386 /* print element tree */
 387
 388 void print_element (element_t *root, int level)
 389 {
 390     char *func = NULL;
 391     int i;
 392
 393     if ((root == NULL) || (root == ERROR_OP)) {
 394         return;
 395     }
 396
 397     for (i = 0; i < level; i++) {
 398         fprintf (stdout, " ");
 399     }
 400
 401     switch (root->func) {
 402     case Val: func = "Value"; break;
 403     case Sig: func = "Sign"; break;
 404     case Add: func = "Addition"; break;
 405     case Sub: func = "Subtraction"; break;
 406     case Mul: func = "Multiplication"; break;
 407     case Div: func = "Division"; break;
 408     case Mod: func = "Modulo"; break;
 409     case Pow: func = "Power"; break;
 410     case Sqr: func = "Square Root"; break;
 411     case Cos: func = "Cosine"; break;
 412     case Sin: func = "Sine"; break;
 413     case Atan: func = "Arc Tangent"; break;
 414     case Log: func = "Logarithm"; break;
 415     case Exp: func = "Exponantial"; break;
 416     case Store: func = "Store"; break;
 417     case Recall: func = "Recall"; break;
 418     case Disp: func = "Display"; break;
 419     case Quit: func = "Quit"; break;
 420     case Help: func = "Help"; break;
 421     case Ans: func = "Ans"; break;
 422     case Pi: func = "Pi"; break;
 423     case E: func = "E"; break;
 424     case Equal: func = "Equal"; break;
 425     case Diff: func = "Different"; break;
 426     case Ge: func = "Greater or equal"; break;
 427     case Le: func = "Lesser or equal"; break;
 428     case Gt: func = "Greater"; break;
 429     case Lt: func = "Lesser"; break;
 430     case And: func = "And"; break;
 431     case Or: func = "Or"; break;
 432     case Not: func = "Not"; break;
 433     }
 434
 435     fprintf (stdout, "Function: %s\n", func);
 436
 437     if ((root->func == Val) && (root->ops[0] == NULL)) {
 438         for (i = 0; i < level; i++) {
 439             fprintf (stdout, " ");
 440         }
 441         fprintf (stdout, "value: %f\n", root->value);
 442     } else {
 443         for (i = 0; i < root->nbops; i++) {
 444             print_element (root->ops[i], level + 1);
 445         }
 446     }
 447 }
 448
 449 /* storage functions */
 450
 451 double store (int index, double value)
 452 {
 453     if ((index > 0) && (index <= STORAGE_SIZE)) {
 454         storage[index - 1] = value;
 455     } else {
 456         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 457     }
 458     return value;
 459 }
 460
 461 double recall (int index)
 462 {
 463     if ((index > 0) && (index <= STORAGE_SIZE)) {
 464         return storage[index - 1];
 465     } else {
 466         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 467     }
 468     return 0;
 469 }
 470
 471 void display (void)
 472 {
 473     int i;
 474     fprintf (stdout, "storage:");
 475     for (i = 0; i < STORAGE_SIZE; i++) {
 476         fprintf (stdout, " %g", storage[i]);
 477     }
 478     fprintf (stdout, "\n");
 479 }
 480
 481 /* quit function */
 482
 483 void quit (void)
 484 {
 485     fprintf (stdout, "bye\n");
 486     exit (0);
 487 }
 488
 489 /* help message */
 490
 491 void help (void)
 492 {
 493     fprintf (stdout, "calc is a simple calculator\n\n");
 494     fprintf (stdout, "supported operators:\n");
 495     fprintf (stdout, " + - * / %% ^\n\n");
 496     fprintf (stdout, "camparison operators:\n");
 497     fprintf (stdout, " == != >= <= > <\n\n");
 498     fprintf (stdout, "logical operators:\n");
 499     fprintf (stdout, " & | !\n\n");
 500     fprintf (stdout, "supported functions:\n");
 501     fprintf (stdout, " pow sqrt cos sin atan log exp\n\n");
 502     fprintf (stdout, "storage functions:\n");
 503     fprintf (stdout, " sto rcl\n\n");
 504     fprintf (stdout, "miscellaneous functions:\n");
 505     fprintf (stdout, " quit help\n\n");
 506     fprintf (stdout, "supported constants:\n");
 507     fprintf (stdout, " e pi\n");
 508 }
 509
 510 /* evaluate element tree */
 511
 512 #define MASK_SUB 0x1
 513 #define MASK_DIV 0x2
 514
 515 double evaluate_element (element_t *root, char mask)
 516 {
 517     double op0 = 0, op1 = 0;
 518     char nextmask = mask;
 519
 520     if ((root == NULL) || (root == ERROR_OP)) {
 521         VERBOSE (WARNING, fprintf (stdout, "error while evaluating\n"));
 522         return 0;
 523     }
 524
 525     /* mask to manage sub operator sub and div */
 526     switch (root->func) {
 527     case Add:
 528         nextmask &= ~MASK_SUB;
 529         nextmask &= ~MASK_DIV;
 530         break;
 531     case Sub:
 532         nextmask |= MASK_SUB;
 533         nextmask &= ~MASK_DIV;
 534         break;
 535     case Mul:
 536         nextmask &= ~MASK_DIV;
 537         break;
 538     case Div:
 539         nextmask |= MASK_DIV;
 540         break;
 541     default:
 542         nextmask = mask;
 543     }
 544
 545     switch (root->func) {
 546     case Val:
 547     case Sig:
 548         op0 = (root->ops[0]) ? evaluate_element (root->ops[0], nextmask) : root->value;
 549         break;
 550     case Add:
 551     case Sub:
 552     case Mul:
 553     case Div:
 554     case Mod:
 555     case Pow:
 556     case Store:
 557     case Equal:
 558     case Diff:
 559     case Ge:
 560     case Le:
 561     case Gt:
 562     case Lt:
 563     case And:
 564     case Or:
 565         if (root->ops[1]) {
 566             op1 = evaluate_element (root->ops[1], nextmask);
 567         } else if (root->func != Store) {
 568             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[1])\n"));
 569             return 0;
 570         }
 571         /* fallthrough */
 572     case Sqr:
 573     case Cos:
 574     case Sin:
 575     case Atan:
 576     case Log:
 577     case Exp:
 578     case Recall:
 579     case Not:
 580         if (root->ops[0]) {
 581             op0 = evaluate_element (root->ops[0], 0);
 582         } else {
 583             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[0])\n"));
 584             return 0;
 585         }
 586         break;
 587     case Disp:
 588     case Quit:
 589     case Help:
 590     case Ans:
 591     case Pi:
 592     case E:
 593         break;
 594     }
 595
 596     switch (root->func) {
 597     case Val: return op0;
 598     case Sig: return -op0;
 599     case Add: return ((mask & MASK_SUB) == 0) ? op0 + op1 : op0 - op1;
 600     case Sub: return ((mask & MASK_SUB) == 0) ? op0 - op1 : op0 + op1;
 601     case Mul: return ((mask & MASK_DIV) == 0) ? op0 * op1 : op0 / op1;
 602     case Div: return ((mask & MASK_DIV) == 0) ? op0 / op1 : op0 * op1;
 603     case Mod: return fmod (op0, op1);
 604     case Pow: return pow (op0, op1);
 605     case Sqr: return sqrt (op0);
 606     case Cos: return cos (op0);
 607     case Sin: return sin (op0);
 608     case Atan: return atan (op0);
 609     case Log: return log (op0);
 610     case Exp: return exp (op0);
 611     case Store: return store ((int)op0, (op1) ? op1 : answer);
 612     case Recall: return recall ((int)op0);
 613     case Disp: display (); break;
 614     case Quit: quit (); break;
 615     case Help: help (); break;
 616     case Ans: return answer;
 617     case Pi: return M_PI;
 618     case E: return M_E;
 619     case Equal: return op0 == op1;
 620     case Diff: return op0 != op1;
 621     case Ge: return op0 >= op1;
 622     case Le: return op0 <= op1;
 623     case Gt: return op0 > op1;
 624     case Lt: return op0 < op1;
 625     case And: return (op0 != 0) && (op1 != 0);
 626     case Or: return (op0 != 0) || (op1 != 0);
 627     case Not: return (op0 == 0);
 628     }
 629
 630     return 0;
 631 }
 632
 633 /* vim: set ts=4 sw=4 et: */