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
  74 keyword_t operators[NB_OPERATORS] = {
  75     { "+\t", Add, 2, 1, 1},
  76     { "-\t", Sub, 2, 1, 1},
  77     { "*",   Mul, 2, 1, 2},
  78     { "/",   Div, 2, 1, 2},
  79     { "%",   Mod, 2, 1, 3},
  80     { "^",   Pow, 2, 1, 4},
  81     { "==",  Equal, 2, 2, -1},
  82     { "!=",  Diff, 2, 2, -1},
  83     { ">=",  Ge, 2, 2, -1},
  84     { "<=",  Le, 2, 2, -1},
  85     { ">",   Gt, 2, 1, -1},
  86     { "<",   Lt, 2, 1, -1},
  87     { "&",   And, 2, 1, -2},
  88     { "|",   Or, 2, 1, -2}
  89 };
  90
  91 #define NB_FUNCTIONS 13
  92 keyword_t functions[NB_FUNCTIONS] = {
  93     { "sqrt", Sqr, 1, 4, 5},
  94     { "pow",  Pow, 2, 3, 5},
  95     { "cos",  Cos, 1, 3, 5},
  96     { "sin",  Sin, 1, 3, 5},
  97     { "atan", Atan, 1, 4, 5},
  98     { "exp",  Exp, 1, 3, 5},
  99     { "log",  Log, 1, 3, 5},
 100     { "sto",  Store, 2, 3, 9},
 101     { "rcl",  Recall, 1, 3, 5},
 102     { "disp", Disp, 0, 4, 9},
 103     { "quit", Quit, 0, 4, 9},
 104     { "help", Help, 0, 4, 9},
 105     { "!",    Not, 1, 1, 5}
 106 };
 107
 108 #define NB_CONSTANTS 3
 109 keyword_t constants[NB_CONSTANTS] = {
 110     { "ans", Ans, 0, 3, 5},
 111     { "e",   E, 0, 1, 5},
 112     { "pi",  Pi, 0, 2, 5}
 113 };
 114
 115 /* subparser function */
 116
 117 element_t *subparser (element_t **proot, char **pstr, func_t func, int nbops, int prio)
 118 {
 119     element_t *new = newelement (func, nbops, prio);
 120     if (new == NULL) {
 121         return ERROR_OP;
 122     }
 123     new->ops[0] = *proot;
 124     new->ops[1] = parser (*pstr, pstr, new->prio);
 125     if ((new->ops[1] == NULL) || ((new->ops[1] != ERROR_OP) && (new->ops[1]->prio == 9))) {
 126         delelement (new->ops[1]);
 127         new->ops[1] = ERROR_OP;
 128     }
 129     if (new->ops[1] == ERROR_OP) {
 130         delelement (new);
 131         *proot = NULL;
 132         return ERROR_OP;
 133     }
 134     *proot = newelement (Val, 1, 5);
 135     if (*proot == NULL) {
 136         delelement (new);
 137         return ERROR_OP;
 138     }
 139     (*proot)->ops[0] = new;
 140
 141     return *proot;
 142 }
 143
 144 /* parser function */
 145
 146 element_t *parser (char *str, char **next, int prio)
 147 {
 148     element_t *root = NULL;
 149     int i;
 150
 151     VERBOSE (DEBUG, fprintf (stdout, "Starting parsing\n"));
 152
 153     /* main loop */
 154     while (*str != '\0') {
 155         int found = 0;
 156         element_t *new = NULL;
 157         VERBOSE (INFO, fprintf (stdout, "Processing: %s\n", str));
 158
 159         /* skip spaces and tabs */
 160
 161         if ((*str == ' ') || (*str == '\t')) {
 162             str++;
 163             continue;
 164         }
 165
 166         /* check for open bracket */
 167
 168         if (*str == '(') {
 169             VERBOSE (DEBUG, fprintf (stdout, "start processing bracket\n"));
 170             if (root) {
 171                 do {
 172                     found = 0;
 173                     new = parser (str + 1, &str, 0);
 174                     if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 175                         delelement (new);
 176                         new = ERROR_OP;
 177                     }
 178                     if ((new == NULL) || (new == ERROR_OP)) {
 179                         delelement (root);
 180                         return ERROR_OP;
 181                     }
 182                     for (i = 0; i < root->nbops; i++) {
 183                         if (root->ops[i] == NULL) {
 184                             root->ops[i] = new;
 185                             found = 1;
 186                             break;
 187                         }
 188                     }
 189                     if (!found) {
 190                         delelement (new);
 191                         delelement (root);
 192                         return ERROR_OP;
 193                     }
 194                 } while (*str == ',');
 195             } else {
 196                 root = newelement (Val, 1, 5);
 197                 if (root == NULL) {
 198                     return ERROR_OP;
 199                 }
 200                 new = parser (str + 1, &str, 0);
 201                 if ((new == NULL) || ((new != ERROR_OP) && (new->prio == 9))) {
 202                     delelement (new);
 203                     new = ERROR_OP;
 204                 }
 205                 if ((new == NULL) || (new == ERROR_OP) || (*str == ',')) {
 206                     delelement (new);
 207                     delelement (root);
 208                     return ERROR_OP;
 209                 }
 210                 root->ops[0] = new;
 211             }
 212             if (*str != ')') {
 213                 delelement (root);
 214                 return ERROR_OP;
 215             }
 216             str++;
 217             VERBOSE (DEBUG, fprintf (stdout, "stop processing bracket\n"));
 218             continue;
 219         }
 220
 221         /* check for closing bracket or koma */
 222
 223         if ((*str == ')') || (*str == ',')) {
 224             if (next != NULL) {
 225                 *next = str;
 226             }
 227             return root;
 228         }
 229
 230         /* look for operators */
 231
 232         for (i = 0; i < NB_OPERATORS; i++) {
 233             keyword_t *operator = operators + i;
 234             if (codecmp (operator->keyword, str) == 0) {
 235                 VERBOSE (DEBUG, fprintf (stdout, "start processing operator\n"));
 236                 if (root) {
 237                     if ((prio) && (prio > operator->prio)) {
 238                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 239                         *next = str;
 240                         return root;
 241                     }
 242                     str += operator->offset;
 243                     VERBOSE (INFO, fprintf (stdout, "Oper: %d\n", operator->func));
 244                     if (subparser (&root, &str, operator->func, operator->nbops, operator->prio) == ERROR_OP) {
 245                         delelement (root);
 246                         return ERROR_OP;
 247                     }
 248                 } else if (*str == '-') {
 249                     new = newelement (Sig, 1, 9);
 250                     if (new == NULL) {
 251                         return ERROR_OP;
 252                     }
 253                     root = new;
 254                 } else {
 255                     return ERROR_OP;
 256                 }
 257                 found = 1;
 258                 VERBOSE (DEBUG, fprintf (stdout, "stop processing operator\n"));
 259                 break;
 260             }
 261         }
 262         if (found) {
 263             continue;
 264         }
 265
 266         /* look for functions */
 267
 268         for (i = 0; i < NB_FUNCTIONS; i++) {
 269             keyword_t *function = functions + i;
 270             if (codecmp (function->keyword, str) == 0) {
 271                 VERBOSE (DEBUG, fprintf (stdout, "start processing function\n"));
 272                 if (root == NULL) {
 273                     VERBOSE (INFO, fprintf (stdout, "Func: %d\n", function->func));
 274                     new = newelement (function->func, function->nbops, function->prio);
 275                     if (new == NULL) {
 276                         return ERROR_OP;
 277                     }
 278                     root = new;
 279                 } else {
 280                     delelement (root);
 281                     return ERROR_OP;
 282                 }
 283                 str += function->offset;
 284                 found = 1;
 285                 VERBOSE (DEBUG, fprintf (stdout, "stop processing function\n"));
 286                 break;
 287             }
 288         }
 289         if (found) {
 290             continue;
 291         }
 292
 293         /* look for constant */
 294
 295         for (i = 0; i < NB_CONSTANTS; i++) {
 296             keyword_t *constant = constants + i;
 297             if (codecmp (constant->keyword, str) == 0) {
 298                 VERBOSE (DEBUG, fprintf (stdout, "start processing constant\n"));
 299                 if (root == NULL) {
 300                     VERBOSE (INFO, fprintf (stdout, "Const: %d\n", constant->func));
 301                     new = newelement (constant->func, constant->nbops, constant->prio);
 302                     if (new == NULL) {
 303                         return ERROR_OP;
 304                     }
 305                     root = new;
 306                 } else {
 307                     delelement (root);
 308                     return ERROR_OP;
 309                 }
 310                 str += constant->offset;
 311                 found = 1;
 312                 VERBOSE (DEBUG, fprintf (stdout, "stop processing constant\n"));
 313                 break;
 314             }
 315         }
 316         if (found) {
 317             continue;
 318         }
 319
 320         /* look for number */
 321
 322         if (((*str >= '0') && (*str <= '9')) ||
 323             (*str == '.') || (*str == '+') || (*str == '-')) {
 324             VERBOSE (DEBUG, fprintf (stdout, "start processing value\n"));
 325             char *pt;
 326             double value = strtod (str, &pt);
 327             VERBOSE (INFO, fprintf (stdout, "Value: %f\n", value));
 328             if (str != pt) {
 329                 if (root == NULL) {
 330                     new = newelement (Val, 1, 5);
 331                     if (new == NULL) {
 332                         return ERROR_OP;
 333                     }
 334                     new->value = value;
 335                     root = new;
 336                     str = pt;
 337                 } else if ((*str == '+') || (*str == '-')) {
 338                     if ((prio) && (prio > 1)) {
 339                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 340                         *next = str;
 341                         return root;
 342                     }
 343                     if (subparser (&root, &str, Add, 2, 1) == ERROR_OP) {
 344                         delelement (root);
 345                         return ERROR_OP;
 346                     }
 347                 } else {
 348                     delelement (root);
 349                     return ERROR_OP;
 350                 }
 351                 found = 1;
 352             }
 353             VERBOSE (DEBUG, fprintf (stdout, "stop processing value\n"));
 354         }
 355
 356         /* error */
 357
 358         if (!found) {
 359             delelement (root);
 360             return ERROR_OP;
 361         }
 362
 363     }
 364
 365     if (next != NULL) {
 366         *next = str;
 367     }
 368
 369     return root;
 370 }
 371
 372 /* print element tree */
 373
 374 void print_element (element_t *root, int level)
 375 {
 376     char *func = NULL;
 377     int i;
 378
 379     if ((root == NULL) || (root == ERROR_OP)) {
 380         return;
 381     }
 382
 383     for (i = 0; i < level; i++) {
 384         fprintf (stdout, " ");
 385     }
 386
 387     switch (root->func) {
 388     case Val: func = "Value"; break;
 389     case Sig: func = "Sign"; break;
 390     case Add: func = "Addition"; break;
 391     case Sub: func = "Subtraction"; break;
 392     case Mul: func = "Multiplication"; break;
 393     case Div: func = "Division"; break;
 394     case Mod: func = "Modulo"; break;
 395     case Pow: func = "Power"; break;
 396     case Sqr: func = "Square Root"; break;
 397     case Cos: func = "Cosine"; break;
 398     case Sin: func = "Sine"; break;
 399     case Atan: func = "Arc Tangent"; break;
 400     case Log: func = "Logarithm"; break;
 401     case Exp: func = "Exponantial"; break;
 402     case Store: func = "Store"; break;
 403     case Recall: func = "Recall"; break;
 404     case Disp: func = "Display"; break;
 405     case Quit: func = "Quit"; break;
 406     case Help: func = "Help"; break;
 407     case Ans: func = "Ans"; break;
 408     case Pi: func = "Pi"; break;
 409     case E: func = "E"; break;
 410     case Equal: func = "Equal"; break;
 411     case Diff: func = "Different"; break;
 412     case Ge: func = "Greater or equal"; break;
 413     case Le: func = "Lesser or equal"; break;
 414     case Gt: func = "Greater"; break;
 415     case Lt: func = "Lesser"; break;
 416     case And: func = "And"; break;
 417     case Or: func = "Or"; break;
 418     case Not: func = "Not"; break;
 419     }
 420
 421     fprintf (stdout, "Function: %s\n", func);
 422
 423     if ((root->func == Val) && (root->ops[0] == NULL)) {
 424         for (i = 0; i < level; i++) {
 425             fprintf (stdout, " ");
 426         }
 427         fprintf (stdout, "value: %f\n", root->value);
 428     } else {
 429         for (i = 0; i < root->nbops; i++) {
 430             print_element (root->ops[i], level + 1);
 431         }
 432     }
 433 }
 434
 435 /* storage functions */
 436
 437 double store (int index, double value)
 438 {
 439     if ((index > 0) && (index <= STORAGE_SIZE)) {
 440         storage[index - 1] = value;
 441     } else {
 442         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 443     }
 444     return value;
 445 }
 446
 447 double recall (int index)
 448 {
 449     if ((index > 0) && (index <= STORAGE_SIZE)) {
 450         return storage[index - 1];
 451     } else {
 452         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 453     }
 454     return 0;
 455 }
 456
 457 void display (void)
 458 {
 459     int i;
 460     fprintf (stdout, "storage:");
 461     for (i = 0; i < STORAGE_SIZE; i++) {
 462         fprintf (stdout, " %g", storage[i]);
 463     }
 464     fprintf (stdout, "\n");
 465 }
 466
 467 /* quit function */
 468
 469 void quit (void)
 470 {
 471     fprintf (stdout, "bye\n");
 472     exit (0);
 473 }
 474
 475 /* help message */
 476
 477 void help (void)
 478 {
 479     fprintf (stdout, "calc is a simple calculator\n\n");
 480     fprintf (stdout, "supported operators:\n");
 481     fprintf (stdout, " + - * / %% ^\n\n");
 482     fprintf (stdout, "camparison operators:\n");
 483     fprintf (stdout, " == != >= <= > <\n\n");
 484     fprintf (stdout, "supported functions:\n");
 485     fprintf (stdout, " pow sqrt cos sin atan log exp\n\n");
 486     fprintf (stdout, "storage functions:\n");
 487     fprintf (stdout, " sto rcl\n\n");
 488     fprintf (stdout, "miscellaneous functions:\n");
 489     fprintf (stdout, " quit help\n\n");
 490     fprintf (stdout, "supported constants:\n");
 491     fprintf (stdout, " e pi\n");
 492 }
 493
 494 /* evaluate element tree */
 495
 496 #define MASK_SUB 0x1
 497 #define MASK_DIV 0x2
 498
 499 double evaluate_element (element_t *root, char mask)
 500 {
 501     double op0 = 0, op1 = 0;
 502     char nextmask = mask;
 503
 504     if ((root == NULL) || (root == ERROR_OP)) {
 505         VERBOSE (WARNING, fprintf (stdout, "error while evaluating\n"));
 506         return 0;
 507     }
 508
 509     /* mask to manage sub operator sub and div */
 510     switch (root->func) {
 511     case Add:
 512         nextmask &= ~MASK_SUB;
 513         nextmask &= ~MASK_DIV;
 514         break;
 515     case Sub:
 516         nextmask |= MASK_SUB;
 517         nextmask &= ~MASK_DIV;
 518         break;
 519     case Mul:
 520         nextmask &= ~MASK_DIV;
 521         break;
 522     case Div:
 523         nextmask |= MASK_DIV;
 524         break;
 525     default:
 526         nextmask = mask;
 527     }
 528
 529     switch (root->func) {
 530     case Val:
 531     case Sig:
 532         op0 = (root->ops[0]) ? evaluate_element (root->ops[0], nextmask) : root->value;
 533         break;
 534     case Add:
 535     case Sub:
 536     case Mul:
 537     case Div:
 538     case Mod:
 539     case Pow:
 540     case Store:
 541     case Equal:
 542     case Diff:
 543     case Ge:
 544     case Le:
 545     case Gt:
 546     case Lt:
 547     case And:
 548     case Or:
 549         if (root->ops[1]) {
 550             op1 = evaluate_element (root->ops[1], nextmask);
 551         } else if (root->func != Store) {
 552             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[1])\n"));
 553             return 0;
 554         }
 555         /* fallthrough */
 556     case Sqr:
 557     case Cos:
 558     case Sin:
 559     case Atan:
 560     case Log:
 561     case Exp:
 562     case Recall:
 563     case Not:
 564         if (root->ops[0]) {
 565             op0 = evaluate_element (root->ops[0], 0);
 566         } else {
 567             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[0])\n"));
 568             return 0;
 569         }
 570         break;
 571     case Disp:
 572     case Quit:
 573     case Help:
 574     case Ans:
 575     case Pi:
 576     case E:
 577         break;
 578     }
 579
 580     switch (root->func) {
 581     case Val: return op0;
 582     case Sig: return -op0;
 583     case Add: return ((mask & MASK_SUB) == 0) ? op0 + op1 : op0 - op1;
 584     case Sub: return ((mask & MASK_SUB) == 0) ? op0 - op1 : op0 + op1;
 585     case Mul: return ((mask & MASK_DIV) == 0) ? op0 * op1 : op0 / op1;
 586     case Div: return ((mask & MASK_DIV) == 0) ? op0 / op1 : op0 * op1;
 587     case Mod: return fmod (op0, op1);
 588     case Pow: return pow (op0, op1);
 589     case Sqr: return sqrt (op0);
 590     case Cos: return cos (op0);
 591     case Sin: return sin (op0);
 592     case Atan: return atan (op0);
 593     case Log: return log (op0);
 594     case Exp: return exp (op0);
 595     case Store: return store ((int)op0, (op1) ? op1 : answer);
 596     case Recall: return recall ((int)op0);
 597     case Disp: display (); break;
 598     case Quit: quit (); break;
 599     case Help: help (); break;
 600     case Ans: return answer;
 601     case Pi: return M_PI;
 602     case E: return M_E;
 603     case Equal: return op0 == op1;
 604     case Diff: return op0 != op1;
 605     case Ge: return op0 >= op1;
 606     case Le: return op0 <= op1;
 607     case Gt: return op0 > op1;
 608     case Lt: return op0 < op1;
 609     case And: return (op0 != 0) && (op1 != 0);
 610     case Or: return (op0 != 0) || (op1 != 0);
 611     case Not: return (op0 == 0);
 612     }
 613
 614     return 0;
 615 }
 616
 617 /* vim: set ts=4 sw=4 et: */