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