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 12
  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, 6},
  82     { "!=",  Diff, 2, 2, 6},
  83     { ">=",  Ge, 2, 2, 6},
  84     { "<=",  Le, 2, 2, 6},
  85     { ">",   Gt, 2, 1, 6},
  86     { "<",   Lt, 2, 1, 6}
  87 };
  88
  89 #define NB_FUNCTIONS 12
  90 keyword_t functions[NB_FUNCTIONS] = {
  91     { "sqrt", Sqr, 1, 4, 5},
  92     { "pow",  Pow, 2, 3, 5},
  93     { "cos",  Cos, 1, 3, 5},
  94     { "sin",  Sin, 1, 3, 5},
  95     { "atan", Atan, 1, 4, 5},
  96     { "exp",  Exp, 1, 3, 5},
  97     { "log",  Log, 1, 3, 5},
  98     { "sto",  Store, 2, 3, 5},
  99     { "rcl",  Recall, 1, 3, 5},
 100     { "disp", Disp, 0, 4, 5},
 101     { "quit", Quit, 0, 4, 5},
 102     { "help", Help, 0, 4, 5}
 103 };
 104
 105 #define NB_CONSTANTS 3
 106 keyword_t constants[NB_CONSTANTS] = {
 107     { "ans", Ans, 0, 3, 5},
 108     { "e",   E, 0, 1, 5},
 109     { "pi",  Pi, 0, 2, 5}
 110 };
 111
 112 /* subparser function */
 113
 114 element_t *subparser (element_t **proot, char **pstr, func_t func, int nbops, int prio)
 115 {
 116     element_t *new = newelement (func, nbops, prio);
 117     if (new == NULL) {
 118         return ERROR_OP;
 119     }
 120     new->ops[0] = *proot;
 121     new->ops[1] = parser (*pstr, pstr, new->prio);
 122     if (new->ops[1] == ERROR_OP) {
 123         delelement (new);
 124         *proot = NULL;
 125         return ERROR_OP;
 126     }
 127     *proot = newelement (Val, 1, 5);
 128     if (*proot == NULL) {
 129         delelement (new);
 130         return ERROR_OP;
 131     }
 132     (*proot)->ops[0] = new;
 133
 134     return *proot;
 135 }
 136
 137 /* parser function */
 138
 139 element_t *parser (char *str, char **next, int prio)
 140 {
 141     element_t *root = NULL;
 142     int i;
 143
 144     VERBOSE (DEBUG, fprintf (stdout, "Starting parsing\n"));
 145
 146     /* main loop */
 147     while (*str != '\0') {
 148         int found = 0;
 149         element_t *new = NULL;
 150         VERBOSE (INFO, fprintf (stdout, "Processing: %s\n", str));
 151
 152         /* skip spaces and tabs */
 153
 154         if ((*str == ' ') || (*str == '\t')) {
 155             str++;
 156             continue;
 157         }
 158
 159         /* check for open bracket */
 160
 161         if (*str == '(') {
 162             VERBOSE (DEBUG, fprintf (stdout, "start processing bracket\n"));
 163             if (root) {
 164                 do {
 165                     found = 0;
 166                     new = parser (str + 1, &str, 0);
 167                     if (new == ERROR_OP) {
 168                         delelement (root);
 169                         return ERROR_OP;
 170                     }
 171                     for (i = 0; i < root->nbops; i++) {
 172                         if (root->ops[i] == NULL) {
 173                             root->ops[i] = new;
 174                             found = 1;
 175                             break;
 176                         }
 177                     }
 178                     if (!found) {
 179                         delelement (new);
 180                         delelement (root);
 181                         return ERROR_OP;
 182                     }
 183                 } while (*str == ',');
 184             } else {
 185                 root = newelement (Val, 1, 5);
 186                 if (root == NULL) {
 187                     return ERROR_OP;
 188                 }
 189                 new = parser (str + 1, &str, 0);
 190                 if ((new == ERROR_OP) || (*str == ',')) {
 191                     delelement (new);
 192                     delelement (root);
 193                     return ERROR_OP;
 194                 }
 195                 root->ops[0] = new;
 196             }
 197             str++;
 198             VERBOSE (DEBUG, fprintf (stdout, "stop processing bracket\n"));
 199             continue;
 200         }
 201
 202         /* check for closing bracket or koma */
 203
 204         if ((*str == ')') || (*str == ',')) {
 205             if (next != NULL) {
 206                 *next = str;
 207             }
 208             return root;
 209         }
 210
 211         /* look for operators */
 212
 213         for (i = 0; i < NB_OPERATORS; i++) {
 214             keyword_t *operator = operators + i;
 215             if (codecmp (operator->keyword, str) == 0) {
 216                 VERBOSE (DEBUG, fprintf (stdout, "start processing operator\n"));
 217                 if (root) {
 218                     if ((prio) && (prio > operator->prio)) {
 219                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 220                         *next = str;
 221                         return root;
 222                     }
 223                     str += operator->offset;
 224                     VERBOSE (INFO, fprintf (stdout, "Oper: %d\n", operator->func));
 225                     if (subparser (&root, &str, operator->func, operator->nbops, operator->prio) == ERROR_OP) {
 226                         delelement (root);
 227                         return ERROR_OP;
 228                     }
 229                 } else if (*str == '-') {
 230                     new = newelement (Sig, 1, 9);
 231                     if (new == NULL) {
 232                         return ERROR_OP;
 233                     }
 234                     root = new;
 235                 } else {
 236                     return ERROR_OP;
 237                 }
 238                 found = 1;
 239                 VERBOSE (DEBUG, fprintf (stdout, "stop processing operator\n"));
 240                 break;
 241             }
 242         }
 243         if (found) {
 244             continue;
 245         }
 246
 247         /* look for functions */
 248
 249         for (i = 0; i < NB_FUNCTIONS; i++) {
 250             keyword_t *function = functions + i;
 251             if (codecmp (function->keyword, str) == 0) {
 252                 VERBOSE (DEBUG, fprintf (stdout, "start processing function\n"));
 253                 if (root == NULL) {
 254                     VERBOSE (INFO, fprintf (stdout, "Func: %d\n", function->func));
 255                     new = newelement (function->func, function->nbops, function->prio);
 256                     if (new == NULL) {
 257                         return ERROR_OP;
 258                     }
 259                     root = new;
 260                 } else {
 261                     delelement (root);
 262                     return ERROR_OP;
 263                 }
 264                 str += function->offset;
 265                 found = 1;
 266                 VERBOSE (DEBUG, fprintf (stdout, "stop processing function\n"));
 267                 break;
 268             }
 269         }
 270         if (found) {
 271             continue;
 272         }
 273
 274         /* look for constant */
 275
 276         for (i = 0; i < NB_CONSTANTS; i++) {
 277             keyword_t *constant = constants + i;
 278             if (codecmp (constant->keyword, str) == 0) {
 279                 VERBOSE (DEBUG, fprintf (stdout, "start processing constant\n"));
 280                 if (root == NULL) {
 281                     VERBOSE (INFO, fprintf (stdout, "Const: %d\n", constant->func));
 282                     new = newelement (constant->func, constant->nbops, constant->prio);
 283                     if (new == NULL) {
 284                         return ERROR_OP;
 285                     }
 286                     root = new;
 287                 } else {
 288                     delelement (root);
 289                     return ERROR_OP;
 290                 }
 291                 str += constant->offset;
 292                 found = 1;
 293                 VERBOSE (DEBUG, fprintf (stdout, "stop processing constant\n"));
 294                 break;
 295             }
 296         }
 297         if (found) {
 298             continue;
 299         }
 300
 301         /* look for number */
 302
 303         if (((*str >= '0') && (*str <= '9')) ||
 304             (*str == '.') || (*str == '+') || (*str == '-')) {
 305             VERBOSE (DEBUG, fprintf (stdout, "start processing value\n"));
 306             char *pt;
 307             double value = strtod (str, &pt);
 308             VERBOSE (INFO, fprintf (stdout, "Value: %f\n", value));
 309             if (str != pt) {
 310                 if (root == NULL) {
 311                     new = newelement (Val, 1, 5);
 312                     if (new == NULL) {
 313                         return ERROR_OP;
 314                     }
 315                     new->value = value;
 316                     root = new;
 317                     str = pt;
 318                 } else if ((*str == '+') || (*str == '-')) {
 319                     if ((prio) && (prio > 1)) {
 320                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 321                         *next = str;
 322                         return root;
 323                     }
 324                     if (subparser (&root, &str, Add, 2, 1) == ERROR_OP) {
 325                         delelement (root);
 326                         return ERROR_OP;
 327                     }
 328                 } else {
 329                     delelement (root);
 330                     return ERROR_OP;
 331                 }
 332                 found = 1;
 333             }
 334             VERBOSE (DEBUG, fprintf (stdout, "stop processing value\n"));
 335         }
 336
 337         /* error */
 338
 339         if (!found) {
 340             delelement (root);
 341             return ERROR_OP;
 342         }
 343
 344     }
 345
 346     if (next != NULL) {
 347         *next = str;
 348     }
 349
 350     return root;
 351 }
 352
 353 /* print element tree */
 354
 355 void print_element (element_t *root, int level)
 356 {
 357     char *func = NULL;
 358     int i;
 359
 360     if ((root == NULL) || (root == ERROR_OP)) {
 361         return;
 362     }
 363
 364     for (i = 0; i < level; i++) {
 365         fprintf (stdout, " ");
 366     }
 367
 368     switch (root->func) {
 369     case Val: func = "Value"; break;
 370     case Sig: func = "Sign"; break;
 371     case Add: func = "Addition"; break;
 372     case Sub: func = "Subtraction"; break;
 373     case Mul: func = "Multiplication"; break;
 374     case Div: func = "Division"; break;
 375     case Mod: func = "Modulo"; break;
 376     case Pow: func = "Power"; break;
 377     case Sqr: func = "Square Root"; break;
 378     case Cos: func = "Cosine"; break;
 379     case Sin: func = "Sine"; break;
 380     case Atan: func = "Arc Tangent"; break;
 381     case Log: func = "Logarithm"; break;
 382     case Exp: func = "Exponantial"; break;
 383     case Store: func = "Store"; break;
 384     case Recall: func = "Recall"; break;
 385     case Disp: func = "Display"; break;
 386     case Quit: func = "Quit"; break;
 387     case Help: func = "Help"; break;
 388     case Ans: func = "Ans"; break;
 389     case Pi: func = "Pi"; break;
 390     case E: func = "E"; break;
 391     case Equal: func = "Equal"; break;
 392     case Diff: func = "Different"; break;
 393     case Ge: func = "Greater or equal"; break;
 394     case Le: func = "Lesser or equal"; break;
 395     case Gt: func = "Greater"; break;
 396     case Lt: func = "Lesser"; break;
 397     }
 398
 399     fprintf (stdout, "Function: %s\n", func);
 400
 401     if ((root->func == Val) && (root->ops[0] == NULL)) {
 402         for (i = 0; i < level; i++) {
 403             fprintf (stdout, " ");
 404         }
 405         fprintf (stdout, "value: %f\n", root->value);
 406     } else {
 407         for (i = 0; i < root->nbops; i++) {
 408             print_element (root->ops[i], level + 1);
 409         }
 410     }
 411 }
 412
 413 /* storage functions */
 414
 415 double store (int index, double value)
 416 {
 417     if ((index > 0) && (index <= STORAGE_SIZE)) {
 418         storage[index - 1] = value;
 419     } else {
 420         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 421     }
 422     return value;
 423 }
 424
 425 double recall (int index)
 426 {
 427     if ((index > 0) && (index <= STORAGE_SIZE)) {
 428         return storage[index - 1];
 429     } else {
 430         VERBOSE (WARNING, fprintf (stdout, "invalid index (%d) [1, %d]\n", index, STORAGE_SIZE));
 431     }
 432     return 0;
 433 }
 434
 435 void display (void)
 436 {
 437     int i;
 438     fprintf (stdout, "storage:");
 439     for (i = 0; i < STORAGE_SIZE; i++) {
 440         fprintf (stdout, " %g", storage[i]);
 441     }
 442     fprintf (stdout, "\n");
 443 }
 444
 445 /* quit function */
 446
 447 void quit (void)
 448 {
 449     fprintf (stdout, "bye\n");
 450     exit (0);
 451 }
 452
 453 /* help message */
 454
 455 void help (void)
 456 {
 457     fprintf (stdout, "calc is a simple calculator\n\n");
 458     fprintf (stdout, "supported operators:\n");
 459     fprintf (stdout, " + - * / %% ^\n\n");
 460     fprintf (stdout, "camparison operators:\n");
 461     fprintf (stdout, " == != >= <= > <\n\n");
 462     fprintf (stdout, "supported functions:\n");
 463     fprintf (stdout, " pow sqrt cos sin atan log exp\n\n");
 464     fprintf (stdout, "storage functions:\n");
 465     fprintf (stdout, " sto rcl\n\n");
 466     fprintf (stdout, "miscellaneous functions:\n");
 467     fprintf (stdout, " quit help\n\n");
 468     fprintf (stdout, "supported constants:\n");
 469     fprintf (stdout, " e pi\n");
 470 }
 471
 472 /* evaluate element tree */
 473
 474 #define MASK_SUB 0x1
 475 #define MASK_DIV 0x2
 476
 477 double evaluate_element (element_t *root, char mask)
 478 {
 479     double op0 = 0, op1 = 0;
 480     char nextmask = mask;
 481
 482     if ((root == NULL) || (root == ERROR_OP)) {
 483         VERBOSE (WARNING, fprintf (stdout, "error while evaluating\n"));
 484         return 0;
 485     }
 486
 487     /* mask to manage sub operator sub and div */
 488     switch (root->func) {
 489     case Add:
 490         nextmask &= ~MASK_SUB;
 491         nextmask &= ~MASK_DIV;
 492         break;
 493     case Sub:
 494         nextmask |= MASK_SUB;
 495         nextmask &= ~MASK_DIV;
 496         break;
 497     case Mul:
 498         nextmask &= ~MASK_DIV;
 499         break;
 500     case Div:
 501         nextmask |= MASK_DIV;
 502         break;
 503     default:
 504         nextmask = mask;
 505     }
 506
 507     switch (root->func) {
 508     case Val:
 509     case Sig:
 510         op0 = (root->ops[0]) ? evaluate_element (root->ops[0], nextmask) : root->value;
 511         break;
 512     case Add:
 513     case Sub:
 514     case Mul:
 515     case Div:
 516     case Mod:
 517     case Pow:
 518     case Store:
 519     case Equal:
 520     case Diff:
 521     case Ge:
 522     case Le:
 523     case Gt:
 524     case Lt:
 525         if (root->ops[1]) {
 526             op1 = evaluate_element (root->ops[1], nextmask);
 527         } else if (root->func != Store) {
 528             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[1])\n"));
 529             return 0;
 530         }
 531         /* fallthrough */
 532     case Sqr:
 533     case Cos:
 534     case Sin:
 535     case Atan:
 536     case Log:
 537     case Exp:
 538     case Recall:
 539         if (root->ops[0]) {
 540             op0 = evaluate_element (root->ops[0], 0);
 541         } else {
 542             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[0])\n"));
 543             return 0;
 544         }
 545         break;
 546     case Disp:
 547     case Quit:
 548     case Help:
 549     case Ans:
 550     case Pi:
 551     case E:
 552         break;
 553     }
 554
 555     switch (root->func) {
 556     case Val: return op0;
 557     case Sig: return -op0;
 558     case Add: return ((mask & MASK_SUB) == 0) ? op0 + op1 : op0 - op1;
 559     case Sub: return ((mask & MASK_SUB) == 0) ? op0 - op1 : op0 + op1;
 560     case Mul: return ((mask & MASK_DIV) == 0) ? op0 * op1 : op0 / op1;
 561     case Div: return ((mask & MASK_DIV) == 0) ? op0 / op1 : op0 * op1;
 562     case Mod: return fmod (op0, op1);
 563     case Pow: return pow (op0, op1);
 564     case Sqr: return sqrt (op0);
 565     case Cos: return cos (op0);
 566     case Sin: return sin (op0);
 567     case Atan: return atan (op0);
 568     case Log: return log (op0);
 569     case Exp: return exp (op0);
 570     case Store: return store ((int)op0, (op1) ? op1 : answer);
 571     case Recall: return recall ((int)op0);
 572     case Disp: display (); break;
 573     case Quit: quit (); break;
 574     case Help: help (); break;
 575     case Ans: return answer;
 576     case Pi: return M_PI;
 577     case E: return M_E;
 578     case Equal: return op0 == op1;
 579     case Diff: return op0 != op1;
 580     case Ge: return op0 >= op1;
 581     case Le: return op0 <= op1;
 582     case Gt: return op0 > op1;
 583     case Lt: return op0 < op1;
 584     }
 585
 586     return 0;
 587 }
 588
 589 /* vim: set ts=4 sw=4 et: */