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