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