parser.c

   1 #include <malloc.h>
   2 #include <math.h>
   3 #include <stdlib.h>
   4
   5 #include "debug.h"
   6
   7 #include "parser.h"
   8
   9 /* compare codes */
  10
  11 int codecmp (char *ref, char *str)
  12 {
  13     int sig;
  14
  15     while (*ref != '\0') {
  16         if (*ref == '\t') {
  17              sig = (*str == '.') ? -1 : ((*str >= '0') && (*str <= '9'));
  18         } else {
  19             sig = *str - *ref;
  20         }
  21         if (sig != 0) {
  22             return (sig > 0) ? 1 : -1;
  23         }
  24         str++;
  25         ref++;
  26     }
  27
  28     return 0;
  29 }
  30
  31 /* allocate new element */
  32
  33 element_t *newelement (func_t function, int nbops, int prio)
  34 {
  35     element_t *new = (element_t *) calloc (1, sizeof (element_t));
  36     if (new == NULL) {
  37         VERBOSE (ERROR, fprintf (stderr, "can't allocate memory\n"));
  38         return NULL;
  39     }
  40     new->func = function;
  41     new->nbops = nbops;
  42     new->prio = prio;
  43
  44     return new;
  45 }
  46
  47 /* desallocate element */
  48
  49 void delelement (element_t *root)
  50 {
  51     int i;
  52     if ((root != NULL) && (root != ERROR_OP)) {
  53         for (i = 0; i < root->nbops; i++) {
  54             if ((root->ops[i] != NULL) && (root->ops[i] != ERROR_OP)) {
  55                 delelement (root->ops[i]);
  56             }
  57         }
  58         free (root);
  59     }
  60 }
  61
  62 /* functions */
  63
  64 #define NB_OPERATORS 6
  65
  66 keyword_t operators[NB_OPERATORS] = {
  67     { "+\t", Add, 2, 1, 1},
  68     { "-\t", Sub, 2, 1, 1},
  69     { "*",   Mul, 2, 1, 2},
  70     { "/",   Div, 2, 1, 2},
  71     { "%",   Mod, 2, 1, 3},
  72     { "^",   Pow, 2, 1, 4}
  73 };
  74
  75 #define NB_FUNCTIONS 9
  76 keyword_t functions[NB_FUNCTIONS] = {
  77     { "sqrt", Sqr, 1, 4, 5},
  78     { "pow",  Pow, 2, 3, 5},
  79     { "cos",  Cos, 1, 3, 5},
  80     { "sin",  Sin, 1, 3, 5},
  81     { "atan", Atn, 1, 4, 5},
  82     { "exp",  Exp, 1, 3, 5},
  83     { "log",  Log, 1, 3, 5},
  84     { "quit", Qui, 0, 4, 5},
  85     { "help", Hel, 0, 4, 5}
  86 };
  87
  88 /* subparser function */
  89
  90 element_t *subparser (element_t **proot, char **pstr, func_t func, int nbops, int prio)
  91 {
  92     element_t *new = newelement (func, nbops, prio);
  93     if (new == NULL) {
  94         return ERROR_OP;
  95     }
  96     new->ops[0] = *proot;
  97     new->ops[1] = parser (*pstr, pstr, new->prio);
  98     if (new->ops[1] == ERROR_OP) {
  99         delelement (new);
 100         *proot = NULL;
 101         return ERROR_OP;
 102     }
 103     *proot = newelement (Val, 1, 5);
 104     if (*proot == NULL) {
 105         delelement (new);
 106         return ERROR_OP;
 107     }
 108     (*proot)->ops[0] = new;
 109
 110     return *proot;
 111 }
 112
 113 /* parser function */
 114
 115 element_t *parser (char *str, char **next, int prio)
 116 {
 117     element_t *root = NULL;
 118     int i;
 119
 120     VERBOSE (DEBUG, fprintf (stdout, "Starting parsing\n"));
 121
 122     /* main loop */
 123     while (*str != '\0') {
 124         int found = 0;
 125         element_t *new = NULL;
 126         VERBOSE (INFO, fprintf (stdout, "Processing: %s\n", str));
 127
 128         /* skip spaces and tabs */
 129
 130         if ((*str == ' ') || (*str == '\t')) {
 131             str++;
 132             continue;
 133         }
 134
 135         /* check for open bracket */
 136
 137         if (*str == '(') {
 138             VERBOSE (DEBUG, fprintf (stdout, "start processing bracket\n"));
 139             if (root) {
 140                 do {
 141                     found = 0;
 142                     new = parser (str + 1, &str, 0);
 143                     if (new == ERROR_OP) {
 144                         delelement (root);
 145                         return ERROR_OP;
 146                     }
 147                     for (i = 0; i < root->nbops; i++) {
 148                         if (root->ops[i] == NULL) {
 149                             root->ops[i] = new;
 150                             found = 1;
 151                             break;
 152                         }
 153                     }
 154                     if (!found) {
 155                         delelement (new);
 156                         delelement (root);
 157                         return ERROR_OP;
 158                     }
 159                 } while (*str == ',');
 160             } else {
 161                 root = newelement (Val, 1, 5);
 162                 if (root == NULL) {
 163                     return ERROR_OP;
 164                 }
 165                 new = parser (str + 1, &str, 0);
 166                 if ((new == ERROR_OP) || (*str == ',')) {
 167                     delelement (new);
 168                     delelement (root);
 169                     return ERROR_OP;
 170                 }
 171                 root->ops[0] = new;
 172             }
 173             str++;
 174             VERBOSE (DEBUG, fprintf (stdout, "stop processing bracket\n"));
 175             continue;
 176         }
 177
 178         /* check for closing bracket or koma */
 179
 180         if ((*str == ')') || (*str == ',')) {
 181             if (next != NULL) {
 182                 *next = str;
 183             }
 184             return root;
 185         }
 186
 187         /* look for operators */
 188
 189         for (i = 0; i < NB_OPERATORS; i++) {
 190             keyword_t *operator = operators + i;
 191             if (codecmp (operator->keyword, str) == 0) {
 192                 VERBOSE (DEBUG, fprintf (stdout, "start processing operator\n"));
 193                 if (root) {
 194                     if ((prio) && (prio > operator->prio)) {
 195                         VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 196                         *next = str;
 197                         return root;
 198                     }
 199                     str += operator->offset;
 200                     VERBOSE (INFO, fprintf (stdout, "Oper: %d\n", operator->func));
 201                     if (subparser (&root, &str, operator->func, operator->nbops, operator->prio) == ERROR_OP) {
 202                         delelement (root);
 203                         return ERROR_OP;
 204                     }
 205                 } else if (*str == '-') {
 206                     new = newelement (Sig, 1, 9);
 207                     if (new == NULL) {
 208                         return ERROR_OP;
 209                     }
 210                     root = new;
 211                 } else {
 212                     return ERROR_OP;
 213                 }
 214                 found = 1;
 215                 VERBOSE (DEBUG, fprintf (stdout, "stop processing operator\n"));
 216                 break;
 217             }
 218         }
 219         if (found) {
 220             continue;
 221         }
 222
 223         /* look for functions */
 224
 225         for (i = 0; i < NB_FUNCTIONS; i++) {
 226             keyword_t *function = functions + i;
 227             if (codecmp (function->keyword, str) == 0) {
 228                 VERBOSE (DEBUG, fprintf (stdout, "start processing function\n"));
 229                 if (root == NULL) {
 230                     VERBOSE (INFO, fprintf (stdout, "Func: %d\n", function->func));
 231                     new = newelement (function->func, function->nbops, function->prio);
 232                     if (new == NULL) {
 233                         return ERROR_OP;
 234                     }
 235                     root = new;
 236                 } else {
 237                     delelement (root);
 238                     return ERROR_OP;
 239                 }
 240                 str += function->offset;
 241                 found = 1;
 242                 VERBOSE (DEBUG, fprintf (stdout, "stop processing function\n"));
 243                 break;
 244             }
 245         }
 246         if (found) {
 247             continue;
 248         }
 249
 250         /* look for number */
 251
 252         if (((*str >= '0') && (*str <= '9')) ||
 253             (*str == '.') || (*str == '+') || (*str == '-')) {
 254             VERBOSE (DEBUG, fprintf (stdout, "start processing value\n"));
 255             char *pt;
 256             double value = strtod (str, &pt);
 257             VERBOSE (INFO, fprintf (stdout, "Value: %f\n", value));
 258             if (str != pt) {
 259                 if (root == NULL) {
 260                     new = newelement (Val, 1, 5);
 261                     if (new == NULL) {
 262                         return ERROR_OP;
 263                     }
 264                     new->value = value;
 265                     root = new;
 266                     str = pt;
 267                 } else if (root->func == Val) {
 268                     if ((*str == '+') || (*str == '-')) {
 269                         if ((prio) && (prio > 1)) {
 270                             VERBOSE (DEBUG, fprintf (stdout, "stop because operator priority\n"));
 271                             *next = str;
 272                             return root;
 273                         }
 274                         if (subparser (&root, &str, Add, 2, 1) == ERROR_OP) {
 275                             delelement (root);
 276                             return ERROR_OP;
 277                         }
 278                     } else {
 279                         delelement (root);
 280                         return ERROR_OP;
 281                     }
 282                 } else {
 283                     delelement (root);
 284                     return ERROR_OP;
 285                 }
 286                 found = 1;
 287             }
 288             VERBOSE (DEBUG, fprintf (stdout, "stop processing value\n"));
 289         }
 290
 291         /* error */
 292
 293         if (!found) {
 294             delelement (root);
 295             return ERROR_OP;
 296         }
 297
 298     }
 299
 300     if (next != NULL) {
 301         *next = str;
 302     }
 303
 304     return root;
 305 }
 306
 307 /* print element tree */
 308
 309 void print_element (element_t *root, int level)
 310 {
 311     char *func = NULL;
 312     int i;
 313
 314     if ((root == NULL) || (root == ERROR_OP)) {
 315         return;
 316     }
 317
 318     for (i = 0; i < level; i++) {
 319         fprintf (stdout, " ");
 320     }
 321
 322     switch (root->func) {
 323     case Val: func = "Value"; break;
 324     case Sig: func = "Sign"; break;
 325     case Add: func = "Addition"; break;
 326     case Sub: func = "Subtraction"; break;
 327     case Mul: func = "Multiplication"; break;
 328     case Div: func = "Division"; break;
 329     case Mod: func = "Modulo"; break;
 330     case Pow: func = "Power"; break;
 331     case Sqr: func = "Square Root"; break;
 332     case Cos: func = "Cosine"; break;
 333     case Sin: func = "Sine"; break;
 334     case Atn: func = "Arc Tangent"; break;
 335     case Log: func = "Logarithm"; break;
 336     case Exp: func = "Exponantial"; break;
 337     case Qui: func = "Quit"; break;
 338     case Hel: func = "Help"; break;
 339     }
 340
 341     fprintf (stdout, "Function: %s\n", func);
 342
 343     if ((root->func == Val) && (root->ops[0] == NULL)) {
 344         for (i = 0; i < level; i++) {
 345             fprintf (stdout, " ");
 346         }
 347         fprintf (stdout, "value: %f\n", root->value);
 348     } else {
 349         for (i = 0; i < root->nbops; i++) {
 350             print_element (root->ops[i], level + 1);
 351         }
 352     }
 353 }
 354
 355 /* quit function */
 356
 357 void quit (void)
 358 {
 359     fprintf (stdout, "bye\n");
 360     exit (0);
 361 }
 362
 363 /* help message */
 364
 365 void help (void)
 366 {
 367     fprintf (stdout, "calc is a simple calculator\n\n");
 368     fprintf (stdout, "supported operators:\n");
 369     fprintf (stdout, " + - * / %% ^\n\n");
 370     fprintf (stdout, "supported functions:\n");
 371     fprintf (stdout, " pow sqrt cos sin atan log exp\n\n");
 372     fprintf (stdout, "miscellaneous functions:\n");
 373     fprintf (stdout, " quit help\n");
 374 }
 375
 376 /* evaluate element tree */
 377
 378 #define MASK_SUB 0x1
 379 #define MASK_DIV 0x2
 380
 381 double evaluate_element (element_t *root, char mask)
 382 {
 383     double op0 = 0, op1 = 0;
 384     char nextmask = mask;
 385
 386     if ((root == NULL) || (root == ERROR_OP)) {
 387         VERBOSE (WARNING, fprintf (stdout, "error while evaluating\n"));
 388         return 0;
 389     }
 390
 391     /* mask to manage sub operator sub and div */
 392     switch (root->func) {
 393     case Add:
 394         nextmask &= ~MASK_SUB;
 395         nextmask &= ~MASK_DIV;
 396         break;
 397     case Sub:
 398         nextmask |= MASK_SUB;
 399         nextmask &= ~MASK_DIV;
 400         break;
 401     case Mul:
 402         nextmask &= ~MASK_DIV;
 403         break;
 404     case Div:
 405         nextmask |= MASK_DIV;
 406         break;
 407     default:
 408         nextmask = mask;
 409     }
 410
 411     switch (root->func) {
 412     case Val:
 413     case Sig:
 414         op0 = (root->ops[0]) ? evaluate_element (root->ops[0], nextmask) : root->value;
 415         break;
 416     case Add:
 417     case Sub:
 418     case Mul:
 419     case Div:
 420     case Mod:
 421     case Pow:
 422         if (root->ops[1]) {
 423             op1 = evaluate_element (root->ops[1], nextmask);
 424         } else {
 425             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[1])\n"));
 426             return 0;
 427         }
 428         /* fallthrough */
 429     case Sqr:
 430     case Cos:
 431     case Sin:
 432     case Atn:
 433     case Log:
 434     case Exp:
 435         if (root->ops[0]) {
 436             op0 = evaluate_element (root->ops[0], 0);
 437         } else {
 438             VERBOSE (WARNING, fprintf (stdout, "error while evaluating (op[0])\n"));
 439             return 0;
 440         }
 441         break;
 442     case Qui:
 443     case Hel:
 444         break;
 445     }
 446
 447     switch (root->func) {
 448     case Val: return op0;
 449     case Sig: return -op0;
 450     case Add: return ((mask & MASK_SUB) == 0) ? op0 + op1 : op0 - op1;
 451     case Sub: return ((mask & MASK_SUB) == 0) ? op0 - op1 : op0 + op1;
 452     case Mul: return ((mask & MASK_DIV) == 0) ? op0 * op1 : op0 / op1;
 453     case Div: return ((mask & MASK_DIV) == 0) ? op0 / op1 : op0 * op1;
 454     case Mod: return fmod (op0, op1);
 455     case Pow: return pow (op0, op1);
 456     case Sqr: return sqrt (op0);
 457     case Cos: return cos (op0);
 458     case Sin: return sin (op0);
 459     case Atn: return atan (op0);
 460     case Log: return log (op0);
 461     case Exp: return exp (op0);
 462     case Qui: quit (); break;
 463     case Hel: help (); break;
 464     }
 465
 466     return 0;
 467 }
 468
 469 /* vim: set ts=4 sw=4 et: */