parser.c

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