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annotate lwlib/lw_expr.c @ 347:1649bc7bda5a
Some data oriented pseudo ops added
| author | lost@starbug |
|---|---|
| date | Sat, 27 Mar 2010 20:16:24 -0600 |
| parents | a82c55070624 |
| children | 34dfc9747f23 |
| rev | line source |
|---|---|
| 334 | 1 /* |
| 2 lwexpr.c | |
| 3 | |
| 4 Copyright © 2010 William Astle | |
| 5 | |
| 6 This file is part of LWTOOLS. | |
| 7 | |
| 8 LWTOOLS is free software: you can redistribute it and/or modify it under the | |
| 9 terms of the GNU General Public License as published by the Free Software | |
| 10 Foundation, either version 3 of the License, or (at your option) any later | |
| 11 version. | |
| 12 | |
| 13 This program is distributed in the hope that it will be useful, but WITHOUT | |
| 14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
| 16 more details. | |
| 17 | |
| 18 You should have received a copy of the GNU General Public License along with | |
| 19 this program. If not, see <http://www.gnu.org/licenses/>. | |
| 20 */ | |
| 21 | |
| 22 #include <config.h> | |
| 23 | |
| 24 #include <stdarg.h> | |
| 25 #include <stdio.h> | |
| 26 #include <string.h> | |
| 27 | |
| 28 #define ___lw_expr_c_seen___ | |
| 29 #include "lw_alloc.h" | |
| 30 #include "lw_expr.h" | |
| 31 #include "lw_error.h" | |
| 32 #include "lw_string.h" | |
| 33 | |
| 342 | 34 static lw_expr_fn_t *evaluate_special = NULL; |
| 35 static lw_expr_fn2_t *evaluate_var = NULL; | |
|
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36 static lw_expr_fn3_t *parse_term = NULL; |
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37 |
| 347 | 38 int lw_expr_istype(lw_expr_t e, int t) |
| 39 { | |
| 40 if (e -> type == t) | |
| 41 return 1; | |
| 42 return 0; | |
| 43 } | |
| 44 | |
| 45 int lw_expr_intval(lw_expr_t e) | |
| 46 { | |
| 47 if (e -> type == lw_expr_type_int) | |
| 48 return e -> value; | |
| 49 return -1; | |
| 50 } | |
| 51 | |
|
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52 void lw_expr_set_term_parser(lw_expr_fn3_t *fn) |
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53 { |
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54 parse_term = fn; |
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55 } |
| 337 | 56 |
| 342 | 57 void lw_expr_set_special_handler(lw_expr_fn_t *fn) |
| 337 | 58 { |
| 59 evaluate_special = fn; | |
| 60 } | |
| 61 | |
| 342 | 62 void lw_expr_set_var_handler(lw_expr_fn2_t *fn) |
| 337 | 63 { |
| 64 evaluate_var = fn; | |
| 65 } | |
| 66 | |
| 334 | 67 lw_expr_t lw_expr_create(void) |
| 68 { | |
| 69 lw_expr_t r; | |
| 70 | |
| 71 r = lw_alloc(sizeof(struct lw_expr_priv)); | |
| 72 r -> operands = NULL; | |
| 73 | |
| 74 return r; | |
| 75 } | |
| 76 | |
| 77 void lw_expr_destroy(lw_expr_t E) | |
| 78 { | |
| 337 | 79 struct lw_expr_opers *o; |
| 80 for (o = E -> operands; o; o = o -> next) | |
| 81 lw_expr_destroy(o -> p); | |
| 82 if (E -> type == lw_expr_type_var) | |
| 83 lw_free(E -> value2); | |
| 84 lw_free(E); | |
| 334 | 85 } |
| 86 | |
| 337 | 87 /* actually duplicates the entire expression */ |
| 88 void lw_expr_add_operand(lw_expr_t E, lw_expr_t O); | |
| 334 | 89 lw_expr_t lw_expr_copy(lw_expr_t E) |
| 90 { | |
| 337 | 91 lw_expr_t r, t; |
| 92 struct lw_expr_opers *o; | |
| 93 | |
| 94 r = lw_alloc(sizeof(struct lw_expr_priv)); | |
| 95 *r = *E; | |
| 96 r -> operands = NULL; | |
| 97 | |
| 98 if (E -> type == lw_expr_type_var) | |
| 99 r -> value2 = lw_strdup(E -> value2); | |
| 100 for (o = E -> operands; o; o = o -> next) | |
| 101 { | |
| 102 lw_expr_add_operand(r, lw_expr_copy(o -> p)); | |
| 103 } | |
| 104 | |
| 105 return r; | |
| 334 | 106 } |
| 107 | |
| 108 void lw_expr_add_operand(lw_expr_t E, lw_expr_t O) | |
| 109 { | |
| 110 struct lw_expr_opers *o, *t; | |
| 111 | |
| 112 o = lw_alloc(sizeof(struct lw_expr_opers)); | |
| 113 o -> p = lw_expr_copy(O); | |
| 114 o -> next = NULL; | |
| 115 for (t = E -> operands; t && t -> next; t = t -> next) | |
| 116 /* do nothing */ ; | |
| 117 | |
| 118 if (t) | |
| 119 t -> next = o; | |
| 120 else | |
| 121 E -> operands = o; | |
| 122 } | |
| 123 | |
| 335 | 124 lw_expr_t lw_expr_build_aux(int exprtype, va_list args) |
| 334 | 125 { |
| 126 lw_expr_t r; | |
| 127 int t; | |
| 128 void *p; | |
| 129 | |
| 130 lw_expr_t te1, te2; | |
| 131 | |
| 132 r = lw_expr_create(); | |
| 133 | |
| 134 switch (exprtype) | |
| 135 { | |
| 136 case lw_expr_type_int: | |
| 137 t = va_arg(args, int); | |
| 138 r -> type = lw_expr_type_int; | |
| 139 r -> value = t; | |
| 140 break; | |
| 141 | |
| 142 case lw_expr_type_var: | |
| 143 p = va_arg(args, char *); | |
| 144 r -> type = lw_expr_type_var; | |
| 145 r -> value2 = lw_strdup(p); | |
| 146 break; | |
| 147 | |
| 148 case lw_expr_type_special: | |
| 149 t = va_arg(args, int); | |
| 150 p = va_arg(args, char *); | |
| 151 r -> type = lw_expr_type_special; | |
| 337 | 152 r -> value = t; |
| 334 | 153 r -> value2 = p; |
| 154 break; | |
| 155 | |
| 156 case lw_expr_type_oper: | |
| 157 t = va_arg(args, int); | |
| 158 te1 = va_arg(args, lw_expr_t); | |
| 159 if (t != lw_expr_oper_com && t != lw_expr_oper_neg) | |
| 160 te2 = va_arg(args, lw_expr_t); | |
| 161 else | |
| 162 te2 = NULL; | |
| 163 | |
| 164 r -> type = lw_expr_type_oper; | |
| 165 r -> value = t; | |
| 166 lw_expr_add_operand(r, te1); | |
| 167 lw_expr_add_operand(r, te2); | |
| 168 break; | |
| 169 | |
| 170 default: | |
| 171 lw_error("Invalid expression type specified to lw_expr_build"); | |
| 172 } | |
| 173 | |
| 335 | 174 return r; |
| 175 } | |
| 176 | |
| 177 lw_expr_t lw_expr_build(int exprtype, ...) | |
| 178 { | |
| 179 va_list args; | |
| 180 lw_expr_t r; | |
| 181 | |
| 182 va_start(args, exprtype); | |
| 183 r = lw_expr_build_aux(exprtype, args); | |
| 184 va_end(args); | |
| 185 return r; | |
| 186 } | |
| 187 | |
| 334 | 188 void lw_expr_print(lw_expr_t E) |
| 189 { | |
| 190 struct lw_expr_opers *o; | |
| 335 | 191 int c = 0; |
| 192 | |
| 334 | 193 for (o = E -> operands; o; o = o -> next) |
| 194 { | |
| 335 | 195 c++; |
| 334 | 196 lw_expr_print(o -> p); |
| 197 } | |
| 198 | |
| 199 switch (E -> type) | |
| 200 { | |
| 201 case lw_expr_type_int: | |
| 202 printf("%d ", E -> value); | |
| 203 break; | |
| 335 | 204 |
| 205 case lw_expr_type_var: | |
| 206 printf("V(%s) ", (char *)(E -> value2)); | |
| 207 break; | |
| 208 | |
| 209 case lw_expr_type_special: | |
| 210 printf("S(%d,%p) ", E -> value, E -> value2); | |
| 211 break; | |
| 212 | |
| 334 | 213 case lw_expr_type_oper: |
| 335 | 214 printf("[%d]", c); |
| 334 | 215 switch (E -> value) |
| 216 { | |
| 217 case lw_expr_oper_plus: | |
| 218 printf("+ "); | |
| 219 break; | |
| 220 | |
| 221 case lw_expr_oper_minus: | |
| 222 printf("- "); | |
| 223 break; | |
| 224 | |
| 225 case lw_expr_oper_times: | |
| 226 printf("* "); | |
| 227 break; | |
| 228 | |
| 229 case lw_expr_oper_divide: | |
| 230 printf("/ "); | |
| 231 break; | |
| 232 | |
| 233 case lw_expr_oper_mod: | |
| 234 printf("%% "); | |
| 235 break; | |
| 236 | |
| 237 case lw_expr_oper_intdiv: | |
| 238 printf("\\ "); | |
| 239 break; | |
| 240 | |
| 241 case lw_expr_oper_bwand: | |
| 242 printf("BWAND "); | |
| 243 break; | |
| 244 | |
| 245 case lw_expr_oper_bwor: | |
| 246 printf("BWOR "); | |
| 247 break; | |
| 248 | |
| 249 case lw_expr_oper_bwxor: | |
| 250 printf("BWXOR "); | |
| 251 break; | |
| 252 | |
| 253 case lw_expr_oper_and: | |
| 254 printf("AND "); | |
| 255 break; | |
| 256 | |
| 257 case lw_expr_oper_or: | |
| 258 printf("OR "); | |
| 259 break; | |
| 260 | |
| 261 case lw_expr_oper_neg: | |
| 262 printf("NEG "); | |
| 263 break; | |
| 264 | |
| 265 case lw_expr_oper_com: | |
| 266 printf("COM "); | |
| 267 break; | |
| 268 | |
| 269 default: | |
| 270 printf("OPER "); | |
| 271 break; | |
| 272 } | |
| 273 break; | |
| 274 default: | |
| 275 printf("ERR "); | |
| 276 break; | |
| 277 } | |
| 278 } | |
| 279 | |
| 280 /* | |
| 281 Return: | |
| 282 nonzero if expressions are the same (identical pointers or matching values) | |
| 283 zero if expressions are not the same | |
| 284 | |
| 285 */ | |
| 286 int lw_expr_compare(lw_expr_t E1, lw_expr_t E2) | |
| 287 { | |
| 288 struct lw_expr_opers *o1, *o2; | |
| 289 | |
| 290 if (E1 == E2) | |
| 291 return 1; | |
| 292 | |
| 293 if (!(E1 -> type == E2 -> type && E1 -> value == E2 -> value)) | |
| 294 return 0; | |
| 295 | |
| 296 if (E1 -> type == lw_expr_type_var) | |
| 297 { | |
| 298 if (!strcmp(E1 -> value2, E2 -> value2)) | |
| 299 return 1; | |
| 300 else | |
| 301 return 0; | |
| 302 } | |
| 303 | |
| 304 if (E1 -> type == lw_expr_type_special) | |
| 305 { | |
| 306 if (E1 -> value2 == E2 -> value2) | |
| 307 return 1; | |
| 308 else | |
| 309 return 0; | |
| 310 } | |
| 311 | |
| 312 for (o1 = E1 -> operands, o2 = E2 -> operands; o1 && o2; o1 = o1 -> next, o2 = o2 -> next) | |
| 313 if (lw_expr_compare(o1 -> p, o2 -> p) == 0) | |
| 314 return 0; | |
| 315 if (o1 || o2) | |
| 316 return 0; | |
| 317 | |
| 318 return 1; | |
| 319 } | |
| 320 | |
| 321 /* return true if E is an operator of type oper */ | |
| 322 int lw_expr_isoper(lw_expr_t E, int oper) | |
| 323 { | |
| 324 if (E -> type == lw_expr_type_oper && E -> value == oper) | |
| 325 return 1; | |
| 326 return 0; | |
| 327 } | |
| 335 | 328 |
| 329 | |
| 330 void lw_expr_simplify_sortconstfirst(lw_expr_t E) | |
| 331 { | |
| 332 struct lw_expr_opers *o; | |
| 333 | |
| 334 for (o = E -> operands; o; o = o -> next) | |
| 335 lw_expr_simplify_sortconstfirst(o -> p); | |
| 336 | |
| 337 for (o = E -> operands; o; o = o -> next) | |
| 338 { | |
| 339 if (o -> p -> type == lw_expr_type_int && o != E -> operands) | |
| 340 { | |
| 341 struct lw_expr_opers *o2; | |
| 342 for (o2 = E -> operands; o2 -> next != o; o2 = o2 -> next) | |
| 343 /* do nothing */ ; | |
| 344 o2 -> next = o -> next; | |
| 345 o -> next = E -> operands; | |
| 346 E -> operands = o; | |
| 347 o = o2; | |
| 348 } | |
| 349 } | |
| 350 } | |
| 351 | |
| 336 | 352 void lw_expr_sortoperandlist(struct lw_expr_opers **o) |
| 353 { | |
| 354 fprintf(stderr, "lw_expr_sortoperandlist() not yet implemented\n"); | |
| 355 } | |
| 356 | |
| 335 | 357 // return 1 if the operand lists match, 0 if not |
| 358 // may re-order the argument lists | |
| 359 int lw_expr_simplify_compareoperandlist(struct lw_expr_opers **ol1, struct lw_expr_opers **ol2) | |
| 360 { | |
| 361 struct lw_expr_opers *o1, *o2; | |
| 362 | |
| 363 lw_expr_sortoperandlist(ol1); | |
| 364 lw_expr_sortoperandlist(ol2); | |
| 365 | |
| 366 for (o1 = *ol1, o2 = *ol2; o1 && o2; o1 = o1 -> next, o2 = o2 -> next) | |
| 367 { | |
| 368 if (!lw_expr_compare(o1 -> p, o2 -> p)) | |
| 369 return 0; | |
| 370 } | |
| 371 if (o1 || o2) | |
| 372 return 0; | |
| 373 return 1; | |
| 374 } | |
| 375 | |
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376 void lw_expr_simplify(lw_expr_t E, void *priv) |
| 335 | 377 { |
| 378 struct lw_expr_opers *o; | |
| 379 | |
| 337 | 380 again: |
| 381 // try to resolve non-constant terms to constants here | |
| 382 if (E -> type == lw_expr_type_special && evaluate_special) | |
| 383 { | |
| 384 lw_expr_t te; | |
| 385 | |
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386 te = evaluate_special(E -> value, E -> value2, priv); |
| 337 | 387 if (te) |
| 388 { | |
| 389 for (o = E -> operands; o; o = o -> next) | |
| 390 lw_expr_destroy(o -> p); | |
| 391 if (E -> type == lw_expr_type_var) | |
| 392 lw_free(E -> value2); | |
| 393 *E = *te; | |
| 394 E -> operands = NULL; | |
| 395 | |
| 396 if (te -> type == lw_expr_type_var) | |
| 397 E -> value2 = lw_strdup(te -> value2); | |
| 398 for (o = te -> operands; o; o = o -> next) | |
| 399 { | |
| 400 lw_expr_add_operand(E, lw_expr_copy(o -> p)); | |
| 401 } | |
| 402 lw_expr_destroy(te); | |
| 403 goto again; | |
| 404 } | |
| 405 return; | |
| 406 } | |
| 407 | |
| 408 if (E -> type == lw_expr_type_var && evaluate_var) | |
| 409 { | |
| 410 lw_expr_t te; | |
| 411 | |
|
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412 te = evaluate_var(E -> value2, priv); |
| 337 | 413 if (te) |
| 414 { | |
| 415 for (o = E -> operands; o; o = o -> next) | |
| 416 lw_expr_destroy(o -> p); | |
| 417 if (E -> type == lw_expr_type_var) | |
| 418 lw_free(E -> value2); | |
| 419 *E = *te; | |
| 420 E -> operands = NULL; | |
| 421 | |
| 422 if (te -> type == lw_expr_type_var) | |
| 423 E -> value2 = lw_strdup(te -> value2); | |
| 424 for (o = te -> operands; o; o = o -> next) | |
| 425 { | |
| 426 lw_expr_add_operand(E, lw_expr_copy(o -> p)); | |
| 427 } | |
| 428 lw_expr_destroy(te); | |
| 429 goto again; | |
| 430 } | |
| 431 return; | |
| 432 } | |
| 433 | |
| 434 // non-operators have no simplification to do! | |
| 435 if (E -> type != lw_expr_type_oper) | |
| 436 return; | |
| 437 | |
| 335 | 438 // sort "constants" to the start of each operand list for + and * |
| 439 lw_expr_simplify_sortconstfirst(E); | |
| 440 | |
| 337 | 441 // simplify operands |
| 442 for (o = E -> operands; o; o = o -> next) | |
|
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443 lw_expr_simplify(o -> p, priv); |
| 337 | 444 |
| 445 for (o = E -> operands; o; o = o -> next) | |
| 446 { | |
| 447 if (o -> p -> type != lw_expr_type_int) | |
| 448 break; | |
| 449 } | |
| 450 | |
| 451 if (!o) | |
| 452 { | |
| 453 // we can do the operation here! | |
| 454 int tr = -42424242; | |
| 455 | |
| 456 switch (E -> value) | |
| 457 { | |
| 458 case lw_expr_oper_neg: | |
| 459 tr = -(E -> operands -> p -> value); | |
| 460 break; | |
| 461 | |
| 462 case lw_expr_oper_com: | |
| 463 tr = ~(E -> operands -> p -> value); | |
| 464 break; | |
| 465 | |
| 466 case lw_expr_oper_plus: | |
| 467 tr = E -> operands -> p -> value; | |
| 468 for (o = E -> operands -> next; o; o = o -> next) | |
| 469 tr += o -> p -> value; | |
| 470 break; | |
| 471 | |
| 472 case lw_expr_oper_minus: | |
| 473 tr = E -> operands -> p -> value; | |
| 474 for (o = E -> operands -> next; o; o = o -> next) | |
| 475 tr -= o -> p -> value; | |
| 476 break; | |
| 477 | |
| 478 case lw_expr_oper_times: | |
| 479 tr = E -> operands -> p -> value; | |
| 480 for (o = E -> operands -> next; o; o = o -> next) | |
| 481 tr *= o -> p -> value; | |
| 482 break; | |
| 483 | |
| 484 case lw_expr_oper_divide: | |
| 485 tr = E -> operands -> p -> value / E -> operands -> next -> p -> value; | |
| 486 break; | |
| 487 | |
| 488 case lw_expr_oper_mod: | |
| 489 tr = E -> operands -> p -> value % E -> operands -> next -> p -> value; | |
| 490 break; | |
| 491 | |
| 492 case lw_expr_oper_intdiv: | |
| 493 tr = E -> operands -> p -> value / E -> operands -> next -> p -> value; | |
| 494 break; | |
| 495 | |
| 496 case lw_expr_oper_bwand: | |
| 497 tr = E -> operands -> p -> value & E -> operands -> next -> p -> value; | |
| 498 break; | |
| 499 | |
| 500 case lw_expr_oper_bwor: | |
| 501 tr = E -> operands -> p -> value | E -> operands -> next -> p -> value; | |
| 502 break; | |
| 503 | |
| 504 case lw_expr_oper_bwxor: | |
| 505 tr = E -> operands -> p -> value ^ E -> operands -> next -> p -> value; | |
| 506 break; | |
| 507 | |
| 508 case lw_expr_oper_and: | |
| 509 tr = E -> operands -> p -> value && E -> operands -> next -> p -> value; | |
| 510 break; | |
| 511 | |
| 512 case lw_expr_oper_or: | |
| 513 tr = E -> operands -> p -> value || E -> operands -> next -> p -> value; | |
| 514 break; | |
| 515 | |
| 516 } | |
| 517 | |
| 518 while (E -> operands) | |
| 519 { | |
| 520 o = E -> operands; | |
| 521 E -> operands = o -> next; | |
| 522 lw_expr_destroy(o -> p); | |
| 523 lw_free(o); | |
| 524 } | |
| 525 E -> type = lw_expr_type_int; | |
| 526 E -> value = tr; | |
| 335 | 527 return; |
| 337 | 528 } |
| 335 | 529 |
| 530 if (E -> value == lw_expr_oper_times) | |
| 531 { | |
| 532 for (o = E -> operands; o; o = o -> next) | |
| 533 { | |
| 534 if (o -> p -> type == lw_expr_type_int && o -> p -> value == 0) | |
| 535 { | |
| 536 // one operand of times is 0, replace operation with 0 | |
| 537 while (E -> operands) | |
| 538 { | |
| 539 o = E -> operands; | |
| 540 E -> operands = o -> next; | |
| 541 lw_expr_destroy(o -> p); | |
| 542 lw_free(o); | |
| 543 } | |
| 544 E -> type = lw_expr_type_int; | |
| 545 E -> value = 0; | |
| 546 return; | |
| 547 } | |
| 548 } | |
| 549 } | |
| 550 | |
| 551 // look for like terms and collect them together | |
| 552 if (E -> value == lw_expr_oper_plus) | |
| 553 { | |
| 554 for (o = E -> operands; o; o = o -> next) | |
| 555 { | |
| 556 if (o -> p -> type == lw_expr_type_oper && o -> p -> value == lw_expr_oper_times) | |
| 557 { | |
| 558 // we have a "times" here | |
| 559 // find first non-const operand | |
| 560 struct lw_expr_opers *op1, *op2, *o2; | |
| 561 for (op1 = o -> p -> operands; op1; op1 = op1 -> next) | |
| 562 if (op1 -> p -> type != lw_expr_type_int) | |
| 563 break; | |
| 564 | |
| 565 for (o2 = o -> next; o2; o2 = o2 -> next) | |
| 566 { | |
| 567 if (o2 -> p -> type == lw_expr_type_oper && o2 -> p -> value == lw_expr_oper_times) | |
| 568 { | |
| 569 // another "times" | |
| 570 for (op2 = o2 -> p -> operands; op2; op2 = op2 -> next) | |
| 571 if (op2 -> p -> type != lw_expr_type_int) | |
| 572 break; | |
| 573 | |
| 336 | 574 if (lw_expr_simplify_compareoperandlist(&op1, &op2)) |
| 335 | 575 { |
| 576 // we have like terms here | |
| 577 // do something about it | |
| 578 } | |
| 579 } | |
| 580 } | |
| 581 } | |
| 582 } | |
| 583 } | |
| 584 | |
| 585 | |
| 586 if (E -> value == lw_expr_oper_plus) | |
| 587 { | |
| 588 int c = 0, t = 0; | |
| 589 for (o = E -> operands; o; o = o -> next) | |
| 590 { | |
| 591 t++; | |
| 592 if (!(o -> p -> type == lw_expr_type_int && o -> p -> value == 0)) | |
| 593 { | |
| 594 c++; | |
| 595 } | |
| 596 } | |
| 597 if (c == 1) | |
| 598 { | |
| 599 lw_expr_t r; | |
| 600 // find the value and "move it up" | |
| 601 while (E -> operands) | |
| 602 { | |
| 603 o = E -> operands; | |
| 604 if (o -> p -> type != lw_expr_type_int || o -> p -> value != 0) | |
| 605 { | |
| 337 | 606 r = lw_expr_copy(o -> p); |
| 335 | 607 } |
| 608 E -> operands = o -> next; | |
| 609 lw_expr_destroy(o -> p); | |
| 610 lw_free(o); | |
| 611 } | |
| 612 *E = *r; | |
| 613 return; | |
| 614 } | |
| 615 else if (c == 0) | |
| 616 { | |
| 617 // replace with 0 | |
| 618 while (E -> operands) | |
| 619 { | |
| 620 o = E -> operands; | |
| 621 E -> operands = o -> next; | |
| 622 lw_expr_destroy(o -> p); | |
| 623 lw_free(o); | |
| 624 } | |
| 625 E -> type = lw_expr_type_int; | |
| 626 E -> value = 0; | |
| 627 return; | |
| 628 } | |
| 629 else if (c != t) | |
| 630 { | |
| 631 // collapse out zero terms | |
| 632 struct lw_expr_opers *o2; | |
| 633 | |
| 634 for (o = E -> operands; o; o = o -> next) | |
| 635 { | |
| 636 if (o -> p -> type == lw_expr_type_int && o -> p -> value == 0) | |
| 637 { | |
| 638 if (o == E -> operands) | |
| 639 { | |
| 640 E -> operands = o -> next; | |
| 641 lw_expr_destroy(o -> p); | |
| 642 lw_free(o); | |
| 643 o = E -> operands; | |
| 644 } | |
| 645 else | |
| 646 { | |
| 647 for (o2 = E -> operands; o2 -> next == o; o2 = o2 -> next) | |
| 648 /* do nothing */ ; | |
| 649 o2 -> next = o -> next; | |
| 650 lw_expr_destroy(o -> p); | |
| 651 lw_free(o); | |
| 652 o = o2; | |
| 653 } | |
| 654 } | |
| 655 } | |
| 656 } | |
| 657 return; | |
| 658 } | |
| 659 } | |
|
346
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660 |
|
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661 /* |
|
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|
662 |
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|
663 The following two functions are co-routines which evaluate an infix |
|
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|
664 expression. lw_expr_parse_term checks for unary prefix operators then, if |
|
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|
665 none found, passes the string off the the defined helper function to |
|
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|
666 determine what the term really is. It also handles parentheses. |
|
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|
667 |
|
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|
668 lw_expr_parse_expr evaluates actual expressions with infix operators. It |
|
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|
669 respects the order of operations. |
|
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|
670 |
|
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|
671 The end of an expression is determined by the presence of any of the |
|
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|
672 following conditions: |
|
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|
673 |
|
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|
674 1. a NUL character |
|
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|
675 2. a whitespace character |
|
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|
676 3. a ) |
|
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|
677 4. a , |
|
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|
678 5. any character that is not recognized as a term |
|
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|
679 |
|
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|
680 lw_expr_parse_term returns NULL if there is no term (end of expr, etc.) |
|
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|
681 |
|
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|
682 lw_expr_parse_expr returns NULL if there is no expression or on a syntax |
|
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|
683 error. |
|
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|
684 |
|
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|
685 */ |
|
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|
686 |
|
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|
687 lw_expr_t lw_expr_parse_expr(char **p, void *priv, int prec); |
|
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|
688 |
|
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|
689 lw_expr_t lw_expr_parse_term(char **p, void *priv) |
|
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diff
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|
690 { |
|
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|
691 lw_expr_t term, term2; |
|
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diff
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|
692 |
|
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|
693 eval_next: |
|
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|
694 if (!**p || isspace(**p) || **p == ')' || **p == ']') |
|
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|
695 return NULL; |
|
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diff
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|
696 |
|
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|
697 // parentheses |
|
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|
698 if (**p == '(') |
|
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diff
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|
699 { |
|
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|
700 (*p)++; |
|
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|
701 term = lw_expr_parse_expr(p, priv, 0); |
|
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|
702 if (**p != ')') |
|
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diff
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|
703 { |
|
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|
704 lw_expr_destroy(term); |
|
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|
705 return NULL; |
|
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|
706 } |
|
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|
707 (*p)++; |
|
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|
708 return term; |
|
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|
709 } |
|
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diff
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|
710 |
|
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|
711 // unary + |
|
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|
712 if (**p == '+') |
|
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diff
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|
713 { |
|
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|
714 (*p)++; |
|
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|
715 goto eval_next; |
|
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|
716 } |
|
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|
717 |
|
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|
718 // unary - (prec 200) |
|
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diff
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|
719 if (**p == '-') |
|
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diff
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|
720 { |
|
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diff
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|
721 (*p)++; |
|
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|
722 term = lw_expr_parse_expr(p, priv, 200); |
|
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diff
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|
723 if (!term) |
|
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|
724 return NULL; |
|
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diff
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|
725 |
|
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diff
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|
726 term2 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_neg, term); |
|
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diff
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|
727 lw_expr_destroy(term); |
|
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diff
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|
728 return term2; |
|
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342
diff
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|
729 } |
|
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342
diff
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|
730 |
|
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342
diff
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|
731 // unary ^ or ~ (complement, prec 200) |
|
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342
diff
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|
732 if (**p == '^' || **p == '~') |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
733 { |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
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|
734 (*p)++; |
|
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342
diff
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|
735 term = lw_expr_parse_expr(p, priv, 200); |
|
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diff
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|
736 if (!term) |
|
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342
diff
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|
737 return NULL; |
|
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342
diff
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|
738 |
|
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diff
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|
739 term2 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_com, term); |
|
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diff
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|
740 lw_expr_destroy(term); |
|
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342
diff
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|
741 return term2; |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
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|
742 } |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
743 |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
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|
744 // non-operator - pass to caller |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
745 return parse_term(p, priv); |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
746 } |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
747 |
|
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diff
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|
748 lw_expr_t lw_expr_parse_expr(char **p, void *priv, int prec) |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
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|
749 { |
|
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342
diff
changeset
|
750 static const struct operinfo |
|
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342
diff
changeset
|
751 { |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
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|
752 int opernum; |
|
a82c55070624
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342
diff
changeset
|
753 char *operstr; |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
754 int operprec; |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
755 } operators[] = |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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diff
changeset
|
756 { |
|
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342
diff
changeset
|
757 { lw_expr_oper_plus, "+", 100 }, |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
758 { lw_expr_oper_minus, "-", 100 }, |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
759 { lw_expr_oper_times, "*", 100 }, |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
760 { lw_expr_oper_divide, "/", 150 }, |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
761 { lw_expr_oper_mod, "%", 150 }, |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
762 { lw_expr_oper_intdiv, "\\", 150 }, |
|
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342
diff
changeset
|
763 |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
764 { lw_expr_oper_and, "&&", 25 }, |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
765 { lw_expr_oper_or, "||", 25 }, |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
766 |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
767 { lw_expr_oper_bwand, "&", 50 }, |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
768 { lw_expr_oper_bwor, "|", 50 }, |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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parents:
342
diff
changeset
|
769 { lw_expr_oper_bwxor, "^", 50 }, |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
770 |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
771 { lw_expr_oper_none, "", 0 } |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
772 }; |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
773 |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
774 int opern, i; |
|
a82c55070624
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342
diff
changeset
|
775 lw_expr_t term1, term2, term3; |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
776 |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
777 if (!**p || isspace(**p) || **p == ')' || **p == ',' || **p == ']') |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
778 return NULL; |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
779 |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
780 term1 = lw_expr_parse_term(p, priv); |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
781 if (!term1) |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
782 return NULL; |
|
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Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
783 |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
784 eval_next: |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
785 if (!**p || isspace(**p) || **p == ')' || **p == ',' || **p == ']') |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
786 return term1; |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
787 |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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parents:
342
diff
changeset
|
788 // expecting an operator here |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
789 for (opern = 0; operators[opern].opernum != lw_expr_oper_none; opern++) |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
790 { |
|
a82c55070624
Added expression parsing infrastructure and misc fixes
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342
diff
changeset
|
791 for (i = 0; (*p)[i] && operators[opern].operstr[i] && ((*p)[i] == operators[opern].operstr[i]); i++) |
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792 /* do nothing */; |
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793 if (operators[opern].operstr[i] == '\0') |
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794 break; |
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795 } |
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796 |
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797 if (operators[opern].opernum == lw_expr_oper_none) |
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798 { |
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799 // unrecognized operator |
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800 lw_expr_destroy(term1); |
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801 return NULL; |
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802 } |
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803 |
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804 // operator number is in opern, length of oper in i |
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805 |
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806 // logic: |
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807 // if the precedence of this operation is <= to the "prec" flag, |
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808 // we simply return without advancing the input pointer; the operator |
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809 // will be evaluated again in the enclosing function call |
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810 if (operators[opern].operprec <= prec) |
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811 return term1; |
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812 |
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813 // logic: |
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814 // we have a higher precedence operator here so we will advance the |
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815 // input pointer to the next term and let the expression evaluator |
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816 // loose on it after which time we will push our operator onto the |
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817 // stack and then go on with the expression evaluation |
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818 (*p) += i; |
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819 |
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820 // evaluate next expression(s) of higher precedence |
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821 term2 = lw_expr_parse_expr(p, priv, operators[opern].operprec); |
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822 if (!term2) |
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823 { |
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824 lw_expr_destroy(term1); |
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825 return NULL; |
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826 } |
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827 |
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828 // now create operator |
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829 term3 = lw_expr_build(lw_expr_type_oper, operators[opern].opernum, term1, term2); |
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830 lw_expr_destroy(term1); |
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831 lw_expr_destroy(term2); |
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832 |
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833 // the new "expression" is the next "left operand" |
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834 term1 = term3; |
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835 |
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836 // continue evaluating |
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837 goto eval_next; |
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838 } |
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839 |
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840 lw_expr_t lw_expr_parse(char **p, void *priv) |
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841 { |
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842 return lw_expr_parse_expr(p, priv, 0); |
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843 } |