1 /* $NetBSD: expr.c,v 1.4 1999/10/20 15:49:15 hubertf Exp $ */ 2 3 /* 4 * Korn expression evaluation 5 */ 6 /* 7 * todo: better error handling: if in builtin, should be builtin error, etc. 8 */ 9 10 #include "sh.h" 11 #include <ctype.h> 12 13 14 /* The order of these enums is constrained by the order of opinfo[] */ 15 enum token { 16 /* some (long) unary operators */ 17 O_PLUSPLUS = 0, O_MINUSMINUS, 18 /* binary operators */ 19 O_EQ, O_NE, 20 /* assignments are assumed to be in range O_ASN .. O_BORASN */ 21 O_ASN, O_TIMESASN, O_DIVASN, O_MODASN, O_PLUSASN, O_MINUSASN, 22 O_LSHIFTASN, O_RSHIFTASN, O_BANDASN, O_BXORASN, O_BORASN, 23 O_LSHIFT, O_RSHIFT, 24 O_LE, O_GE, O_LT, O_GT, 25 O_LAND, 26 O_LOR, 27 O_TIMES, O_DIV, O_MOD, 28 O_PLUS, O_MINUS, 29 O_BAND, 30 O_BXOR, 31 O_BOR, 32 O_TERN, 33 O_COMMA, 34 /* things after this aren't used as binary operators */ 35 /* unary that are not also binaries */ 36 O_BNOT, O_LNOT, 37 /* misc */ 38 OPEN_PAREN, CLOSE_PAREN, CTERN, 39 /* things that don't appear in the opinfo[] table */ 40 VAR, LIT, END, BAD 41 }; 42 #define IS_BINOP(op) (((int)op) >= (int)O_EQ && ((int)op) <= (int)O_COMMA) 43 #define IS_ASSIGNOP(op) ((int)(op) >= (int)O_ASN && (int)(op) <= (int)O_BORASN) 44 45 enum prec { 46 P_PRIMARY = 0, /* VAR, LIT, (), ~ ! - + */ 47 P_MULT, /* * / % */ 48 P_ADD, /* + - */ 49 P_SHIFT, /* << >> */ 50 P_RELATION, /* < <= > >= */ 51 P_EQUALITY, /* == != */ 52 P_BAND, /* & */ 53 P_BXOR, /* ^ */ 54 P_BOR, /* | */ 55 P_LAND, /* && */ 56 P_LOR, /* || */ 57 P_TERN, /* ?: */ 58 P_ASSIGN, /* = *= /= %= += -= <<= >>= &= ^= |= */ 59 P_COMMA /* , */ 60 }; 61 #define MAX_PREC P_COMMA 62 63 struct opinfo { 64 char name[4]; 65 int len; /* name length */ 66 enum prec prec; /* precidence: lower is higher */ 67 }; 68 69 /* Tokens in this table must be ordered so the longest are first 70 * (eg, += before +). If you change something, change the order 71 * of enum token too. 72 */ 73 static const struct opinfo opinfo[] = { 74 { "++", 2, P_PRIMARY }, /* before + */ 75 { "--", 2, P_PRIMARY }, /* before - */ 76 { "==", 2, P_EQUALITY }, /* before = */ 77 { "!=", 2, P_EQUALITY }, /* before ! */ 78 { "=", 1, P_ASSIGN }, /* keep assigns in a block */ 79 { "*=", 2, P_ASSIGN }, 80 { "/=", 2, P_ASSIGN }, 81 { "%=", 2, P_ASSIGN }, 82 { "+=", 2, P_ASSIGN }, 83 { "-=", 2, P_ASSIGN }, 84 { "<<=", 3, P_ASSIGN }, 85 { ">>=", 3, P_ASSIGN }, 86 { "&=", 2, P_ASSIGN }, 87 { "^=", 2, P_ASSIGN }, 88 { "|=", 2, P_ASSIGN }, 89 { "<<", 2, P_SHIFT }, 90 { ">>", 2, P_SHIFT }, 91 { "<=", 2, P_RELATION }, 92 { ">=", 2, P_RELATION }, 93 { "<", 1, P_RELATION }, 94 { ">", 1, P_RELATION }, 95 { "&&", 2, P_LAND }, 96 { "||", 2, P_LOR }, 97 { "*", 1, P_MULT }, 98 { "/", 1, P_MULT }, 99 { "%", 1, P_MULT }, 100 { "+", 1, P_ADD }, 101 { "-", 1, P_ADD }, 102 { "&", 1, P_BAND }, 103 { "^", 1, P_BXOR }, 104 { "|", 1, P_BOR }, 105 { "?", 1, P_TERN }, 106 { ",", 1, P_COMMA }, 107 { "~", 1, P_PRIMARY }, 108 { "!", 1, P_PRIMARY }, 109 { "(", 1, P_PRIMARY }, 110 { ")", 1, P_PRIMARY }, 111 { ":", 1, P_PRIMARY }, 112 { "", 0, P_PRIMARY } /* end of table */ 113 }; 114 115 116 typedef struct expr_state Expr_state; 117 struct expr_state { 118 const char *expression; /* expression being evaluated */ 119 const char *tokp; /* lexical position */ 120 enum token tok; /* token from token() */ 121 int noassign; /* don't do assigns (for ?:,&&,||) */ 122 struct tbl *val; /* value from token() */ 123 struct tbl *evaling; /* variable that is being recursively 124 * expanded (EXPRINEVAL flag set) 125 */ 126 }; 127 128 enum error_type { ET_UNEXPECTED, ET_BADLIT, ET_RECURSIVE, 129 ET_LVALUE, ET_RDONLY, ET_STR }; 130 131 static void evalerr ARGS((Expr_state *es, enum error_type type, 132 const char *str)) GCC_FUNC_ATTR(noreturn); 133 static struct tbl *evalexpr ARGS((Expr_state *es, enum prec prec)); 134 static void token ARGS((Expr_state *es)); 135 static struct tbl *do_ppmm ARGS((Expr_state *es, enum token op, 136 struct tbl *vasn, bool_t is_prefix)); 137 static void assign_check ARGS((Expr_state *es, enum token op, 138 struct tbl *vasn)); 139 static struct tbl *tempvar ARGS((void)); 140 static struct tbl *intvar ARGS((Expr_state *es, struct tbl *vp)); 141 142 /* 143 * parse and evalute expression 144 */ 145 int 146 evaluate(expr, rval, error_ok) 147 const char *expr; 148 long *rval; 149 int error_ok; 150 { 151 struct tbl v; 152 int ret; 153 154 v.flag = DEFINED|INTEGER; 155 v.type = 0; 156 ret = v_evaluate(&v, expr, error_ok); 157 *rval = v.val.i; 158 return ret; 159 } 160 161 /* 162 * parse and evalute expression, storing result in vp. 163 */ 164 int 165 v_evaluate(vp, expr, error_ok) 166 struct tbl *vp; 167 const char *expr; 168 volatile int error_ok; 169 { 170 struct tbl *v; 171 Expr_state curstate; 172 Expr_state * const es = &curstate; 173 int i; 174 175 /* save state to allow recursive calls */ 176 curstate.expression = curstate.tokp = expr; 177 curstate.noassign = 0; 178 curstate.evaling = (struct tbl *) 0; 179 180 newenv(E_ERRH); 181 i = ksh_sigsetjmp(e->jbuf, 0); 182 if (i) { 183 /* Clear EXPRINEVAL in of any variables we were playing with */ 184 if (curstate.evaling) 185 curstate.evaling->flag &= ~EXPRINEVAL; 186 quitenv(); 187 if (i == LAEXPR) { 188 if (error_ok == KSH_RETURN_ERROR) 189 return 0; 190 errorf(null); 191 } 192 unwind(i); 193 /*NOTREACHED*/ 194 } 195 196 token(es); 197 #if 1 /* ifdef-out to disallow empty expressions to be treated as 0 */ 198 if (es->tok == END) { 199 es->tok = LIT; 200 es->val = tempvar(); 201 } 202 #endif /* 0 */ 203 v = intvar(es, evalexpr(es, MAX_PREC)); 204 205 if (es->tok != END) 206 evalerr(es, ET_UNEXPECTED, (char *) 0); 207 208 if (vp->flag & INTEGER) 209 setint_v(vp, v); 210 else 211 /* can fail if readony */ 212 setstr(vp, str_val(v), error_ok); 213 214 quitenv(); 215 216 return 1; 217 } 218 219 static void 220 evalerr(es, type, str) 221 Expr_state *es; 222 enum error_type type; 223 const char *str; 224 { 225 char tbuf[2]; 226 const char *s; 227 228 switch (type) { 229 case ET_UNEXPECTED: 230 switch (es->tok) { 231 case VAR: 232 s = es->val->name; 233 break; 234 case LIT: 235 s = str_val(es->val); 236 break; 237 case END: 238 s = "end of expression"; 239 break; 240 case BAD: 241 tbuf[0] = *es->tokp; 242 tbuf[1] = '\0'; 243 s = tbuf; 244 break; 245 default: 246 s = opinfo[(int)es->tok].name; 247 } 248 warningf(TRUE, "%s: unexpected `%s'", es->expression, s); 249 break; 250 251 case ET_BADLIT: 252 warningf(TRUE, "%s: bad number `%s'", es->expression, str); 253 break; 254 255 case ET_RECURSIVE: 256 warningf(TRUE, "%s: expression recurses on parameter `%s'", 257 es->expression, str); 258 break; 259 260 case ET_LVALUE: 261 warningf(TRUE, "%s: %s requires lvalue", 262 es->expression, str); 263 break; 264 265 case ET_RDONLY: 266 warningf(TRUE, "%s: %s applied to read only variable", 267 es->expression, str); 268 break; 269 270 default: /* keep gcc happy */ 271 case ET_STR: 272 warningf(TRUE, "%s: %s", es->expression, str); 273 break; 274 } 275 unwind(LAEXPR); 276 } 277 278 static struct tbl * 279 evalexpr(es, prec) 280 Expr_state *es; 281 enum prec prec; 282 { 283 struct tbl *vl, UNINITIALIZED(*vr), *vasn; 284 enum token op; 285 long UNINITIALIZED(res); 286 287 if (prec == P_PRIMARY) { 288 op = es->tok; 289 if (op == O_BNOT || op == O_LNOT || op == O_MINUS 290 || op == O_PLUS) 291 { 292 token(es); 293 vl = intvar(es, evalexpr(es, P_PRIMARY)); 294 if (op == O_BNOT) 295 vl->val.i = ~vl->val.i; 296 else if (op == O_LNOT) 297 vl->val.i = !vl->val.i; 298 else if (op == O_MINUS) 299 vl->val.i = -vl->val.i; 300 /* op == O_PLUS is a no-op */ 301 } else if (op == OPEN_PAREN) { 302 token(es); 303 vl = evalexpr(es, MAX_PREC); 304 if (es->tok != CLOSE_PAREN) 305 evalerr(es, ET_STR, "missing )"); 306 token(es); 307 } else if (op == O_PLUSPLUS || op == O_MINUSMINUS) { 308 token(es); 309 vl = do_ppmm(es, op, es->val, TRUE); 310 token(es); 311 } else if (op == VAR || op == LIT) { 312 vl = es->val; 313 token(es); 314 } else { 315 evalerr(es, ET_UNEXPECTED, (char *) 0); 316 /*NOTREACHED*/ 317 } 318 if (es->tok == O_PLUSPLUS || es->tok == O_MINUSMINUS) { 319 vl = do_ppmm(es, es->tok, vl, FALSE); 320 token(es); 321 } 322 return vl; 323 } 324 vl = evalexpr(es, ((int) prec) - 1); 325 for (op = es->tok; IS_BINOP(op) && opinfo[(int) op].prec == prec; 326 op = es->tok) 327 { 328 token(es); 329 vasn = vl; 330 if (op != O_ASN) /* vl may not have a value yet */ 331 vl = intvar(es, vl); 332 if (IS_ASSIGNOP(op)) { 333 assign_check(es, op, vasn); 334 vr = intvar(es, evalexpr(es, P_ASSIGN)); 335 } else if (op != O_TERN && op != O_LAND && op != O_LOR) 336 vr = intvar(es, evalexpr(es, ((int) prec) - 1)); 337 if ((op == O_DIV || op == O_MOD || op == O_DIVASN 338 || op == O_MODASN) && vr->val.i == 0) 339 { 340 if (es->noassign) 341 vr->val.i = 1; 342 else 343 evalerr(es, ET_STR, "zero divisor"); 344 } 345 switch ((int) op) { 346 case O_TIMES: 347 case O_TIMESASN: 348 res = vl->val.i * vr->val.i; 349 break; 350 case O_DIV: 351 case O_DIVASN: 352 res = vl->val.i / vr->val.i; 353 break; 354 case O_MOD: 355 case O_MODASN: 356 res = vl->val.i % vr->val.i; 357 break; 358 case O_PLUS: 359 case O_PLUSASN: 360 res = vl->val.i + vr->val.i; 361 break; 362 case O_MINUS: 363 case O_MINUSASN: 364 res = vl->val.i - vr->val.i; 365 break; 366 case O_LSHIFT: 367 case O_LSHIFTASN: 368 res = vl->val.i << vr->val.i; 369 break; 370 case O_RSHIFT: 371 case O_RSHIFTASN: 372 res = vl->val.i >> vr->val.i; 373 break; 374 case O_LT: 375 res = vl->val.i < vr->val.i; 376 break; 377 case O_LE: 378 res = vl->val.i <= vr->val.i; 379 break; 380 case O_GT: 381 res = vl->val.i > vr->val.i; 382 break; 383 case O_GE: 384 res = vl->val.i >= vr->val.i; 385 break; 386 case O_EQ: 387 res = vl->val.i == vr->val.i; 388 break; 389 case O_NE: 390 res = vl->val.i != vr->val.i; 391 break; 392 case O_BAND: 393 case O_BANDASN: 394 res = vl->val.i & vr->val.i; 395 break; 396 case O_BXOR: 397 case O_BXORASN: 398 res = vl->val.i ^ vr->val.i; 399 break; 400 case O_BOR: 401 case O_BORASN: 402 res = vl->val.i | vr->val.i; 403 break; 404 case O_LAND: 405 if (!vl->val.i) 406 es->noassign++; 407 vr = intvar(es, evalexpr(es, ((int) prec) - 1)); 408 res = vl->val.i && vr->val.i; 409 if (!vl->val.i) 410 es->noassign--; 411 break; 412 case O_LOR: 413 if (vl->val.i) 414 es->noassign++; 415 vr = intvar(es, evalexpr(es, ((int) prec) - 1)); 416 res = vl->val.i || vr->val.i; 417 if (vl->val.i) 418 es->noassign--; 419 break; 420 case O_TERN: 421 { 422 int e = vl->val.i != 0; 423 if (!e) 424 es->noassign++; 425 vl = evalexpr(es, MAX_PREC); 426 if (!e) 427 es->noassign--; 428 if (es->tok != CTERN) 429 evalerr(es, ET_STR, "missing :"); 430 token(es); 431 if (e) 432 es->noassign++; 433 vr = evalexpr(es, P_TERN); 434 if (e) 435 es->noassign--; 436 vl = e ? vl : vr; 437 } 438 break; 439 case O_ASN: 440 res = vr->val.i; 441 break; 442 case O_COMMA: 443 res = vr->val.i; 444 break; 445 } 446 if (IS_ASSIGNOP(op)) { 447 vr->val.i = res; 448 if (vasn->flag & INTEGER) 449 setint_v(vasn, vr); 450 else 451 setint(vasn, res); 452 vl = vr; 453 } else if (op != O_TERN) 454 vl->val.i = res; 455 } 456 return vl; 457 } 458 459 static void 460 token(es) 461 Expr_state *es; 462 { 463 const char *cp; 464 int c; 465 char *tvar; 466 467 /* skip white space */ 468 for (cp = es->tokp; (c = *cp), isspace(c); cp++) 469 ; 470 es->tokp = cp; 471 472 if (c == '\0') 473 es->tok = END; 474 else if (letter(c)) { 475 for (; letnum(c); c = *cp) 476 cp++; 477 if (c == '[') { 478 int len; 479 480 len = array_ref_len(cp); 481 if (len == 0) 482 evalerr(es, ET_STR, "missing ]"); 483 cp += len; 484 } 485 #ifdef KSH 486 else if (c == '(' /*)*/ ) { 487 /* todo: add math functions (all take single argument): 488 * abs acos asin atan cos cosh exp int log sin sinh sqrt 489 * tan tanh 490 */ 491 ; 492 } 493 #endif /* KSH */ 494 if (es->noassign) { 495 es->val = tempvar(); 496 es->val->flag |= EXPRLVALUE; 497 } else { 498 tvar = str_nsave(es->tokp, cp - es->tokp, ATEMP); 499 es->val = global(tvar); 500 afree(tvar, ATEMP); 501 } 502 es->tok = VAR; 503 } else if (digit(c)) { 504 for (; c != '_' && (letnum(c) || c == '#'); c = *cp++) 505 ; 506 tvar = str_nsave(es->tokp, --cp - es->tokp, ATEMP); 507 es->val = tempvar(); 508 es->val->flag &= ~INTEGER; 509 es->val->type = 0; 510 es->val->val.s = tvar; 511 if (setint_v(es->val, es->val) == NULL) 512 evalerr(es, ET_BADLIT, tvar); 513 afree(tvar, ATEMP); 514 es->tok = LIT; 515 } else { 516 int i, n0; 517 518 for (i = 0; (n0 = opinfo[i].name[0]); i++) 519 if (c == n0 520 && strncmp(cp, opinfo[i].name, opinfo[i].len) == 0) 521 { 522 es->tok = (enum token) i; 523 cp += opinfo[i].len; 524 break; 525 } 526 if (!n0) 527 es->tok = BAD; 528 } 529 es->tokp = cp; 530 } 531 532 /* Do a ++ or -- operation */ 533 static struct tbl * 534 do_ppmm(es, op, vasn, is_prefix) 535 Expr_state *es; 536 enum token op; 537 struct tbl *vasn; 538 bool_t is_prefix; 539 { 540 struct tbl *vl; 541 int oval; 542 543 assign_check(es, op, vasn); 544 545 vl = intvar(es, vasn); 546 oval = op == O_PLUSPLUS ? vl->val.i++ : vl->val.i--; 547 if (vasn->flag & INTEGER) 548 setint_v(vasn, vl); 549 else 550 setint(vasn, vl->val.i); 551 if (!is_prefix) /* undo the inc/dec */ 552 vl->val.i = oval; 553 554 return vl; 555 } 556 557 static void 558 assign_check(es, op, vasn) 559 Expr_state *es; 560 enum token op; 561 struct tbl *vasn; 562 { 563 if (vasn->name[0] == '\0' && !(vasn->flag & EXPRLVALUE)) 564 evalerr(es, ET_LVALUE, opinfo[(int) op].name); 565 else if (vasn->flag & RDONLY) 566 evalerr(es, ET_RDONLY, opinfo[(int) op].name); 567 } 568 569 static struct tbl * 570 tempvar() 571 { 572 register struct tbl *vp; 573 574 vp = (struct tbl*) alloc(sizeof(struct tbl), ATEMP); 575 vp->flag = ISSET|INTEGER; 576 vp->type = 0; 577 vp->areap = ATEMP; 578 vp->val.i = 0; 579 vp->name[0] = '\0'; 580 return vp; 581 } 582 583 /* cast (string) variable to temporary integer variable */ 584 static struct tbl * 585 intvar(es, vp) 586 Expr_state *es; 587 struct tbl *vp; 588 { 589 struct tbl *vq; 590 591 /* try to avoid replacing a temp var with another temp var */ 592 if (vp->name[0] == '\0' 593 && (vp->flag & (ISSET|INTEGER|EXPRLVALUE)) == (ISSET|INTEGER)) 594 return vp; 595 596 vq = tempvar(); 597 if (setint_v(vq, vp) == NULL) { 598 if (vp->flag & EXPRINEVAL) 599 evalerr(es, ET_RECURSIVE, vp->name); 600 es->evaling = vp; 601 vp->flag |= EXPRINEVAL; 602 v_evaluate(vq, str_val(vp), KSH_UNWIND_ERROR); 603 vp->flag &= ~EXPRINEVAL; 604 es->evaling = (struct tbl *) 0; 605 } 606 return vq; 607 } 608