cpp.c

   1 /* neatcc preprocessor */
   2 #include <ctype.h>
   3 #include <fcntl.h>
   4 #include <stdarg.h>
   5 #include <stddef.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10 #include <sys/types.h>
  11 #include <sys/stat.h>
  12 #include "mem.h"
  13 #include "ncc.h"
  14 #include "tok.h"
  15
  16 static char *buf;
  17 static int len;
  18 static int cur;
  19
  20 static struct macro {
  21         char name[NAMELEN];     /* macro name */
  22         char def[MDEFLEN];      /* macro definition */
  23         char args[NARGS][NAMELEN];
  24         int nargs;              /* number of arguments */
  25         int isfunc;             /* macro is a function */
  26         int undef;              /* macro is removed */
  27 } macros[NDEFS];
  28 static int mcount = 1;          /* number of macros */
  29 static int mhead[256];          /* macro hash table heads */
  30 static int mnext[NDEFS];        /* macro hash table next entries */
  31
  32 #define BUF_FILE                0
  33 #define BUF_MACRO               1
  34 #define BUF_ARG                 2
  35 #define BUF_EVAL                3
  36 #define BUF_TEMP                4
  37
  38 /* preprocessing input buffers for files, macros and macro arguments */
  39 static struct buf {
  40         char *buf;
  41         int len;
  42         int cur;
  43         int type;
  44         /* for BUF_FILE */
  45         char path[NAMELEN];
  46         /* for BUF_MACRO */
  47         struct macro *macro;
  48         char args[NARGS][MARGLEN];      /* arguments passed to a macro */
  49         /* for BUF_ARG */
  50         int arg_buf;                    /* the bufs index of the owning macro */
  51 } bufs[NBUFS];
  52 static int nbufs;
  53 static int bufs_limit = 1;              /* cpp_read() limit; useful in cpp_eval() */
  54
  55 void die(char *fmt, ...)
  56 {
  57         va_list ap;
  58         char msg[512];
  59         va_start(ap, fmt);
  60         vsprintf(msg, fmt, ap);
  61         va_end(ap);
  62         write(2, msg, strlen(msg));
  63         exit(1);
  64 }
  65
  66 static void buf_new(int type, char *dat, int dlen)
  67 {
  68         if (nbufs) {
  69                 bufs[nbufs - 1].buf = buf;
  70                 bufs[nbufs - 1].cur = cur;
  71                 bufs[nbufs - 1].len = len;
  72         }
  73         if (nbufs >= NBUFS)
  74                 die("nomem: NBUFS reached!\n");
  75         nbufs++;
  76         cur = 0;
  77         buf = dat;
  78         len = dlen;
  79         bufs[nbufs - 1].type = type;
  80 }
  81
  82 static void buf_file(char *path, char *dat, int dlen)
  83 {
  84         buf_new(BUF_FILE, dat, dlen);
  85         strcpy(bufs[nbufs - 1].path, path ? path : "");
  86 }
  87
  88 static void buf_macro(struct macro *m)
  89 {
  90         buf_new(BUF_MACRO, m->def, strlen(m->def));
  91         bufs[nbufs - 1].macro = m;
  92 }
  93
  94 static void buf_arg(char *arg, int mbuf)
  95 {
  96         buf_new(BUF_ARG, arg, strlen(arg));
  97         bufs[nbufs - 1].arg_buf = mbuf;
  98 }
  99
 100 static void buf_pop(void)
 101 {
 102         nbufs--;
 103         if (nbufs) {
 104                 cur = bufs[nbufs - 1].cur;
 105                 len = bufs[nbufs - 1].len;
 106                 buf = bufs[nbufs - 1].buf;
 107         }
 108 }
 109
 110 static int buf_iseval(void)
 111 {
 112         int i;
 113         for (i = nbufs - 1; i >= 0; i--)
 114                 if (bufs[i].type == BUF_EVAL)
 115                         return 1;
 116         return 0;
 117 }
 118
 119 static size_t file_size(int fd)
 120 {
 121         struct stat st;
 122         if (!fstat(fd, &st))
 123                 return st.st_size;
 124         return 0;
 125 }
 126
 127 static int include_file(char *path)
 128 {
 129         int fd = open(path, O_RDONLY);
 130         int n = 0, nr = 0;
 131         char *dat;
 132         int size;
 133         if (fd == -1)
 134                 return -1;
 135         size = file_size(fd) + 1;
 136         dat = malloc(size);
 137         while ((n = read(fd, dat + nr, size - nr)) > 0)
 138                 nr += n;
 139         close(fd);
 140         dat[nr] = '\0';
 141         buf_file(path, dat, nr);
 142         return 0;
 143 }
 144
 145 int cpp_init(char *path)
 146 {
 147         return include_file(path);
 148 }
 149
 150 static int jumpws(void)
 151 {
 152         int old = cur;
 153         while (cur < len && isspace(buf[cur]))
 154                 cur++;
 155         return cur == old;
 156 }
 157
 158 static void read_word(char *dst)
 159 {
 160         jumpws();
 161         while (cur < len && (isalnum(buf[cur]) || buf[cur] == '_'))
 162                 *dst++ = buf[cur++];
 163         *dst = '\0';
 164 }
 165
 166 static int jumpcomment(void)
 167 {
 168         if (buf[cur] == '/' && buf[cur + 1] == '*') {
 169                 while (++cur < len) {
 170                         if (buf[cur] == '*' && buf[cur + 1] == '/') {
 171                                 cur += 2;
 172                                 return 0;
 173                         }
 174                 }
 175         }
 176         if (buf[cur] == '/' && buf[cur + 1] == '/') {
 177                 while (++cur < len)
 178                         if (buf[cur] == '\n')
 179                                 break;
 180                 return 0;
 181         }
 182         return 1;
 183 }
 184
 185 static int jumpstr(void)
 186 {
 187         if (buf[cur] == '\'') {
 188                 while (cur < len && buf[++cur] != '\'')
 189                         if (buf[cur] == '\\')
 190                                 cur++;
 191                 cur++;
 192                 return 0;
 193         }
 194         if (buf[cur] == '"') {
 195                 while (cur < len && buf[++cur] != '"')
 196                         if (buf[cur] == '\\')
 197                                 cur++;
 198                 cur++;
 199                 return 0;
 200         }
 201         return 1;
 202 }
 203
 204 static void read_tilleol(char *dst)
 205 {
 206         while (cur < len && isspace(buf[cur]) && buf[cur] != '\n')
 207                 cur++;
 208         while (cur < len && buf[cur] != '\n') {
 209                 int last = cur;
 210                 if (buf[cur] == '\\' && buf[cur + 1] == '\n') {
 211                         cur += 2;
 212                         continue;
 213                 }
 214                 if (!jumpstr()) {
 215                         memcpy(dst, buf + last, cur - last);
 216                         dst += cur - last;
 217                         continue;
 218                 }
 219                 if (!jumpcomment())
 220                         continue;
 221                 *dst++ = buf[cur++];
 222         }
 223         *dst = '\0';
 224 }
 225
 226 static char *locs[NLOCS] = {};
 227 static int nlocs = 0;
 228
 229 void cpp_addpath(char *s)
 230 {
 231         locs[nlocs++] = s;
 232 }
 233
 234 static int include_find(char *name, int std)
 235 {
 236         int i;
 237         for (i = std ? nlocs - 1 : nlocs; i >= 0; i--) {
 238                 char path[1 << 10];
 239                 if (locs[i])
 240                         sprintf(path, "%s/%s", locs[i], name);
 241                 else
 242                         strcpy(path, name);
 243                 if (!include_file(path))
 244                         return 0;
 245         }
 246         return -1;
 247 }
 248
 249 static void readarg(char *s)
 250 {
 251         int depth = 0;
 252         int beg = cur;
 253         while (cur < len && (depth || (buf[cur] != ',' && buf[cur] != ')'))) {
 254                 if (!jumpstr() || !jumpcomment())
 255                         continue;
 256                 switch (buf[cur++]) {
 257                 case '(':
 258                 case '[':
 259                 case '{':
 260                         depth++;
 261                         break;
 262                 case ')':
 263                 case ']':
 264                 case '}':
 265                         depth--;
 266                         break;
 267                 }
 268         }
 269         if (s) {
 270                 memcpy(s, buf + beg, cur - beg);
 271                 s[cur - beg] = '\0';
 272         }
 273 }
 274
 275 /* find a macro; if undef is nonzero, search #undef-ed macros too */
 276 static int macro_find(char *name, int undef)
 277 {
 278         int i = mhead[(unsigned char) name[0]];
 279         while (i > 0) {
 280                 if (!strcmp(name, macros[i].name))
 281                         if (!macros[i].undef || undef)
 282                                 return i;
 283                 i = mnext[i];
 284         }
 285         return -1;
 286 }
 287
 288 static void macro_undef(char *name)
 289 {
 290         int i = macro_find(name, 0);
 291         if (i >= 0)
 292                 macros[i].undef = 1;
 293 }
 294
 295 static int macro_new(char *name)
 296 {
 297         int i = macro_find(name, 1);
 298         if (i >= 0)
 299                 return i;
 300         if (mcount >= NDEFS)
 301                 die("nomem: NDEFS reached!\n");
 302         i = mcount++;
 303         strcpy(macros[i].name, name);
 304         mnext[i] = mhead[(unsigned char) name[0]];
 305         mhead[(unsigned char) name[0]] = i;
 306         return i;
 307 }
 308
 309 static void macro_define(void)
 310 {
 311         char name[NAMELEN];
 312         struct macro *d;
 313         read_word(name);
 314         d = &macros[macro_new(name)];
 315         d->isfunc = 0;
 316         d->nargs = 0;
 317         if (buf[cur] == '(') {
 318                 cur++;
 319                 jumpws();
 320                 while (cur < len && buf[cur] != ')') {
 321                         readarg(d->args[d->nargs++]);
 322                         jumpws();
 323                         if (buf[cur] != ',')
 324                                 break;
 325                         cur++;
 326                         jumpws();
 327                 }
 328                 cur++;
 329                 d->isfunc = 1;
 330         }
 331         read_tilleol(d->def);
 332 }
 333
 334 static char ebuf[MARGLEN];
 335 static int elen;
 336 static int ecur;
 337
 338 static long evalexpr(void);
 339
 340 static int cpp_eval(void)
 341 {
 342         char evalbuf[MARGLEN];
 343         int old_limit;
 344         int ret, clen;
 345         char *cbuf;
 346         read_tilleol(evalbuf);
 347         buf_new(BUF_EVAL, evalbuf, strlen(evalbuf));
 348         elen = 0;
 349         ecur = 0;
 350         old_limit = bufs_limit;
 351         bufs_limit = nbufs;
 352         while (!cpp_read(&cbuf, &clen)) {
 353                 memcpy(ebuf + elen, cbuf, clen);
 354                 elen += clen;
 355         }
 356         bufs_limit = old_limit;
 357         ret = evalexpr();
 358         buf_pop();
 359         return ret;
 360 }
 361
 362 static void jumpifs(int jumpelse)
 363 {
 364         int depth = 0;
 365         while (cur < len) {
 366                 if (buf[cur] == '#') {
 367                         char cmd[NAMELEN];
 368                         cur++;
 369                         read_word(cmd);
 370                         if (!strcmp("else", cmd))
 371                                 if (!depth && !jumpelse)
 372                                         break;
 373                         if (!strcmp("elif", cmd))
 374                                 if (!depth && !jumpelse && cpp_eval())
 375                                         break;
 376                         if (!strcmp("endif", cmd)) {
 377                                 if (!depth)
 378                                         break;
 379                                 else
 380                                         depth--;
 381                         }
 382                         if (!strcmp("ifdef", cmd) || !strcmp("ifndef", cmd) ||
 383                                         !strcmp("if", cmd))
 384                                 depth++;
 385                         continue;
 386                 }
 387                 if (!jumpcomment())
 388                         continue;
 389                 if (!jumpstr())
 390                         continue;
 391                 cur++;
 392         }
 393 }
 394
 395 static int cpp_cmd(void)
 396 {
 397         char cmd[NAMELEN];
 398         cur++;
 399         read_word(cmd);
 400         if (!strcmp("define", cmd)) {
 401                 macro_define();
 402                 return 0;
 403         }
 404         if (!strcmp("undef", cmd)) {
 405                 char name[NAMELEN];
 406                 read_word(name);
 407                 macro_undef(name);
 408                 return 0;
 409         }
 410         if (!strcmp("ifdef", cmd) || !strcmp("ifndef", cmd) ||
 411                                                 !strcmp("if", cmd)) {
 412                 char name[NAMELEN];
 413                 int matched = 0;
 414                 if (cmd[2]) {
 415                         int not = cmd[2] == 'n';
 416                         read_word(name);
 417                         matched = not ? macro_find(name, 0) < 0 :
 418                                         macro_find(name, 0) >= 0;
 419                 } else {
 420                         matched = cpp_eval();
 421                 }
 422                 if (!matched)
 423                         jumpifs(0);
 424                 return 0;
 425         }
 426         if (!strcmp("else", cmd) || !strcmp("elif", cmd)) {
 427                 jumpifs(1);
 428                 return 0;
 429         }
 430         if (!strcmp("endif", cmd))
 431                 return 0;
 432         if (!strcmp("include", cmd)) {
 433                 char file[NAMELEN];
 434                 char *s, *e;
 435                 jumpws();
 436                 s = buf + cur + 1;
 437                 e = strchr(buf + cur + 1, buf[cur] == '"' ? '"' : '>');
 438                 memcpy(file, s, e - s);
 439                 file[e - s] = '\0';
 440                 cur += e - s + 2;
 441                 if (include_find(file, *e == '>') == -1)
 442                         err("cannot include <%s>\n", file);
 443                 return 0;
 444         }
 445         return 1;
 446 }
 447
 448 static int macro_arg(struct macro *m, char *arg)
 449 {
 450         int i;
 451         for (i = 0; i < m->nargs; i++)
 452                 if (!strcmp(arg, m->args[i]))
 453                         return i;
 454         return -1;
 455 }
 456
 457 static int buf_arg_find(char *name)
 458 {
 459         int i;
 460         for (i = nbufs - 1; i >= 0; i--) {
 461                 struct buf *mbuf = &bufs[i];
 462                 struct macro *m = mbuf->macro;
 463                 if (mbuf->type == BUF_MACRO && macro_arg(m, name) >= 0)
 464                         return i;
 465                 if (mbuf->type == BUF_ARG)
 466                         i = mbuf->arg_buf;
 467         }
 468         return -1;
 469 }
 470
 471 static void macro_expand(char *name)
 472 {
 473         struct macro *m;
 474         int mbuf;
 475         if ((mbuf = buf_arg_find(name)) >= 0) {
 476                 int arg = macro_arg(bufs[mbuf].macro, name);
 477                 char *dat = bufs[mbuf].args[arg];
 478                 buf_arg(dat, mbuf);
 479                 return;
 480         }
 481         m = &macros[macro_find(name, 0)];
 482         if (!m->isfunc) {
 483                 buf_macro(m);
 484                 return;
 485         }
 486         jumpws();
 487         if (buf[cur] == '(') {
 488                 int i = 0;
 489                 struct buf *mbuf = &bufs[nbufs];
 490                 cur++;
 491                 jumpws();
 492                 while (cur < len && buf[cur] != ')') {
 493                         readarg(mbuf->args[i++]);
 494                         jumpws();
 495                         if (buf[cur] != ',')
 496                                 break;
 497                         cur++;
 498                         jumpws();
 499                 }
 500                 while (i < m->nargs)
 501                         mbuf->args[i++][0] = '\0';
 502                 cur++;
 503                 buf_macro(m);
 504         }
 505 }
 506
 507 static int buf_expanding(char *macro)
 508 {
 509         int i;
 510         for (i = nbufs - 1; i >= 0; i--) {
 511                 if (bufs[i].type == BUF_ARG)
 512                         return 0;
 513                 if (bufs[i].type == BUF_MACRO &&
 514                                 !strcmp(macro, bufs[i].macro->name))
 515                         return 1;
 516         }
 517         return 0;
 518 }
 519
 520 /* return 1 for plain macros and arguments and 2 for function macros */
 521 static int expandable(char *word)
 522 {
 523         int i;
 524         if (buf_arg_find(word) >= 0)
 525                 return 1;
 526         if (buf_expanding(word))
 527                 return 0;
 528         i = macro_find(word, 0);
 529         return i >= 0 ? macros[i].isfunc + 1 : 0;
 530 }
 531
 532 void cpp_define(char *name, char *def)
 533 {
 534         char tmp_buf[MDEFLEN];
 535         sprintf(tmp_buf, "%s\t%s", name, def);
 536         buf_new(BUF_TEMP, tmp_buf, strlen(tmp_buf));
 537         macro_define();
 538         buf_pop();
 539 }
 540
 541 static int seen_macro;          /* seen a macro; 2 if a function macro */
 542 static char seen_name[NAMELEN]; /* the name of the last macro */
 543
 544 static int hunk_off;
 545 static int hunk_len;
 546
 547 int cpp_read(char **obuf, int *olen)
 548 {
 549         int old, end;
 550         int jump_name = 0;
 551         *olen = 0;
 552         *obuf = "";
 553         if (seen_macro == 1) {
 554                 macro_expand(seen_name);
 555                 seen_macro = 0;
 556         }
 557         if (cur == len) {
 558                 struct buf *cbuf = &bufs[nbufs - 1];
 559                 if (nbufs < bufs_limit + 1)
 560                         return -1;
 561                 if (cbuf->type == BUF_FILE)
 562                         free(buf);
 563                 buf_pop();
 564         }
 565         old = cur;
 566         if (buf[cur] == '#')
 567                 if (!cpp_cmd())
 568                         return 0;
 569         while (cur < len) {
 570                 if (!jumpws())
 571                         continue;
 572                 if (buf[cur] == '#')
 573                         break;
 574                 if (!jumpcomment())
 575                         continue;
 576                 if (seen_macro == 2) {
 577                         if (buf[cur] == '(')
 578                                 macro_expand(seen_name);
 579                         seen_macro = 0;
 580                         old = cur;
 581                         continue;
 582                 }
 583                 if (!jumpstr())
 584                         continue;
 585                 if (isalnum(buf[cur]) || buf[cur] == '_') {
 586                         char word[NAMELEN];
 587                         read_word(word);
 588                         seen_macro = expandable(word);
 589                         if (seen_macro) {
 590                                 strcpy(seen_name, word);
 591                                 jump_name = 1;
 592                                 break;
 593                         }
 594                         if (buf_iseval() && !strcmp("defined", word)) {
 595                                 int parens = 0;
 596                                 jumpws();
 597                                 if (buf[cur] == '(') {
 598                                         parens = 1;
 599                                         cur++;
 600                                 }
 601                                 read_word(word);
 602                                 if (parens) {
 603                                         jumpws();
 604                                         cur++;
 605                                 }
 606                         }
 607                         continue;
 608                 }
 609                 cur++;
 610         }
 611         /* macros are expanded later; ignoring their names */
 612         end = jump_name ? cur - strlen(seen_name) : cur;
 613         if (!buf_iseval()) {
 614                 hunk_off += hunk_len;
 615                 hunk_len = end - old;
 616         }
 617         *obuf = buf + old;
 618         *olen = end - old;
 619         return 0;
 620 }
 621
 622 /* preprocessor constant expression evaluation */
 623
 624 static char etok[NAMELEN];
 625 static int enext;
 626
 627 static char *tok2[] = {
 628         "<<", ">>", "&&", "||", "==", "!=", "<=", ">="
 629 };
 630
 631 static int eval_tok(void)
 632 {
 633         char *s = etok;
 634         int i;
 635         while (ecur < elen) {
 636                 while (ecur < elen && isspace(ebuf[ecur]))
 637                         ecur++;
 638                 if (ebuf[ecur] == '/' && ebuf[ecur + 1] == '*') {
 639                         while (ecur < elen && (ebuf[ecur - 2] != '*' ||
 640                                                 ebuf[ecur - 1] != '/'))
 641                                 ecur++;
 642                         continue;
 643                 }
 644                 break;
 645         }
 646         if (ecur >= elen)
 647                 return TOK_EOF;
 648         if (isalpha(ebuf[ecur]) || ebuf[ecur] == '_') {
 649                 while (isalnum(ebuf[ecur]) || ebuf[ecur] == '_')
 650                         *s++ = ebuf[ecur++];
 651                 *s = '\0';
 652                 return TOK_NAME;
 653         }
 654         if (isdigit(ebuf[ecur])) {
 655                 while (isdigit(ebuf[ecur]))
 656                         *s++ = ebuf[ecur++];
 657                 while (tolower(ebuf[ecur]) == 'u' || tolower(ebuf[ecur]) == 'l')
 658                         ecur++;
 659                 *s = '\0';
 660                 return TOK_NUM;
 661         }
 662         for (i = 0; i < LEN(tok2); i++)
 663                 if (TOK2(tok2[i]) == TOK2(ebuf + ecur)) {
 664                         int ret = TOK2(tok2[i]);
 665                         ecur += 2;
 666                         return ret;
 667                 }
 668         return ebuf[ecur++];
 669 }
 670
 671 static int eval_see(void)
 672 {
 673         if (enext == -1)
 674                 enext = eval_tok();
 675         return enext;
 676 }
 677
 678 static int eval_get(void)
 679 {
 680         if (enext != -1) {
 681                 int ret = enext;
 682                 enext = -1;
 683                 return ret;
 684         }
 685         return eval_tok();
 686 }
 687
 688 static long eval_num(void)
 689 {
 690         return atol(etok);
 691 }
 692
 693 static int eval_jmp(int tok)
 694 {
 695         if (eval_see() == tok) {
 696                 eval_get();
 697                 return 0;
 698         }
 699         return 1;
 700 }
 701
 702 static void eval_expect(int tok)
 703 {
 704         eval_jmp(tok);
 705 }
 706
 707 static char *eval_id(void)
 708 {
 709         return etok;
 710 }
 711
 712 static long evalcexpr(void);
 713
 714 static long evalatom(void)
 715 {
 716         if (!eval_jmp(TOK_NUM))
 717                 return eval_num();
 718         if (!eval_jmp(TOK_NAME)) {
 719                 int parens = !eval_jmp('(');
 720                 long ret;
 721                 eval_expect(TOK_NAME);
 722                 ret = macro_find(eval_id(), 0) >= 0;
 723                 if (parens)
 724                         eval_expect(')');
 725                 return ret;
 726         }
 727         if (!eval_jmp('(')) {
 728                 long ret = evalcexpr();
 729                 eval_expect(')');
 730                 return ret;
 731         }
 732         return -1;
 733 }
 734
 735 static long evalpre(void)
 736 {
 737         if (!eval_jmp('!'))
 738                 return !evalpre();
 739         if (!eval_jmp('-'))
 740                 return -evalpre();
 741         if (!eval_jmp('~'))
 742                 return ~evalpre();
 743         return evalatom();
 744 }
 745
 746 static long evalmul(void)
 747 {
 748         long ret = evalpre();
 749         while (1) {
 750                 if (!eval_jmp('*')) {
 751                         ret *= evalpre();
 752                         continue;
 753                 }
 754                 if (!eval_jmp('/')) {
 755                         ret /= evalpre();
 756                         continue;
 757                 }
 758                 if (!eval_jmp('%')) {
 759                         ret %= evalpre();
 760                         continue;
 761                 }
 762                 break;
 763         }
 764         return ret;
 765 }
 766
 767 static long evaladd(void)
 768 {
 769         long ret = evalmul();
 770         while (1) {
 771                 if (!eval_jmp('+')) {
 772                         ret += evalmul();
 773                         continue;
 774                 }
 775                 if (!eval_jmp('-')) {
 776                         ret -= evalmul();
 777                         continue;
 778                 }
 779                 break;
 780         }
 781         return ret;
 782 }
 783
 784 static long evalshift(void)
 785 {
 786         long ret = evaladd();
 787         while (1) {
 788                 if (!eval_jmp(TOK2("<<"))) {
 789                         ret <<= evaladd();
 790                         continue;
 791                 }
 792                 if (!eval_jmp(TOK2(">>"))) {
 793                         ret >>= evaladd();
 794                         continue;
 795                 }
 796                 break;
 797         }
 798         return ret;
 799 }
 800
 801 static long evalcmp(void)
 802 {
 803         long ret = evalshift();
 804         while (1) {
 805                 if (!eval_jmp('<')) {
 806                         ret = ret < evalshift();
 807                         continue;
 808                 }
 809                 if (!eval_jmp('>')) {
 810                         ret = ret > evalshift();
 811                         continue;
 812                 }
 813                 if (!eval_jmp(TOK2("<="))) {
 814                         ret = ret <= evalshift();
 815                         continue;
 816                 }
 817                 if (!eval_jmp(TOK2(">="))) {
 818                         ret = ret >= evalshift();
 819                         continue;
 820                 }
 821                 break;
 822         }
 823         return ret;
 824 }
 825
 826 static long evaleq(void)
 827 {
 828         long ret = evalcmp();
 829         while (1) {
 830                 if (!eval_jmp(TOK2("=="))) {
 831                         ret = ret == evalcmp();
 832                         continue;
 833                 }
 834                 if (!eval_jmp(TOK2("!="))) {
 835                         ret = ret != evalcmp();
 836                         continue;
 837                 }
 838                 break;
 839         }
 840         return ret;
 841 }
 842
 843 static long evalbitand(void)
 844 {
 845         long ret = evaleq();
 846         while (!eval_jmp('&'))
 847                 ret &= evaleq();
 848         return ret;
 849 }
 850
 851 static long evalxor(void)
 852 {
 853         long ret = evalbitand();
 854         while (!eval_jmp('^'))
 855                 ret ^= evalbitand();
 856         return ret;
 857 }
 858
 859 static long evalbitor(void)
 860 {
 861         long ret = evalxor();
 862         while (!eval_jmp('|'))
 863                 ret |= evalxor();
 864         return ret;
 865 }
 866
 867 static long evaland(void)
 868 {
 869         long ret = evalbitor();
 870         while (!eval_jmp(TOK2("&&")))
 871                 ret = ret && evalbitor();
 872         return ret;
 873 }
 874
 875 static long evalor(void)
 876 {
 877         long ret = evaland();
 878         while (!eval_jmp(TOK2("||")))
 879                 ret = ret || evaland();
 880         return ret;
 881 }
 882
 883 static long evalcexpr(void)
 884 {
 885         long ret = evalor();
 886         if (eval_jmp('?'))
 887                 return ret;
 888         if (ret)
 889                 return evalor();
 890         while (eval_get() != ':')
 891                 ;
 892         return evalor();
 893 }
 894
 895 static long evalexpr(void)
 896 {
 897         enext = -1;
 898         return evalcexpr();
 899 }
 900
 901 static int buf_loc(char *s, int off)
 902 {
 903         char *e = s + off;
 904         int n = 1;
 905         while ((s = strchr(s, '\n')) && s < e) {
 906                 n++;
 907                 s++;
 908         }
 909         return n;
 910 }
 911
 912 char *cpp_loc(long addr)
 913 {
 914         static char loc[256];
 915         int line = -1;
 916         int i;
 917         for (i = nbufs - 1; i > 0; i--)
 918                 if (bufs[i].type == BUF_FILE)
 919                         break;
 920         if (addr >= hunk_off && i == nbufs - 1)
 921                 line = buf_loc(buf, (cur - hunk_len) + (addr - hunk_off));
 922         else
 923                 line = buf_loc(bufs[i].buf, bufs[i].cur);
 924         sprintf(loc, "%s:%d", bufs[i].path, line);
 925         return loc;
 926 }