1 /**************************************************************************** 2 * Copyright (c) 1998,1999,2000,2001 Free Software Foundation, Inc. * 3 * * 4 * Permission is hereby granted, free of charge, to any person obtaining a * 5 * copy of this software and associated documentation files (the * 6 * "Software"), to deal in the Software without restriction, including * 7 * without limitation the rights to use, copy, modify, merge, publish, * 8 * distribute, distribute with modifications, sublicense, and/or sell * 9 * copies of the Software, and to permit persons to whom the Software is * 10 * furnished to do so, subject to the following conditions: * 11 * * 12 * The above copyright notice and this permission notice shall be included * 13 * in all copies or substantial portions of the Software. * 14 * * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * 16 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * 17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * 18 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * 19 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * 20 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * 21 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. * 22 * * 23 * Except as contained in this notice, the name(s) of the above copyright * 24 * holders shall not be used in advertising or otherwise to promote the * 25 * sale, use or other dealings in this Software without prior written * 26 * authorization. * 27 ****************************************************************************/ 28 29 /**************************************************************************** 30 * Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995 * 31 * and: Eric S. Raymond <esr@snark.thyrsus.com> * 32 ****************************************************************************/ 33 34 /* $FreeBSD$ */ 35 36 /* 37 * comp_scan.c --- Lexical scanner for terminfo compiler. 38 * 39 * _nc_reset_input() 40 * _nc_get_token() 41 * _nc_panic_mode() 42 * int _nc_syntax; 43 * int _nc_curr_line; 44 * long _nc_curr_file_pos; 45 * long _nc_comment_start; 46 * long _nc_comment_end; 47 */ 48 49 #include <curses.priv.h> 50 51 #include <ctype.h> 52 #include <term_entry.h> 53 #include <tic.h> 54 55 MODULE_ID("$Id: comp_scan.c,v 1.59 2001/09/23 00:56:29 tom Exp $") 56 57 /* 58 * Maximum length of string capability we'll accept before raising an error. 59 * Yes, there is a real capability in /etc/termcap this long, an "is". 60 */ 61 #define MAXCAPLEN 600 62 63 #define iswhite(ch) (ch == ' ' || ch == '\t') 64 65 NCURSES_EXPORT_VAR(int) 66 _nc_syntax = 0; /* termcap or terminfo? */ 67 NCURSES_EXPORT_VAR(long) 68 _nc_curr_file_pos = 0; /* file offset of current line */ 69 NCURSES_EXPORT_VAR(long) 70 _nc_comment_start = 0; /* start of comment range before name */ 71 NCURSES_EXPORT_VAR(long) 72 _nc_comment_end = 0; /* end of comment range before name */ 73 NCURSES_EXPORT_VAR(long) 74 _nc_start_line = 0; /* start line of current entry */ 75 76 NCURSES_EXPORT_VAR(struct token) 77 _nc_curr_token = 78 { 79 0, 0, 0 80 }; 81 82 /***************************************************************************** 83 * 84 * Token-grabbing machinery 85 * 86 *****************************************************************************/ 87 88 static bool first_column; /* See 'next_char()' below */ 89 static char separator; /* capability separator */ 90 static int pushtype; /* type of pushback token */ 91 static char *pushname; 92 93 #if NCURSES_EXT_FUNCS 94 NCURSES_EXPORT_VAR(bool) 95 _nc_disable_period = FALSE; /* used by tic -a option */ 96 #endif 97 98 static int last_char(void); 99 static int next_char(void); 100 static long stream_pos(void); 101 static bool end_of_stream(void); 102 static void push_back(char c); 103 104 /* Assume we may be looking at a termcap-style continuation */ 105 static inline int 106 eat_escaped_newline(int ch) 107 { 108 if (ch == '\\') 109 while ((ch = next_char()) == '\n' || iswhite(ch)) 110 continue; 111 return ch; 112 } 113 114 /* 115 * int 116 * get_token() 117 * 118 * Scans the input for the next token, storing the specifics in the 119 * global structure 'curr_token' and returning one of the following: 120 * 121 * NAMES A line beginning in column 1. 'name' 122 * will be set to point to everything up to but 123 * not including the first separator on the line. 124 * BOOLEAN An entry consisting of a name followed by 125 * a separator. 'name' will be set to point to 126 * the name of the capability. 127 * NUMBER An entry of the form 128 * name#digits, 129 * 'name' will be set to point to the capability 130 * name and 'valnumber' to the number given. 131 * STRING An entry of the form 132 * name=characters, 133 * 'name' is set to the capability name and 134 * 'valstring' to the string of characters, with 135 * input translations done. 136 * CANCEL An entry of the form 137 * name@, 138 * 'name' is set to the capability name and 139 * 'valnumber' to -1. 140 * EOF The end of the file has been reached. 141 * 142 * A `separator' is either a comma or a semicolon, depending on whether 143 * we are in termcap or terminfo mode. 144 * 145 */ 146 147 NCURSES_EXPORT(int) 148 _nc_get_token(bool silent) 149 { 150 static const char terminfo_punct[] = "@%&*!#"; 151 static char *buffer; 152 153 char *numchk; 154 char *ptr; 155 char numbuf[80]; 156 int ch; 157 int dot_flag = FALSE; 158 int type; 159 long number; 160 long token_start; 161 unsigned found; 162 163 if (pushtype != NO_PUSHBACK) { 164 int retval = pushtype; 165 166 _nc_set_type(pushname != 0 ? pushname : ""); 167 DEBUG(3, ("pushed-back token: `%s', class %d", 168 _nc_curr_token.tk_name, pushtype)); 169 170 pushtype = NO_PUSHBACK; 171 if (pushname != 0) 172 pushname[0] = '\0'; 173 174 /* currtok wasn't altered by _nc_push_token() */ 175 return (retval); 176 } 177 178 if (end_of_stream()) 179 return (EOF); 180 181 start_token: 182 token_start = stream_pos(); 183 while ((ch = next_char()) == '\n' || iswhite(ch)) 184 continue; 185 186 ch = eat_escaped_newline(ch); 187 188 if (ch == EOF) 189 type = EOF; 190 else { 191 /* if this is a termcap entry, skip a leading separator */ 192 if (separator == ':' && ch == ':') 193 ch = next_char(); 194 195 if (ch == '.' 196 #if NCURSES_EXT_FUNCS 197 && !_nc_disable_period 198 #endif 199 ) { 200 dot_flag = TRUE; 201 DEBUG(8, ("dot-flag set")); 202 203 while ((ch = next_char()) == '.' || iswhite(ch)) 204 continue; 205 } 206 207 if (ch == EOF) { 208 type = EOF; 209 goto end_of_token; 210 } 211 212 /* have to make some punctuation chars legal for terminfo */ 213 if (!isalnum(ch) 214 #if NCURSES_EXT_FUNCS 215 && !(ch == '.' && _nc_disable_period) 216 #endif 217 && !strchr(terminfo_punct, (char) ch)) { 218 if (!silent) 219 _nc_warning("Illegal character (expected alphanumeric or %s) - %s", 220 terminfo_punct, unctrl((chtype) ch)); 221 _nc_panic_mode(separator); 222 goto start_token; 223 } 224 225 if (buffer == 0) 226 buffer = _nc_doalloc(buffer, MAX_ENTRY_SIZE); 227 228 ptr = buffer; 229 *(ptr++) = ch; 230 231 if (first_column) { 232 char *desc; 233 234 _nc_comment_start = token_start; 235 _nc_comment_end = _nc_curr_file_pos; 236 _nc_start_line = _nc_curr_line; 237 238 _nc_syntax = ERR; 239 while ((ch = next_char()) != '\n') { 240 if (ch == EOF) 241 _nc_err_abort("premature EOF"); 242 else if (ch == ':' && last_char() != ',') { 243 _nc_syntax = SYN_TERMCAP; 244 separator = ':'; 245 break; 246 } else if (ch == ',') { 247 _nc_syntax = SYN_TERMINFO; 248 separator = ','; 249 /* 250 * Fall-through here is not an accident. The idea is that 251 * if we see a comma, we figure this is terminfo unless we 252 * subsequently run into a colon -- but we don't stop 253 * looking for that colon until hitting a newline. This 254 * allows commas to be embedded in description fields of 255 * either syntax. 256 */ 257 /* FALLTHRU */ 258 } else 259 ch = eat_escaped_newline(ch); 260 261 *ptr++ = ch; 262 } 263 ptr[0] = '\0'; 264 if (_nc_syntax == ERR) { 265 /* 266 * Grrr...what we ought to do here is barf, complaining that 267 * the entry is malformed. But because a couple of name fields 268 * in the 8.2 termcap file end with |\, we just have to assume 269 * it's termcap syntax. 270 */ 271 _nc_syntax = SYN_TERMCAP; 272 separator = ':'; 273 } else if (_nc_syntax == SYN_TERMINFO) { 274 /* throw away trailing /, *$/ */ 275 for (--ptr; iswhite(*ptr) || *ptr == ','; ptr--) 276 continue; 277 ptr[1] = '\0'; 278 } 279 280 /* 281 * This is the soonest we have the terminal name fetched. Set up 282 * for following warning messages. 283 */ 284 ptr = strchr(buffer, '|'); 285 if (ptr == (char *) NULL) 286 ptr = buffer + strlen(buffer); 287 ch = *ptr; 288 *ptr = '\0'; 289 _nc_set_type(buffer); 290 *ptr = ch; 291 292 /* 293 * Compute the boundary between the aliases and the description 294 * field for syntax-checking purposes. 295 */ 296 desc = strrchr(buffer, '|'); 297 if (!silent && desc) { 298 if (*desc == '\0') 299 _nc_warning("empty longname field"); 300 #ifndef FREEBSD_NATIVE 301 else if (strchr(desc, ' ') == (char *) NULL) 302 _nc_warning("older tic versions may treat the description field as an alias"); 303 #endif 304 } 305 if (!desc) 306 desc = buffer + strlen(buffer); 307 308 /* 309 * Whitespace in a name field other than the long name can confuse 310 * rdist and some termcap tools. Slashes are a no-no. Other 311 * special characters can be dangerous due to shell expansion. 312 */ 313 for (ptr = buffer; ptr < desc; ptr++) { 314 if (isspace(UChar(*ptr))) { 315 if (!silent) 316 _nc_warning("whitespace in name or alias field"); 317 break; 318 } else if (*ptr == '/') { 319 if (!silent) 320 _nc_warning("slashes aren't allowed in names or aliases"); 321 break; 322 } else if (strchr("$[]!*?", *ptr)) { 323 if (!silent) 324 _nc_warning("dubious character `%c' in name or alias field", *ptr); 325 break; 326 } 327 } 328 329 ptr = buffer; 330 331 _nc_curr_token.tk_name = buffer; 332 type = NAMES; 333 } else { 334 while ((ch = next_char()) != EOF) { 335 if (!isalnum(ch)) { 336 if (_nc_syntax == SYN_TERMINFO) { 337 if (ch != '_') 338 break; 339 } else { /* allow ';' for "k;" */ 340 if (ch != ';') 341 break; 342 } 343 } 344 *(ptr++) = ch; 345 } 346 347 *ptr++ = '\0'; 348 switch (ch) { 349 case ',': 350 case ':': 351 if (ch != separator) 352 _nc_err_abort("Separator inconsistent with syntax"); 353 _nc_curr_token.tk_name = buffer; 354 type = BOOLEAN; 355 break; 356 case '@': 357 if ((ch = next_char()) != separator && !silent) 358 _nc_warning("Missing separator after `%s', have %s", 359 buffer, unctrl((chtype) ch)); 360 _nc_curr_token.tk_name = buffer; 361 type = CANCEL; 362 break; 363 364 case '#': 365 found = 0; 366 while (isalnum(ch = next_char())) { 367 numbuf[found++] = ch; 368 if (found >= sizeof(numbuf) - 1) 369 break; 370 } 371 numbuf[found] = '\0'; 372 number = strtol(numbuf, &numchk, 0); 373 if (!silent) { 374 if (numchk == numbuf) 375 _nc_warning("no value given for `%s'", buffer); 376 if ((*numchk != '\0') || (ch != separator)) 377 _nc_warning("Missing separator"); 378 } 379 _nc_curr_token.tk_name = buffer; 380 _nc_curr_token.tk_valnumber = number; 381 type = NUMBER; 382 break; 383 384 case '=': 385 ch = _nc_trans_string(ptr, buffer + MAX_ENTRY_SIZE); 386 if (!silent && ch != separator) 387 _nc_warning("Missing separator"); 388 _nc_curr_token.tk_name = buffer; 389 _nc_curr_token.tk_valstring = ptr; 390 type = STRING; 391 break; 392 393 case EOF: 394 type = EOF; 395 break; 396 default: 397 /* just to get rid of the compiler warning */ 398 type = UNDEF; 399 if (!silent) 400 _nc_warning("Illegal character - %s", unctrl((chtype) ch)); 401 } 402 } /* end else (first_column == FALSE) */ 403 } /* end else (ch != EOF) */ 404 405 end_of_token: 406 407 #ifdef TRACE 408 if (dot_flag == TRUE) 409 DEBUG(8, ("Commented out ")); 410 411 if (_nc_tracing >= DEBUG_LEVEL(7)) { 412 switch (type) { 413 case BOOLEAN: 414 _tracef("Token: Boolean; name='%s'", 415 _nc_curr_token.tk_name); 416 break; 417 418 case NUMBER: 419 _tracef("Token: Number; name='%s', value=%d", 420 _nc_curr_token.tk_name, 421 _nc_curr_token.tk_valnumber); 422 break; 423 424 case STRING: 425 _tracef("Token: String; name='%s', value=%s", 426 _nc_curr_token.tk_name, 427 _nc_visbuf(_nc_curr_token.tk_valstring)); 428 break; 429 430 case CANCEL: 431 _tracef("Token: Cancel; name='%s'", 432 _nc_curr_token.tk_name); 433 break; 434 435 case NAMES: 436 437 _tracef("Token: Names; value='%s'", 438 _nc_curr_token.tk_name); 439 break; 440 441 case EOF: 442 _tracef("Token: End of file"); 443 break; 444 445 default: 446 _nc_warning("Bad token type"); 447 } 448 } 449 #endif 450 451 if (dot_flag == TRUE) /* if commented out, use the next one */ 452 type = _nc_get_token(silent); 453 454 DEBUG(3, ("token: `%s', class %d", 455 _nc_curr_token.tk_name != 0 ? _nc_curr_token.tk_name : 456 "<null>", 457 type)); 458 459 return (type); 460 } 461 462 /* 463 * char 464 * trans_string(ptr) 465 * 466 * Reads characters using next_char() until encountering a separator, nl, 467 * or end-of-file. The returned value is the character which caused 468 * reading to stop. The following translations are done on the input: 469 * 470 * ^X goes to ctrl-X (i.e. X & 037) 471 * {\E,\n,\r,\b,\t,\f} go to 472 * {ESCAPE,newline,carriage-return,backspace,tab,formfeed} 473 * {\^,\\} go to {carat,backslash} 474 * \ddd (for ddd = up to three octal digits) goes to the character ddd 475 * 476 * \e == \E 477 * \0 == \200 478 * 479 */ 480 481 NCURSES_EXPORT(char) 482 _nc_trans_string(char *ptr, char *last) 483 { 484 int count = 0; 485 int number = 0; 486 int i, c; 487 chtype ch, last_ch = '\0'; 488 bool ignored = FALSE; 489 bool long_warning = FALSE; 490 491 while ((ch = c = next_char()) != (chtype) separator && c != EOF) { 492 if (ptr == (last - 1)) 493 break; 494 if ((_nc_syntax == SYN_TERMCAP) && c == '\n') 495 break; 496 if (ch == '^' && last_ch != '%') { 497 ch = c = next_char(); 498 if (c == EOF) 499 _nc_err_abort("Premature EOF"); 500 501 if (!(is7bits(ch) && isprint(ch))) { 502 _nc_warning("Illegal ^ character - %s", unctrl(ch)); 503 } 504 if (ch == '?') { 505 *(ptr++) = '\177'; 506 if (_nc_tracing) 507 _nc_warning("Allow ^? as synonym for \\177"); 508 } else { 509 if ((ch &= 037) == 0) 510 ch = 128; 511 *(ptr++) = (char) (ch); 512 } 513 } else if (ch == '\\') { 514 ch = c = next_char(); 515 if (c == EOF) 516 _nc_err_abort("Premature EOF"); 517 518 if (ch >= '0' && ch <= '7') { 519 number = ch - '0'; 520 for (i = 0; i < 2; i++) { 521 ch = c = next_char(); 522 if (c == EOF) 523 _nc_err_abort("Premature EOF"); 524 525 if (c < '0' || c > '7') { 526 if (isdigit(c)) { 527 _nc_warning("Non-octal digit `%c' in \\ sequence", c); 528 /* allow the digit; it'll do less harm */ 529 } else { 530 push_back((char) c); 531 break; 532 } 533 } 534 535 number = number * 8 + c - '0'; 536 } 537 538 if (number == 0) 539 number = 0200; 540 *(ptr++) = (char) number; 541 } else { 542 switch (c) { 543 case 'E': 544 case 'e': 545 *(ptr++) = '\033'; 546 break; 547 548 case 'a': 549 *(ptr++) = '\007'; 550 break; 551 552 case 'l': 553 case 'n': 554 *(ptr++) = '\n'; 555 break; 556 557 case 'r': 558 *(ptr++) = '\r'; 559 break; 560 561 case 'b': 562 *(ptr++) = '\010'; 563 break; 564 565 case 's': 566 *(ptr++) = ' '; 567 break; 568 569 case 'f': 570 *(ptr++) = '\014'; 571 break; 572 573 case 't': 574 *(ptr++) = '\t'; 575 break; 576 577 case '\\': 578 *(ptr++) = '\\'; 579 break; 580 581 case '^': 582 *(ptr++) = '^'; 583 break; 584 585 case ',': 586 *(ptr++) = ','; 587 break; 588 589 case ':': 590 *(ptr++) = ':'; 591 break; 592 593 case '\n': 594 continue; 595 596 default: 597 _nc_warning("Illegal character %s in \\ sequence", 598 unctrl(ch)); 599 *(ptr++) = (char) ch; 600 } /* endswitch (ch) */ 601 } /* endelse (ch < '0' || ch > '7') */ 602 } 603 /* end else if (ch == '\\') */ 604 else if (ch == '\n' && (_nc_syntax == SYN_TERMINFO)) { 605 /* newlines embedded in a terminfo string are ignored */ 606 ignored = TRUE; 607 } else { 608 *(ptr++) = (char) ch; 609 } 610 611 if (!ignored) { 612 last_ch = ch; 613 count++; 614 } 615 ignored = FALSE; 616 617 if (count > MAXCAPLEN && !long_warning) { 618 _nc_warning("Very long string found. Missing separator?"); 619 long_warning = TRUE; 620 } 621 } /* end while */ 622 623 *ptr = '\0'; 624 625 return (ch); 626 } 627 628 /* 629 * _nc_push_token() 630 * 631 * Push a token of given type so that it will be reread by the next 632 * get_token() call. 633 */ 634 635 NCURSES_EXPORT(void) 636 _nc_push_token(int tokclass) 637 { 638 /* 639 * This implementation is kind of bogus, it will fail if we ever do more 640 * than one pushback at a time between get_token() calls. It relies on the 641 * fact that _nc_curr_token is static storage that nothing but 642 * _nc_get_token() touches. 643 */ 644 pushtype = tokclass; 645 if (pushname == 0) 646 pushname = _nc_doalloc(pushname, MAX_NAME_SIZE + 1); 647 _nc_get_type(pushname); 648 649 DEBUG(3, ("pushing token: `%s', class %d", 650 _nc_curr_token.tk_name, pushtype)); 651 } 652 653 /* 654 * Panic mode error recovery - skip everything until a "ch" is found. 655 */ 656 NCURSES_EXPORT(void) 657 _nc_panic_mode(char ch) 658 { 659 int c; 660 661 for (;;) { 662 c = next_char(); 663 if (c == ch) 664 return; 665 if (c == EOF) 666 return; 667 } 668 } 669 670 /***************************************************************************** 671 * 672 * Character-stream handling 673 * 674 *****************************************************************************/ 675 676 #define LEXBUFSIZ 1024 677 678 static char *bufptr; /* otherwise, the input buffer pointer */ 679 static char *bufstart; /* start of buffer so we can compute offsets */ 680 static FILE *yyin; /* scanner's input file descriptor */ 681 682 /* 683 * _nc_reset_input() 684 * 685 * Resets the input-reading routines. Used on initialization, 686 * or after a seek has been done. Exactly one argument must be 687 * non-null. 688 */ 689 690 NCURSES_EXPORT(void) 691 _nc_reset_input(FILE * fp, char *buf) 692 { 693 pushtype = NO_PUSHBACK; 694 if (pushname != 0) 695 pushname[0] = '\0'; 696 yyin = fp; 697 bufstart = bufptr = buf; 698 _nc_curr_file_pos = 0L; 699 if (fp != 0) 700 _nc_curr_line = 0; 701 _nc_curr_col = 0; 702 } 703 704 /* 705 * int last_char() 706 * 707 * Returns the final nonblank character on the current input buffer 708 */ 709 static int 710 last_char(void) 711 { 712 size_t len = strlen(bufptr); 713 while (len--) { 714 if (!isspace(UChar(bufptr[len]))) 715 return bufptr[len]; 716 } 717 return 0; 718 } 719 720 /* 721 * int next_char() 722 * 723 * Returns the next character in the input stream. Comments and leading 724 * white space are stripped. 725 * 726 * The global state variable 'firstcolumn' is set TRUE if the character 727 * returned is from the first column of the input line. 728 * 729 * The global variable _nc_curr_line is incremented for each new line. 730 * The global variable _nc_curr_file_pos is set to the file offset of the 731 * beginning of each line. 732 */ 733 734 static int 735 next_char(void) 736 { 737 if (!yyin) { 738 /* 739 * An string with an embedded null will truncate the input. This is 740 * intentional (we don't read binary files here). 741 */ 742 if (*bufptr == '\0') 743 return (EOF); 744 if (*bufptr == '\n') { 745 _nc_curr_line++; 746 _nc_curr_col = 0; 747 } 748 } else if (!bufptr || !*bufptr) { 749 /* 750 * In theory this could be recoded to do its I/O one character at a 751 * time, saving the buffer space. In practice, this turns out to be 752 * quite hard to get completely right. Try it and see. If you 753 * succeed, don't forget to hack push_back() correspondingly. 754 */ 755 static char *result; 756 static size_t allocated; 757 size_t used; 758 size_t len; 759 760 do { 761 bufstart = 0; 762 used = 0; 763 do { 764 if (used + (LEXBUFSIZ / 4) >= allocated) { 765 allocated += (allocated + LEXBUFSIZ); 766 result = _nc_doalloc(result, allocated); 767 if (result == 0) 768 return (EOF); 769 } 770 if (used == 0) 771 _nc_curr_file_pos = ftell(yyin); 772 773 if (fgets(result + used, allocated - used, yyin) != NULL) { 774 bufstart = result; 775 if (used == 0) { 776 _nc_curr_line++; 777 _nc_curr_col = 0; 778 } 779 } else { 780 if (used != 0) 781 strcat(result, "\n"); 782 } 783 if ((bufptr = bufstart) != 0) { 784 used = strlen(bufptr); 785 while (iswhite(*bufptr)) 786 bufptr++; 787 788 /* 789 * Treat a trailing <cr><lf> the same as a <newline> so we 790 * can read files on OS/2, etc. 791 */ 792 if ((len = strlen(bufptr)) > 1) { 793 if (bufptr[len - 1] == '\n' 794 && bufptr[len - 2] == '\r') { 795 len--; 796 bufptr[len - 1] = '\n'; 797 bufptr[len] = '\0'; 798 } 799 } 800 } else { 801 return (EOF); 802 } 803 } while (bufptr[len - 1] != '\n'); /* complete a line */ 804 } while (result[0] == '#'); /* ignore comments */ 805 } 806 807 first_column = (bufptr == bufstart); 808 809 _nc_curr_col++; 810 return (*bufptr++); 811 } 812 813 static void 814 push_back(char c) 815 /* push a character back onto the input stream */ 816 { 817 if (bufptr == bufstart) 818 _nc_syserr_abort("Can't backspace off beginning of line"); 819 *--bufptr = c; 820 } 821 822 static long 823 stream_pos(void) 824 /* return our current character position in the input stream */ 825 { 826 return (yyin ? ftell(yyin) : (bufptr ? bufptr - bufstart : 0)); 827 } 828 829 static bool 830 end_of_stream(void) 831 /* are we at end of input? */ 832 { 833 return ((yyin ? feof(yyin) : (bufptr && *bufptr == '\0')) 834 ? TRUE : FALSE); 835 } 836