1 /* 2 * Copyright (C) 1984-2024 Mark Nudelman 3 * 4 * You may distribute under the terms of either the GNU General Public 5 * License or the Less License, as specified in the README file. 6 * 7 * For more information, see the README file. 8 */ 9 10 11 /* 12 * Low level character input from the input file. 13 * We use these special purpose routines which optimize moving 14 * both forward and backward from the current read pointer. 15 */ 16 17 #include "less.h" 18 #if MSDOS_COMPILER==WIN32C 19 #include <errno.h> 20 #include <windows.h> 21 #endif 22 23 typedef POSITION BLOCKNUM; 24 25 public int ignore_eoi; 26 27 /* 28 * Pool of buffers holding the most recently used blocks of the input file. 29 * The buffer pool is kept as a doubly-linked circular list, 30 * in order from most- to least-recently used. 31 * The circular list is anchored by the file state "thisfile". 32 */ 33 struct bufnode { 34 struct bufnode *next, *prev; 35 struct bufnode *hnext, *hprev; 36 }; 37 38 #define LBUFSIZE 8192 39 struct buf { 40 struct bufnode node; 41 BLOCKNUM block; 42 size_t datasize; 43 unsigned char data[LBUFSIZE]; 44 }; 45 #define bufnode_buf(bn) ((struct buf *) bn) 46 47 /* 48 * The file state is maintained in a filestate structure. 49 * A pointer to the filestate is kept in the ifile structure. 50 */ 51 #define BUFHASH_SIZE 1024 52 struct filestate { 53 struct bufnode buflist; 54 struct bufnode hashtbl[BUFHASH_SIZE]; 55 int file; 56 int flags; 57 POSITION fpos; 58 int nbufs; 59 BLOCKNUM block; 60 size_t offset; 61 POSITION fsize; 62 }; 63 64 #define ch_bufhead thisfile->buflist.next 65 #define ch_buftail thisfile->buflist.prev 66 #define ch_nbufs thisfile->nbufs 67 #define ch_block thisfile->block 68 #define ch_offset thisfile->offset 69 #define ch_fpos thisfile->fpos 70 #define ch_fsize thisfile->fsize 71 #define ch_flags thisfile->flags 72 #define ch_file thisfile->file 73 74 #define END_OF_CHAIN (&thisfile->buflist) 75 #define END_OF_HCHAIN(h) (&thisfile->hashtbl[h]) 76 #define BUFHASH(blk) ((blk) & (BUFHASH_SIZE-1)) 77 78 /* 79 * Macros to manipulate the list of buffers in thisfile->buflist. 80 */ 81 #define FOR_BUFS(bn) \ 82 for (bn = ch_bufhead; bn != END_OF_CHAIN; bn = bn->next) 83 84 #define BUF_RM(bn) \ 85 (bn)->next->prev = (bn)->prev; \ 86 (bn)->prev->next = (bn)->next; 87 88 #define BUF_INS_HEAD(bn) \ 89 (bn)->next = ch_bufhead; \ 90 (bn)->prev = END_OF_CHAIN; \ 91 ch_bufhead->prev = (bn); \ 92 ch_bufhead = (bn); 93 94 #define BUF_INS_TAIL(bn) \ 95 (bn)->next = END_OF_CHAIN; \ 96 (bn)->prev = ch_buftail; \ 97 ch_buftail->next = (bn); \ 98 ch_buftail = (bn); 99 100 /* 101 * Macros to manipulate the list of buffers in thisfile->hashtbl[n]. 102 */ 103 #define FOR_BUFS_IN_CHAIN(h,bn) \ 104 for (bn = thisfile->hashtbl[h].hnext; \ 105 bn != END_OF_HCHAIN(h); bn = bn->hnext) 106 107 #define BUF_HASH_RM(bn) \ 108 (bn)->hnext->hprev = (bn)->hprev; \ 109 (bn)->hprev->hnext = (bn)->hnext; 110 111 #define BUF_HASH_INS(bn,h) \ 112 (bn)->hnext = thisfile->hashtbl[h].hnext; \ 113 (bn)->hprev = END_OF_HCHAIN(h); \ 114 thisfile->hashtbl[h].hnext->hprev = (bn); \ 115 thisfile->hashtbl[h].hnext = (bn); 116 117 static struct filestate *thisfile; 118 static unsigned char ch_ungotchar; 119 static lbool ch_have_ungotchar = FALSE; 120 static int maxbufs = -1; 121 122 extern int autobuf; 123 extern int sigs; 124 extern int follow_mode; 125 extern lbool waiting_for_data; 126 extern constant char helpdata[]; 127 extern constant int size_helpdata; 128 extern IFILE curr_ifile; 129 #if LOGFILE 130 extern int logfile; 131 extern char *namelogfile; 132 #endif 133 134 static int ch_addbuf(); 135 136 /* 137 * Return the file position corresponding to an offset within a block. 138 */ 139 static POSITION ch_position(BLOCKNUM block, size_t offset) 140 { 141 return (block * LBUFSIZE) + (POSITION) offset; 142 } 143 144 /* 145 * Get the character pointed to by the read pointer. 146 */ 147 static int ch_get(void) 148 { 149 struct buf *bp; 150 struct bufnode *bn; 151 ssize_t n; 152 lbool read_again; 153 int h; 154 POSITION pos; 155 POSITION len; 156 157 if (thisfile == NULL) 158 return (EOI); 159 160 /* 161 * Quick check for the common case where 162 * the desired char is in the head buffer. 163 */ 164 if (ch_bufhead != END_OF_CHAIN) 165 { 166 bp = bufnode_buf(ch_bufhead); 167 if (ch_block == bp->block && ch_offset < bp->datasize) 168 return bp->data[ch_offset]; 169 } 170 171 /* 172 * Look for a buffer holding the desired block. 173 */ 174 waiting_for_data = FALSE; 175 h = BUFHASH(ch_block); 176 FOR_BUFS_IN_CHAIN(h, bn) 177 { 178 bp = bufnode_buf(bn); 179 if (bp->block == ch_block) 180 { 181 if (ch_offset >= bp->datasize) 182 /* 183 * Need more data in this buffer. 184 */ 185 break; 186 goto found; 187 } 188 } 189 if (ABORT_SIGS()) 190 return (EOI); 191 if (bn == END_OF_HCHAIN(h)) 192 { 193 /* 194 * Block is not in a buffer. 195 * Take the least recently used buffer 196 * and read the desired block into it. 197 * If the LRU buffer has data in it, 198 * then maybe allocate a new buffer. 199 */ 200 if (ch_buftail == END_OF_CHAIN || 201 bufnode_buf(ch_buftail)->block != -1) 202 { 203 /* 204 * There is no empty buffer to use. 205 * Allocate a new buffer if: 206 * 1. We can't seek on this file and -b is not in effect; or 207 * 2. We haven't allocated the max buffers for this file yet. 208 */ 209 if ((autobuf && !(ch_flags & CH_CANSEEK)) || 210 (maxbufs < 0 || ch_nbufs < maxbufs)) 211 if (ch_addbuf()) 212 /* 213 * Allocation failed: turn off autobuf. 214 */ 215 autobuf = OPT_OFF; 216 } 217 bn = ch_buftail; 218 bp = bufnode_buf(bn); 219 BUF_HASH_RM(bn); /* Remove from old hash chain. */ 220 bp->block = ch_block; 221 bp->datasize = 0; 222 BUF_HASH_INS(bn, h); /* Insert into new hash chain. */ 223 } 224 225 for (;;) 226 { 227 pos = ch_position(ch_block, bp->datasize); 228 if ((len = ch_length()) != NULL_POSITION && pos >= len) 229 /* 230 * At end of file. 231 */ 232 return (EOI); 233 234 if (pos != ch_fpos) 235 { 236 /* 237 * Not at the correct position: must seek. 238 * If input is a pipe, we're in trouble (can't seek on a pipe). 239 * Some data has been lost: just return "?". 240 */ 241 if (!(ch_flags & CH_CANSEEK)) 242 return ('?'); 243 if (less_lseek(ch_file, (less_off_t)pos, SEEK_SET) == BAD_LSEEK) 244 { 245 error("seek error", NULL_PARG); 246 clear_eol(); 247 return (EOI); 248 } 249 ch_fpos = pos; 250 } 251 252 /* 253 * Read the block. 254 * If we read less than a full block, that's ok. 255 * We use partial block and pick up the rest next time. 256 */ 257 if (ch_have_ungotchar) 258 { 259 bp->data[bp->datasize] = ch_ungotchar; 260 n = 1; 261 ch_have_ungotchar = FALSE; 262 } else if (ch_flags & CH_HELPFILE) 263 { 264 bp->data[bp->datasize] = (unsigned char) helpdata[ch_fpos]; 265 n = 1; 266 } else 267 { 268 n = iread(ch_file, &bp->data[bp->datasize], LBUFSIZE - bp->datasize); 269 } 270 271 read_again = FALSE; 272 if (n == READ_INTR) 273 { 274 ch_fsize = pos; 275 return (EOI); 276 } 277 if (n == READ_AGAIN) 278 { 279 read_again = TRUE; 280 n = 0; 281 } 282 if (n < 0) 283 { 284 #if MSDOS_COMPILER==WIN32C 285 if (errno != EPIPE) 286 #endif 287 { 288 error("read error", NULL_PARG); 289 clear_eol(); 290 } 291 n = 0; 292 } 293 294 #if LOGFILE 295 /* 296 * If we have a log file, write the new data to it. 297 */ 298 if (secure_allow(SF_LOGFILE)) 299 { 300 if (logfile >= 0 && n > 0) 301 write(logfile, &bp->data[bp->datasize], (size_t) n); 302 } 303 #endif 304 305 ch_fpos += n; 306 bp->datasize += (size_t) n; 307 308 if (n == 0) 309 { 310 /* Either end of file or no data available. 311 * read_again indicates the latter. */ 312 if (!read_again) 313 ch_fsize = pos; 314 if (ignore_eoi || read_again) 315 { 316 /* Wait a while, then try again. */ 317 if (!waiting_for_data) 318 { 319 PARG parg; 320 parg.p_string = wait_message(); 321 ixerror("%s", &parg); 322 waiting_for_data = TRUE; 323 } 324 sleep_ms(50); /* Reduce system load */ 325 } 326 if (ignore_eoi && follow_mode == FOLLOW_NAME && curr_ifile_changed()) 327 { 328 /* screen_trashed=2 causes make_display to reopen the file. */ 329 screen_trashed_num(2); 330 return (EOI); 331 } 332 if (sigs) 333 return (EOI); 334 } 335 336 found: 337 if (ch_bufhead != bn) 338 { 339 /* 340 * Move the buffer to the head of the buffer chain. 341 * This orders the buffer chain, most- to least-recently used. 342 */ 343 BUF_RM(bn); 344 BUF_INS_HEAD(bn); 345 346 /* 347 * Move to head of hash chain too. 348 */ 349 BUF_HASH_RM(bn); 350 BUF_HASH_INS(bn, h); 351 } 352 353 if (ch_offset < bp->datasize) 354 break; 355 /* 356 * After all that, we still don't have enough data. 357 * Go back and try again. 358 */ 359 } 360 return (bp->data[ch_offset]); 361 } 362 363 /* 364 * ch_ungetchar is a rather kludgy and limited way to push 365 * a single char onto an input file descriptor. 366 */ 367 public void ch_ungetchar(int c) 368 { 369 if (c < 0) 370 ch_have_ungotchar = FALSE; 371 else 372 { 373 if (ch_have_ungotchar) 374 error("ch_ungetchar overrun", NULL_PARG); 375 ch_ungotchar = (unsigned char) c; 376 ch_have_ungotchar = TRUE; 377 } 378 } 379 380 #if LOGFILE 381 /* 382 * Close the logfile. 383 * If we haven't read all of standard input into it, do that now. 384 */ 385 public void end_logfile(void) 386 { 387 static lbool tried = FALSE; 388 389 if (logfile < 0) 390 return; 391 if (!tried && ch_fsize == NULL_POSITION) 392 { 393 tried = TRUE; 394 ierror("Finishing logfile", NULL_PARG); 395 while (ch_forw_get() != EOI) 396 if (ABORT_SIGS()) 397 break; 398 } 399 close(logfile); 400 logfile = -1; 401 free(namelogfile); 402 namelogfile = NULL; 403 } 404 405 /* 406 * Start a log file AFTER less has already been running. 407 * Invoked from the - command; see toggle_option(). 408 * Write all the existing buffered data to the log file. 409 */ 410 public void sync_logfile(void) 411 { 412 struct buf *bp; 413 struct bufnode *bn; 414 lbool warned = FALSE; 415 BLOCKNUM block; 416 BLOCKNUM nblocks; 417 418 if (logfile < 0) 419 return; 420 nblocks = (ch_fpos + LBUFSIZE - 1) / LBUFSIZE; 421 for (block = 0; block < nblocks; block++) 422 { 423 lbool wrote = FALSE; 424 FOR_BUFS(bn) 425 { 426 bp = bufnode_buf(bn); 427 if (bp->block == block) 428 { 429 write(logfile, bp->data, bp->datasize); 430 wrote = TRUE; 431 break; 432 } 433 } 434 if (!wrote && !warned) 435 { 436 error("Warning: log file is incomplete", 437 NULL_PARG); 438 warned = TRUE; 439 } 440 } 441 } 442 443 #endif 444 445 /* 446 * Determine if a specific block is currently in one of the buffers. 447 */ 448 static lbool buffered(BLOCKNUM block) 449 { 450 struct buf *bp; 451 struct bufnode *bn; 452 int h; 453 454 h = BUFHASH(block); 455 FOR_BUFS_IN_CHAIN(h, bn) 456 { 457 bp = bufnode_buf(bn); 458 if (bp->block == block) 459 return (TRUE); 460 } 461 return (FALSE); 462 } 463 464 /* 465 * Seek to a specified position in the file. 466 * Return 0 if successful, non-zero if can't seek there. 467 */ 468 public int ch_seek(POSITION pos) 469 { 470 BLOCKNUM new_block; 471 POSITION len; 472 473 if (thisfile == NULL) 474 return (0); 475 476 len = ch_length(); 477 if (pos < ch_zero() || (len != NULL_POSITION && pos > len)) 478 return (1); 479 480 new_block = pos / LBUFSIZE; 481 if (!(ch_flags & CH_CANSEEK) && pos != ch_fpos && !buffered(new_block)) 482 { 483 if (ch_fpos > pos) 484 return (1); 485 while (ch_fpos < pos) 486 { 487 if (ch_forw_get() == EOI) 488 return (1); 489 if (ABORT_SIGS()) 490 return (1); 491 } 492 return (0); 493 } 494 /* 495 * Set read pointer. 496 */ 497 ch_block = new_block; 498 ch_offset = (size_t) (pos % LBUFSIZE); 499 return (0); 500 } 501 502 /* 503 * Seek to the end of the file. 504 */ 505 public int ch_end_seek(void) 506 { 507 POSITION len; 508 509 if (thisfile == NULL) 510 return (0); 511 512 if (ch_flags & CH_CANSEEK) 513 ch_fsize = filesize(ch_file); 514 515 len = ch_length(); 516 if (len != NULL_POSITION) 517 return (ch_seek(len)); 518 519 /* 520 * Do it the slow way: read till end of data. 521 */ 522 while (ch_forw_get() != EOI) 523 if (ABORT_SIGS()) 524 return (1); 525 return (0); 526 } 527 528 /* 529 * Seek to the last position in the file that is currently buffered. 530 */ 531 public int ch_end_buffer_seek(void) 532 { 533 struct buf *bp; 534 struct bufnode *bn; 535 POSITION buf_pos; 536 POSITION end_pos; 537 538 if (thisfile == NULL || (ch_flags & CH_CANSEEK)) 539 return (ch_end_seek()); 540 541 end_pos = 0; 542 FOR_BUFS(bn) 543 { 544 bp = bufnode_buf(bn); 545 buf_pos = ch_position(bp->block, bp->datasize); 546 if (buf_pos > end_pos) 547 end_pos = buf_pos; 548 } 549 550 return (ch_seek(end_pos)); 551 } 552 553 /* 554 * Seek to the beginning of the file, or as close to it as we can get. 555 * We may not be able to seek there if input is a pipe and the 556 * beginning of the pipe is no longer buffered. 557 */ 558 public int ch_beg_seek(void) 559 { 560 struct bufnode *bn; 561 struct bufnode *firstbn; 562 563 /* 564 * Try a plain ch_seek first. 565 */ 566 if (ch_seek(ch_zero()) == 0) 567 return (0); 568 569 /* 570 * Can't get to position 0. 571 * Look thru the buffers for the one closest to position 0. 572 */ 573 firstbn = ch_bufhead; 574 if (firstbn == END_OF_CHAIN) 575 return (1); 576 FOR_BUFS(bn) 577 { 578 if (bufnode_buf(bn)->block < bufnode_buf(firstbn)->block) 579 firstbn = bn; 580 } 581 ch_block = bufnode_buf(firstbn)->block; 582 ch_offset = 0; 583 return (0); 584 } 585 586 /* 587 * Return the length of the file, if known. 588 */ 589 public POSITION ch_length(void) 590 { 591 if (thisfile == NULL) 592 return (NULL_POSITION); 593 if (ignore_eoi) 594 return (NULL_POSITION); 595 if (ch_flags & CH_HELPFILE) 596 return (size_helpdata); 597 if (ch_flags & CH_NODATA) 598 return (0); 599 return (ch_fsize); 600 } 601 602 /* 603 * Return the current position in the file. 604 */ 605 public POSITION ch_tell(void) 606 { 607 if (thisfile == NULL) 608 return (NULL_POSITION); 609 return ch_position(ch_block, ch_offset); 610 } 611 612 /* 613 * Get the current char and post-increment the read pointer. 614 */ 615 public int ch_forw_get(void) 616 { 617 int c; 618 619 if (thisfile == NULL) 620 return (EOI); 621 c = ch_get(); 622 if (c == EOI) 623 return (EOI); 624 if (ch_offset < LBUFSIZE-1) 625 ch_offset++; 626 else 627 { 628 ch_block ++; 629 ch_offset = 0; 630 } 631 return (c); 632 } 633 634 /* 635 * Pre-decrement the read pointer and get the new current char. 636 */ 637 public int ch_back_get(void) 638 { 639 if (thisfile == NULL) 640 return (EOI); 641 if (ch_offset > 0) 642 ch_offset --; 643 else 644 { 645 if (ch_block <= 0) 646 return (EOI); 647 if (!(ch_flags & CH_CANSEEK) && !buffered(ch_block-1)) 648 return (EOI); 649 ch_block--; 650 ch_offset = LBUFSIZE-1; 651 } 652 return (ch_get()); 653 } 654 655 /* 656 * Set max amount of buffer space. 657 * bufspace is in units of 1024 bytes. -1 mean no limit. 658 */ 659 public void ch_setbufspace(ssize_t bufspace) 660 { 661 if (bufspace < 0) 662 maxbufs = -1; 663 else 664 { 665 size_t lbufk = LBUFSIZE / 1024; 666 maxbufs = (int) (bufspace / lbufk + (bufspace % lbufk != 0)); 667 if (maxbufs < 1) 668 maxbufs = 1; 669 } 670 } 671 672 /* 673 * Flush (discard) any saved file state, including buffer contents. 674 */ 675 public void ch_flush(void) 676 { 677 struct bufnode *bn; 678 679 if (thisfile == NULL) 680 return; 681 682 if (!(ch_flags & CH_CANSEEK)) 683 { 684 /* 685 * If input is a pipe, we don't flush buffer contents, 686 * since the contents can't be recovered. 687 */ 688 ch_fsize = NULL_POSITION; 689 return; 690 } 691 692 /* 693 * Initialize all the buffers. 694 */ 695 FOR_BUFS(bn) 696 { 697 bufnode_buf(bn)->block = -1; 698 } 699 700 /* 701 * Seek to a known position: the beginning of the file. 702 */ 703 ch_fpos = 0; 704 ch_block = 0; /* ch_fpos / LBUFSIZE; */ 705 ch_offset = 0; /* ch_fpos % LBUFSIZE; */ 706 707 if (ch_flags & CH_NOTRUSTSIZE) 708 { 709 ch_fsize = NULL_POSITION; 710 ch_flags &= ~CH_CANSEEK; 711 } else 712 { 713 ch_fsize = (ch_flags & CH_HELPFILE) ? size_helpdata : filesize(ch_file); 714 } 715 716 if (less_lseek(ch_file, (less_off_t)0, SEEK_SET) == BAD_LSEEK) 717 { 718 /* 719 * Warning only; even if the seek fails for some reason, 720 * there's a good chance we're at the beginning anyway. 721 * {{ I think this is bogus reasoning. }} 722 */ 723 error("seek error to 0", NULL_PARG); 724 } 725 } 726 727 /* 728 * Allocate a new buffer. 729 * The buffer is added to the tail of the buffer chain. 730 */ 731 static int ch_addbuf(void) 732 { 733 struct buf *bp; 734 struct bufnode *bn; 735 736 /* 737 * Allocate and initialize a new buffer and link it 738 * onto the tail of the buffer list. 739 */ 740 bp = (struct buf *) calloc(1, sizeof(struct buf)); 741 if (bp == NULL) 742 return (1); 743 ch_nbufs++; 744 bp->block = -1; 745 bn = &bp->node; 746 747 BUF_INS_TAIL(bn); 748 BUF_HASH_INS(bn, 0); 749 return (0); 750 } 751 752 /* 753 * 754 */ 755 static void init_hashtbl(void) 756 { 757 int h; 758 759 for (h = 0; h < BUFHASH_SIZE; h++) 760 { 761 thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h); 762 thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h); 763 } 764 } 765 766 /* 767 * Delete all buffers for this file. 768 */ 769 static void ch_delbufs(void) 770 { 771 struct bufnode *bn; 772 773 while (ch_bufhead != END_OF_CHAIN) 774 { 775 bn = ch_bufhead; 776 BUF_RM(bn); 777 free(bufnode_buf(bn)); 778 } 779 ch_nbufs = 0; 780 init_hashtbl(); 781 } 782 783 /* 784 * Is it possible to seek on a file descriptor? 785 */ 786 public int seekable(int f) 787 { 788 #if MSDOS_COMPILER 789 extern int fd0; 790 if (f == fd0 && !isatty(fd0)) 791 { 792 /* 793 * In MS-DOS, pipes are seekable. Check for 794 * standard input, and pretend it is not seekable. 795 */ 796 return (0); 797 } 798 #endif 799 return (less_lseek(f, (less_off_t)1, SEEK_SET) != BAD_LSEEK); 800 } 801 802 /* 803 * Force EOF to be at the current read position. 804 * This is used after an ignore_eof read, during which the EOF may change. 805 */ 806 public void ch_set_eof(void) 807 { 808 if (ch_fsize != NULL_POSITION && ch_fsize < ch_fpos) 809 ch_fsize = ch_fpos; 810 } 811 812 813 /* 814 * Initialize file state for a new file. 815 */ 816 public void ch_init(int f, int flags, ssize_t nread) 817 { 818 /* 819 * See if we already have a filestate for this file. 820 */ 821 thisfile = (struct filestate *) get_filestate(curr_ifile); 822 if (thisfile == NULL) 823 { 824 /* 825 * Allocate and initialize a new filestate. 826 */ 827 thisfile = (struct filestate *) 828 ecalloc(1, sizeof(struct filestate)); 829 thisfile->buflist.next = thisfile->buflist.prev = END_OF_CHAIN; 830 thisfile->nbufs = 0; 831 thisfile->flags = flags; 832 thisfile->fpos = 0; 833 thisfile->block = 0; 834 thisfile->offset = 0; 835 thisfile->file = -1; 836 thisfile->fsize = NULL_POSITION; 837 init_hashtbl(); 838 /* 839 * Try to seek; set CH_CANSEEK if it works. 840 */ 841 if ((flags & CH_CANSEEK) && !seekable(f)) 842 ch_flags &= ~CH_CANSEEK; 843 set_filestate(curr_ifile, (void *) thisfile); 844 } 845 if (thisfile->file == -1) 846 thisfile->file = f; 847 848 /* 849 * Figure out the size of the file, if we can. 850 */ 851 ch_fsize = (flags & CH_HELPFILE) ? size_helpdata : filesize(ch_file); 852 853 /* 854 * This is a kludge to workaround a Linux kernel bug: files in some 855 * pseudo filesystems like /proc and tracefs have a size of 0 according 856 * to fstat() but have readable data. 857 */ 858 if (ch_fsize == 0 && nread > 0) 859 { 860 ch_flags |= CH_NOTRUSTSIZE; 861 } 862 863 ch_flush(); 864 } 865 866 /* 867 * Close a filestate. 868 */ 869 public void ch_close(void) 870 { 871 lbool keepstate = FALSE; 872 873 if (thisfile == NULL) 874 return; 875 876 if ((ch_flags & (CH_CANSEEK|CH_POPENED|CH_HELPFILE)) && !(ch_flags & CH_KEEPOPEN)) 877 { 878 /* 879 * We can seek or re-open, so we don't need to keep buffers. 880 */ 881 ch_delbufs(); 882 } else 883 keepstate = TRUE; 884 if (!(ch_flags & CH_KEEPOPEN)) 885 { 886 /* 887 * We don't need to keep the file descriptor open 888 * (because we can re-open it.) 889 * But don't really close it if it was opened via popen(), 890 * because pclose() wants to close it. 891 */ 892 if (!(ch_flags & (CH_POPENED|CH_HELPFILE))) 893 close(ch_file); 894 ch_file = -1; 895 } else 896 keepstate = TRUE; 897 if (!keepstate) 898 { 899 /* 900 * We don't even need to keep the filestate structure. 901 */ 902 free(thisfile); 903 thisfile = NULL; 904 set_filestate(curr_ifile, (void *) NULL); 905 } 906 } 907 908 /* 909 * Return ch_flags for the current file. 910 */ 911 public int ch_getflags(void) 912 { 913 if (thisfile == NULL) 914 return (0); 915 return (ch_flags); 916 } 917 918 #if 0 919 static void ch_dump(struct filestate *fs) 920 { 921 struct buf *bp; 922 struct bufnode *bn; 923 unsigned char *s; 924 925 if (fs == NULL) 926 { 927 printf(" --no filestate\n"); 928 return; 929 } 930 printf(" file %d, flags %x, fpos %x, fsize %x, blk/off %x/%x\n", 931 fs->file, fs->flags, fs->fpos, 932 fs->fsize, fs->block, fs->offset); 933 printf(" %d bufs:\n", fs->nbufs); 934 for (bn = fs->next; bn != &fs->buflist; bn = bn->next) 935 { 936 bp = bufnode_buf(bn); 937 printf("%x: blk %x, size %x \"", 938 bp, bp->block, bp->datasize); 939 for (s = bp->data; s < bp->data + 30; s++) 940 if (*s >= ' ' && *s < 0x7F) 941 printf("%c", *s); 942 else 943 printf("."); 944 printf("\"\n"); 945 } 946 } 947 #endif 948