ch.c revision 294286 
1/*
2 * Copyright (C) 1984-2015  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#if HAVE_STAT_INO
24#include <sys/stat.h>
25extern dev_t curr_dev;
26extern ino_t curr_ino;
27#endif
28
29typedef POSITION BLOCKNUM;
30
31public int ignore_eoi;
32
33/*
34 * Pool of buffers holding the most recently used blocks of the input file.
35 * The buffer pool is kept as a doubly-linked circular list,
36 * in order from most- to least-recently used.
37 * The circular list is anchored by the file state "thisfile".
38 */
39struct bufnode {
40	struct bufnode *next, *prev;
41	struct bufnode *hnext, *hprev;
42};
43
44#define	LBUFSIZE	8192
45struct buf {
46	struct bufnode node;
47	BLOCKNUM block;
48	unsigned int datasize;
49	unsigned char data[LBUFSIZE];
50};
51#define bufnode_buf(bn)  ((struct buf *) bn)
52
53/*
54 * The file state is maintained in a filestate structure.
55 * A pointer to the filestate is kept in the ifile structure.
56 */
57#define	BUFHASH_SIZE	1024
58struct filestate {
59	struct bufnode buflist;
60	struct bufnode hashtbl[BUFHASH_SIZE];
61	int file;
62	int flags;
63	POSITION fpos;
64	int nbufs;
65	BLOCKNUM block;
66	unsigned int offset;
67	POSITION fsize;
68};
69
70#define	ch_bufhead	thisfile->buflist.next
71#define	ch_buftail	thisfile->buflist.prev
72#define	ch_nbufs	thisfile->nbufs
73#define	ch_block	thisfile->block
74#define	ch_offset	thisfile->offset
75#define	ch_fpos		thisfile->fpos
76#define	ch_fsize	thisfile->fsize
77#define	ch_flags	thisfile->flags
78#define	ch_file		thisfile->file
79
80#define	END_OF_CHAIN	(&thisfile->buflist)
81#define	END_OF_HCHAIN(h) (&thisfile->hashtbl[h])
82#define BUFHASH(blk)	((blk) & (BUFHASH_SIZE-1))
83
84/*
85 * Macros to manipulate the list of buffers in thisfile->buflist.
86 */
87#define	FOR_BUFS(bn) \
88	for (bn = ch_bufhead;  bn != END_OF_CHAIN;  bn = bn->next)
89
90#define BUF_RM(bn) \
91	(bn)->next->prev = (bn)->prev; \
92	(bn)->prev->next = (bn)->next;
93
94#define BUF_INS_HEAD(bn) \
95	(bn)->next = ch_bufhead; \
96	(bn)->prev = END_OF_CHAIN; \
97	ch_bufhead->prev = (bn); \
98	ch_bufhead = (bn);
99
100#define BUF_INS_TAIL(bn) \
101	(bn)->next = END_OF_CHAIN; \
102	(bn)->prev = ch_buftail; \
103	ch_buftail->next = (bn); \
104	ch_buftail = (bn);
105
106/*
107 * Macros to manipulate the list of buffers in thisfile->hashtbl[n].
108 */
109#define	FOR_BUFS_IN_CHAIN(h,bn) \
110	for (bn = thisfile->hashtbl[h].hnext;  \
111	     bn != END_OF_HCHAIN(h);  bn = bn->hnext)
112
113#define	BUF_HASH_RM(bn) \
114	(bn)->hnext->hprev = (bn)->hprev; \
115	(bn)->hprev->hnext = (bn)->hnext;
116
117#define	BUF_HASH_INS(bn,h) \
118	(bn)->hnext = thisfile->hashtbl[h].hnext; \
119	(bn)->hprev = END_OF_HCHAIN(h); \
120	thisfile->hashtbl[h].hnext->hprev = (bn); \
121	thisfile->hashtbl[h].hnext = (bn);
122
123static struct filestate *thisfile;
124static int ch_ungotchar = -1;
125static int maxbufs = -1;
126
127extern int autobuf;
128extern int sigs;
129extern int secure;
130extern int screen_trashed;
131extern int follow_mode;
132extern constant char helpdata[];
133extern constant int size_helpdata;
134extern IFILE curr_ifile;
135#if LOGFILE
136extern int logfile;
137extern char *namelogfile;
138#endif
139
140static int ch_addbuf();
141
142
143/*
144 * Get the character pointed to by the read pointer.
145 */
146	int
147ch_get()
148{
149	register struct buf *bp;
150	register struct bufnode *bn;
151	register int n;
152	register int slept;
153	register 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	slept = FALSE;
172
173	/*
174	 * Look for a buffer holding the desired block.
175	 */
176	h = BUFHASH(ch_block);
177	FOR_BUFS_IN_CHAIN(h, bn)
178	{
179		bp = bufnode_buf(bn);
180		if (bp->block == ch_block)
181		{
182			if (ch_offset >= bp->datasize)
183				/*
184				 * Need more data in this buffer.
185				 */
186				break;
187			goto found;
188		}
189	}
190	if (bn == END_OF_HCHAIN(h))
191	{
192		/*
193		 * Block is not in a buffer.
194		 * Take the least recently used buffer
195		 * and read the desired block into it.
196		 * If the LRU buffer has data in it,
197		 * then maybe allocate a new buffer.
198		 */
199		if (ch_buftail == END_OF_CHAIN ||
200			bufnode_buf(ch_buftail)->block != -1)
201		{
202			/*
203			 * There is no empty buffer to use.
204			 * Allocate a new buffer if:
205			 * 1. We can't seek on this file and -b is not in effect; or
206			 * 2. We haven't allocated the max buffers for this file yet.
207			 */
208			if ((autobuf && !(ch_flags & CH_CANSEEK)) ||
209				(maxbufs < 0 || ch_nbufs < maxbufs))
210				if (ch_addbuf())
211					/*
212					 * Allocation failed: turn off autobuf.
213					 */
214					autobuf = OPT_OFF;
215		}
216		bn = ch_buftail;
217		bp = bufnode_buf(bn);
218		BUF_HASH_RM(bn); /* Remove from old hash chain. */
219		bp->block = ch_block;
220		bp->datasize = 0;
221		BUF_HASH_INS(bn, h); /* Insert into new hash chain. */
222	}
223
224    read_more:
225	pos = (ch_block * LBUFSIZE) + bp->datasize;
226	if ((len = ch_length()) != NULL_POSITION && pos >= len)
227		/*
228		 * At end of file.
229		 */
230		return (EOI);
231
232	if (pos != ch_fpos)
233	{
234		/*
235		 * Not at the correct position: must seek.
236		 * If input is a pipe, we're in trouble (can't seek on a pipe).
237		 * Some data has been lost: just return "?".
238		 */
239		if (!(ch_flags & CH_CANSEEK))
240			return ('?');
241		if (lseek(ch_file, (off_t)pos, SEEK_SET) == BAD_LSEEK)
242		{
243 			error("seek error", NULL_PARG);
244			clear_eol();
245			return (EOI);
246 		}
247 		ch_fpos = pos;
248 	}
249
250	/*
251	 * Read the block.
252	 * If we read less than a full block, that's ok.
253	 * We use partial block and pick up the rest next time.
254	 */
255	if (ch_ungotchar != -1)
256	{
257		bp->data[bp->datasize] = ch_ungotchar;
258		n = 1;
259		ch_ungotchar = -1;
260	} else if (ch_flags & CH_HELPFILE)
261	{
262		bp->data[bp->datasize] = helpdata[ch_fpos];
263		n = 1;
264	} else
265	{
266		n = iread(ch_file, &bp->data[bp->datasize],
267			(unsigned int)(LBUFSIZE - bp->datasize));
268	}
269
270	if (n == READ_INTR)
271		return (EOI);
272	if (n < 0)
273	{
274#if MSDOS_COMPILER==WIN32C
275		if (errno != EPIPE)
276#endif
277		{
278			error("read error", NULL_PARG);
279			clear_eol();
280		}
281		n = 0;
282	}
283
284#if LOGFILE
285	/*
286	 * If we have a log file, write the new data to it.
287	 */
288	if (!secure && logfile >= 0 && n > 0)
289		write(logfile, (char *) &bp->data[bp->datasize], n);
290#endif
291
292	ch_fpos += n;
293	bp->datasize += n;
294
295	/*
296	 * If we have read to end of file, set ch_fsize to indicate
297	 * the position of the end of file.
298	 */
299	if (n == 0)
300	{
301		ch_fsize = pos;
302		if (ignore_eoi)
303		{
304			/*
305			 * We are ignoring EOF.
306			 * Wait a while, then try again.
307			 */
308			if (!slept)
309			{
310				PARG parg;
311				parg.p_string = wait_message();
312				ierror("%s", &parg);
313			}
314#if !MSDOS_COMPILER
315	 		sleep(1);
316#else
317#if MSDOS_COMPILER==WIN32C
318			Sleep(1000);
319#endif
320#endif
321			slept = TRUE;
322
323#if HAVE_STAT_INO
324			if (follow_mode == FOLLOW_NAME)
325			{
326				/* See whether the file's i-number has changed,
327				 * or the file has shrunk.
328				 * If so, force the file to be closed and
329				 * reopened. */
330				struct stat st;
331				POSITION curr_pos = ch_tell();
332				int r = stat(get_filename(curr_ifile), &st);
333				if (r == 0 && (st.st_ino != curr_ino ||
334					st.st_dev != curr_dev ||
335					(curr_pos != NULL_POSITION && st.st_size < curr_pos)))
336				{
337					/* screen_trashed=2 causes
338					 * make_display to reopen the file. */
339					screen_trashed = 2;
340					return (EOI);
341				}
342			}
343#endif
344		}
345		if (sigs)
346			return (EOI);
347	}
348
349    found:
350	if (ch_bufhead != bn)
351	{
352		/*
353		 * Move the buffer to the head of the buffer chain.
354		 * This orders the buffer chain, most- to least-recently used.
355		 */
356		BUF_RM(bn);
357		BUF_INS_HEAD(bn);
358
359		/*
360		 * Move to head of hash chain too.
361		 */
362		BUF_HASH_RM(bn);
363		BUF_HASH_INS(bn, h);
364	}
365
366	if (ch_offset >= bp->datasize)
367		/*
368		 * After all that, we still don't have enough data.
369		 * Go back and try again.
370		 */
371		goto read_more;
372
373	return (bp->data[ch_offset]);
374}
375
376/*
377 * ch_ungetchar is a rather kludgy and limited way to push
378 * a single char onto an input file descriptor.
379 */
380	public void
381ch_ungetchar(c)
382	int c;
383{
384	if (c != -1 && ch_ungotchar != -1)
385		error("ch_ungetchar overrun", NULL_PARG);
386	ch_ungotchar = c;
387}
388
389#if LOGFILE
390/*
391 * Close the logfile.
392 * If we haven't read all of standard input into it, do that now.
393 */
394	public void
395end_logfile()
396{
397	static int tried = FALSE;
398
399	if (logfile < 0)
400		return;
401	if (!tried && ch_fsize == NULL_POSITION)
402	{
403		tried = TRUE;
404		ierror("Finishing logfile", NULL_PARG);
405		while (ch_forw_get() != EOI)
406			if (ABORT_SIGS())
407				break;
408	}
409	close(logfile);
410	logfile = -1;
411	namelogfile = NULL;
412}
413
414/*
415 * Start a log file AFTER less has already been running.
416 * Invoked from the - command; see toggle_option().
417 * Write all the existing buffered data to the log file.
418 */
419	public void
420sync_logfile()
421{
422	register struct buf *bp;
423	register struct bufnode *bn;
424	int warned = FALSE;
425	BLOCKNUM block;
426	BLOCKNUM nblocks;
427
428	nblocks = (ch_fpos + LBUFSIZE - 1) / LBUFSIZE;
429	for (block = 0;  block < nblocks;  block++)
430	{
431		int wrote = FALSE;
432		FOR_BUFS(bn)
433		{
434			bp = bufnode_buf(bn);
435			if (bp->block == block)
436			{
437				write(logfile, (char *) bp->data, bp->datasize);
438				wrote = TRUE;
439				break;
440			}
441		}
442		if (!wrote && !warned)
443		{
444			error("Warning: log file is incomplete",
445				NULL_PARG);
446			warned = TRUE;
447		}
448	}
449}
450
451#endif
452
453/*
454 * Determine if a specific block is currently in one of the buffers.
455 */
456	static int
457buffered(block)
458	BLOCKNUM block;
459{
460	register struct buf *bp;
461	register struct bufnode *bn;
462	register int h;
463
464	h = BUFHASH(block);
465	FOR_BUFS_IN_CHAIN(h, bn)
466	{
467		bp = bufnode_buf(bn);
468		if (bp->block == block)
469			return (TRUE);
470	}
471	return (FALSE);
472}
473
474/*
475 * Seek to a specified position in the file.
476 * Return 0 if successful, non-zero if can't seek there.
477 */
478	public int
479ch_seek(pos)
480	register POSITION pos;
481{
482	BLOCKNUM new_block;
483	POSITION len;
484
485	if (thisfile == NULL)
486		return (0);
487
488	len = ch_length();
489	if (pos < ch_zero() || (len != NULL_POSITION && pos > len))
490		return (1);
491
492	new_block = pos / LBUFSIZE;
493	if (!(ch_flags & CH_CANSEEK) && pos != ch_fpos && !buffered(new_block))
494	{
495		if (ch_fpos > pos)
496			return (1);
497		while (ch_fpos < pos)
498		{
499			if (ch_forw_get() == EOI)
500				return (1);
501			if (ABORT_SIGS())
502				return (1);
503		}
504		return (0);
505	}
506	/*
507	 * Set read pointer.
508	 */
509	ch_block = new_block;
510	ch_offset = pos % LBUFSIZE;
511	return (0);
512}
513
514/*
515 * Seek to the end of the file.
516 */
517	public int
518ch_end_seek()
519{
520	POSITION len;
521
522	if (thisfile == NULL)
523		return (0);
524
525	if (ch_flags & CH_CANSEEK)
526		ch_fsize = filesize(ch_file);
527
528	len = ch_length();
529	if (len != NULL_POSITION)
530		return (ch_seek(len));
531
532	/*
533	 * Do it the slow way: read till end of data.
534	 */
535	while (ch_forw_get() != EOI)
536		if (ABORT_SIGS())
537			return (1);
538	return (0);
539}
540
541/*
542 * Seek to the last position in the file that is currently buffered.
543 */
544	public int
545ch_end_buffer_seek()
546{
547	register struct buf *bp;
548	register struct bufnode *bn;
549	POSITION buf_pos;
550	POSITION end_pos;
551
552	if (thisfile == NULL || (ch_flags & CH_CANSEEK))
553		return (ch_end_seek());
554
555	end_pos = 0;
556	FOR_BUFS(bn)
557	{
558		bp = bufnode_buf(bn);
559		buf_pos = (bp->block * LBUFSIZE) + bp->datasize;
560		if (buf_pos > end_pos)
561			end_pos = buf_pos;
562	}
563
564	return (ch_seek(end_pos));
565}
566
567/*
568 * Seek to the beginning of the file, or as close to it as we can get.
569 * We may not be able to seek there if input is a pipe and the
570 * beginning of the pipe is no longer buffered.
571 */
572	public int
573ch_beg_seek()
574{
575	register struct bufnode *bn;
576	register struct bufnode *firstbn;
577
578	/*
579	 * Try a plain ch_seek first.
580	 */
581	if (ch_seek(ch_zero()) == 0)
582		return (0);
583
584	/*
585	 * Can't get to position 0.
586	 * Look thru the buffers for the one closest to position 0.
587	 */
588	firstbn = ch_bufhead;
589	if (firstbn == END_OF_CHAIN)
590		return (1);
591	FOR_BUFS(bn)
592	{
593		if (bufnode_buf(bn)->block < bufnode_buf(firstbn)->block)
594			firstbn = bn;
595	}
596	ch_block = bufnode_buf(firstbn)->block;
597	ch_offset = 0;
598	return (0);
599}
600
601/*
602 * Return the length of the file, if known.
603 */
604	public POSITION
605ch_length()
606{
607	if (thisfile == NULL)
608		return (NULL_POSITION);
609	if (ignore_eoi)
610		return (NULL_POSITION);
611	if (ch_flags & CH_HELPFILE)
612		return (size_helpdata);
613	if (ch_flags & CH_NODATA)
614		return (0);
615	return (ch_fsize);
616}
617
618/*
619 * Return the current position in the file.
620 */
621	public POSITION
622ch_tell()
623{
624	if (thisfile == NULL)
625		return (NULL_POSITION);
626	return (ch_block * LBUFSIZE) + ch_offset;
627}
628
629/*
630 * Get the current char and post-increment the read pointer.
631 */
632	public int
633ch_forw_get()
634{
635	register int c;
636
637	if (thisfile == NULL)
638		return (EOI);
639	c = ch_get();
640	if (c == EOI)
641		return (EOI);
642	if (ch_offset < LBUFSIZE-1)
643		ch_offset++;
644	else
645	{
646		ch_block ++;
647		ch_offset = 0;
648	}
649	return (c);
650}
651
652/*
653 * Pre-decrement the read pointer and get the new current char.
654 */
655	public int
656ch_back_get()
657{
658	if (thisfile == NULL)
659		return (EOI);
660	if (ch_offset > 0)
661		ch_offset --;
662	else
663	{
664		if (ch_block <= 0)
665			return (EOI);
666		if (!(ch_flags & CH_CANSEEK) && !buffered(ch_block-1))
667			return (EOI);
668		ch_block--;
669		ch_offset = LBUFSIZE-1;
670	}
671	return (ch_get());
672}
673
674/*
675 * Set max amount of buffer space.
676 * bufspace is in units of 1024 bytes.  -1 mean no limit.
677 */
678	public void
679ch_setbufspace(bufspace)
680	int bufspace;
681{
682	if (bufspace < 0)
683		maxbufs = -1;
684	else
685	{
686		maxbufs = ((bufspace * 1024) + LBUFSIZE-1) / LBUFSIZE;
687		if (maxbufs < 1)
688			maxbufs = 1;
689	}
690}
691
692/*
693 * Flush (discard) any saved file state, including buffer contents.
694 */
695	public void
696ch_flush()
697{
698	register struct bufnode *bn;
699
700	if (thisfile == NULL)
701		return;
702
703	if (!(ch_flags & CH_CANSEEK))
704	{
705		/*
706		 * If input is a pipe, we don't flush buffer contents,
707		 * since the contents can't be recovered.
708		 */
709		ch_fsize = NULL_POSITION;
710		return;
711	}
712
713	/*
714	 * Initialize all the buffers.
715	 */
716	FOR_BUFS(bn)
717	{
718		bufnode_buf(bn)->block = -1;
719	}
720
721	/*
722	 * Figure out the size of the file, if we can.
723	 */
724	ch_fsize = filesize(ch_file);
725
726	/*
727	 * Seek to a known position: the beginning of the file.
728	 */
729	ch_fpos = 0;
730	ch_block = 0; /* ch_fpos / LBUFSIZE; */
731	ch_offset = 0; /* ch_fpos % LBUFSIZE; */
732
733#if 1
734	/*
735	 * This is a kludge to workaround a Linux kernel bug: files in
736	 * /proc have a size of 0 according to fstat() but have readable
737	 * data.  They are sometimes, but not always, seekable.
738	 * Force them to be non-seekable here.
739	 */
740	if (ch_fsize == 0)
741	{
742		ch_fsize = NULL_POSITION;
743		ch_flags &= ~CH_CANSEEK;
744	}
745#endif
746
747	if (lseek(ch_file, (off_t)0, SEEK_SET) == BAD_LSEEK)
748	{
749		/*
750		 * Warning only; even if the seek fails for some reason,
751		 * there's a good chance we're at the beginning anyway.
752		 * {{ I think this is bogus reasoning. }}
753		 */
754		error("seek error to 0", NULL_PARG);
755	}
756}
757
758/*
759 * Allocate a new buffer.
760 * The buffer is added to the tail of the buffer chain.
761 */
762	static int
763ch_addbuf()
764{
765	register struct buf *bp;
766	register struct bufnode *bn;
767
768	/*
769	 * Allocate and initialize a new buffer and link it
770	 * onto the tail of the buffer list.
771	 */
772	bp = (struct buf *) calloc(1, sizeof(struct buf));
773	if (bp == NULL)
774		return (1);
775	ch_nbufs++;
776	bp->block = -1;
777	bn = &bp->node;
778
779	BUF_INS_TAIL(bn);
780	BUF_HASH_INS(bn, 0);
781	return (0);
782}
783
784/*
785 *
786 */
787	static void
788init_hashtbl()
789{
790	register int h;
791
792	for (h = 0;  h < BUFHASH_SIZE;  h++)
793	{
794		thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h);
795		thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h);
796	}
797}
798
799/*
800 * Delete all buffers for this file.
801 */
802	static void
803ch_delbufs()
804{
805	register struct bufnode *bn;
806
807	while (ch_bufhead != END_OF_CHAIN)
808	{
809		bn = ch_bufhead;
810		BUF_RM(bn);
811		free(bufnode_buf(bn));
812	}
813	ch_nbufs = 0;
814	init_hashtbl();
815}
816
817/*
818 * Is it possible to seek on a file descriptor?
819 */
820	public int
821seekable(f)
822	int f;
823{
824#if MSDOS_COMPILER
825	extern int fd0;
826	if (f == fd0 && !isatty(fd0))
827	{
828		/*
829		 * In MS-DOS, pipes are seekable.  Check for
830		 * standard input, and pretend it is not seekable.
831		 */
832		return (0);
833	}
834#endif
835	return (lseek(f, (off_t)1, SEEK_SET) != BAD_LSEEK);
836}
837
838/*
839 * Force EOF to be at the current read position.
840 * This is used after an ignore_eof read, during which the EOF may change.
841 */
842	public void
843ch_set_eof()
844{
845	ch_fsize = ch_fpos;
846}
847
848
849/*
850 * Initialize file state for a new file.
851 */
852	public void
853ch_init(f, flags)
854	int f;
855	int flags;
856{
857	/*
858	 * See if we already have a filestate for this file.
859	 */
860	thisfile = (struct filestate *) get_filestate(curr_ifile);
861	if (thisfile == NULL)
862	{
863		/*
864		 * Allocate and initialize a new filestate.
865		 */
866		thisfile = (struct filestate *)
867				calloc(1, sizeof(struct filestate));
868		thisfile->buflist.next = thisfile->buflist.prev = END_OF_CHAIN;
869		thisfile->nbufs = 0;
870		thisfile->flags = 0;
871		thisfile->fpos = 0;
872		thisfile->block = 0;
873		thisfile->offset = 0;
874		thisfile->file = -1;
875		thisfile->fsize = NULL_POSITION;
876		ch_flags = flags;
877		init_hashtbl();
878		/*
879		 * Try to seek; set CH_CANSEEK if it works.
880		 */
881		if ((flags & CH_CANSEEK) && !seekable(f))
882			ch_flags &= ~CH_CANSEEK;
883		set_filestate(curr_ifile, (void *) thisfile);
884	}
885	if (thisfile->file == -1)
886		thisfile->file = f;
887	ch_flush();
888}
889
890/*
891 * Close a filestate.
892 */
893	public void
894ch_close()
895{
896	int keepstate = FALSE;
897
898	if (thisfile == NULL)
899		return;
900
901	if (ch_flags & (CH_CANSEEK|CH_POPENED|CH_HELPFILE))
902	{
903		/*
904		 * We can seek or re-open, so we don't need to keep buffers.
905		 */
906		ch_delbufs();
907	} else
908		keepstate = TRUE;
909	if (!(ch_flags & CH_KEEPOPEN))
910	{
911		/*
912		 * We don't need to keep the file descriptor open
913		 * (because we can re-open it.)
914		 * But don't really close it if it was opened via popen(),
915		 * because pclose() wants to close it.
916		 */
917		if (!(ch_flags & (CH_POPENED|CH_HELPFILE)))
918			close(ch_file);
919		ch_file = -1;
920	} else
921		keepstate = TRUE;
922	if (!keepstate)
923	{
924		/*
925		 * We don't even need to keep the filestate structure.
926		 */
927		free(thisfile);
928		thisfile = NULL;
929		set_filestate(curr_ifile, (void *) NULL);
930	}
931}
932
933/*
934 * Return ch_flags for the current file.
935 */
936	public int
937ch_getflags()
938{
939	if (thisfile == NULL)
940		return (0);
941	return (ch_flags);
942}
943
944#if 0
945	public void
946ch_dump(struct filestate *fs)
947{
948	struct buf *bp;
949	struct bufnode *bn;
950	unsigned char *s;
951
952	if (fs == NULL)
953	{
954		printf(" --no filestate\n");
955		return;
956	}
957	printf(" file %d, flags %x, fpos %x, fsize %x, blk/off %x/%x\n",
958		fs->file, fs->flags, fs->fpos,
959		fs->fsize, fs->block, fs->offset);
960	printf(" %d bufs:\n", fs->nbufs);
961	for (bn = fs->next; bn != &fs->buflist;  bn = bn->next)
962	{
963		bp = bufnode_buf(bn);
964		printf("%x: blk %x, size %x \"",
965			bp, bp->block, bp->datasize);
966		for (s = bp->data;  s < bp->data + 30;  s++)
967			if (*s >= ' ' && *s < 0x7F)
968				printf("%c", *s);
969			else
970				printf(".");
971		printf("\"\n");
972	}
973}
974#endif
975