1/*
2 * Copyright (C) 1984-2023  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_PROCFS
24#include <sys/statfs.h>
25#if HAVE_LINUX_MAGIC_H
26#include <linux/magic.h>
27#endif
28#endif
29
30typedef POSITION BLOCKNUM;
31
32public int ignore_eoi;
33
34/*
35 * Pool of buffers holding the most recently used blocks of the input file.
36 * The buffer pool is kept as a doubly-linked circular list,
37 * in order from most- to least-recently used.
38 * The circular list is anchored by the file state "thisfile".
39 */
40struct bufnode {
41	struct bufnode *next, *prev;
42	struct bufnode *hnext, *hprev;
43};
44
45#define LBUFSIZE        8192
46struct buf {
47	struct bufnode node;
48	BLOCKNUM block;
49	unsigned int datasize;
50	unsigned char data[LBUFSIZE];
51};
52#define bufnode_buf(bn)  ((struct buf *) bn)
53
54/*
55 * The file state is maintained in a filestate structure.
56 * A pointer to the filestate is kept in the ifile structure.
57 */
58#define BUFHASH_SIZE    1024
59struct filestate {
60	struct bufnode buflist;
61	struct bufnode hashtbl[BUFHASH_SIZE];
62	int file;
63	int flags;
64	POSITION fpos;
65	int nbufs;
66	BLOCKNUM block;
67	unsigned int offset;
68	POSITION fsize;
69};
70
71#define ch_bufhead      thisfile->buflist.next
72#define ch_buftail      thisfile->buflist.prev
73#define ch_nbufs        thisfile->nbufs
74#define ch_block        thisfile->block
75#define ch_offset       thisfile->offset
76#define ch_fpos         thisfile->fpos
77#define ch_fsize        thisfile->fsize
78#define ch_flags        thisfile->flags
79#define ch_file         thisfile->file
80
81#define END_OF_CHAIN    (&thisfile->buflist)
82#define END_OF_HCHAIN(h) (&thisfile->hashtbl[h])
83#define BUFHASH(blk)    ((blk) & (BUFHASH_SIZE-1))
84
85/*
86 * Macros to manipulate the list of buffers in thisfile->buflist.
87 */
88#define FOR_BUFS(bn) \
89	for (bn = ch_bufhead;  bn != END_OF_CHAIN;  bn = bn->next)
90
91#define BUF_RM(bn) \
92	(bn)->next->prev = (bn)->prev; \
93	(bn)->prev->next = (bn)->next;
94
95#define BUF_INS_HEAD(bn) \
96	(bn)->next = ch_bufhead; \
97	(bn)->prev = END_OF_CHAIN; \
98	ch_bufhead->prev = (bn); \
99	ch_bufhead = (bn);
100
101#define BUF_INS_TAIL(bn) \
102	(bn)->next = END_OF_CHAIN; \
103	(bn)->prev = ch_buftail; \
104	ch_buftail->next = (bn); \
105	ch_buftail = (bn);
106
107/*
108 * Macros to manipulate the list of buffers in thisfile->hashtbl[n].
109 */
110#define FOR_BUFS_IN_CHAIN(h,bn) \
111	for (bn = thisfile->hashtbl[h].hnext;  \
112	     bn != END_OF_HCHAIN(h);  bn = bn->hnext)
113
114#define BUF_HASH_RM(bn) \
115	(bn)->hnext->hprev = (bn)->hprev; \
116	(bn)->hprev->hnext = (bn)->hnext;
117
118#define BUF_HASH_INS(bn,h) \
119	(bn)->hnext = thisfile->hashtbl[h].hnext; \
120	(bn)->hprev = END_OF_HCHAIN(h); \
121	thisfile->hashtbl[h].hnext->hprev = (bn); \
122	thisfile->hashtbl[h].hnext = (bn);
123
124static struct filestate *thisfile;
125static int ch_ungotchar = -1;
126static int maxbufs = -1;
127
128extern int autobuf;
129extern int sigs;
130extern int secure;
131extern int screen_trashed;
132extern int follow_mode;
133extern int waiting_for_data;
134extern constant char helpdata[];
135extern constant int size_helpdata;
136extern IFILE curr_ifile;
137#if LOGFILE
138extern int logfile;
139extern char *namelogfile;
140#endif
141
142static int ch_addbuf();
143
144
145/*
146 * Get the character pointed to by the read pointer.
147 */
148static int ch_get(void)
149{
150	struct buf *bp;
151	struct bufnode *bn;
152	int n;
153	int read_again;
154	int h;
155	POSITION pos;
156	POSITION len;
157
158	if (thisfile == NULL)
159		return (EOI);
160
161	/*
162	 * Quick check for the common case where
163	 * the desired char is in the head buffer.
164	 */
165	if (ch_bufhead != END_OF_CHAIN)
166	{
167		bp = bufnode_buf(ch_bufhead);
168		if (ch_block == bp->block && ch_offset < bp->datasize)
169			return bp->data[ch_offset];
170	}
171
172	/*
173	 * Look for a buffer holding the desired block.
174	 */
175	waiting_for_data = FALSE;
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	for (;;)
225	{
226		pos = (ch_block * LBUFSIZE) + bp->datasize;
227		if ((len = ch_length()) != NULL_POSITION && pos >= len)
228			/*
229			 * At end of file.
230			 */
231			return (EOI);
232
233		if (pos != ch_fpos)
234		{
235			/*
236			 * Not at the correct position: must seek.
237			 * If input is a pipe, we're in trouble (can't seek on a pipe).
238			 * Some data has been lost: just return "?".
239			 */
240			if (!(ch_flags & CH_CANSEEK))
241				return ('?');
242			if (lseek(ch_file, (off_t)pos, SEEK_SET) == BAD_LSEEK)
243			{
244				error("seek error", NULL_PARG);
245				clear_eol();
246				return (EOI);
247			}
248			ch_fpos = pos;
249		}
250
251		/*
252		 * Read the block.
253		 * If we read less than a full block, that's ok.
254		 * We use partial block and pick up the rest next time.
255		 */
256		if (ch_ungotchar != -1)
257		{
258			bp->data[bp->datasize] = ch_ungotchar;
259			n = 1;
260			ch_ungotchar = -1;
261		} else if (ch_flags & CH_HELPFILE)
262		{
263			bp->data[bp->datasize] = helpdata[ch_fpos];
264			n = 1;
265		} else
266		{
267			n = iread(ch_file, &bp->data[bp->datasize],
268				(unsigned int)(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 && logfile >= 0 && n > 0)
299			write(logfile, (char *) &bp->data[bp->datasize], n);
300#endif
301
302		ch_fpos += n;
303		bp->datasize += n;
304
305		if (n == 0)
306		{
307			/* Either end of file or no data available.
308			 * read_again indicates the latter. */
309			if (!read_again)
310				ch_fsize = pos;
311			if (ignore_eoi || read_again)
312			{
313				/* Wait a while, then try again. */
314				if (!waiting_for_data)
315				{
316					PARG parg;
317					parg.p_string = wait_message();
318					ixerror("%s", &parg);
319					waiting_for_data = TRUE;
320				}
321				sleep_ms(50); /* Reduce system load */
322			}
323			if (ignore_eoi && follow_mode == FOLLOW_NAME && curr_ifile_changed())
324			{
325				/* screen_trashed=2 causes make_display to reopen the file. */
326				screen_trashed = 2;
327				return (EOI);
328			}
329			if (sigs)
330				return (EOI);
331		}
332
333		found:
334		if (ch_bufhead != bn)
335		{
336			/*
337			 * Move the buffer to the head of the buffer chain.
338			 * This orders the buffer chain, most- to least-recently used.
339			 */
340			BUF_RM(bn);
341			BUF_INS_HEAD(bn);
342
343			/*
344			 * Move to head of hash chain too.
345			 */
346			BUF_HASH_RM(bn);
347			BUF_HASH_INS(bn, h);
348		}
349
350		if (ch_offset < bp->datasize)
351			break;
352		/*
353		 * After all that, we still don't have enough data.
354		 * Go back and try again.
355		 */
356	}
357	return (bp->data[ch_offset]);
358}
359
360/*
361 * ch_ungetchar is a rather kludgy and limited way to push
362 * a single char onto an input file descriptor.
363 */
364public void ch_ungetchar(int c)
365{
366	if (c != -1 && ch_ungotchar != -1)
367		error("ch_ungetchar overrun", NULL_PARG);
368	ch_ungotchar = c;
369}
370
371#if LOGFILE
372/*
373 * Close the logfile.
374 * If we haven't read all of standard input into it, do that now.
375 */
376public void end_logfile(void)
377{
378	static int tried = FALSE;
379
380	if (logfile < 0)
381		return;
382	if (!tried && ch_fsize == NULL_POSITION)
383	{
384		tried = TRUE;
385		ierror("Finishing logfile", NULL_PARG);
386		while (ch_forw_get() != EOI)
387			if (ABORT_SIGS())
388				break;
389	}
390	close(logfile);
391	logfile = -1;
392	free(namelogfile);
393	namelogfile = NULL;
394}
395
396/*
397 * Start a log file AFTER less has already been running.
398 * Invoked from the - command; see toggle_option().
399 * Write all the existing buffered data to the log file.
400 */
401public void sync_logfile(void)
402{
403	struct buf *bp;
404	struct bufnode *bn;
405	int warned = FALSE;
406	BLOCKNUM block;
407	BLOCKNUM nblocks;
408
409	if (logfile < 0)
410		return;
411	nblocks = (ch_fpos + LBUFSIZE - 1) / LBUFSIZE;
412	for (block = 0;  block < nblocks;  block++)
413	{
414		int wrote = FALSE;
415		FOR_BUFS(bn)
416		{
417			bp = bufnode_buf(bn);
418			if (bp->block == block)
419			{
420				write(logfile, (char *) bp->data, bp->datasize);
421				wrote = TRUE;
422				break;
423			}
424		}
425		if (!wrote && !warned)
426		{
427			error("Warning: log file is incomplete",
428				NULL_PARG);
429			warned = TRUE;
430		}
431	}
432}
433
434#endif
435
436/*
437 * Determine if a specific block is currently in one of the buffers.
438 */
439static int buffered(BLOCKNUM block)
440{
441	struct buf *bp;
442	struct bufnode *bn;
443	int h;
444
445	h = BUFHASH(block);
446	FOR_BUFS_IN_CHAIN(h, bn)
447	{
448		bp = bufnode_buf(bn);
449		if (bp->block == block)
450			return (TRUE);
451	}
452	return (FALSE);
453}
454
455/*
456 * Seek to a specified position in the file.
457 * Return 0 if successful, non-zero if can't seek there.
458 */
459public int ch_seek(POSITION pos)
460{
461	BLOCKNUM new_block;
462	POSITION len;
463
464	if (thisfile == NULL)
465		return (0);
466
467	len = ch_length();
468	if (pos < ch_zero() || (len != NULL_POSITION && pos > len))
469		return (1);
470
471	new_block = pos / LBUFSIZE;
472	if (!(ch_flags & CH_CANSEEK) && pos != ch_fpos && !buffered(new_block))
473	{
474		if (ch_fpos > pos)
475			return (1);
476		while (ch_fpos < pos)
477		{
478			if (ch_forw_get() == EOI)
479				return (1);
480			if (ABORT_SIGS())
481				return (1);
482		}
483		return (0);
484	}
485	/*
486	 * Set read pointer.
487	 */
488	ch_block = new_block;
489	ch_offset = pos % LBUFSIZE;
490	return (0);
491}
492
493/*
494 * Seek to the end of the file.
495 */
496public int ch_end_seek(void)
497{
498	POSITION len;
499
500	if (thisfile == NULL)
501		return (0);
502
503	if (ch_flags & CH_CANSEEK)
504		ch_fsize = filesize(ch_file);
505
506	len = ch_length();
507	if (len != NULL_POSITION)
508		return (ch_seek(len));
509
510	/*
511	 * Do it the slow way: read till end of data.
512	 */
513	while (ch_forw_get() != EOI)
514		if (ABORT_SIGS())
515			return (1);
516	return (0);
517}
518
519/*
520 * Seek to the last position in the file that is currently buffered.
521 */
522public int ch_end_buffer_seek(void)
523{
524	struct buf *bp;
525	struct bufnode *bn;
526	POSITION buf_pos;
527	POSITION end_pos;
528
529	if (thisfile == NULL || (ch_flags & CH_CANSEEK))
530		return (ch_end_seek());
531
532	end_pos = 0;
533	FOR_BUFS(bn)
534	{
535		bp = bufnode_buf(bn);
536		buf_pos = (bp->block * LBUFSIZE) + bp->datasize;
537		if (buf_pos > end_pos)
538			end_pos = buf_pos;
539	}
540
541	return (ch_seek(end_pos));
542}
543
544/*
545 * Seek to the beginning of the file, or as close to it as we can get.
546 * We may not be able to seek there if input is a pipe and the
547 * beginning of the pipe is no longer buffered.
548 */
549public int ch_beg_seek(void)
550{
551	struct bufnode *bn;
552	struct bufnode *firstbn;
553
554	/*
555	 * Try a plain ch_seek first.
556	 */
557	if (ch_seek(ch_zero()) == 0)
558		return (0);
559
560	/*
561	 * Can't get to position 0.
562	 * Look thru the buffers for the one closest to position 0.
563	 */
564	firstbn = ch_bufhead;
565	if (firstbn == END_OF_CHAIN)
566		return (1);
567	FOR_BUFS(bn)
568	{
569		if (bufnode_buf(bn)->block < bufnode_buf(firstbn)->block)
570			firstbn = bn;
571	}
572	ch_block = bufnode_buf(firstbn)->block;
573	ch_offset = 0;
574	return (0);
575}
576
577/*
578 * Return the length of the file, if known.
579 */
580public POSITION ch_length(void)
581{
582	if (thisfile == NULL)
583		return (NULL_POSITION);
584	if (ignore_eoi)
585		return (NULL_POSITION);
586	if (ch_flags & CH_HELPFILE)
587		return (size_helpdata);
588	if (ch_flags & CH_NODATA)
589		return (0);
590	return (ch_fsize);
591}
592
593/*
594 * Return the current position in the file.
595 */
596public POSITION ch_tell(void)
597{
598	if (thisfile == NULL)
599		return (NULL_POSITION);
600	return (ch_block * LBUFSIZE) + ch_offset;
601}
602
603/*
604 * Get the current char and post-increment the read pointer.
605 */
606public int ch_forw_get(void)
607{
608	int c;
609
610	if (thisfile == NULL)
611		return (EOI);
612	c = ch_get();
613	if (c == EOI)
614		return (EOI);
615	if (ch_offset < LBUFSIZE-1)
616		ch_offset++;
617	else
618	{
619		ch_block ++;
620		ch_offset = 0;
621	}
622	return (c);
623}
624
625/*
626 * Pre-decrement the read pointer and get the new current char.
627 */
628public int ch_back_get(void)
629{
630	if (thisfile == NULL)
631		return (EOI);
632	if (ch_offset > 0)
633		ch_offset --;
634	else
635	{
636		if (ch_block <= 0)
637			return (EOI);
638		if (!(ch_flags & CH_CANSEEK) && !buffered(ch_block-1))
639			return (EOI);
640		ch_block--;
641		ch_offset = LBUFSIZE-1;
642	}
643	return (ch_get());
644}
645
646/*
647 * Set max amount of buffer space.
648 * bufspace is in units of 1024 bytes.  -1 mean no limit.
649 */
650public void ch_setbufspace(int bufspace)
651{
652	if (bufspace < 0)
653		maxbufs = -1;
654	else
655	{
656		int lbufk = LBUFSIZE / 1024;
657		maxbufs = bufspace / lbufk + (bufspace % lbufk != 0);
658		if (maxbufs < 1)
659			maxbufs = 1;
660	}
661}
662
663/*
664 * Flush (discard) any saved file state, including buffer contents.
665 */
666public void ch_flush(void)
667{
668	struct bufnode *bn;
669
670	if (thisfile == NULL)
671		return;
672
673	if (!(ch_flags & CH_CANSEEK))
674	{
675		/*
676		 * If input is a pipe, we don't flush buffer contents,
677		 * since the contents can't be recovered.
678		 */
679		ch_fsize = NULL_POSITION;
680		return;
681	}
682
683	/*
684	 * Initialize all the buffers.
685	 */
686	FOR_BUFS(bn)
687	{
688		bufnode_buf(bn)->block = -1;
689	}
690
691	/*
692	 * Figure out the size of the file, if we can.
693	 */
694	ch_fsize = filesize(ch_file);
695
696	/*
697	 * Seek to a known position: the beginning of the file.
698	 */
699	ch_fpos = 0;
700	ch_block = 0; /* ch_fpos / LBUFSIZE; */
701	ch_offset = 0; /* ch_fpos % LBUFSIZE; */
702
703	/*
704	 * This is a kludge to workaround a Linux kernel bug: files in
705	 * /proc have a size of 0 according to fstat() but have readable
706	 * data.  They are sometimes, but not always, seekable.
707	 * Force them to be non-seekable here.
708	 */
709	if (ch_fsize == 0)
710	{
711		ch_fsize = NULL_POSITION;
712		ch_flags &= ~CH_CANSEEK;
713	}
714
715	if (lseek(ch_file, (off_t)0, SEEK_SET) == BAD_LSEEK)
716	{
717		/*
718		 * Warning only; even if the seek fails for some reason,
719		 * there's a good chance we're at the beginning anyway.
720		 * {{ I think this is bogus reasoning. }}
721		 */
722		error("seek error to 0", NULL_PARG);
723	}
724}
725
726/*
727 * Allocate a new buffer.
728 * The buffer is added to the tail of the buffer chain.
729 */
730static int ch_addbuf(void)
731{
732	struct buf *bp;
733	struct bufnode *bn;
734
735	/*
736	 * Allocate and initialize a new buffer and link it
737	 * onto the tail of the buffer list.
738	 */
739	bp = (struct buf *) calloc(1, sizeof(struct buf));
740	if (bp == NULL)
741		return (1);
742	ch_nbufs++;
743	bp->block = -1;
744	bn = &bp->node;
745
746	BUF_INS_TAIL(bn);
747	BUF_HASH_INS(bn, 0);
748	return (0);
749}
750
751/*
752 *
753 */
754static void init_hashtbl(void)
755{
756	int h;
757
758	for (h = 0;  h < BUFHASH_SIZE;  h++)
759	{
760		thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h);
761		thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h);
762	}
763}
764
765/*
766 * Delete all buffers for this file.
767 */
768static void ch_delbufs(void)
769{
770	struct bufnode *bn;
771
772	while (ch_bufhead != END_OF_CHAIN)
773	{
774		bn = ch_bufhead;
775		BUF_RM(bn);
776		free(bufnode_buf(bn));
777	}
778	ch_nbufs = 0;
779	init_hashtbl();
780}
781
782/*
783 * Is it possible to seek on a file descriptor?
784 */
785public int seekable(int f)
786{
787#if MSDOS_COMPILER
788	extern int fd0;
789	if (f == fd0 && !isatty(fd0))
790	{
791		/*
792		 * In MS-DOS, pipes are seekable.  Check for
793		 * standard input, and pretend it is not seekable.
794		 */
795		return (0);
796	}
797#endif
798	return (lseek(f, (off_t)1, SEEK_SET) != BAD_LSEEK);
799}
800
801/*
802 * Force EOF to be at the current read position.
803 * This is used after an ignore_eof read, during which the EOF may change.
804 */
805public void ch_set_eof(void)
806{
807	if (ch_fsize != NULL_POSITION && ch_fsize < ch_fpos)
808		ch_fsize = ch_fpos;
809}
810
811
812/*
813 * Initialize file state for a new file.
814 */
815public void ch_init(int f, int flags)
816{
817	/*
818	 * See if we already have a filestate for this file.
819	 */
820	thisfile = (struct filestate *) get_filestate(curr_ifile);
821	if (thisfile == NULL)
822	{
823		/*
824		 * Allocate and initialize a new filestate.
825		 */
826		thisfile = (struct filestate *)
827				ecalloc(1, sizeof(struct filestate));
828		thisfile->buflist.next = thisfile->buflist.prev = END_OF_CHAIN;
829		thisfile->nbufs = 0;
830		thisfile->flags = flags;
831		thisfile->fpos = 0;
832		thisfile->block = 0;
833		thisfile->offset = 0;
834		thisfile->file = -1;
835		thisfile->fsize = NULL_POSITION;
836		init_hashtbl();
837		/*
838		 * Try to seek; set CH_CANSEEK if it works.
839		 */
840		if ((flags & CH_CANSEEK) && !seekable(f))
841			ch_flags &= ~CH_CANSEEK;
842		set_filestate(curr_ifile, (void *) thisfile);
843	}
844	if (thisfile->file == -1)
845		thisfile->file = f;
846	ch_flush();
847}
848
849/*
850 * Close a filestate.
851 */
852public void ch_close(void)
853{
854	int keepstate = FALSE;
855
856	if (thisfile == NULL)
857		return;
858
859	if ((ch_flags & (CH_CANSEEK|CH_POPENED|CH_HELPFILE)) && !(ch_flags & CH_KEEPOPEN))
860	{
861		/*
862		 * We can seek or re-open, so we don't need to keep buffers.
863		 */
864		ch_delbufs();
865	} else
866		keepstate = TRUE;
867	if (!(ch_flags & CH_KEEPOPEN))
868	{
869		/*
870		 * We don't need to keep the file descriptor open
871		 * (because we can re-open it.)
872		 * But don't really close it if it was opened via popen(),
873		 * because pclose() wants to close it.
874		 */
875		if (!(ch_flags & (CH_POPENED|CH_HELPFILE)))
876			close(ch_file);
877		ch_file = -1;
878	} else
879		keepstate = TRUE;
880	if (!keepstate)
881	{
882		/*
883		 * We don't even need to keep the filestate structure.
884		 */
885		free(thisfile);
886		thisfile = NULL;
887		set_filestate(curr_ifile, (void *) NULL);
888	}
889}
890
891/*
892 * Return ch_flags for the current file.
893 */
894public int ch_getflags(void)
895{
896	if (thisfile == NULL)
897		return (0);
898	return (ch_flags);
899}
900
901#if 0
902static void ch_dump(struct filestate *fs)
903{
904	struct buf *bp;
905	struct bufnode *bn;
906	unsigned char *s;
907
908	if (fs == NULL)
909	{
910		printf(" --no filestate\n");
911		return;
912	}
913	printf(" file %d, flags %x, fpos %x, fsize %x, blk/off %x/%x\n",
914		fs->file, fs->flags, fs->fpos,
915		fs->fsize, fs->block, fs->offset);
916	printf(" %d bufs:\n", fs->nbufs);
917	for (bn = fs->next; bn != &fs->buflist;  bn = bn->next)
918	{
919		bp = bufnode_buf(bn);
920		printf("%x: blk %x, size %x \"",
921			bp, bp->block, bp->datasize);
922		for (s = bp->data;  s < bp->data + 30;  s++)
923			if (*s >= ' ' && *s < 0x7F)
924				printf("%c", *s);
925			else
926				printf(".");
927		printf("\"\n");
928	}
929}
930#endif
931