v06i102: New version of less (less2), Part01/02

Tue Aug 12 06:43:01 AEST 1986

Submitted by: seismo!lll-crg!csustan!casey
Mod.sources: Volume 6, Issue 102
Archive-name: less2/Part01

[  This version of less provides support for "boldening," as in a^Ha^Ha,
   and a "-z" flag to set the window size (for compatiblity with more).
   It also provides a small front-end program for systems/programs that
   don't support the PAGER environment variable.  And, as Casey said in
   his cover note to me... "If you can find Mark Nudelman, send him a copy."
   --r$  ]

---- cut here ---- cut here ---- cut here ---- cut here ---- cut here ----
#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create:
#	INSTALLATION
#	README-casey
#	README-usenet
#	ch.c
#	command.c
#	funcs.h
#	help.c
#	input.c
#	less.h
#	less.l
#	line.c
#	main.c
#	makefile.bsd41
#	makefile.bsd42
export PATH; PATH=/bin:/usr/bin:$PATH
if test -f 'INSTALLATION'
then
	echo shar: "will not over-write existing file 'INSTALLATION'"
else
cat << \SHAR_EOF > 'INSTALLATION'
This is the distribution of "less", a paginator similar to "more" or "pg".
The manual page is in less.l.

INSTALLATION:

1. Move the distributed source to its own directory and 
   unpack it by running "sh" on the distribution file,
   if you have not already done so.

2. If your system is System V:
	cp makefile.sys5 makefile
   If your system is Berkeley 4.2bsd:
	cp makefile.bsd42 makefile
   If your system is Berkeley 4.1bsd:
	cp makefile.bsd41 makefile
   If your system is Xenix 3.0:
	cp makefile.xen makefile
   Otherwise, edit the makefile to make the 
   system parameters match your system.

   These features are selectable at compile time:
	shell escapes (SHELL_ESCAPE)
	editor invocation (EDITOR)
	alternate error message handling (ONLY_RETURN)
   If you want to have any of these features, 
   edit the makefile appropriately.
   (If you do not include either SHELL_ESCAPE or EDITOR,
    you may wish to edit the manual page "less.l" to remove
    the references to the "!" and/or "v" commands.)

3. Type "make" and watch the fun.

4. If the make succeeds, it will generate a program "less"
   in your current directory.  Test the generated program.

5. When satisfied that it works, if you wish to install it
   in a public place, edit the makefile so that INSTALL_LESS
   and INSTALL_MAN are the proper filenames.
   Then type "make install".

If you have any problems building or running "less", 
you may mail to the author via USENET at:
	...!tektronix!reed!nsc-pdc!mark
  or	...!ihnp4!nsc!nsc-pdc!mark

Note to hackers: comments noting possible improvements are enclosed
in double curly brackets {{ like this }}.
SHAR_EOF
fi
if test -f 'README-casey'
then
	echo shar: "will not over-write existing file 'README-casey'"
else
cat << \SHAR_EOF > 'README-casey'
						Monday July 14, 1986

I've made four changes to less:

1.	You can now install the pager_patch program to let you use less as
	your default pager even if the programs you're using don't pay
	attention to the PAGER environment variable.

2.	It's now allowable to invoke less with "-[z]N" to specify the window
	scroll size ala more (note that the "z" may be omitted) - this
	was done for compatibility with more(1) as some programs (ex: msgs)
	called the pager with a window size specification.

3.	Less will now detect "boldfacing sequences" and use the /etc/termcap
	capability "md" and "me" to boldface the corresponding text.
	Boldface sequences are sequences of a character overstruck with
	backspaces (ex: a^Hab^Hb ...).  Any number of overstrikes are ok.
	For those whose nroff doesn't generate these sequences for [default]
	boldfacing, look at the file n10-diff for the necessary changes to
	nroff [n10.c].

4.	The manual page has been reformatted to have more boldface sequences
	(some may find my avoidance of ".B", ".I", etc. to be annoying, but
	what the hey, I'll let Mark Nudelman (less's original author) have
	the final decision).  I haven't reorganized the command and switch
	descriptions to be in alphabetic order ...  Still not sure whether
	that should be done ...

Leith (Casey) Leedom				lll-crg.arpa!csustan!casey
Computer Science Department			work: (209) 667-3185
California State University, Stanislaus		home: (209) 634-2775
Turlock, CA  95380
SHAR_EOF
fi
if test -f 'README-usenet'
then
	echo shar: "will not over-write existing file 'README-usenet'"
else
cat << \SHAR_EOF > 'README-usenet'
>From sources-request at panda.UUCP Tue Feb 11 15:30:56 1986
Relay-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site lll-crg.ARpA
Path: lll-crg!topaz!harvard!talcott!panda!sources-request
From: sources-request at panda.UUCP
Newsgroups: mod.sources
Subject: less part 1 of 2
Message-ID: <1400 at panda.UUCP>
Date: 11 Feb 86 23:30:56 GMT
Date-Received: 12 Feb 86 05:00:57 GMT
Sender: jpn at panda.UUCP
Lines: 2500
Approved: jpn at panda.UUCP

Mod.sources:  Volume 3, Issue 120
Submitted by: ihnp4!nsc!nsc-pdc!rgb (Robert Bond)

Here is the last distribution of less made by Mark Nudelman to net.sources
before he left National Semiconductor.  Since it is taking so long for him
to get back on the net, and because lots of folks did not get part 2
of the last distribution, we have decided to submit less to mod.sources.
Mark is still promising to return to the net Real Soon Now.
SHAR_EOF
fi
if test -f 'ch.c'
then
	echo shar: "will not over-write existing file 'ch.c'"
else
cat << \SHAR_EOF > 'ch.c'
/*
 * Low level character input from the input file.
 * We use these special purpose routines which optimize moving
 * both forward and backward from the current read pointer.
 */

#include "less.h"

public int file = -1;	/* File descriptor of the input file */

/*
 * Pool of buffers holding the most recently used blocks of the input file.
 */
#define BUFSIZ	1024
static struct buf {
	struct buf *next, *prev;
	long block;
	char data[BUFSIZ];
};
static struct buf *bufs = NULL;
public int nbufs;

/*
 * The buffer pool is kept as a doubly-linked circular list,
 * in order from most- to least-recently used.
 * The circular list is anchored by buf_anchor.
 */
static struct {
	struct buf *next, *prev;
} buf_anchor;
#define	END_OF_CHAIN	((struct buf *)&buf_anchor)
#define	buf_head	buf_anchor.next
#define	buf_tail	buf_anchor.prev

/*
 * If we fail to allocate enough memory for buffers, we try to limp
 * along with a minimum number of buffers.  
 */
#define	DEF_NBUFS	2	/* Minimum number of buffers */

extern int clean_data;
extern int ispipe;

/*
 * Current position in file.
 * Stored as a block number and an offset into the block.
 */
static long ch_block;
static int ch_offset;

/* 
 * Length of file, needed if input is a pipe.
 */
static POSITION ch_fsize;

/*
 * Largest block number read if input is standard input (a pipe).
 */
static long last_piped_block;

/*
 * Get the character pointed to by the read pointer.
 * ch_get() is a macro which is more efficient to call
 * than fch_get (the function), in the usual case 
 * that the block desired is at the head of the chain.
 */
#define	ch_get()   ((buf_head->block == ch_block) ? \
			buf_head->data[ch_offset] : fch_get())
	static int
fch_get()
{
	register struct buf *bp;
	register int n;
	register int end;
	POSITION pos;

	/*
	 * Look for a buffer holding the desired block.
	 */
	for (bp = buf_head;  bp != END_OF_CHAIN;  bp = bp->next)
		if (bp->block == ch_block)
			goto found;
	/*
	 * Block is not in a buffer.  
	 * Take the least recently used buffer 
	 * and read the desired block into it.
	 */
	bp = buf_tail;
	bp->block = ch_block;
	pos = ch_block * BUFSIZ;
	if (ispipe)
	{
		/*
		 * The block requested should be one more than
		 * the last block read.
		 */
		if (ch_block != ++last_piped_block)
		{
			/* This "should not happen". */
			char message[80];
			sprintf(message, "Pipe error: last %ld, want %ld\n",
				last_piped_block-1, ch_block);
			error(message);
			quit();
		}
	} else
		lseek(file, pos, 0);

	/*
	 * Read the block.  This may take several reads if the input
	 * is coming from standard input, due to the nature of pipes.
	 */
	end = 0;
	while ((n = read(file, &bp->data[end], BUFSIZ-end)) > 0)
		if ((end += n) >= BUFSIZ)
			break;

	if (n < 0)
	{
		error("read error");
		quit();
	}

	/*
	 * Set an EOF marker in the buffered data itself.
	 * Then ensure the data is "clean": there are no 
	 * extra EOF chars in the data and that the "meta"
	 * bit (the 0200 bit) is reset in each char.
	 */
	if (end < BUFSIZ)
	{
		ch_fsize = pos + end;
		bp->data[end] = EOF;
	}

	if (!clean_data)
		while (--end >= 0)
		{
			bp->data[end] &= 0177;
			if (bp->data[end] == EOF)
				bp->data[end] = '@';
		}

    found:
	/* if (buf_head != bp) {this is guaranteed by the ch_get macro} */
	{
		/*
		 * Move the buffer to the head of the buffer chain.
		 * This orders the buffer chain, most- to least-recently used.
		 */
		bp->next->prev = bp->prev;
		bp->prev->next = bp->next;

		bp->next = buf_head;
		bp->prev = END_OF_CHAIN;
		buf_head->prev = bp;
		buf_head = bp;
	}
	return (bp->data[ch_offset]);
}

/*
 * Determine if a specific block is currently in one of the buffers.
 */
	static int
buffered(block)
	long block;
{
	register struct buf *bp;

	for (bp = buf_head;  bp != END_OF_CHAIN;  bp = bp->next)
		if (bp->block == block)
			return (1);
	return (0);
}

/*
 * Seek to a specified position in the file.
 * Return 0 if successful, non-zero if can't seek there.
 */
	public int
ch_seek(pos)
	register POSITION pos;
{
	long new_block;

	new_block = pos / BUFSIZ;
	if (!ispipe || new_block == last_piped_block + 1 || buffered(new_block))
	{
		/*
		 * Set read pointer.
		 */
		ch_block = new_block;
		ch_offset = pos % BUFSIZ;
		return (0);
	}
	return (1);
}

/*
 * Seek to the end of the file.
 */
	public int
ch_end_seek()
{
	if (ispipe)
	{
		/*
		 * Do it the slow way: read till end of data.
		 */
		while (ch_forw_get() != EOF)
			;
	} else
	{
		(void) ch_seek((POSITION)(lseek(file, (off_t)0, 2)));
	}
	return (0);
}

/*
 * Return the length of the file, if known.
 */
	public POSITION
ch_length()
{
	if (ispipe)
		return (ch_fsize);
	return ((POSITION)(lseek(file, (off_t)0, 2)));
}

/*
 * Return the current position in the file.
 */
	public POSITION
ch_tell()
{
	return (ch_block * BUFSIZ + ch_offset);
}

/*
 * Get the current char and post-increment the read pointer.
 */
	public int
ch_forw_get()
{
	register int c;

	c = ch_get();
	if (c != EOF && ++ch_offset >= BUFSIZ)
	{
		ch_offset = 0;
		ch_block ++;
	}
	return (c);
}

/*
 * Pre-decrement the read pointer and get the new current char.
 */
	public int
ch_back_get()
{
	register int c;

	if (--ch_offset < 0)
	{
		if (ch_block <= 0 || (ispipe && !buffered(ch_block-1)))
		{
			ch_offset = 0;
			return (EOF);
		}
		ch_offset = BUFSIZ - 1;
		ch_block--;
	}
	c = ch_get();
	return (c);
}

/*
 * Initialize the buffer pool to all empty.
 * Caller suggests that we use want_nbufs buffers.
 */
	public void
ch_init(want_nbufs)
	int want_nbufs;
{
	register struct buf *bp;
	char *calloc();

	if (nbufs < want_nbufs)
	{
		/*
		 * We don't have enough buffers.  
		 * Free what we have (if any) and allocate some new ones.
		 */
		if (bufs != NULL)
			free((char *)bufs);
		bufs = (struct buf *) calloc(want_nbufs, sizeof(struct buf));
		nbufs = want_nbufs;
		if (bufs == NULL)
		{
			/*
			 * Couldn't get that many.
			 * Try for a small default number of buffers.
			 */
			char message[80];
			sprintf(message,
			  "Cannot allocate %d buffers.  Using %d buffers.", 
			  nbufs, DEF_NBUFS);
			error(message);
			bufs = (struct buf *) calloc(DEF_NBUFS, sizeof(struct buf));
			nbufs = DEF_NBUFS;
			if (bufs == NULL)
			{
				/*
				 * Couldn't even get the smaller number of bufs.
				 * Something is wrong here, don't continue.
				 */
				sprintf(message, 
				"Cannot even allocate %d buffers!  Quitting.\n",
				  DEF_NBUFS);
				error(message);
				quit();
				/*NOTREACHED*/
			}
		}
	}

	/*
	 * Initialize the buffers to empty.
	 * Set up the circular list.
	 */
	for (bp = &bufs[0];  bp < &bufs[nbufs];  bp++)
	{
		bp->next = bp + 1;
		bp->prev = bp - 1;
		bp->block = (long)(-1);
	}
	bufs[0].prev = bufs[nbufs-1].next = END_OF_CHAIN;
	buf_head = &bufs[0];
	buf_tail = &bufs[nbufs-1];
	last_piped_block = -1;
	ch_fsize = NULL_POSITION;
	(void) ch_seek((POSITION)0);
}
SHAR_EOF
fi
if test -f 'command.c'
then
	echo shar: "will not over-write existing file 'command.c'"
else
cat << \SHAR_EOF > 'command.c'
/*
 * User-level command processor.
 */

#include "less.h"
#include "position.h"
#include <setjmp.h>

extern jmp_buf main_loop;
extern int erase_char, kill_char;
extern int pr_type;
extern int sigs;
extern int ispipe;
extern int quit_at_eof;
extern int hit_eof;
extern int sc_width, sc_height;
extern int sc_window;
extern char *first_cmd;
extern char version[];
extern char current_file[];
extern char *editor;

static char cmdbuf[90];		/* Buffer for holding a multi-char command */
static char *cp;		/* Pointer into cmdbuf */
static int cmd_col;		/* Current column of the multi-char command */
static char mcc;		/* The multi-char command letter (e.g. '/') */
static char last_mcc;		/* The previous mcc */

/*
 * Reset command buffer (to empty).
 */
cmd_reset()
{
	cp = cmdbuf;
}

/*
 * Backspace in command buffer.
 */
	static int
cmd_erase()
{
	if (cp == cmdbuf)
		/*
		 * Backspace past beginning of the string:
		 * this usually means abort the command.
		 */
		return (1);

	if (control_char(*--cp))
	{
		/*
		 * Erase an extra character, for the carat.
		 */
		backspace();
		cmd_col--;
	}
	backspace();
	cmd_col--;
	return (0);
}

/*
 * Set up the display to start a new multi-character command.
 */
start_mcc()
{
	lower_left();
	clear_eol();
	putc(mcc);
	cmd_col = 1;
}

/*
 * Process a single character of a multi-character command, such as
 * a number, or the pattern of a search command.
 */
	static int
cmd_char(c)
	int c;
{
	if (c == erase_char)
	{
		if (cmd_erase())
			return (1);
	} else if (c == kill_char)
	{
		/* {{ Could do this faster, but who cares? }} */
		while (cmd_erase() == 0)
			;
	} else
	{
		/*
		 * Append the character to the string,
		 * if there is room in the buffer and on the screen.
		 */
		if (cp < &cmdbuf[sizeof(cmdbuf)-1] && cmd_col < sc_width-3)
		{
			*cp++ = c;
			if (control_char(c))
			{
				putc('^');
				cmd_col++;
				c = carat_char(c);
			}
			putc(c);
			cmd_col++;
		} else
			bell();
	}
	return (0);
}

/*
 * Return the number currently in the command buffer.
 */
	static int
cmd_int()
{
	*cp = '\0';
	cp = cmdbuf;
	return (atoi(cmdbuf));
}

/*
 * Move the cursor to lower left before executing a command.
 * This looks nicer if the command takes a long time before
 * updating the screen.
 */
	static void
cmd_exec()
{
	lower_left();
	flush();
}

/*
 * Display the appropriate prompt.
 */
	static void
prompt()
{
	register char *p;

	if (first_cmd != NULL && *first_cmd != '\0')
		/*
		 * No prompt necessary if commands are from first_cmd
		 * rather than from the user.
		 */
		return;

	/*
	 * Select the proper prompt and display it.
	 */
	p = pr_string();
	if (p == NULL)
		putc(':');
	else
	{
		so_enter();
		puts(p);
		so_exit();
	}
}

/*
 * Get command character.
 * The character normally comes from the keyboard,
 * but may come from the "first_cmd" string.
 */
	static int
getcc()
{
	if (first_cmd == NULL)
		return (getc());

	if (*first_cmd == '\0')
	{
		/*
		 * Reached end of first_cmd input.
		 */
		first_cmd = NULL;
		if (cp > cmdbuf && position(TOP) == NULL_POSITION)
		{
			/*
			 * Command is incomplete, so try to complete it.
			 * There are only two cases:
			 * 1. We have "/string" but no newline.  Add the \n.
			 * 2. We have a number but no command.  Treat as #g.
			 * (This is all pretty hokey.)
			 */
			if (mcc != ':')
				return ('\n'); 
			else
				return ('g');
		}
		return (getc());
	}
	return (*first_cmd++);
}

/*
 * Main command processor.
 * Accept and execute commands until a quit command, then return.
 */
	public void
commands()
{
	register int c;
	register int n;
	register int scroll = 10;

	mcc = last_mcc = 0;

	setjmp(main_loop);
	for (;;)
	{
		/*
		 * Display prompt and accept a character.
		 */
		psignals();	/* See if any signals need processing */

		if (quit_at_eof && hit_eof > 1)
			/*
			 * After hitting end-of-file for the second time,
			 * automatically advance to the next file.
			 * If there are no more files, quit.
			 */
			next_file(1);

		cmd_reset();
		lower_left();
		clear_eol();
		prompt();
		c = getcc();

	again:
		if (sigs)
			continue;

		if (mcc)
		{
			/*
			 * We are in a multi-character command.  
			 * All chars until newline go into the command buffer.
			 * (Note that mcc == ':' is a special case that
			 *  means a number is being entered.)
			 */
			if (mcc != ':' && (c == '\n' || c == '\r'))
			{
				/*
				 * Execute the command.
				 */
				*cp = '\0';
				cmd_exec();
				if (mcc == 'E')
				{
					char *p;
					/*
					 * Ignore leading spaces 
					 * in the filename.
					 */
					for (p = cmdbuf;  *p == ' ';  p++) ;
					edit(p);
#if SHELL_ESCAPE
				} else if (mcc == '!')
				{
					lsystem(cmdbuf);
					error("!done");
					first_cmd = "r";	/* Repaint */
#endif
				} else
					search(mcc, cmdbuf, n);
				mcc = 0;
			} else
			{
				if (mcc == ':' && (c < '0' || c > '9') &&
					c != erase_char && c != kill_char)
				{
					/*
					 * This is not part of the number
					 * we were entering.  Process
					 * it as a regular character.
					 */
					mcc = 0;
					goto again;
				}

				/*
				 * Append the char to the command buffer.
				 */
				if (cmd_char(c))
				{
					/* Abort the multi-char command. */
					mcc = 0;
					continue;
				}
				c = getcc();
				goto again;
			}
		} else switch (c)
		{
		case '0': case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9':
			/*
			 * First digit of a number.
			 */
			mcc = ':';
			start_mcc();
			goto again;

		case 'f':
		case ' ':
		case CONTROL('F'):
			/*
			 * Forward one screen.
			 */
			n = cmd_int();
			if (n <= 0)
				n = sc_window;
			forward(n, 1);
			break;

		case 'b':
		case CONTROL('B'):
			/*
			 * Backward one screen.
			 */
			n = cmd_int();
			if (n <= 0)
				n = sc_window;
			backward(n, 1);
			break;

		case 'e':
		case 'j':
		case '\r':
		case '\n':
		case CONTROL('E'):
			/*
			 * Forward N (default 1) line.
			 */
			n = cmd_int();
			if (n <= 0)
				n = 1;
			forward(n, 0);
			break;

		case 'y':
		case 'k':
		case CONTROL('K'):
		case CONTROL('Y'):
			/*
			 * Backward N (default 1) line.
			 */
			n = cmd_int();
			if (n <= 0)
				n = 1;
			backward(n, 0);
			break;

		case 'd':
		case CONTROL('D'):
			/*
			 * Forward N lines 
			 * (default same as last 'd' or 'u' command).
			 */
			n = cmd_int();
			if (n > 0)
				scroll = n;
			forward(scroll, 0);
			break;

		case 'u':
		case CONTROL('U'):
			/*
			 * Forward N lines 
			 * (default same as last 'd' or 'u' command).
			 */
			n = cmd_int();
			if (n > 0)
				scroll = n;
			backward(scroll, 0);
			break;

		case 'R':
			/*
			 * Flush buffers, then repaint screen.
			 */
			ch_init(0);
			/* Fall thru */
		case 'r':
		case CONTROL('R'):
		case CONTROL('L'):
			/*
			 * Repaint screen.
			 */
			repaint();
			break;

		case 'g':
			/*
			 * Go to line N, default beginning of file.
			 */
			n = cmd_int();
			if (n <= 0)
				n = 1;
			cmd_exec();
			jump_back(n);
			break;

		case 'p':
		case '%':
			/*
			 * Go to a specified percentage into the file.
			 */
			n = cmd_int();
			if (n < 0)
				n = 0;
			if (n > 100)
				n = 100;
			cmd_exec();
			jump_percent(n);
			break;

		case 'G':
			/*
			 * Go to line N, default end of file.
			 */
			n = cmd_int();
			cmd_exec();
			if (n <= 0)
				jump_forw();
			else
				jump_back(n);
			break;

		case '=':
		case CONTROL('G'):
			/*
			 * Print file name, etc.
			 */
			error(eq_message());
			break;

		case 'V':
			/*
			 * Print version number, without the "@(#)".
			 */
			error(version+4);
			break;

		case 'q':
			/*
			 * Exit.
			 */
			return;

		case '/':
		case '?':
			/*
			 * Search for a pattern.
			 * Accept chars of the pattern until \n.
			 */
			n = cmd_int();
			if (n <= 0)
				n = 1;
			mcc = last_mcc = c;
			start_mcc();
			c = getcc();
			goto again;

		case 'n':
			/*
			 * Repeat previous search.
			 */
			n = cmd_int();
			if (n <= 0)
				n = 1;
			mcc = last_mcc;
			start_mcc();
			cmd_exec();
			search(mcc, (char *)NULL, n);
			mcc = 0;
			break;

		case 'h':
			/*
			 * Help.
			 */
			help();
			repaint();
			break;

		case 'E':
			/*
			 * Edit a new file.  Get the filename.
			 */
			cmd_reset();
			mcc = 'E';
			start_mcc();
			puts("dit: ");	/* This looks nicer */
			cmd_col += 5;
			c = getcc();
			goto again;

#if SHELL_ESCAPE
		case '!':
			/*
			 * Shell escape.
			 */
			cmd_reset();
			mcc = '!';
			start_mcc();
			c = getcc();
			goto again;
#endif

#if EDITOR
		case 'v':
			if (ispipe)
			{
				error("Cannot edit standard input");
				break;
			}
			sprintf(cmdbuf, "%s %s", editor, current_file);
			lsystem(cmdbuf);
			first_cmd = "R";
			break;
#endif

		case 'N':
			/*
			 * Examine next file.
			 */
			n = cmd_int();
			if (n <= 0)
				n = 1;
			next_file(n);
			break;

		case 'P':
			/*
			 * Examine previous file.
			 */
			n = cmd_int();
			if (n <= 0)
				n = 1;
			prev_file(n);
			break;

		case '-':
			/*
			 * Toggle a flag setting.
			 */
			mcc = '-';
			start_mcc();
			c = getcc();
			mcc = 0;
			if (c == erase_char || c == kill_char)
				break;
			toggle_option(c);
			break;

		case 'm':
			/*
			 * Set a mark.
			 */
			lower_left();
			clear_eol();
			puts("mark: ");
			c = getcc();
			if (c == erase_char || c == kill_char)
				break;
			setmark(c);
			break;

		case '\'':
			/*
			 * Go to a mark.
			 */
			lower_left();
			clear_eol();
			puts("goto mark: ");
			c = getcc();
			if (c == erase_char || c == kill_char)
				break;
			gomark(c);
			break;

		default:
			bell();
			break;
		}
	}
}
SHAR_EOF
fi
if test -f 'funcs.h'
then
	echo shar: "will not over-write existing file 'funcs.h'"
else
cat << \SHAR_EOF > 'funcs.h'
	public void edit ();
	public void next_file ();
	public void prev_file ();
	public void quit ();
	public void init_option ();
	public void toggle_option ();
	public void scan_option ();
	public void forward ();
	public void backward ();
	public void repaint ();
	public void jump_forw ();
	public void jump_back ();
	public void jump_percent ();
	public void jump_loc ();
	public void init_mark ();
	public void setmark ();
	public void gomark ();
	public void search ();
	public int ch_seek ();
	public int ch_end_seek ();
	public POSITION ch_length ();
	public POSITION ch_tell ();
	public int ch_forw_get ();
	public int ch_back_get ();
	public void ch_init ();
	public POSITION position ();
	public void add_forw_pos ();
	public void add_back_pos ();
	public void pos_clear ();
	public int onscreen ();
	public POSITION forw_line ();
	public POSITION back_line ();
	public void put_line ();
	public int control_char ();
	public int carat_char ();
	public void flush ();
	public void dropout ();
	public void putc ();
	public void puts ();
	public void error ();
	public int error_width ();
	public void raw_mode ();
	public void get_term ();
	public void init ();
	public void deinit ();
	public void home ();
	public void add_line ();
	public void lower_left ();
	public void bell ();
	public void vbell ();
	public void clear ();
	public void clear_eol ();
	public void so_enter ();
	public void so_exit ();
	public void ul_enter ();
	public void ul_exit ();
	public void backspace ();
	public void putbs ();
	public char * eq_message ();
	public char * pr_string ();
	public void prewind ();
	public int pappend ();
	public POSITION forw_raw_line ();
	public POSITION back_raw_line ();
	public void init_signals ();
	public void  psignals ();
	public void lsystem ();
	public void help ();
	public void open_getc ();
	public int getc ();
	public void commands ();
SHAR_EOF
fi
if test -f 'help.c'
then
	echo shar: "will not over-write existing file 'help.c'"
else
cat << \SHAR_EOF > 'help.c'
#include  "less.h"

/*
 * Display some help.
 * Help is in two pages.
 */
	static void
help0()
{
	puts("f, SPACE       Forward one screen.\n");
	puts("b              Backward one screen.\n");
	puts("e, j, CR    *  Forward N lines, default 1.\n");
	puts("y, k        *  Backward N lines, default 1.\n");
	puts("d           *  Forward N lines, default 10 or last N to d or u command.\n");
	puts("u           *  Backward N lines, default 10 or last N to d or u command.\n");
	puts("r              Repaint screen.\n");
	puts("g           *  Go to line N, default 1.\n");
	puts("G           *  Like g, but default is last line in file.\n");
	puts("=              Print current file name\n");
	puts("/pattern    *  Search forward for N-th occurence of pattern.\n");
	puts("?pattern    *  Search backward for N-th occurence of pattern.\n");
	puts("n           *  Repeat previous search (for N-th occurence).\n");
	puts("q              Exit.\n");
	error("More help...");
}

	static void
help1()
{
	char message[100];
	extern char all_options[];

	puts("R              Repaint screen, discarding buffered input.\n");
	puts("p, %        *  Position to N percent into the file.\n");
	puts("m<letter>      Mark the current position with <letter>.\n");
	puts("'<letter>      Return to a previously marked position.\n");
	sprintf(message, 
	     "-X             Toggle a flag (X may be one of \"%s\").\n", 
				all_options);
	puts(message);
	puts("E [file]       Examine a new file.\n");
	puts("N              Examine the next file (from the command line).\n");
	puts("P              Examine the previous file (from the command line).\n");
	puts("V              Print version number.\n");
#if SHELL_ESCAPE
	puts("!command       Passes the command to a shell to be executed.\n");
#endif
#if EDITOR
	sprintf(message,
	     "v              Edit the current file with $EDITOR (default %s).\n",
				EDIT_PGM);
	puts(message);
#endif
	error("");
}

	public void
help()
{
	register int i;

	for (i = 0;  i < 2;  i++)
	{
		clear();
		puts("Commands marked with * may be preceeded by a number, N.\n\n");

		switch (i)
		{
		case 0:		help0();	break;
		case 1:		help1();	break;
		}
	}
}
SHAR_EOF
fi
if test -f 'input.c'
then
	echo shar: "will not over-write existing file 'input.c'"
else
cat << \SHAR_EOF > 'input.c'
/*
 * High level routines dealing with getting lines of input 
 * from the file being viewed.
 *
 * When we speak of "lines" here, we mean PRINTABLE lines;
 * lines processed with respect to the screen width.
 * We use the term "raw line" to refer to lines simply
 * delimited by newlines; not processed with respect to screen width.
 */

#include "less.h"

extern int do_bs;
extern int squeeze;
extern char *line;

/*
 * Get the next line.
 * A "current" position is passed and a "new" position is returned.
 * The current position is the position of the first character of
 * a line.  The new position is the position of the first character
 * of the NEXT line.  The line obtained is the line starting at curr_pos.
 */
	public POSITION
forw_line(curr_pos)
	POSITION curr_pos;
{
	POSITION new_pos;
	register int c;

	if (curr_pos == NULL_POSITION || ch_seek(curr_pos))
		return (NULL_POSITION);

	c = ch_forw_get();
	if (c == EOF)
		return (NULL_POSITION);

	prewind();
	for (;;)
	{
		if (c == '\n' || c == EOF)
		{
			/*
			 * End of the line.
			 */
			new_pos = ch_tell();
			break;
		}

		/*
		 * Append the char to the line and get the next char.
		 */
		if (pappend(c))
		{
			/*
			 * The char won't fit in the line; the line
			 * is too long to print in the screen width.
			 * End the line here.
			 */
			new_pos = ch_tell() - 1;
			break;
		}
		c = ch_forw_get();
	}
	(void) pappend('\0');

	if (squeeze && *line == '\0')
	{
		/*
		 * This line is blank.
		 * Skip down to the last contiguous blank line
		 * and pretend it is the one which we are returning.
		 */
		while ((c = ch_forw_get()) == '\n')
			;
		if (c != EOF)
			(void) ch_back_get();
		new_pos = ch_tell();
	}

	return (new_pos);
}

/*
 * Get the previous line.
 * A "current" position is passed and a "new" position is returned.
 * The current position is the position of the first character of
 * a line.  The new position is the position of the first character
 * of the PREVIOUS line.  The line obtained is the one starting at new_pos.
 */
	public POSITION
back_line(curr_pos)
	POSITION curr_pos;
{
	POSITION new_pos, begin_new_pos;
	int c;

	if (curr_pos == NULL_POSITION || curr_pos <= (POSITION)0 ||
		ch_seek(curr_pos-1))
		return (NULL_POSITION);

	if (squeeze)
	{
		/*
		 * Find out if the "current" line was blank.
		 */
		(void) ch_forw_get();	/* Skip the newline */
		c = ch_forw_get();	/* First char of "current" line */
		(void) ch_back_get();	/* Restore our position */
		(void) ch_back_get();

		if (c == '\n')
		{
			/*
			 * The "current" line was blank.
			 * Skip over any preceeding blank lines,
			 * since we skipped them in forw_line().
			 */
			while ((c = ch_back_get()) == '\n')
				;
			if (c == EOF)
				return (NULL_POSITION);
			(void) ch_forw_get();
		}
	}

	/*
	 * Scan backwards until we hit the beginning of the line.
	 */
	for (;;)
	{
		c = ch_back_get();
		if (c == '\n')
		{
			/*
			 * This is the newline ending the previous line.
			 * We have hit the beginning of the line.
			 */
			new_pos = ch_tell() + 1;
			break;
		}
		if (c == EOF)
		{
			/*
			 * We have hit the beginning of the file.
			 * This must be the first line in the file.
			 * This must, of course, be the beginning of the line.
			 */
			new_pos = (POSITION)0;
			break;
		}
	}

	/*
	 * Now scan forwards from the beginning of this line.
	 * We keep discarding "printable lines" (based on screen width)
	 * until we reach the curr_pos.
	 *
	 * {{ This algorithm is pretty inefficient if the lines
	 *    are much longer than the screen width, 
	 *    but I don't know of any better way. }}
	 */
	if (ch_seek(new_pos))
		return (NULL_POSITION);
    loop:
	begin_new_pos = new_pos;
	prewind();

	do
	{
		c = ch_forw_get();
		new_pos++;
		if (c == '\n')
			break;
		if (pappend(c))
		{
			/*
			 * Got a full printable line, but we haven't
			 * reached our curr_pos yet.  Discard the line
			 * and start a new one.
			 */
			(void) pappend('\0');
			(void) ch_back_get();
			new_pos--;
			goto loop;
		}
	} while (new_pos < curr_pos);

	(void) pappend('\0');

	return (begin_new_pos);
}
SHAR_EOF
fi
if test -f 'less.h'
then
	echo shar: "will not over-write existing file 'less.h'"
else
cat << \SHAR_EOF > 'less.h'
/*
 * Standard include file for "less".
 */

/*
 * Language details.
 */
#if !VOID
#define	void  int
#endif
#define	public		/* PUBLIC FUNCTION */

/*
 * Special types and constants.
 */
typedef long		POSITION;
/*
 * {{ Warning: if POSITION is changed to other than "long",
 *    you may have to change some of the printfs which use "%ld"
 *    to print a variable of type POSITION. }}
 */

#define	END_POSITION	((POSITION)(-2))
#define	NULL_POSITION	((POSITION)(-1))

#define	EOF		(0)
#define	NULL		(0)

/* How quiet should we be? */
#define	NOT_QUIET	0	/* Ring bell at eof and for errors */
#define	LITTLE_QUIET	1	/* Ring bell only for errors */
#define	VERY_QUIET	2	/* Never ring bell */

/* How should we prompt? */
#define	PR_SHORT	0	/* Prompt with colon */
#define	PR_MEDIUM	1	/* Prompt with message */
#define	PR_LONG		2	/* Prompt with longer message */

/* How should we handle backspaces? */
#define	BS_SPECIAL	0	/* Do special things for underlining and bold */
#define	BS_NORMAL	1	/* \b treated as normal char; actually output */
#define	BS_CONTROL	2	/* \b treated as control char; prints as ^H */

/* Flag to eq_message() telling what to put in the message */
#define	MNAME		001	/* File name */
#define	MOF		002	/* "file x of y" */
#define	MBYTE		004	/* "byte x/y" */
#define	MPCT		010	/* Percentage into the file */

/* Special chars used to tell put_line() to do something special */
#define	UL_CHAR		'\201'	/* Enter underline mode */
#define	UE_CHAR		'\202'	/* Exit underline mode */
#define	BO_CHAR		'\203'	/* Enter boldface mode */
#define	BE_CHAR		'\204'	/* Exit boldface mode */

#define	CONTROL(c)		((c)&037)
#define	SIGNAL(sig,func)	signal(sig,func)

off_t lseek();

#include "funcs.h"
SHAR_EOF
fi
if test -f 'less.l'
then
	echo shar: "will not over-write existing file 'less.l'"
else
cat << \SHAR_EOF > 'less.l'
.TH LESS l
.SH NAME
less \- opposite of more
.SH SYNOPSIS
.B "less [\-cdepstwmMqQuU] [\-h\fIn\fB] [\-b[fp]\fIn\fB] [\-x\fIn\fB] [\-[z]\fIn\fB] [+\fIcmd\fB] [\fIname\fB] ..."
.SH DESCRIPTION
\fILess\fR is a program similar to \fImore\fR(1), but which allows backwards
movement in the file as well as forward movement.  Also, \fIless\fR does not
have to read the entire input file before starting, so with large input
files it starts up faster than text editors like \fIvi\fR(1).  \fILess\fR
uses termcap, so it can run on a variety of terminals.  There is even
limited support for hardcopy terminals.  (On a hardcopy terminal, lines
which should be printed at the top of the screen are prefixed with an
up-arrow.)
.PP
Commands are based on both \fImore\fR and \fIvi\fR.  Commands may be
preceeded by a decimal number, called N in the descriptions below.  The
number is used by some commands, as indicated.
.SH COMMANDS
.IP \fBh\fR
Help: display a summary of these commands.  If you forget all the other
commands, remember this one.
.PP
.IP \fBSPACE\fR
Scroll forward N lines, default one window (see option \fB\-z\fR below).  If
N is more than the screen size, only one screenful is displayed.
.PP
.IP \fBf\fR
Same as \fBSPACE\fR.
.PP
.IP \fBb\fR
Scroll backward N lines, default one window (see option \fB\-z\fR below).
If N is more than the screen size, only one screenful is displayed.
.PP
.IP \fBRETURN\fR
Scroll forward N lines, default 1.  If N is more than the screen size, the
entire N lines are displayed.
.PP
.IP \fBe\fR
Same as \fBRETURN\fR.
.PP
.IP \fBj\fR
Also the same as \fBRETURN\fR.
.PP
.IP \fBy\fR
Scroll backward N lines, default 1.  If N is more than the screen size, the
entire N lines are displayed.
.IP \fBk\fR
Same as \fBy\fR.
.PP
.IP \fBd\fR
Scroll forward N lines, default 10.  If N is specified, it becomes the new
default for all \fBd\fR and \fBu\fR commands.
.PP
.IP \fBu\fR
Scroll backward N lines, default 10.  If N is specified, it becomes the new
default for all \fBd\fR and \fBu\fR commands.
.PP
.IP \fBr\fR
Repaint the screen.
.PP
.IP \fBR\fR
Repaint the screen, discarding any buffered input.  Useful if the file is
changing while it is being viewed.
.PP
.IP \fBg\fR
Go to line N in the file, default 1 (beginning of file).  (Warning: this may
be slow if N is large.)
.PP
.IP \fBG\fR
Go to line N in the file, default the end of the file.  (Warning: this may
be slow if standard input, rather than a file, is being read.)
.PP
.IP \fBp\fR
Go to a position N percent into the file.  N should be between 0 and 100.
(This is possible if standard input is being read, but only if \fIless\fR
has already read to the end of the file.  It is always fast, but not always
useful.)
.PP
.IP \fB%\fR
Same as \fBp\fR.
.PP
.IP \fBm\fIl\fR
Followed by any lowercase letter, \fIl\fR, marks the current position with
that letter.
.PP
.IP \fB'\fIl\fR
Followed by any lowercase letter, \fIl\fR, returns to the position which was
previously marked with that letter.  All marks are lost when a new file is
examined.
.PP
.IP \fB/pattern\fR
Search forward in the file for the N-th occurence of the \fIpattern\fR.  N
defaults to 1.  The \fIpattern\fR is a regular expression, as recognized by
\fIed\fR.  The search starts at the second line displayed (but see the
\fB\-t\fR option, which changes this).
.PP
.IP \fB?pattern\fR
Search backward in the file for the N-th occurence of the \fIpattern\fR.
The search starts at the line immediately before the top line displayed.
.PP
.IP \fBn\fR
Repeat previous search, for N-th occurence of the last \fIpattern\fR.
.PP
.IP \fBE\fR\ \fI[filename]\fR
Examine a new file.  If the \fIfilename\fR is missing, the "current" file
(see the \fBN\fR and \fBP\fR commands below) from the list of files in the
command line is re-examined.
.PP
.IP \fBN\fR
Examine the next file (from the list of files given in the command line).
If a number N is specified (not to be confused with the command \fBN\fR),
the N-th next file is examined.
.PP
.IP \fBP\fR
Examine the previous file.  If a number N is specified, the N-th previous
file is examined.
.PP
.IP \fB=\fR
Prints the name of the file being viewed and the byte offset of the bottom
line being displayed.  If possible, it also prints the length of the file
and the percent of the file above the last displayed line.
.PP
.IP \fB\-\fR
Followed by one of the command line option letters (see below), this will
toggle the setting of that option and print a message describing the new
setting.
.PP
.IP \fBV\fR
Prints the version number of \fIless\fR being run.
.PP
.IP \fBq\fR
Exits \fIless\fR.
.PP
The following two commands may or may not be valid, depending on your
particular installation.
.PP
.IP \fBv\fR
Invokes an editor to edit the current file being viewed.  The editor is
taken from the environment variable \fBEDITOR\fR, or defaults to \fIvi\fR.
.PP
.IP \fB!\fR\ \fIshell-command\fR
Invokes a shell to run the
.I shell-command
given.
.PP
.SH OPTIONS
Command line options are described below.  Options are also taken from the
environment variable \fBLESS\fR.  (The environment variable is parsed before
the command line, so command line options override the \fBLESS\fR environment
variable.  Options may be changed while \fIless\fR is running via the
\fB"\-"\fR command.)  For example, if you like more-style prompting, to
avoid typing \fBless\ \-m\ ...\fR each time \fIless\fR is invoked, you might
tell \fIcsh\fR:
.sp
.B setenv LESS m
.sp
or if you use \fIsh\fR:
.sp
.B LESS=m; export LESS
.IP \fB\-s\fR
The \fB\-s\fR flag causes consecutive blank lines to be squeezed into a
single blank line.  This is useful when viewing \fInroff\fR output.
.IP \fB\-t\fR
Normally, forward searches start just after the top displayed line (that is,
at the second displayed line).  Thus forward searches include the currently
displayed screen.  The \fB\-t\fR command line option causes forward searches
to start just after the bottom line displayed, thus skipping the currently
displayed screen.
.IP \fB\-m\fR
Normally, \fIless\fR prompts with a colon.  The \fB\-m\fR command line
option causes \fIless\fR to prompt verbosely like \fImore\fR, printing the
file name and percent into the file.
.IP \fB\-M\fR
The \fB\-M\fR command line option causes \fIless\fR to prompt even more
verbosely than \fImore\fR.
.IP \fB\-q\fR
Normally, if an attempt is made to scroll past the end of the file or before
the beginning of the file, the terminal bell is rung to indicate this fact.
The \fB\-q\fR command line option tells \fIless\fR not to ring the bell at
such times.  If the terminal has a "visual bell", it is used instead.
.IP \fB\-Q\fR
Even if \fB\-q\fR is given, \fIless\fR will ring the bell on certain other
errors, such as typing an invalid character.  The \fB\-Q\fR command line
option tells \fIless\fR to be quiet all the time; that is, never ring the
terminal bell.  If the terminal has a "visual bell", it is used instead.
.IP \fB\-e\fR
Normally the only way to exit less is via the "q" command.  The \fB\-e\fR
command line option tells less to automatically exit the second time it
reaches end-of-file.
.IP \fB\-u\fR
If the \fB\-u\fR command line option is given, backspaces are treated as
printable characters; that is, they are sent to the terminal when they
appear in the input.
.IP \fB\-U\fR
If the \fB\-U\fR command line option is given, backspaces are printed as the
two character sequence "^H".  If neither \fB\-u\fR nor \fB\-U\fR is given,
backspaces which appear adjacent to an underscore character or sequences of
a character interleaved with backspaces are treated specially:  the
underlined or boldfaced text is displayed using the terminal's hardware
capability.  Note that the \fB\-v\fR option below superceeds both \fB\-u\fR
and \fB\-U\fR.
.IP \fB\-w\fR
Normally, \fIless\fR uses a tilde character to represent lines past the end
of the file.  The \fB\-w\fR option causes blank lines to be used instead.
.IP \fB\-d\fR
Normally, \fIless\fR will complain if the terminal is dumb; that is, lacks
some important capability, such as the ability to clear the screen or scroll
backwards.  The \fB\-d\fR flag suppresses this complaint (but does not
otherwise change the behavior of the program on a dumb terminal).
.IP \fB\-p\fR
Normally, \fIless\fR will repaint the screen by scrolling from the bottom of
the screen.  If the \fB\-p\fR flag is set, when \fIless\fR needs to change
the entire display, it will clear the screen and paint from the top line
down.
.IP \fB\-h\fIn\fR
Normally, \fIless\fR will scroll backwards when backwards movement is
necessary.  The \fB\-h\fR option specifies a maximum number of lines to
scroll backwards.  If it is necessary to move backwards more than this many
lines, the screen is repainted in a forward direction.  (If the terminal
does not have the ability to scroll backwards, \fB\-h\fI0\fR is implied.)
.IP \fB\-[z]\fIn\fR
When given a backwards or forwards window command, \fIless\fR will by
default scroll backwards or forwards one screenful of lines.  The \fB\-z\fR
option changes the default scrolling window size to \fIn\fR lines.  If
\fIn\fR is greater than the screen size, the scrolling window size will be
set to one screenful.  Note that the \fBz\fR is optional for compatibility
with more.
.IP \fB\-x\fR
The \fB\-x\fR command line option sets tab stops every \fIn\fR positions.
The default for \fIn\fR is 8.
.IP \fB\-b[fp]\fIn\fR
The \fB\-b\fR command line option tells \fIless\fR to use a non-standard
buffer size.  There are two standard (default) buffer sizes, one is used
when a file is being read and the other when a pipe (standard input) is
being read.  The current defaults are 5 buffers for files and 12 for pipes.
(Buffers are 1024 bytes.)  The number \fIn\fR specifies a different number
of buffers to use.  The \fB\-b\fR may be followed by \fBf\fR, in which case
only the file default is changed, or by \fBp\fR in which case only the pipe
default is changed.  Otherwise, both are changed.
.IP \fB\-c\fR
Normally, when data is read by \fIless\fR, it is scanned to ensure that bit
7 (the high order bit) is turned off in each byte read, and to ensure that
there are no null (zero) bytes in the data (null bytes are turned into "@"
characters).  If the data is known to be "clean", the \fB\-c\fR command line
option will tell \fIless\fR to skip this checking, causing an imperceptible
speed improvement.  (However, if the data is not "clean", unpredicatable
results may occur.)
.IP \fB\-v\fR
The \fB\-v\fR option tells less to print non-printing characters in a
visible way ala \fIcat\fR(1).  Control characters are printed as ^X (the
delete character (octal 0177) is printed as ^?).  Characters with the 0200
bit set are printed as M- followed by the character represented by the low
order seven bits.
.IP \fB+\fIcommand\fR
If a command line option begins with \fB+\fR, the remainder of that option
is taken to be an initial command to \fIless\fR.  For example, \fB+\fIG\fR
tells \fIless\fR to start at the end of the file rather than the beginning,
and \fB+\fI/xyz\fR tells it to start at the first occurence of \fIxyz\fR in
the file.  As a special case, \fB+\fI<number>\fR acts like
\fB+\fI<number>g\fR; that is, it starts the display at the specified line
number (however, see the caveat under the \fBg\fR command above).  If the
option starts with \fB++\fR, the initial command applies to every file being
viewed, not just the first one.
.SH BUGS
When used on standard input (rather than a file), you can move backwards
only a finite amount, corresponding to that portion of the file which is
still buffered.
SHAR_EOF
fi
if test -f 'line.c'
then
	echo shar: "will not over-write existing file 'line.c'"
else
cat << \SHAR_EOF > 'line.c'
/*
 * Routines to manipulate the "line buffer".
 * The line buffer holds a line of output as it is being built
 * in preparation for output to the screen.
 * We keep track of the PRINTABLE length of the line as it is being built.
 */

#include "less.h"

static char linebuf[1024];	/* Buffer which holds the current output line */
static char *curr;		/* Pointer into linebuf */
static int column;		/* Printable length, accounting for
				   backspaces, etc. */
/*
 * A ridiculously complex state machine takes care of backspaces 
 * when in BS_SPECIAL mode.  The complexity arises from the attempt
 * to deal with all cases, especially involving long lines with underlining,
 * boldfacing or whatever.  There are still some cases which will break it.
 *
 * There are four states:
 *	LN_NORMAL is the normal state (not in underline mode).
 *	LN_UNDERLINE means we are in underline mode.  We expect to get
 *		either a sequence like "_\bX" or "X\b_" to continue
 *		underline mode, or anything else to end underline mode.
 *	LN_BOLDFACE means we are in boldface mode.  We expect to get sequences
 *		like "X\bX\b...X\bX" to continue boldface mode, or anything
 *		else to end boldface mode.
 *	LN_UL_X means we are one character after LN_UNDERLINE
 *		(we have gotten the '_' in "_\bX" or the 'X' in "X\b_").
 *	LN_UL_XB means we are one character after LN_UL_X 
 *		(we have gotten the backspace in "_\bX" or "X\b_";
 *		we expect one more ordinary character, 
 *		which will put us back in state LN_UNDERLINE).
 *	LN_BO_X means we are one character after LN_BOLDFACE
 *		(we have gotten the 'X' in "X\bX").
 *	LN_BO_XB means we are one character after LN_BO_X
 *		(we have gotten the backspace in "X\bX";
 *		we expect one more 'X' which will put us back
 *		in LN_BOLDFACE).
 */
static int ln_state;		/* Currently in normal/underline/bold/etc mode? */
#define	LN_NORMAL	0	/* Not in underline, boldface or whatever mode */
#define	LN_UNDERLINE	1	/* In underline, need next char */
#define	LN_UL_X		2	/* In underline, got char, need \b */
#define	LN_UL_XB	3	/* In underline, got char & \b, need one more */
#define	LN_BOLDFACE	4	/* In boldface, need next char */
#define	LN_BO_X		5	/* In boldface, got char, need \b */
#define	LN_BO_XB	6	/* In boldface, got char & \b, need same char */

public char *line;		/* Pointer to the current line.
				   Usually points to linebuf. */

extern int bs_mode;
extern int tabstop;
extern int bo_width, be_width;
extern int ul_width, ue_width;
extern int sc_width, sc_height;

/*
 * Rewind the line buffer.
 */
	public void
prewind()
{
	line = curr = linebuf;
	ln_state = LN_NORMAL;
	column = 0;
}

/*
 * Append a character to the line buffer.
 * Expand tabs into spaces, handle underlining, boldfacing, etc.
 * Returns 0 if ok, 1 if couldn't fit in buffer.
 */

#define	NEW_COLUMN(newcol)	if ((newcol) + ((ln_state)?ue_width:0) > sc_width) \
					return (1); else column = (newcol)

	public int
pappend(c)
	int c;
{
	if (c == '\0')
	{
		/*
		 * Terminate any special modes, if necessary.
		 * Append a '\0' to the end of the line.
		 */
		switch (ln_state)
		{
		case LN_UL_X:
			curr[0] = curr[-1];
			curr[-1] = UE_CHAR;
			curr++;
			break;
		case LN_BO_X:
			curr[0] = curr[-1];
			curr[-1] = BE_CHAR;
			curr++;
			break;
		case LN_UL_XB:
		case LN_UNDERLINE:
			*curr++ = UE_CHAR;
			break;
		case LN_BO_XB:
		case LN_BOLDFACE:
			*curr++ = BE_CHAR;
			break;
		}
		ln_state = LN_NORMAL;
		*curr = '\0';
		return (0);
	}

	if (curr > linebuf + sizeof(linebuf) - 12)
		/*
		 * Almost out of room in the line buffer.
		 * Don't take any chances.
		 * {{ Linebuf is supposed to be big enough that this
		 *    will never happen, but may need to be made 
		 *    bigger for wide screens or lots of backspaces. }}
		 */
		return (1);

	if (bs_mode == BS_SPECIAL)
	{
		/*
		 * Advance the state machine.
		 */
		switch (ln_state)
		{
		case LN_NORMAL:
			if (curr <= linebuf + 1 || curr[-1] != '\b')
				break;

			if (c == curr[-2])
				goto enter_boldface;
			if (c == '_' || curr[-2] == '_')
				goto enter_underline;
			curr -= 2;
			break;

enter_boldface:
			/*
			 * We have "X\bX" (including the current char).
			 * Switch into boldface mode.
			 */
			if (column + bo_width + be_width + 1 >= sc_width)
				/*
				 * Not enough room left on the screen to 
				 * enter and exit boldface mode.
				 */
				return (1);

			if (bo_width > 0 && 
			    curr > linebuf + 2 && curr[-3] == ' ')
			{
				/*
				 * Special case for magic cookie terminals:
				 * if the previous char was a space, replace 
				 * it with the "enter boldface" sequence.
				 */
				curr[-3] = BO_CHAR;
				column += bo_width-1;
			} else
			{
				curr[-1] = curr[-2];
				curr[-2] = BO_CHAR;
				column += bo_width;
				curr++;
			}
			goto ln_bo_xb_case;

enter_underline:
			/*
			 * We have either "_\bX" or "X\b_" (including
			 * the current char).  Switch into underline mode.
			 */
			if (column + ul_width + ue_width + 1 >= sc_width)
				/*
				 * Not enough room left on the screen to 
				 * enter and exit underline mode.
				 */
				return (1);

			if (ul_width > 0 && 
			    curr > linebuf + 2 && curr[-3] == ' ')
			{
				/*
				 * Special case for magic cookie terminals:
				 * if the previous char was a space, replace 
				 * it with the "enter underline" sequence.
				 */
				curr[-3] = UL_CHAR;
				column += ul_width-1;
			} else
			{
				curr[-1] = curr[-2];
				curr[-2] = UL_CHAR;
				column += ul_width;
				curr++;
			}
			goto ln_ul_xb_case;
			/*NOTREACHED*/
		case LN_UL_XB:
			/*
			 * Termination of a sequence "_\bX" or "X\b_".
			 */
			if (c != '_' && curr[-2] != '_' && c == curr[-2])
			{
				/*
				 * We seem to have run on from underlining
				 * into boldfacing - this is a nasty fix, but
				 * until this whole routine is rewritten as a
				 * real DFA, ...  well ...
				 */
				curr[0] = curr[-2];
				curr[-2] = UE_CHAR;
				curr[-1] = BO_CHAR;
				curr += 2; /* char & non-existent backspace */
				ln_state = LN_BO_XB;
				goto ln_bo_xb_case;
			}
ln_ul_xb_case:
			if (c == '_')
				c = curr[-2];
			curr -= 2;
			ln_state = LN_UNDERLINE;
			break;
		case LN_BO_XB:
			/*
			 * Termination of a sequnce "X\bX".
			 */
			if (c != curr[-2] && (c == '_' || curr[-2] == '_'))
			{
				/*
				 * We seem to have run on from
				 * boldfacing into underlining.
				 */
				curr[0] = curr[-2];
				curr[-2] = BE_CHAR;
				curr[-1] = UL_CHAR;
				curr += 2; /* char & non-existent backspace */
				ln_state = LN_UL_XB;
				goto ln_ul_xb_case;
			}
ln_bo_xb_case:
			curr -= 2;
			ln_state = LN_BOLDFACE;
			break;
		case LN_UNDERLINE:
			if (column + ue_width + bo_width + 1 + be_width >= sc_width)
				/*
				 * We have just barely enough room to 
				 * exit underline mode and handle a possible
				 * underline/boldface run on mixup.
				 */
				return (1);
			ln_state = LN_UL_X;
			break;
		case LN_BOLDFACE:
			if (c == '\b')
			{
				ln_state = LN_BO_XB;
				break;
			}
			if (column + be_width + ul_width + 1 + ue_width >= sc_width)
				/*
				 * We have just barely enough room to 
				 * exit underline mode and handle a possible
				 * underline/boldface run on mixup.
				 */
				return (1);
			ln_state = LN_BO_X;
			break;
		case LN_UL_X:
			if (c == '\b')
				ln_state = LN_UL_XB;
			else
			{
				/*
				 * Exit underline mode.
				 * We have to shuffle the chars a bit
				 * to make this work.
				 */
				curr[0] = curr[-1];
				curr[-1] = UE_CHAR;
				column += ue_width;
				if (ue_width > 0 && curr[0] == ' ')
					/*
					 * Another special case for magic
					 * cookie terminals: if the next
					 * char is a space, replace it
					 * with the "exit underline" sequence.
					 */
					column--;
				else
					curr++;
				ln_state = LN_NORMAL;
			} 
			break;
		case LN_BO_X:
			if (c == '\b')
				ln_state = LN_BO_XB;
			else
			{
				/*
				 * Exit boldface mode.
				 * We have to shuffle the chars a bit
				 * to make this work.
				 */
				curr[0] = curr[-1];
				curr[-1] = BE_CHAR;
				column += be_width;
				if (be_width > 0 && curr[0] == ' ')
					/*
					 * Another special case for magic
					 * cookie terminals: if the next
					 * char is a space, replace it
					 * with the "exit boldface" sequence.
					 */
					column--;
				else
					curr++;
				ln_state = LN_NORMAL;
			} 
			break;
		}
	}

	if (c == '\t') 
	{
		/*
		 * Expand a tab into spaces.
		 */
		do
		{
			NEW_COLUMN(column+1);
		} while ((column % tabstop) != 0);
		*curr++ = '\t';
		return (0);
	}

	if (c == '\b')
	{
		if (bs_mode == BS_CONTROL)
		{
			/*
			 * Treat backspace as a control char: output "^H".
			 */
			NEW_COLUMN(column+2);
			*curr++ = ('H' | 0200);
		} else
		{
			/*
			 * Output a real backspace.
			 */
			column--;
			*curr++ = '\b';
		}
		return (0);
	} 

	if (control_char(c))
	{
		/*
		 * Put a "^X" into the buffer.
		 * The 0200 bit is used to tell put_line() to prefix
		 * the char with a ^.  We don't actually put the ^
		 * in the buffer because we sometimes need to move
		 * chars around, and such movement might separate 
		 * the ^ from its following character.
		 */
		NEW_COLUMN(column+2);
		*curr++ = (carat_char(c) | 0200);
		return (0);
	}

	/*
	 * Ordinary character.  Just put it in the buffer.
	 */
	NEW_COLUMN(column+1);
	*curr++ = c;
	return (0);
}

/*
 * Analogous to forw_line(), but deals with "raw lines":
 * lines which are not split for screen width.
 * {{ This is supposed to be more efficient than forw_line(). }}
 */
	public POSITION
forw_raw_line(curr_pos)
	POSITION curr_pos;
{
	register char *p;
	register int c;
	POSITION new_pos;

	if (curr_pos == NULL_POSITION || ch_seek(curr_pos) ||
		(c = ch_forw_get()) == EOF)
		return (NULL_POSITION);

	p = linebuf;

	for (;;)
	{
		if (c == '\n' || c == EOF)
		{
			new_pos = ch_tell();
			break;
		}
		if (p >= &linebuf[sizeof(linebuf)-1])
		{
			/*
			 * Overflowed the input buffer.
			 * Pretend the line ended here.
			 * {{ The line buffer is supposed to be big
			 *    enough that this never happens. }}
			 */
			new_pos = ch_tell() - 1;
			break;
		}
		*p++ = c;
		c = ch_forw_get();
	}
	*p = '\0';
	line = linebuf;
	return (new_pos);
}

/*
 * Analogous to back_line(), but deals with "raw lines".
 * {{ This is supposed to be more efficient than back_line(). }}
 */
	public POSITION
back_raw_line(curr_pos)
	POSITION curr_pos;
{
	register char *p;
	register int c;
	POSITION new_pos;

	if (curr_pos == NULL_POSITION || curr_pos <= (POSITION)0 ||
		ch_seek(curr_pos-1))
		return (NULL_POSITION);

	p = &linebuf[sizeof(linebuf)];
	*--p = '\0';

	for (;;)
	{
		c = ch_back_get();
		if (c == '\n')
		{
			/*
			 * This is the newline ending the previous line.
			 * We have hit the beginning of the line.
			 */
			new_pos = ch_tell() + 1;
			break;
		}
		if (c == EOF)
		{
			/*
			 * We have hit the beginning of the file.
			 * This must be the first line in the file.
			 * This must, of course, be the beginning of the line.
			 */
			new_pos = (POSITION)0;
			break;
		}
		if (p <= linebuf)
		{
			/*
			 * Overflowed the input buffer.
			 * Pretend the line ended here.
			 */
			new_pos = ch_tell() + 1;
			break;
		}
		*--p = c;
	}
	line = p;
	return (new_pos);
}
SHAR_EOF
fi
if test -f 'main.c'
then
	echo shar: "will not over-write existing file 'main.c'"
else
cat << \SHAR_EOF > 'main.c'
/*
 * Entry point, initialization, miscellaneous routines.
 */

#include "less.h"
#include "position.h"
#include <setjmp.h>

public int	ispipe;
public jmp_buf	main_loop;
public char *	first_cmd;
public char *	every_first_cmd;
public int	new_file;
public int	is_tty;
public char 	current_file[128];
public int ac;
public char **av;
public int curr_ac;
#if EDITOR
public char *	editor;
#endif

extern int file;
extern int nbufs;
extern int sigs;
extern int quit_at_eof;
extern int p_nbufs, f_nbufs;
extern int back_scroll;
extern int top_scroll;
extern int sc_height;

/*
 * Edit a new file.
 * Filename "-" means standard input.
 * No filename means the "current" file, from the command line.
 */
	public void
edit(filename)
	char *filename;
{
	register int f;
	char message[100];
	static int any_edited = 0;
	static int hold_scroll = 0;

	if (filename == NULL || *filename == '\0')
	{
		if (curr_ac >= ac)
		{
			error("No current file");
			return;
		}
		filename = av[curr_ac];
	}
	if (strcmp(filename, "-") == 0)
		f = 0;	/* Standard input */
	else if ((f = open(filename, 0)) < 0)
	{
		sprintf(message, "Cannot open %.*s", 
			error_width()-13, filename);
		if (any_edited)
			error(message);
		else
		{
			puts(message);
			hold_scroll = 1;
		}
		return;
	}

	if (isatty(f))
	{
		/*
		 * Not really necessary to call this an error,
		 * but if the control terminal (for commands)
		 * and the input file (for data) are the same,
		 * we get weird results at best.
		 */
		error("Can't take input from a terminal");
		if (f > 0)
			close(f);
		return;
	}

	/*
	 * Close the current input file and set up to use the new one.
	 */
	if (file > 0)
		close(file);
	new_file = 1;
	strcpy(current_file, filename);
	ispipe = (f == 0);
	file = f;
	ch_init( (ispipe) ? p_nbufs : f_nbufs );
	init_mark();
	if (every_first_cmd != NULL)
		first_cmd = every_first_cmd;
	if (is_tty)
	{
		any_edited = 1;
		if (hold_scroll)
		{
			/*
			 * Before erasing the screen contents,
			 * display the file name and ask for a keystroke.
			 */
			error(filename);
			hold_scroll = 0;
		}
		if (first_cmd == NULL || *first_cmd == '\0')
		{
			/* 
			 * Display the first screen. 
			 */
			jump_back(1);
		} else
		{
			/* 
			 * The first_cmd will hopefully redisplay the
			 * screen, so we need not display anything yet.
			 * Indicate there is nothing yet on the screen. 
			 */
			pos_clear();
		}
	}
}

/*
 * Edit the next file in the command line list.
 */
	public void
next_file(n)
	int n;
{
	if (curr_ac + n >= ac)
	{
		if (quit_at_eof)
			quit();
		error("No (N-th) next file");
	} else
		edit(av[curr_ac += n]);
}

/*
 * Edit the previous file in the command line list.
 */
	public void
prev_file(n)
	int n;
{
	if (curr_ac - n < 0)
		error("No (N-th) previous file");
	else
		edit(av[curr_ac -= n]);
}

/*
 * Copy a file directly to standard output.
 * Used if standard output is not a tty.
 */
	static void
cat_file()
{
	register int c;

	while ((c = ch_forw_get()) != EOF)
		putc(c);
	flush();
}

/*
 * Entry point.
 */
main(argc, argv)
	int argc;
	char *argv[];
{
	char *getenv();

	/*
	 * Process command line arguments and LESS environment arguments.
	 * Command line arguments override environment arguments.
	 */
	init_option();
	scan_option(getenv("LESS"));
	argv++;
	while ( (--argc > 0) && 
		(argv[0][0] == '-' || argv[0][0] == '+') && 
		argv[0][1] != '\0')
		scan_option(*argv++);

#if EDITOR
	editor = getenv("EDITOR");
	if (editor == NULL || *editor == '\0')
		editor = EDIT_PGM;
#endif

	/*
	 * Set up list of files to be examined.
	 */
	ac = argc;
	av = argv;
	curr_ac = 0;

	/*
	 * Set up terminal, etc.
	 */
	is_tty = isatty(1);
	if (!is_tty)
	{
		/*
		 * Output is not a tty.
		 * Just copy the input file(s) to output.
		 */
		if (ac < 1)
		{
			edit("-");
			cat_file();
		} else
		{
			do
			{
				edit((char *)NULL);
				if (file >= 0)
					cat_file();
			} while (++curr_ac < ac);
		}
		exit(0);
	}

	raw_mode(1);
	get_term();
	open_getc();
	init();

	if (back_scroll < 0)
	{
		/* {{ KLUDGE }} */
		back_scroll = sc_height-1;
		if (top_scroll)
			back_scroll--;
	}

	if (setjmp(main_loop))
		quit();
	init_signals();

	/*
	 * Select the first file to examine.
	 */
	if (ac < 1)
		edit("-");	/* Standard input */
	else 
	{
		/*
		 * Try all the files named as command arguments.
		 * We are simply looking for one which can be
		 * opened without error.
		 */
		do
		{
			edit((char *)NULL);
			if (file >= 0)
				/* We can open this file. */
				break;
			putc('\n');  flush();
		} while (++curr_ac < ac);
	}

	if (file >= 0)
		commands();
	quit();
}

/*
 * Exit the program.
 */
	public void
quit()
{
	/*
	 * Put cursor at bottom left corner, clear the line,
	 * reset the terminal modes, and exit.
	 */
	lower_left();
	clear_eol();
	deinit();
	flush();
	raw_mode(0);
	exit(0);
}
SHAR_EOF
fi
if test -f 'makefile.bsd41'
then
	echo shar: "will not over-write existing file 'makefile.bsd41'"
else
cat << \SHAR_EOF > 'makefile.bsd41'
# Makefile for "less"
#
# Invoked as:
#	make all
#   or	make install
# Plain "make" is equivalent to "make all".
#
# If you add or delete functions, remake funcs.h by doing:
#	make newfuncs
# This depends on the coding convention of function headers looking like:
#	" \t public <function-type> \n <function-name> ( ... ) "
#
# Also provided:
#	make lint	# Runs "lint" on all the sources.
#	make clean	# Removes "less" and the .o files.
#	make clobber	# Pretty much the same as make "clean".
#
#	make pager_patch		# makes PAGER environment variable
#	make install_pager_patch	# catcher and installs it (see below)

##########################################################################
# System-specific parameters
##########################################################################

# Define XENIX if running under XENIX 3.0
XENIX = 0

# VOID is 1 if your C compiler supports the "void" type,
# 0 if it does not.
VOID = 1

# off_t is the type which lseek() returns.
# It is also the type of lseek()'s second argument.
off_t = long

# TERMIO is 1 if your system has /usr/include/termio.h.
# This is normally the case for System 5.
# If TERMIO is 0 your system must have /usr/include/sgtty.h.
# This is normally the case for BSD.
TERMIO = 0

# SIGSETMASK is 1 if your system has the sigsetmask() call.
# This is normally the case only for BSD 4.2,
# not for BSD 4.1 or System 5.
SIGSETMASK = 0

##########################################################################
# Optional and semi-optional features
##########################################################################

# REGCMP is 1 if your system has the regcmp() function.
# This is normally the case for System 5.
# RECOMP is 1 if your system has the re_comp() function.
# This is normally the case for BSD.
# If neither is 1, pattern matching is supported, but without metacharacters.
REGCMP = 0
RECOMP = 1

# SHELL_ESCAPE is 1 if you wish to allow shell escapes.
# (This is possible only if your system supplies the system() function.)
SHELL_ESCAPE = 0

# EDITOR is 1 if you wish to allow editor invocation (the "v" command).
# (This is possible only if your system supplies the system() function.)
# EDIT_PGM is the name of the (default) editor to be invoked.
EDITOR = 0
EDIT_PGM = /usr/ucb/vi

# parameters to "make install_pager_patch".  OLD_PAGER will be moved to
# OLD_PAGER_NEW_LOCATION and pager_patch (in this directory) will be installed
# as OLD_PAGER.  This patch will allow you to set the environment variable
# PAGER to specify your personal pager preference (is this a security hole?)
OLD_PAGER = /usr/ucb/more
OLD_PAGER_NEW_LOCATION = /usr/ucb/More

# ONLY_RETURN is 1 if you want RETURN to be the only input which
# will continue past an error message.
# Otherwise, any key will continue past an error message.
ONLY_RETURN = 0

##########################################################################
# Compilation environment.
##########################################################################

# LIBS is the list of libraries needed.
LIBS = -ltermcap

# INSTALL_LESS is a list of the public versions of less.
# INSTALL_MAN is a list of the public versions of the manual page.
INSTALL_LESS =	/usr/local/less
INSTALL_MAN =	/usr/man/manl/less.l

# OPTIM is passed to the compiler and the loader.
# It is normally "-O" but may be, for example, "-g".
OPTIM = -O

##########################################################################
# Files
##########################################################################

SRC1 =	main.c option.c prim.c 
SRC2 =	ch.c position.c input.c output.c screen.c \
	prompt.c line.c signal.c help.c ttyin.c command.c version.c
SRC =	$(SRC1) $(SRC2)
OBJ =	main.o option.o prim.o ch.o position.o input.o output.o screen.o \
	prompt.o line.o signal.o help.o ttyin.o command.o version.o

##########################################################################
# Rules
##########################################################################

DEFS =	"-DTERMIO=$(TERMIO)" \
	"-DSIGSETMASK=$(SIGSETMASK)" \
	"-Doff_t=$(off_t)" "-DVOID=$(VOID)" \
	"-DREGCMP=$(REGCMP)" "-DRECOMP=$(RECOMP)" \
	"-DSHELL_ESCAPE=$(SHELL_ESCAPE)" \
	"-DEDITOR=$(EDITOR)" "-DEDIT_PGM=\"$(EDIT_PGM)\"" \
	"-DONLY_RETURN=$(ONLY_RETURN)" \
	"-DXENIX=$(XENIX)" \
	"-DOLD_PAGER_NEW_LOCATION=\"$(OLD_PAGER_NEW_LOCATION)\""

CFLAGS = $(OPTIM) $(DEFS)

all: less

less: $(OBJ)
	cc $(OPTIM) -o less $(OBJ) $(LIBS)

install: install_man install_less

install_man: less.l
	for f in $(INSTALL_MAN); do  rm -f $$f; cp less.l $$f;  done
	touch install_man

install_less: less
	for f in $(INSTALL_LESS); do  rm -f $$f; cp less $$f;  done
	touch install_less

pager_patch: pager_patch.c
	cc $(CFLAGS) -s -o pager_patch pager_patch.c

install_pager_patch: pager_patch
	if [ -s $(OLD_PAGER) -a ! -s $(OLD_PAGER_NEW_LOCATION) ]; then \
		mv $(OLD_PAGER) $(OLD_PAGER_NEW_LOCATION); \
		cp pager_patch $(OLD_PAGER); \
	fi
	touch install_pager_patch

$(OBJ): less.h funcs.h

lint:
	lint -hp $(DEFS) $(SRC)

newfuncs:
	mv funcs.h funcs.h.OLD
	awk -f mkfuncs.awk $(SRC) >funcs.h

clean:
	rm -f $(OBJ) less pager_patch

clobber:
	rm -f *.o less pager_patch install_less install_man install_pager_patch

shar:
	shar -v INSTALLATION less.l makefile.* *.h *.awk $(SRC1) > less.shar.a
	shar -v $(SRC2) pager_patch.c > less.shar.b
SHAR_EOF
fi
if test -f 'makefile.bsd42'
then
	echo shar: "will not over-write existing file 'makefile.bsd42'"
else
cat << \SHAR_EOF > 'makefile.bsd42'
# Makefile for "less"
#
# Invoked as:
#	make all
#   or	make install
# Plain "make" is equivalent to "make all".
#
# If you add or delete functions, remake funcs.h by doing:
#	make newfuncs
# This depends on the coding convention of function headers looking like:
#	" \t public <function-type> \n <function-name> ( ... ) "
#
# Also provided:
#	make lint	# Runs "lint" on all the sources.
#	make clean	# Removes "less" and the .o files.
#	make clobber	# Pretty much the same as make "clean".
#
#	make pager_patch		# makes PAGER environment variable
#	make install_pager_patch	# catcher and installs it (see below)

##########################################################################
# System-specific parameters
##########################################################################

# Define XENIX if running under XENIX 3.0
XENIX = 0