#!/bin/sh
# @(#)  /u/des/src/lsn/lsn  1.14  99/08/11  17:04:21
#
# lsn -- list directory out in specifiable number of columns
#
# Copyright (c) 1998 by Daniel E. Singer.  All rights reserved.
# Permission is granted to reproduce and distribute this program
# with the following conditions:
#   1) This copyright notice and the author identification below
#      must be left intact in the program and in any copies.
#   2) Any modifications to the program must be clearly identified
#      in the source file.
#
# Written by Daniel E. Singer, Duke Univ. Dept of Computer Science, 5/94
#
# Modifications:
#
# 6/14/94, D.Singer
#	fixed awk problem, er, feature, by adding "+ 0";
#	added "ls -F" compatibility, ie, not overwriting the special char;
#	added -w;
#	went from 'pr' for columns, to awk processing;
#	added -f;
# 6/17/94, D.Singer
#	added separation between multiple dirs;
# 6/20/94, D.Singer
#	added -v flag to 'cat' to cover screen glitch;
# 3/21/96, D.Singer
#	fix for Solaris 'expr';
# 1/29/97, D.Singer
#	added -l;
#	fixed problem with command line wild cards;
# 6/17/97, D.Singer
#	fixed problem with -l;
# 5/13/98, D.Singer
#	fixed problems with expr;
#	fixed problems with FreeBSD;
#	changed default ls flags to AF;
# 5/18/98, D.Singer
#	updated argument processing;
#	added -W;
#	some other house cleaning;
# 6/10/99, D.Singer
#	more attempts to try to reconcile dir names with spaces and/or
#	wildcards;

PATH='/usr/bin:/bin:/usr/ucb:/usr/bsd:/usr/sbin:/sbin:/usr/local/bin'
export PATH

      LS="ls"
      TR="tr"
      WC="wc"
     AWK="awk"
     CAT="cat"
     SED="sed"
    EXPR="expr"
    MORE="more"
   UNAME="uname -sr"
BASENAME="basename"

SYS=`$UNAME`
case "$SYS" in
  "SunOS "*)
	#EXPR="/usr/ucb/expr"
	AWK="nawk"
  esac

   DFLT_COLS=4
DFLT_SCR_WID=80
WIDE_SCR_WID=132
LS_FLAGS=" -AF"		# flags to pass to LS

PROG=`$BASENAME "$0"`
USAGE="
Usage:  $PROG [-#fhpw] [-l \"flags\"] [-W width] [dir...]

	  -#	specify number of columns, default is $DFLT_COLS;
	  -f	force output columns to maximum width;
	  -h	print help message and exit;
	  -l	flags to pass to 'ls', default is$LS_FLAGS;
	  -p	send the output through a display pager;
	  -w	wide display, $WIDE_SCR_WID characters, default is $DFLT_SCR_WID;
	  -W	specify screen width in characters;
	  dir	directory[s] to list, default is current directory; if using
		wildcards, the dir argument should be quoted;
"
SUMMARY="
'$PROG' will list directories out in a specifiable number of columns.
This can be useful in situations where one or more long filenames
cause the output of 'ls' to be in fewer columns than desired.
"

    COLS="$DFLT_COLS"	# output columns
 SCR_WID="$DFLT_SCR_WID" # screen width, characters
    PAGE=0		# send through pager
   FORCE=0		# force to max width:
			# this changes the output format slightly, and
			# avoids a sometimes missing last column due to
			# certain combinations of num-columns and num-entries
   FIRST=1		# first directory listed
   MULTI=0		# multiple directories

: ${PAGER:=$MORE}	# use environment setting if possible


#
# process command line options
#

colnum_error() {
	echo "$PROG: invalid column number." >&2
	echo "$USAGE" >&2
	exit 1
}

scrwid_error() {
	echo "$PROG: invalid screen width." >&2
	echo "$USAGE" >&2
	exit 1
}

syntax_error() {
	echo "$PROG: option syntax error." >&2
	echo "$USAGE" >&2
	exit 1
}

arg_syntax_check() {
	[ "$1" -lt 1 ] && syntax_error
}

while [ "$#" -gt 0 ]; do
	OPT="$1"
	case "$OPT" in
	  # options without argument
	  -[1-9]|-[1-9][0-9]|-[1-9][0-9][0-9])
		COLS=`$EXPR "$OPT" : '.\(.*\)'`
		;;
	  -f)
		FORCE=1
		;;
	  -h)
		echo "
*** `echo \"$PROG\" | $TR 'a-z' 'A-Z'` ***
$SUMMARY$USAGE"

		exit 0
		;;
	  -p)
		PAGE=1
		;;
	  -w)
		SCR_WID="$WIDE_SCR_WID"
		;;
	  # options with argument
	  -l)
		shift
		arg_syntax_check "$#"
		LS_FLAGS="$1"
		case "$LS_FLAGS" in
		  -*)
			LS_FLAGS=" $LS_FLAGS"
			;;
		  *)
			LS_FLAGS=" -$LS_FLAGS"
		  esac
		;;
	  -W)
		shift
		arg_syntax_check "$#"
		SCR_WID="$1"
		case "$SCR_WID" in
		  [1-9]|[1-9][0-9]|[1-9][0-9][0-9])
			;;
		  *)
			scrwid_error
		  esac
		;;
	  # ...
	  --)
		shift
		break
		;;

	  # unknown option
	  -?)
		syntax_error
		;;
	  # don't want numbers starting with zero
	  -0*)
		colnum_error
		;;
	  # need to do this to avoid an infinite loop
	  -[0-9][0-9][0-9][0-9]*)
		colnum_error
		;;
	  # compound option
	  -??*)
		# break up a compound option;
		# consecutive digits will become a single argument;
		NEW_OPTS=`$AWK 'BEGIN {
			OPT_STR = "'"$OPT"'";
			LEN = length(OPT_STR);
			NEW_OPTS = "";
			STATUS = 0;
			IN_NUM = 0;
			for (POS=2; POS+0 <= LEN; ++POS) {
				OPT = substr(OPT_STR,POS,1);
				if (OPT !~ /[a-zA-Z0-9_]/)
					STATUS = 1;
				if (IN_NUM && OPT ~ /[0-9]/) {
					NEW_OPTS = NEW_OPTS OPT;
					continue;
				}
				NEW_OPTS = NEW_OPTS " -" OPT;
				IN_NUM = (OPT ~ /[0-9]/);
			}
			print NEW_OPTS;
			exit STATUS;
		  }' <&-` || {
			syntax_error
		  }
		shift
		set -- $NEW_OPTS ${1:+"$@"}
		continue
		;;
	  # end of options, just command arguments left
	  *)
		break
	  esac
	shift
  done

#
# check number of arguments remaining
#
if [ "$#" = 0 ]; then
	# push current directory to positional param list
	set -- .
  elif [ "$#" -gt 1 ]; then
	MULTI=1
  fi


#
# calc the width of a column
#
COL_WID=`$EXPR "$SCR_WID" / "$COLS" - 1`

for DIR do

	#
	# escape any spaces or tabs in the DIR name that aren't already escaped;
	# not going to worry about newlines;
	#
	case "$DIR" in
	  *[\ \	]*)
		DIR=`echo "$DIR" | $AWK '{
			S = $0;
			while (match(S,/[^\\\\][ 	]/))
				S = substr(S,1,RSTART) "\\\\" substr(S,RSTART+1);
			if (match(S,/^[ 	]/))
				S = "\\\\" S;
			print S;
}'`

	  esac
#echo "DIR=\"$DIR\""
#continue

	case "$DIR" in
	  */*)
		# strip of path components
		ENTRIES=`eval "$LS$LS_FLAGS $DIR" | $SED 's/\(.*\/\)\([^$]\)/\2/'`
		;;
	  *)
		ENTRIES=`eval "$LS$LS_FLAGS $DIR"`
	  esac

	ENT_CNT=`echo "$ENTRIES" | $WC -l`

	#
	# if multiple dirs, precede each with its name
	#
	if [ "$MULTI" = 1 ]; then
		[ "$FIRST" = 0 ] && echo ""
		FIRST=0
		echo "$DIR:"
	  fi

	echo "$ENTRIES" |
	  $AWK '
	    BEGIN {
		COLS = '"$COLS"';		# number of output columns
		COL_WID = '"$COL_WID"';		# width of output columns
		ENT_CNT = '"$ENT_CNT"';		# number of entries in dir
		FORCE = '"$FORCE"';		# force output format

		LINES = int((ENT_CNT + (COLS - 1)) / COLS); # number of lines

		F_PAT = "[/*@=]$";		# suffixes produces by "ls -F"
		NUM_ENTS = 0;			# count of entries as read in
	    }
	    {
		#
		# make the entries, adjusting the size and suffix
		#
		LEN = length($0);
		if (LEN <= COL_WID)
			ENT[NUM_ENTS++] = $0;
		else {
			# long string:
			# truncate and add "%";
			# preserve the file type indicator
			if ($0 ~ F_PAT) {
				DIFF = 2;
				TYPE = substr($0,LEN,1);
			}
			else {
				DIFF = 1;
				TYPE = "";
			}
			ENT[NUM_ENTS++] = substr($0,1,COL_WID-DIFF) TYPE "%";
		}
	    }
	    END {
		#
		# print out in tabular form
		#
		++COL_WID;
		MOD = NUM_ENTS % COLS;	# used with FORCE
		MOD2 = ((MOD == 0) ? COLS : MOD) + 0;

		# produce output by lines
		for (LINE=0; LINE < LINES; ++LINE) {
			TEXT = "";
			for (COL=0; COL < COLS; ++COL) {
				# compute the index of the next entry
				# on the line
				if (FORCE == 1 && COL >= MOD2) {
				  NUM = (COL >= MOD2 && LINE == LINES - 1) \
				    ? NUM_ENTS \
				    : (LINE + (COL * LINES)) - (COL - MOD);
				}
				else
					NUM = LINE + (COL * LINES);
				# add the entry to the current line,
				# with appropriate space padding
				TEXT = TEXT sprintf("%-"COL_WID"s",ENT[NUM]);
			}

			# get rid of spaces at end of line,
			# and print it
			sub("  *$","",TEXT);
			print TEXT;
		}
	    }'
  done |

  if [ "$PAGE" = 1 ]; then
	$PAGER
    else
	$CAT -v
    fi

exit