#!/bin/bash

# Hacky wrapper which tries to sensibly untar the file(s) it's passed. The
# archives may optionally be .Z, .bz2 or .gz compressed (the file extension need
# not indicate this). Zip, rar, cpio, deb and rpm archives are also supported
# (provided the necessary utilities are available). Each archive should always
# unpack into a single subdirectory of the current location. If the contents of
# an archive would naturally dump into a single subdirectory it isn't nested
# into a new one.
# 
# Limitations:
# 	- Robustness: 1) error checking limited. 2) I probably assume too much
# 	  about the output of the utilities I call.
# 	- You cannot unpack standard input, just files
# 	- It's up to you to check the clobbering behaviour will be what you want.
#
# Iain Murray 2005.

set -e

TAR=tar
UNRAR=unrar

# functions to give a list of archive contents
function tarZlist { uncompress -c "$1" | "$TAR" t; }
function tarbz2list { bzcat "$1" | "$TAR" t; }
function targzlist { "$TAR" ztf "$1"; }
function tarlist { "$TAR" tf "$1"; }
function rarlist { "$UNRAR" vb "$1"; }
function rpmlist { rpm2cpio "$1" | cpio -t --quiet; }
# Warning: deblist is a fragile hack, which will probably break
function deblist { dpkg-deb -c "$1" | sed 's/^[^ ]* *[^ ]* *[^ ]* *[^ ]* *[^ ]* *//'; }
function cpiolist { cpio -t --quiet < "$1"; }
# Fragile hack if don't have zipinfo:
#function tarziplist { unzip -lqq "$1" | sed 's/^ *[0-9]* *[0-9\-]* *[0-9:]* *//'; }
function tarziplist { zipinfo -1 "$1"; }

# functions that actually do the business
function untarZ { uncompress -c "$1" | "$TAR" x; }
function untarbz2 { bzcat "$1" | "$TAR" x; }
function untargz { "$TAR" zxf "$1"; }
function untar { "$TAR" xf "$1"; }
function myunrar { "$UNRAR" x -ap. "$1"; }
function unrpm { rpm2cpio "$1" | cpio -i --no-absolute-filenames -d --quiet; }
function undeb { dpkg-deb -x "$1" .; }
function uncpio { cpio -i --no-absolute-filenames -d --quiet < "$1"; }
function untarzip { unzip "$1"; }

for a in "$@" ; do
	if [ -e "$a" ] ; then
		INFO=$(file "$a")
	else
		echo "$0: $a does not exist."
		exit 1
	fi

	# Set suitable functions for this file.
	# BUG: could match text in filename. I don't care enough to fix.
	if echo $INFO | grep 'gzip compressed' > /dev/null ; then
		# gzipped (.gz, .tgz) tars
		listfunc=targzlist
		exfunc=untargz
	elif echo $INFO | grep "compress'd" > /dev/null ; then
		# compressed (.Z) tars
		listfunc=tarZlist
		exfunc=untarZ
	elif echo $INFO | grep "Zip archive" > /dev/null ; then
		# zip archive
		listfunc=tarziplist
		exfunc=untarzip
	elif echo $INFO | grep "bzip2 compressed" > /dev/null ; then
		# bzip2ed (.bz2) tar
		listfunc=tarbz2list
		exfunc=untarbz2
	elif echo $INFO | grep "RAR archive" > /dev/null ; then
		# (.rar)
		listfunc=rarlist
		exfunc=myunrar
	elif echo $INFO | grep ": RPM " > /dev/null ; then
		# (.rpm)
		listfunc=rpmlist
		exfunc=unrpm
	elif echo $INFO | grep "cpio archive" > /dev/null ; then
		# (.cpio)
		listfunc=cpiolist
		exfunc=uncpio
	elif echo $INFO | grep "Debian .* package" > /dev/null ; then
		# (.cpio)
		listfunc=deblist
		exfunc=undeb
	else
		# otherwise hope plain tar can deal
		listfunc=tarlist
		exfunc=untar
	fi

	# unpack (construct a suitable subdirectory if necessary)
	IFS="
"
	out_dir=`$listfunc "$a" | sed -e 's/^\.\///' -e 's/\/.*//g' -e '/^$/d' | uniq`
	if [ `echo $out_dir | wc -l` -eq 1 ] ; then
		$exfunc "$a"
	else
		out_dir="$a"_contents
		out_dir=`echo $out_dir | sed -e 's/.*\///' \
			-e 's/\(\.tar\|\.tar\.gz\|\.taz\|\.tar\.Z\|\.tgz\|\.tar\.bz2\|\.zip\|\.jar\|\.rar\|\.rpm\|\.cpio\|\.deb\)_contents$//i'`
		mkdir "$out_dir"
		cd "$out_dir"
		if echo "$a" | grep '^\/' > /dev/null ; then
			$exfunc "$a"
		else
			$exfunc ../"$a"
		fi
		cd ..
	fi
	echo Extracted $a to $out_dir
done