bzip3-rs 1.2.0

#!/bin/sh
# Copyright (C) 2026 The bzip3-rs contributors.
# SPDX-License-Identifier: Apache-2.0
# Licensed under the Apache License, Version 2.0 <https://www.apache.org/licenses/LICENSE-2.0>
# bz3diff: compare possibly compressed files with cmp or diff.
# Written from scratch for bzip3-rs. Mirrors the behavior of the
# bzip2 bzdiff wrapper with .bz2 replaced by .bz3.

PATH="$PATH:/usr/bin:/bin"; export PATH

# Write the plain form of "$1" to stdout.
# Uses bzip3 when the file starts with the BZ3v1 magic.
# Uses cat for all other files.
plain() {
	f="$1"
	if [ "$(head -c 5 -- "$f" 2>/dev/null)" = "BZ3v1" ]; then
		bzip3 -dcfq -- "$f"
	else
		cat -- "$f"
	fi
}

prog=`echo "$0" | sed 's|.*/||'`
case "$prog" in
	*cmp)	comp=${CMP-cmp}	;;
	*)	comp=${DIFF-diff}	;;
esac

OPTIONS=
FILES=
for ARG
do
	case "$ARG" in
	-*)	OPTIONS="$OPTIONS $ARG"	;;
	*)
		if test -f "$ARG"; then
			FILES="$FILES $ARG"
		else
			echo "${prog}: $ARG not found or not a regular file"
			exit 1
		fi
		;;
	esac
done
if test -z "$FILES"; then
	echo "Usage: $prog [${comp}_options] file [file]"
	exit 1
fi
set $FILES
if test $# -eq 1; then
	FILE=`echo "$1" | sed 's/.bz3$//'`
	plain "$FILE.bz3" | $comp $OPTIONS - "$FILE"
	STAT="$?"
elif test $# -eq 2; then
	case "$1" in
	*.bz3)
		case "$2" in
		*.bz3)
			F=`echo "$2" | sed 's|.*/||;s|.bz3$||'`
			tmp=`mktemp "${TMPDIR:-/tmp}"/bz3diff.XXXXXXXXXX` || {
				echo 'cannot create a temporary file' >&2
				exit 1
			}
			plain "$2" > "$tmp"
			plain "$1" | $comp $OPTIONS - "$tmp"
			STAT="$?"
			/bin/rm -f "$tmp"
			;;
		*)
			plain "$1" | $comp $OPTIONS - "$2"
			STAT="$?"
			;;
		esac
		;;
	*)
		case "$2" in
		*.bz3)
			plain "$2" | $comp $OPTIONS "$1" -
			STAT="$?"
			;;
		*)
			$comp $OPTIONS "$1" "$2"
			STAT="$?"
			;;
		esac
		;;
	esac
else
	echo "Usage: $prog [${comp}_options] file [file]"
	exit 1
fi
exit "$STAT"