#!/bin/sh
#
# Copyright (c) 2003 Thomas Klausner.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

grep=grep
zcat=zstdcat

endofopts=0
pattern_found=0
grep_args=""
hyphen=0
silent=0

prg=$(basename $0)

# handle being called 'zegrep' or 'zfgrep'
case ${prg} in
    *zegrep)
	grep_args="-E";;
    *zfgrep)
	grep_args="-F";;
esac

# skip all options and pass them on to grep taking care of options
# with arguments, and if -e was supplied

while [ $# -gt 0 -a ${endofopts} -eq 0 ]
do
    case $1 in
    # from GNU grep-2.5.1 -- keep in sync!
	-[ABCDXdefm])
	    if [ $# -lt 2 ]
		then
		echo "${prg}: missing argument for $1 flag" >&2
		exit 1
	    fi
	    case $1 in
		-e)
		    pattern="$2"
		    pattern_found=1
		    shift 2
		    break
		    ;;
		*)
		    ;;
	    esac
	    grep_args="${grep_args} $1 $2"
	    shift 2
	    ;;
	--)
	    shift
	    endofopts=1
	    ;;
	-)
	    hyphen=1
	    shift
	    ;;
	-h)
	    silent=1
	    shift
	    ;;
	-*)
	    grep_args="${grep_args} $1"
	    shift
	    ;;
	*)
	    # pattern to grep for
	    endofopts=1
	    ;;
    esac
done

# if no -e option was found, take next argument as grep-pattern
if [ ${pattern_found} -lt 1 ]
then
    if [ $# -ge 1 ]; then
	pattern="$1"
	shift
    elif [ ${hyphen} -gt 0 ]; then
	pattern="-"
    else
	echo "${prg}: missing pattern" >&2
	exit 1
    fi
fi

# call grep ...
if [ $# -lt 1 ]
then
    # ... on stdin
    ${zcat} -fq - | ${grep} ${grep_args} -- "${pattern}" -
else
    # ... on all files given on the command line
    if [ ${silent} -lt 1 -a $# -gt 1 ]; then
	grep_args="-H ${grep_args}"
    fi
    while [ $# -gt 0 ]
    do
	${zcat} -fq -- "$1" | ${grep} --label="${1}" ${grep_args} -- "${pattern}" -
	shift
    done
fi

exit 0
