#!/usr/bin/perl -w

# Andgrep - designed for use with TWiki, so only supports -l and -i options,
# and is based on egrep.

# $Id: andgrep,v 1.2 2001/07/09 13:29:18 rdonkin Exp rdonkin $

# Copyright (C) 2001 Richard Donkin, rdonkin@orchestream.com

# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details, published at 
# http://www.gnu.org/copyleft/gpl.html

# Usage:
#    andgrep [-l] [-i] pattern file ...
#
# Where 
#     pattern  is of the form 'pattern1;pattern2;...', i.e. ';' is used
#     to indicate matching pattern1 AND pattern2 AND ..., anywhere in the file

# For better performance, put most specific matches first, e.g.
#
#    andgrep 'cupcakes;English' *.txt
#
# The first term cuts down the list of files a great deal,
# resulting in fewer files being re-scanned than if the 
# (presumably more common) term 'English' was used as the first term.

# Unlike agrep, any egrep regular expression can be used.


# Pick up the options
$doListfiles = "";
$doIgnorecase = "";
while ( $ARGV[0] =~ /^-/ ) {
    if ($ARGV[0] eq "-l") { 
	$doListfiles = "-l"; shift(@ARGV);
    } elsif ($ARGV[0] eq "-i") { 
        $doIgnorecase = "-i"; shift(@ARGV);
    }
}


# Handle the case where -l is not specified, to cover
# topicname searching with regular expressions: just do a normal
# egrep with no ANDing.
if ($doListfiles ne "-l") { 
    $simplePattern = shift(@ARGV);
    @filenames = @ARGV;
    $cmd = "egrep $doIgnorecase '$simplePattern' @filenames";
    system("$cmd");
    exit;
}

# Split sub-patterns to be ANDed - semicolon indicates AND, as with agrep.
$fullPattern = shift(@ARGV);
@patterns = split(';', $fullPattern);

# open (DEBUG, ">/tmp/debugit");

# Loop through patterns, one egrep per pattern, reducing initial filename
# list until only those that match all patterns are present.
@filenames = @ARGV;
foreach $simplePattern (@patterns) {

    $cmd = "egrep $doIgnorecase $doListfiles '$simplePattern' @filenames";
    # print DEBUG "$cmd\n" ;
    # print DEBUG "--------\n";

    @filenames = ` $cmd `;
    # print DEBUG "result = @filenames\n";

    # Get rid of the \n after every filename
    chomp(@filenames);
}

# Only produce output if one or more filenames found
if (@filenames) { 
    print join("\n", @filenames) . "\n";
}