ps2txt.in

harvest是一个下载html网页得机器人

#!@PERL@
#
#  ps2txt - PostScript to ASCII converter
#
#  Usage: ps2txt filename
#
#  Uses ps2txt version 2.1 (as posted to alt.sources) as the main
#  PostScript conversion engine.  This Perl program acts as a pre-
#  and post- processor to improve the quality of the ps2txt output.
#
#  Forks off the ps2txt command, and builds a pipeline to feed/filter it.
#
#  Darren Hardy, [e-mail], May 1994
#
#  $Id: ps2txt,v 2.1 1997/03/21 17:19:43 sxw Exp $
#
#############################################################################
#
#  Harvest Indexer http://www.tardis.ed.ac.uk/harvest/
#  ---------------------------------------------------
#
#  The Harvest Indexer is a continued development of code developed by
#  the Harvest Project. Development is carried out by numerous individuals
#  in the Internet community, and is not officially connected with the
#  original Harvest Project or its funding sources.
#
#  Please mail [e-mail] if you are interested in participating
#  in the development effort.
#
#  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.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#

#######################################################################
#
#  Copyright (c) 1994, 1995.  All rights reserved.
#
#    The Harvest software was developed by the Internet Research Task
#    Force Research Group on Resource Discovery (IRTF-RD):
#
#          Mic Bowman of Transarc Corporation.
#          Peter Danzig of the University of Southern California.
#          Darren R. Hardy of the University of Colorado at Boulder.
#          Udi Manber of the University of Arizona.
#          Michael F. Schwartz of the University of Colorado at Boulder.
#          Duane Wessels of the University of Colorado at Boulder.
#
#    This copyright notice applies to software in the Harvest
#    ``src/'' directory only.  Users should consult the individual
#    copyright notices in the ``components/'' subdirectories for
#    copyright information about other software bundled with the
#    Harvest source code distribution.
#
#  TERMS OF USE
#
#    The Harvest software may be used and re-distributed without
#    charge, provided that the software origin and research team are
#    cited in any use of the system.  Most commonly this is
#    accomplished by including a link to the Harvest Home Page
#    (http://harvest.cs.colorado.edu/) from the query page of any
#    Broker you deploy, as well as in the query result pages.  These
#    links are generated automatically by the standard Broker
#    software distribution.
#
#    The Harvest software is provided ``as is'', without express or
#    implied warranty, and with no support nor obligation to assist
#    in its use, correction, modification or enhancement.  We assume
#    no liability with respect to the infringement of copyrights,
#    trade secrets, or any patents, and are not responsible for
#    consequential damages.  Proper use of the Harvest software is
#    entirely the responsibility of the user.
#
#  DERIVATIVE WORKS
#
#    Users may make derivative works from the Harvest software, subject
#    to the following constraints:
#
#      - You must include the above copyright notice and these
#        accompanying paragraphs in all forms of derivative works,
#        and any documentation and other materials related to such
#        distribution and use acknowledge that the software was
#        developed at the above institutions.
#
#      - You must notify IRTF-RD regarding your distribution of
#        the derivative work.
#
#      - You must clearly notify users that your are distributing
#        a modified version and not the original Harvest software.
#
#      - Any derivative product is also subject to these copyright
#        and use restrictions.
#
#    Note that the Harvest software is NOT in the public domain.  We
#    retain copyright, as specified above.
#
#  HISTORY OF FREE SOFTWARE STATUS
#
#    Originally we required sites to license the software in cases
#    where they were going to build commercial products/services
#    around Harvest.  In June 1995 we changed this policy.  We now
#    allow people to use the core Harvest software (the code found in
#    the Harvest ``src/'' directory) for free.  We made this change
#    in the interest of encouraging the widest possible deployment of
#    the technology.  The Harvest software is really a reference
#    implementation of a set of protocols and formats, some of which
#    we intend to standardize.  We encourage commercial
#    re-implementations of code complying to this set of standards.
#
#

&usage() if ($#ARGV != 0);

$filename = shift(@ARGV);

$ps2txt_cmd = "ps2txt-2.1";
$dviflag = "";

$SIG{'INT'} = "cleanup";
$SIG{'PIPE'} = "cleanup";
$SIG{'TERM'} = "cleanup";

#
#  Read the PostScript file and strip the Prolog.  Determine if the
#  PostScript was generated by dvips.
#
$start = 0;
open(IN, "$filename") || die "Cannot read $filename: $!\n";
while (<IN>) {
	$start = 1 if (/^%%EndProlog/o);
	$dviflag = "-dvi" if (/^%.*Creator:\s+dvips.*$/o);
	next if ($start == 0);
	last;	# break the loop
}
seek(IN, 0, 0) if ($start == 0);	# rewind the file to the beginning

#
#  this  ps2txt
#    B--->A
#
pipe(A, B) || die "pipe";	# A is read, B is write

die "fork: $!" unless defined ($pid = fork());

if ($pid == 0) {		# child - ps2txt
	close(B);
	open(STDIN, "<&A") || die "open";
	exec("$ps2txt_cmd $dviflag");
	exit(0);
}
close(A);
while (<IN>) {
	print B;	# feed the ps file to the ps2txt process
}
close(IN);
close(B);		# finish off the pipe
&cleanup();
exit(0);		# END OF PROGRAM

sub cleanup {
	exit(0);
}

sub usage {
	print STDERR "Usage: ps2txt filename\n";
	exit(1);
}