Usenet 1994 October/usenetsourcesnewsgroupsinfomagicoctober1994disk2.iso/misc/volume37/buffer/part01

Text File | 1993-05-15 | 54KB | 1,624 lines

Newsgroups: comp.sources.misc
From: [e-mail] (Lee M J McLoughlin)
Subject: v37i053:  buffer - Very Fast Tape Writer, Part01/01
Message-ID: <[e-mail]>
X-Md4-Signature: 854f99ac7dcc323e8bfd54cd09140d4d
Date: Tue, 11 May 1993 19:44:34 GMT
Approved: [e-mail]

Submitted-by: [e-mail] (Lee M J McLoughlin)
Posting-number: Volume 37, Issue 53
Archive-name: buffer/part01
Environment: SUNOS, SYSV, SYSVR4, HPUX, Shared Memory, Semaphores

This is a program designed to speed up writing tapes on remote tape
drives.  Requirements are shared memory and locks which normally
means that these are supported in your kernel.

Buffer has been tested under SunOS 4.0.*, SunOS 4.1.*, Solarix, HP-UX 7.0,
and Gould UTX 2.1A (sv universe).

The program splits itself into two processes.  The first process reads
(and reblocks) from stdin into a shared memory buffer.  The second
writes from the shared memory buffer to stdout.  Doing it this way
means that the writing side effectly sits in a tight write loop and
doesn't have to wait for input.  Similarly for the input side.  It is
this waiting that slows down other reblocking processes, like dd.

I run an archive and need to write large chunks out to tape regularly
with an ethernet in the way.  Using 'buffer' in a command like:

    tar cvf - stuff | rsh somebox "buffer > /dev/rst8"

is a factor of 5 faster than the best alternative, gnu tar with its
remote tape option:

    tar cvf somebox:/dev/rst8 stuff

We have been using buffer here at Imperial for a couple of years now
for writing tar tapes and the main system dumps.

Thanks to Kevin Twidle <[e-mail]> for the -p and -B code.

INSTALLATION:
    Check that your kernel supports shared memory and semaphores.
    A quick way to check is to build buffer and run it.
    If it says "couldn't create shared memory segment" you probably
    need to reconfigure and rebuild your kernel.

    To install edit the Makefile and tailor the variables to
    your local systems.  Then type make.

DISCLAIMER:
    This package is under the GNU GENERAL PUBLIC LICENSE!
    In addtion under NO circumstances can I, or Imperial College,
    be held liable for any event caused by the running or storing
    of this program or its documentation.

Lee McLoughlin.                          Phone: [phone] X 5085
Dept of Computing, Imperial College,     Fax: [phone]
180 Queens Gate, London, SW7 2BZ, UK.    Email: [e-mail]
-------------------------------------------------------------------------
#! /bin/sh
# This is a shell archive.  Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file".  To overwrite existing
# files, type "sh file -c".  You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g..  If this archive is complete, you
# will see the following message at the end:
#        "End of shell archive."
# Contents:  README buffer.man Makefile buffer.c sem.c COPYING
# Wrapped by [e-mail] on Mon Apr 26 14:22:55 1993
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'README' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'README'\"
else
echo shar: Extracting \"'README'\" \(1979 characters\)
sed "s/^X//" >'README' <<'END_OF_FILE'
XThis is a program designed to speed up writing tapes on remote tape
Xdrives.  Requirements are shared memory and locks which normally
Xmeans that these are supported in your kernel.
X
XBuffer has been tested under SunOS 4.0.*, SunOS 4.1.*, Solarix, HP-UX 7.0,
Xand Gould UTX 2.1A (sv universe).
X
XThe program splits itself into two processes.  The first process reads
X(and reblocks) from stdin into a shared memory buffer.  The second
Xwrites from the shared memory buffer to stdout.  Doing it this way
Xmeans that the writing side effectly sits in a tight write loop and
Xdoesn't have to wait for input.  Similarly for the input side.  It is
Xthis waiting that slows down other reblocking processes, like dd.
X
XI run an archive and need to write large chunks out to tape regularly
Xwith an ethernet in the way.  Using 'buffer' in a command like:
X
X    tar cvf - stuff | rsh somebox "buffer > /dev/rst8"
X
Xis a factor of 5 faster than the best alternative, gnu tar with its
Xremote tape option:
X
X    tar cvf somebox:/dev/rst8 stuff
X
XWe have been using buffer here at Imperial for a couple of years now
Xfor writing tar tapes and the main system dumps.
X
XThanks to Kevin Twidle <[e-mail]> for the -p and -B code.
X
XINSTALLATION:
X    Check that your kernel supports shared memory and semaphores.
X    A quick way to check is to build buffer and run it.
X    If it says "couldn't create shared memory segment" you probably
X    need to reconfigure and rebuild your kernel.
X
X    To install edit the Makefile and tailor the variables to
X    your local systems.  Then type make.
X
XDISCLAIMER:
X    This package is under the GNU GENERAL PUBLIC LICENSE!
X    In addtion under NO circumstances can I, or Imperial College,
X    be held liable for any event caused by the running or storing
X    of this program or its documentation.
X
XLee McLoughlin.                          Phone: [phone] X 5085
XDept of Computing, Imperial College,     Fax: [phone]
X180 Queens Gate, London, SW7 2BZ, UK.    Email: [e-mail]
END_OF_FILE
if test 1979 -ne `wc -c <'README'`; then
    echo shar: \"'README'\" unpacked with wrong size!
fi
# end of 'README'
fi
if test -f 'buffer.man' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'buffer.man'\"
else
echo shar: Extracting \"'buffer.man'\" \(5071 characters\)
sed "s/^X//" >'buffer.man' <<'END_OF_FILE'
X.\"    Buffer.  Very fast reblocking filter speedy writing of tapes.
X.\"    Copyright (C) 1990,1991  Lee McLoughlin
X.\"
X.\"    This program is free software; you can redistribute it and/or modify
X.\"    it under the terms of the GNU General Public License as published by
X.\"    the Free Software Foundation; either version 1, or (at your option)
X.\"    any later version.
X.\"
X.\"    This program is distributed in the hope that it will be useful,
X.\"    but WITHOUT ANY WARRANTY; without even the implied warranty of
X.\"    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
X.\"    GNU General Public License for more details.
X.\"
X.\"    You should have received a copy of the GNU General Public License
X.\"    along with this program; if not, write to the Free Software
X.\"    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
X.\"
X.\"    Lee McLoughlin.
X.\"    Dept of Computing, Imperial College,
X.\"    180 Queens Gate, London, SW7 2BZ, UK.
X.\"
X.\"    Email: [e-mail]
X.TH BUFFER 1 "14 May 1990"
X.SH NAME
Xbuffer \- very fast reblocking program
X.SH SYNTAX
X.B buffer
X[\fB\-S size\fP] [\fB\-b blocks\fP] [\fB\-s size\fP] [\fB\-m size\fP]
X[\fB\-p percentage\fP] [\fB\-u microseconds\fP] [\fB-B\fR] [\fB-t\fR]
X[\fB-Z\fR] [\fB-i filename\fR] [\fB-o filename\fR]
X.SH OPTIONS
X.TP 5
X.B \-i filename
XUse the given file as the input file.  The default is stdin.
X.TP
X.B \-o filename
XUse the given file as the output file.  The default is stdout.
X.TP
X.B \-S size
XAfter every chunk this size has been writen print out how much been writen so far.
XBy default this is not set.
X.B \-s size
XSize in bytes of each block.  The default blocksize is 10k to match
Xthe normal output of the
X.I tar(1)
Xprogram.
X.TP
X.B \-z size
XCombines the
X.B \-S
Xand
X.B \-s
Xflags.
X.TP
X.B \-b blocks
XNumber of blocks to allocate to shared memory circular buffer.
XDefaults to the number required to fill up the shared memory requested.
X.TP
X.B \-m size
XMaximum size of the shared memory chunk to allocate for the circular
Xqueue. Defaults to one megabyte.
X.TP
X.B \-p percentage
XOnly start a write when the given percentage of the internal queue is
Xfull.  A percentage around 75 often proves best. Defaults to zero.
X.TP
X.B \-u microseconds
XAfter every write pause for this many microseconds.  Defaults to zero.
X(Suprisingly a small sleep, 100 usecs, after each write can greatly enhance
Xthroughput on some drives.)
X.TP
X.B \-B
XForce each block writen to be padded out to 1K.  This is needed by some tape
Xand cartridge drives.  Defaults to unpadded.  This only effects the
Xlast block writen.
X.TP
X.B \-t
XOn exiting print to stderr a brief message showing the total number of
Xbytes written.
X.TP
X.B \-Z
XIf reading/writing directly to a character device (like a tape drive)
Xthen after each gigabyte perform an lseek to the start of the file.
XUse this flag with extreme care.  If can only be used on devices where
Xan lseek does not rewind the tape but does reset the kernels position
Xflags.  It is used to allow more than 2 gigabytes to be writen.
X.PP
XSizes are a number with an optional trailing character.   A 'b'
Xmultiplies the size by 512, a 'k' by 1024 and an 'm' by a meg.
X.SH DESCRIPTION
X.I Buffer
Xreads from standard input reblocking to the given blocksize and writes
Xeach block to standard output.
X.PP
XInternally
X.I buffer
Xis a pair of processes communicating via a large circular queue held
Xin shared memory.  The reader process only has to block when the queue
Xis full and the writer process when the queue is empty.
X.I Buffer
Xis designed to try and keep the writer side continuously busy so that
Xit can stream when writing to tape drives.  When used to write tapes
Xwith an intervening network
X.I buffer
Xcan result in a considerable increase in throughput.
X.PP
XThe default settings for
X.I buffer
Xare normally good enough.  If you are a heavy tape user then it is
Xworth your while trying out various different combinations of options.
XIn particular running a
X.I buffer
Xat both ends of the pipe can provide a substantial increase (see last
Xexample below).
X.SH EXAMPLES
X.br
X$ \fBbuffer < /etc/termcap > /dev/rst8\fP
X.br
X.sp
X$ \fBtar cf - . | rsh somehost 'buffer > /dev/rst8'\fP
X.br
X.sp
X$ \fBdump fu - | rsh somehost 'buffer -s 16k > /dev/nrst8'\fP
X.br
X$ \fBtar cf - . | buffer |
X.br
X\ \ \ rsh somehost 'buffer -S 500K -p 75 > /dev/rst0'\fP
X.SH BUGS
XInternally, for printing purposes, buffer counts in terms of the
Xnumber of kilobytes output.  If the blocksize you use is not a whole
Xnumber of kilobytes then the numbers printed will be inaccurate.
X
X.SH THANKS
XThanks to Kevin Twidle <[e-mail]> for a lot of early
Xsuggestions and patches to make it work with non-tar/dump tapes to
Xexabyte drives.
X
XThanks to Andi Karrer <[e-mail]>, Rumi Zahir
X<[e-mail]> and Christoph Wicki <[e-mail]> for patches
Xto make buffer work when trying to write single tape files of greater
Xthan 2 gigabytes.
X
X.SH COPYRIGHT
X.if n Copyright (C) 1990, 1991 by Lee McLoughlin.
X.if t Copyright \(co 1990, 1991 by Lee McLoughlin.
X.SH SEE ALSO
Xdd(1), tar(1), rsh(1)
END_OF_FILE
if test 5071 -ne `wc -c <'buffer.man'`; then
    echo shar: \"'buffer.man'\" unpacked with wrong size!
fi
# end of 'buffer.man'
fi
if test -f 'Makefile' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'Makefile'\"
else
echo shar: Extracting \"'Makefile'\" \(875 characters\)
sed "s/^X//" >'Makefile' <<'END_OF_FILE'
X# Make the buffer program
X
X# Add -DSYS5 for A System 5 (USG) version of unix
X#   You should also add -DSYS5 for Ultrix, AIX, and Solarix.
X# Add -DDEF_SHMEM=n if you can only have n bytes of shared memory
X#   (eg: -DDEF_SHMEM=524288 if you can only have half a meg.)
XCFLAGS=
X
X# Where to install buffer and its manual pages
XINSTBIN=/usr/local/bin
XINSTMAN=/usr/man/manl
X# The manual page section (normally l or 1)
XS=l
X
XRM=/bin/rm
XALL=README buffer.man Makefile buffer.c sem.c COPYING
X
Xall: buffer
X
Xbuffer: buffer.o sem.o
X    $(CC) -o buffer $(CFLAGS) buffer.o sem.o
X
Xclean:
X    $(RM) -f *.o core buffer .merrs
X
Xinstall: buffer
X    cp buffer $(INSTBIN)
X    chmod 111 $(INSTBIN)/buffer
X    cp buffer.man $(INSTMAN)/buffer.$S
X    chmod 444 $(INSTMAN)/buffer.$S
X
Xbuffer.tar: $(ALL)
X    $(RM) -f buffer.tar
X    tar cvf buffer.tar $(ALL)
X
Xbuffer.shar: $(ALL)
X    $(RM) -f buffer.shar
X    shar $(ALL) > buffer.shar
END_OF_FILE
if test 875 -ne `wc -c <'Makefile'`; then
    echo shar: \"'Makefile'\" unpacked with wrong size!
fi
# end of 'Makefile'
fi
if test -f 'buffer.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'buffer.c'\"
else
echo shar: Extracting \"'buffer.c'\" \(18127 characters\)
sed "s/^X//" >'buffer.c' <<'END_OF_FILE'
X/*
X    Buffer.  Very fast reblocking filter speedy writing of tapes.
X    Copyright (C) 1990,1991  Lee McLoughlin
X
X    This program is free software; you can redistribute it and/or modify
X    it under the terms of the GNU General Public License as published by
X    the Free Software Foundation; either version 1, or (at your option)
X    any later version.
X
X    This program is distributed in the hope that it will be useful,
X    but WITHOUT ANY WARRANTY; without even the implied warranty of
X    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
X    GNU General Public License for more details.
X
X    You should have received a copy of the GNU General Public License
X    along with this program; if not, write to the Free Software
X    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
X
X    Lee McLoughlin.
X    Dept of Computing, Imperial College,
X    180 Queens Gate, London, SW7 2BZ, UK.
X
X    Email: [e-mail]
X*/
X
X/* This is a reblocking process, designed to try and read from stdin
X * and write to stdout - but to always try and keep the writing side
X * busy.  It is meant to try and stream tape writes.
X *
X * This program runs in two parts.  The reader and the writer.  They
X * communicate using shared memory with semaphores locking the access.
X * The shared memory implements a circular list of blocks of data.
X *
X * L.McLoughlin, Imperial College, 1990
X *
X * $Log: buffer.c,v $
X * Revision 1.15  1992/11/23  23:32:58  lmjm
X * Oops!  This should be outside the ifdef
X *
X * Revision 1.14  1992/11/23  23:29:58  lmjm
X * allow MAX_BLOCKSIZE and DEF_SHMEM to be configured
X *
X * Revision 1.13  1992/11/23  23:22:29  lmjm
X * Printf's use %lu where appropriate.
X *
X * Revision 1.12  1992/11/23  23:17:55  lmjm
X * Got rid of floats and use Kbyte counters instead.
X *
X * Revision 1.11  1992/11/03  23:11:51  lmjm
X * Forgot Andi Karrer on the patch list.
X *
X * Revision 1.10  1992/11/03  22:58:41  lmjm
X * Cleaned up the debugging prints.
X *
X * Revision 1.9  1992/11/03  22:53:00  lmjm
X * Corrected stdin, stout and showevery use.
X *
X * Revision 1.8  1992/11/03  22:41:34  lmjm
X * Added 2Gig patches from:
X * Andi Karrer <[e-mail]>
X * Rumi Zahir <[e-mail]>
X * Christoph Wicki <[e-mail]>
X *
X * Revision 1.7  1992/07/23  20:42:03  lmjm
X * Added 't' option to print total writen at end.
X *
X * Revision 1.6  1992/04/07  19:57:30  lmjm
X * Added Kevins -B and -p options.
X * Turn off buffering to make -S output appear ok.
X * Added GPL.
X *
X * Revision 1.5  90/07/22  18:46:38  lmjm
X * Added system 5 support.
X *
X * Revision 1.4  90/07/22  18:29:48  lmjm
X * Updated arg handling to be more consistent.
X * Make sofar printing size an option.
X *
X * Revision 1.3  90/05/15  23:27:46  lmjm
X * Added -S option (show how much has been writen).
X * Added -m option to specify how much shared memory to grab.
X * Now tries to fill this with blocks.
X * reader waits for writer to terminate and then frees the shared mem and sems.
X *
X * Revision 1.2  90/01/20  21:37:59  lmjm
X * Reset default number of  blocks and blocksize for best thruput of
X * standard tar 10K blocks.
X * Allow number of blocks to be changed.
X * Don't need a hole in the circular queue since the semaphores prevent block
X * clash.
X *
X * Revision 1.1  90/01/17  11:30:23  lmjm
X * Initial revision
X *
X */
X#include <unistd.h>
X#include <stdio.h>
X#include <signal.h>
X#include <fcntl.h>
X#include <sys/types.h>
X#include <sys/stat.h>
X#include <sys/ipc.h>
X#include <sys/shm.h>
X#include <sys/sem.h>
X
X#ifndef lint
Xstatic char *rcsid = "$Header: /a/swan/home/swan/staff/csg/lmjm/src/buffer/RCS/buffer.c,v 1.15 1992/11/23 23:32:58 lmjm Exp lmjm $";
X#endif
X
Xextern char *shmat();
X
X/* General macros */
X#define TRUE 1
X#define FALSE 0
X#define K *1024
X
X/* Some forward declarations */
Xvoid byee();
Xvoid start_reader_and_writer();
X
X/* When showing print a note every this many bytes writen */
Xint showevery = 0;
X#define PRINT_EVERY 10 K
X
X/* Pause after every write */
Xunsigned write_pause;
X
X/* This is the inter-process buffer - it implements a circular list
X * of blocks. */
X
X#ifndef MAX_BLOCKSIZE
X#define MAX_BLOCKSIZE (512 K)
X#endif
X#define DEF_BLOCKSIZE (10 K)
Xint blocksize = DEF_BLOCKSIZE;
X
X/* Numbers of blocks in the queue.
X */
X#define MAX_BLOCKS 2048
Xint blocks = 1;
X/* Circular increment of a buffer index */
X#define INC(i) (((i)+1) == blocks ? 0 : ((i)+1))
X
X/* Max amount of shared memory you can allocate - can't see a way to look
X * this up.
X */
X#ifndef DEF_SHMEM
X#define DEF_SHMEM (1 K K)
X#endif
Xint max_shmem = DEF_SHMEM;
X
X/* Just a flag to show unfilled */
X#define NONE (-1)
X
X/* the shared memory id of the buffer */
Xint buffer_id = NONE;
Xstruct block {
X    int bytes;
X    char *data;
X} *curr_block;
X
X#define NO_BUFFER ((struct buffer *)-1)
Xstruct buffer {
X    /* writer will hang trying to lock this till reader fills in a block */
X    int blocks_used_lock;
X    /* reader will hang trying to lock this till writer empties a block */
X    int blocks_free_lock;
X
X    int next_block_in;
X    int next_block_out;
X
X    struct block block[ MAX_BLOCKS ];
X
X    /* These actual space for the blocks is here - the array extends
X     * pass 1 */
X    char data_space[ 1 ];
X} *pbuffer = NO_BUFFER;
Xint buffer_size;
X
Xint fdin    = 0;
Xint fdout    = 1;
Xint in_ISCHR    = 0;
Xint out_ISCHR    = 0;
Xint padblock    = FALSE;
Xint writer_pid    = 0;
Xint reader_pid    = 0;
Xint percent    = 0;
Xint debug    = 0;
Xint Zflag    = 0;
Xchar *progname = "buffer";
X
Xchar print_total = 0;
X/* Number of K output */
Xunsigned long outk = 0;
X
Xmain( argc, argv )
X    int argc;
X    char **argv;
X{
X    parse_args( argc, argv );
X
X    set_handlers();
X
X    buffer_allocate();
X
X    start_reader_and_writer();
X
X    byee( 0 );
X}
X
Xparse_args( argc, argv )
X    int argc;
X    char **argv;
X{
X    int c;
X    int iflag = 0;
X    int oflag = 0;
X    int zflag = 0;
X    extern char *optarg;
X    extern int optind;
X    char blocks_given = FALSE;
X    struct stat buf;
X
X
X    while( (c = getopt( argc, argv, "BS:Zdm:s:b:p:u:ti:o:z:" )) != -1 ){
X        switch( c ){
X        case 't': /* Print to stderr the total no of bytes writen */
X            print_total++;
X            break;
X        case 'u': /* pause after write for given microseconds */
X            write_pause = atoi( optarg );
X            break;
X        case 'B':   /* Pad last block */
X            padblock = TRUE;
X            break;
X        case 'Z':   /* Zero by lseek on the tape device */
X            Zflag = TRUE;
X            break;
X        case 'i': /* Input file */
X            iflag++;
X            if( iflag > 1 ){
X                fprintf( stderr, "buffer: -i given twice\n" );
X                byee( -1 );
X            }
X            if( (fdin = open( optarg, O_RDONLY )) < 0 ){
X                perror( "buffer: cannot open input file" );
X                fprintf( stderr, "filename: %s\n", optarg );
X                byee ( -1 );
X            }
X            break;
X        case 'o': /* Output file */
X            oflag++;
X            if( oflag > 1 ){
X                fprintf( stderr, "buffer: -o given twice\n" );
X                byee( -1 );
X            }
X            if( (fdout = open( optarg, O_WRONLY | O_CREAT | O_TRUNC, 0666 )) < 0 ){
X                perror( "buffer: cannot open output file" );
X                fprintf( stderr, "filename: %s\n", optarg );
X                byee ( -1 );
X            }
X            break;
X        case 'S':
X            /* Show every once in a while how much is printed */
X            showevery = do_size( optarg );
X            if( showevery <= 0 )
X                showevery = PRINT_EVERY;
X            break;
X        case 'd':    /* debug */
X            debug++;
X            if( debug == 1 ){
X                setbuf( stdout, NULL );
X                setbuf( stderr, NULL );
X                fprintf( stderr, "debugging turned on\n" );
X            }
X            break;
X        case 'm':
X            /* Max size of shared memory lump */
X            max_shmem = do_size( optarg );
X
X            if( max_shmem < (sizeof( struct buffer ) + (blocksize * blocks)) ){
X                fprintf( stderr, "max_shmem %d too low\n", max_shmem );
X                byee( -1 );
X            }
X            break;
X        case 'b':
X            /* Number of blocks */
X            blocks_given = TRUE;
X            blocks = atoi( optarg );
X            if( (blocks <= 0) || (MAX_BLOCKS < blocks) ){
X                fprintf( stderr, "blocks %d out of range\n", blocks );
X                byee( -1 );
X            }
X            break;
X        case 'p':    /* percent to wait before dumping */
X            percent = atoi( optarg );
X
X            if( (percent < 0) || (100 < percent) ){
X                fprintf( stderr, "percent %d out of range\n", percent );
X                byee( -1 );
X            }
X            if( debug )
X                fprintf( stderr, "percent set to %d\n", percent );
X            break;
X        case 'z':
X            zflag++;
X            /* FALL THRU */
X        case 's':    /* Size of a block */
X            blocksize = do_size( optarg );
X
X            if( (blocksize <= 0) || (MAX_BLOCKSIZE < blocksize) ){
X                fprintf( stderr, "blocksize %d out of range\n", blocksize );
X                byee( -1 );
X            }
X            break;
X        default:
X            fprintf( stderr, "Usage: %s [-B] [-t] [-S size] [-m memsize] [-b blocks] [-p percent] [-s blocksize] [-u pause] [-i infile] [-o outfile] [-z size]\n",
X                progname );
X            fprintf( stderr, "-B = blocked device - pad out last block\n" );
X            fprintf( stderr, "-t = show total amount writen at end\n" );
X            fprintf( stderr, "-S size = show amount writen every size bytes\n" );
X            fprintf( stderr, "-m size = size of shared mem chunk to grab\n" );
X            fprintf( stderr, "-b num = number of blocks in queue\n" );
X            fprintf( stderr, "-p percent = don't start writing until percent blocks filled\n" );
X            fprintf( stderr, "-s size = size of a block\n" );
X            fprintf( stderr, "-u usecs = microseconds to sleep after each write\n" );
X            fprintf( stderr, "-i infile = file to read from\n" );
X            fprintf( stderr, "-o outfile = file to write to\n" );
X            fprintf( stderr, "-z size = combined -S/-s flag\n" );
X            byee( -1 );
X        }
X    }
X
X    if (zflag) showevery = blocksize;
X
X    /* If -b was not given try and work out the max buffer size */
X    if( !blocks_given ){
X        blocks = (max_shmem - sizeof( struct buffer )) / blocksize;
X        if( blocks <= 0 ){
X            fprintf( stderr, "Cannot handle blocks that big, aborting!\n" );
X            byee( -1 );
X        }
X        if( MAX_BLOCKS < blocks  ){
X            fprintf( stderr, "Cannot handle that many blocks, aborting!\n" );
X            byee( -1 );
X        }
X    }
X
X    /* check if fdin or fdout are character special files */
X    if( fstat( fdin, &buf ) != 0 ){
X        perror( "buffer: can't stat input file" );
X        byee( -1 );
X    }
X    in_ISCHR = S_ISCHR( buf.st_mode );
X    if( fstat( fdout, &buf ) != 0 ){
X        perror( "buffer: can't stat output file" );
X        byee( -1 );
X    }
X    out_ISCHR = S_ISCHR( buf.st_mode );
X}
X
X/* The interrupt handler */
Xshutdown()
X{
X    byee( -1 );
X}
X
Xset_handlers()
X{
X    signal( SIGHUP, shutdown );
X    signal( SIGINT, shutdown );
X    signal( SIGQUIT, shutdown );
X    signal( SIGTERM, shutdown );
X
X    if( writer_pid ){
X        /* This is the reader - propogate the signal to the writer */
X        kill( writer_pid, SIGTERM );
X    }
X}
X
Xbuffer_allocate()
X{
X    int i;
X
X    /* Allow for the data space */
X    buffer_size = sizeof( struct buffer ) +
X        ((blocks * blocksize) - sizeof( char ));
X
X    /* Create the space for the buffer */
X    buffer_id = shmget( IPC_PRIVATE,
X               buffer_size,
X               IPC_CREAT|S_IREAD|S_IWRITE );
X    if( buffer_id < 0 ){
X        perror( "buffer: couldn't create shared memory segment" );
X        byee( -1 );
X    }
X
X    get_buffer();
X
X    if( debug )
X        fprintf( stderr, "pbuffer is 0x%08x, buffer_size is %d [%d x %d]\n",
X            (char *)pbuffer, buffer_size, blocks, blocksize );
X
X#ifdef SYS5
X    memset( (char *)pbuffer, '\0', buffer_size );
X#else
X    bzero( (char *)pbuffer, buffer_size );
X#endif
X    pbuffer->blocks_used_lock = -1;
X    pbuffer->blocks_free_lock = -1;
X
X    pbuffer->blocks_used_lock = new_sem();
X    /* Start it off locked - it is unlocked when a buffer gets filled in */
X    lock( pbuffer->blocks_used_lock );
X
X    pbuffer->blocks_free_lock = new_sem();
X    /* start this off so lock() can be called on it for each block
X     * till all the blocks are used up */
X    sem_set( pbuffer->blocks_free_lock, blocks - 1 );
X
X    /* Detattach the shared memory so the fork doesnt do anything odd */
X    shmdt( (char *)pbuffer );
X    pbuffer = NO_BUFFER;
X}
X
Xbuffer_remove()
X{
X    static char removing = FALSE;
X    int i;
X
X    /* Avoid accidental recursion */
X    if( removing )
X        return;
X    removing = TRUE;
X
X    /* Buffer not yet created */
X    if( buffer_id == NONE )
X        return;
X
X    /* There should be a buffer so this must be after its detached it
X     * but before the fork picks it up */
X    if( pbuffer == NO_BUFFER )
X        get_buffer();
X
X    if( debug )
X        fprintf( stderr, "removing semaphores and buffer\n" );
X    remove_sem( pbuffer->blocks_used_lock );
X    remove_sem( pbuffer->blocks_free_lock );
X
X    if( shmctl( buffer_id, IPC_RMID, (struct shmid_ds *)0 ) == -1 )
X        perror( "buffer: failed to remove shared memory buffer" );
X}
X
Xget_buffer()
X{
X    int b;
X
X    /* Grab the buffer space */
X    pbuffer = (struct buffer *)shmat( buffer_id, (char *)0, 0 );
X    if( pbuffer == NO_BUFFER ){
X        perror( "buffer: failed to attach shared memory" );
X        byee( -1 );
X    }
X
X    /* Setup the data space pointers */
X    for( b = 0; b < blocks; b++ )
X        pbuffer->block[ b ].data =
X            &pbuffer->data_space[ b * blocksize ];
X
X}
X
Xvoid
Xstart_reader_and_writer()
X{
X    int status, deadpid;
X
X    fflush( stdout );
X    fflush( stderr );
X
X    if( (writer_pid = fork()) == -1 ){
X        perror( "buffer: unable to fork" );
X        byee( -1 );
X    }
X    else if( writer_pid == 0 ){
X        reader_pid = getppid();
X
X        /* Never trust fork() to propogate signals - reset them */
X        set_handlers();
X
X        writer();
X    }
X    else {
X        reader();
X
X        /* Now wait for the writer to finish */
X        while( ((deadpid = wait( &status )) != writer_pid) &&
X            deadpid != -1 )
X            ;
X    }
X}
X
X/* Read from stdin into the buffer */
Xreader()
X{
X    if( debug )
X        fprintf( stderr, "R: Entering reader\n" );
X
X    get_buffer();
X
X    while( 1 ){
X        get_next_free_block();
X        if( ! fill_block() )
X            break;
X    }
X
X    if( debug )
X        fprintf( stderr, "R: Exiting reader\n" );
X}
X
Xget_next_free_block()
X{
X    /* Maybe wait till there is room in the buffer */
X    lock( pbuffer->blocks_free_lock );
X
X    curr_block = &pbuffer->block[ pbuffer->next_block_in ];
X
X    pbuffer->next_block_in = INC( pbuffer->next_block_in );
X}
X
Xfill_block()
X{
X    int bytes;
X    char *start;
X    int toread;
X    static char eof_reached = 0;
X
X    if( eof_reached ){
X        curr_block->bytes = 0;
X        unlock( pbuffer->blocks_used_lock );
X        return 0;
X    }
X
X    start = curr_block->data;
X    toread = blocksize;
X
X    /* Fill the block with input.  This reblocks the input. */
X    while( toread != 0 && (bytes = read( fdin, start, toread )) > 0 ){
X        start += bytes;
X        toread -= bytes;
X    }
X
X    if( bytes == 0 ){
X        eof_reached = 1;
X    }
X
X    if( bytes < 0 ){
X        perror( "buffer: failed to read input" );
X        byee( -1 );
X    }
X
X    /* number of bytes available. Zero will be taken as eof */
X    if( !padblock || toread == blocksize )
X        curr_block->bytes = blocksize - toread;
X    else {
X        if( toread ) bzero( start, toread );
X        curr_block->bytes = blocksize;
X    }
X
X    if( debug > 1 )
X        fprintf( stderr, "R: got %d bytes\n", curr_block->bytes );
X
X    unlock( pbuffer->blocks_used_lock );
X
X    return curr_block->bytes;
X}
X
X/* Write the buffer to stdout */
Xwriter()
X{
X    int filled = 0;
X    int maxfilled = (blocks * percent) / 100;
X    int first_block;
X
X    if( debug )
X        fprintf( stderr, "\tW: Entering writer\n blocks = %d\n maxfilled = %d\n",
X            blocks,
X            maxfilled );
X
X    get_buffer();
X
X    while( 1 ){
X        if( !filled )
X            first_block = pbuffer->next_block_out;
X        get_next_filled_block();
X        if( !data_to_write() )
X            break;
X
X        filled++;
X        if( debug > 1 )
X            fprintf( stderr, "W: filled = %d\n", filled );
X        if( filled >= maxfilled ){
X            if( debug > 1 )
X                fprintf( stderr, "W: writing\n" );
X            write_blocks_to_stdout( filled, first_block );
X            filled = 0;
X        }
X    }
X
X    write_blocks_to_stdout( filled, first_block );
X
X    if( showevery ){
X        pr_out();
X    }
X
X    if( print_total ){
X        fprintf( stderr, "Kilobytes Out %lu\n", outk );
X    }
X
X    if( debug )
X        fprintf( stderr, "\tW: Exiting writer\n" );
X}
X
Xget_next_filled_block()
X{
X    /* Hang till some data is available */
X    lock( pbuffer->blocks_used_lock );
X
X    curr_block = &pbuffer->block[ pbuffer->next_block_out ];
X
X    pbuffer->next_block_out = INC( pbuffer->next_block_out );
X}
X
Xdata_to_write()
X{
X    return curr_block->bytes;
X}
X
Xwrite_blocks_to_stdout( filled, first_block )
X    int filled;
X    int first_block;
X{
X    pbuffer->next_block_out = first_block;
X
X    while( filled-- ){
X        curr_block = &pbuffer->block[ pbuffer->next_block_out ];
X        pbuffer->next_block_out = INC( pbuffer->next_block_out );
X        write_block_to_stdout();
X    }
X}
X
Xwrite_block_to_stdout()
X{
X    static unsigned long out = 0;
X    static unsigned long last_gb = 0;
X    static unsigned long next_k = 0;
X    int written;
X
X    if( next_k == 0 && showevery ){
X        if( debug > 3 )
X            fprintf( stderr, "next_k = %lu showevery = %lu\n", next_k, showevery );
X        showevery = showevery / 1024;
X        next_k = showevery;
X    }
X
X    if( (written = write( fdout, curr_block->data, curr_block->bytes )) != curr_block->bytes ){
X        perror( "buffer: write of data failed" );
X        fprintf( stderr, "bytes to write=%d, bytes written=%d, total written %10luK\n", curr_block->bytes, written, outk );
X        byee( -1 );
X    }
X
X    if( write_pause ){
X        usleep( write_pause );
X    }
X
X    out = curr_block->bytes / 1024;
X    outk += out;
X    last_gb += out;
X
X    /*
X     * on character special devices (tapes), do an lseek() every 1 Gb,
X     * to overcome the 2Gb limit. This resets the file offset to
X     * zero, but -- at least on exabyte SCSI drives -- does not perform
X     * any actual action on the tape.
X     */
X    if( Zflag && last_gb >= 1 K K ){
X        last_gb = 0;
X        if( in_ISCHR )
X            (void) lseek( fdin, 0, SEEK_SET);
X        if( out_ISCHR )
X            (void) lseek( fdout, 0, SEEK_SET);
X    }
X    if( showevery ){
X        if( debug > 3 )
X            fprintf( stderr, "outk = %lu, next_k = %lu\n",
X                outk, next_k );
X        if( outk >= next_k ){
X            pr_out();
X            next_k += showevery;
X        }
X    }
X
X    unlock( pbuffer->blocks_free_lock );
X}
X
X
Xvoid
Xbyee( exit_val )
X    int exit_val;
X{
X    /* Only the parent (reader) should zap the buffer */
X    if( writer_pid != 0 )
X        buffer_remove();
X    else if( showevery )
X        fprintf( stderr, "\n" );
X
X    exit( exit_val );
X}
X
X/* Given a string of <num>[<suff>] returns a num
X * suff =
X *   m/M for 1meg
X *   k/K for 1k
X *   b/B for 512
X */
Xdo_size( arg )
X    char *arg;
X{
X    char format[ 20 ];
X    int ret;
X
X    *format = '\0';
X    sscanf( arg, "%d%s", &ret, format );
X
X    switch( *format ){
X    case 'm':
X    case 'M':
X        ret = ret K K;
X        break;
X    case 'k':
X    case 'K':
X        ret = ret K;
X        break;
X    case 'b':
X    case 'B':
X        ret *= 512;
X        break;
X    }
X
X    return ret;
X}
X
Xpr_out()
X{
X    fprintf( stderr, "% 10luK\r", outk );
X}
X
X#ifdef SYS5
X#include <sys/time.h>
X
Xbzero( b, l )
X    char *b;
X    unsigned l;
X{
X    memset( b, '\0', l );
X}
X
Xusleep_back()
X{
X}
X
Xusleep( u )
X    unsigned u;
X{
X    struct itimerval old, t;
X    signal( SIGALRM, usleep_back );
X    t.it_interval.tv_sec = 0;
X    t.it_interval.tv_usec = 0;
X    t.it_value.tv_sec = u / 1000000;
X    t.it_value.tv_usec = u % 1000000;
X    setitimer( ITIMER_REAL, &t, &old );
X    pause();
X    setitimer( ITIMER_REAL, &old, NULL );
X}
X#endif
END_OF_FILE
if test 18127 -ne `wc -c <'buffer.c'`; then
    echo shar: \"'buffer.c'\" unpacked with wrong size!
fi
# end of 'buffer.c'
fi
if test -f 'sem.c' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'sem.c'\"
else
echo shar: Extracting \"'sem.c'\" \(2585 characters\)
sed "s/^X//" >'sem.c' <<'END_OF_FILE'
X/*
X    Buffer.  Very fast reblocking filter speedy writing of tapes.
X    Copyright (C) 1990,1991  Lee McLoughlin
X
X    This program is free software; you can redistribute it and/or modify
X    it under the terms of the GNU General Public License as published by
X    the Free Software Foundation; either version 1, or (at your option)
X    any later version.
X
X    This program is distributed in the hope that it will be useful,
X    but WITHOUT ANY WARRANTY; without even the implied warranty of
X    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
X    GNU General Public License for more details.
X
X    You should have received a copy of the GNU General Public License
X    along with this program; if not, write to the Free Software
X    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
X
X    Lee McLoughlin.
X    Dept of Computing, Imperial College,
X    180 Queens Gate, London, SW7 2BZ, UK.
X
X    Email: [e-mail]
X*/
X
X/* This is a simple module to provide an easier to understand interface to
X * semaphores */
X
X#include <stdio.h>
X#include <sys/types.h>
X#include <sys/stat.h>
X#include <sys/ipc.h>
X#include <sys/sem.h>
X
X#if defined(SYS5) || defined(ultrix) || defined(_AIX)
Xunion semun {
X    int val;
X    struct semid_ds *buf;
X    ushort *array;
X};
X#endif
X
X/* Set a semaphore to a particular value - meant to be used before
X * first lock/unlock */
Xvoid
Xsem_set( sem_id, val )
X    int sem_id;
X    int val;
X{
X    union semun arg;
X    extern int errno;
X
X    arg.val = val;
X
X    errno = 0;
X    semctl( sem_id, 0, SETVAL, arg );
X    if( errno != 0 ){
X        perror( "buffer: internal error, sem_set" );
X        exit( -1 );
X    }
X}
X
Xint
Xnew_sem()
X{
X    int sem;
X
X    sem = semget( IPC_PRIVATE, 1, IPC_CREAT|S_IREAD|S_IWRITE );
X    if( sem < 0 ){
X        perror( "buffer: internal error, couldn't create semaphore" );
X        exit( -1 );
X    }
X    sem_set( sem, 1 );
X
X    return sem;
X}
X
Xvoid
Xlock( sem_id )
X    int sem_id;
X{
X    struct sembuf sembuf;
X
X    sembuf.sem_num = 0;
X    sembuf.sem_op = -1;
X    sembuf.sem_flg = 0;
X
X    if( semop( sem_id, &sembuf, 1 ) == -1 ){
X        fprintf( stderr, "internal error, lock id %d\n", sem_id );
X        perror( "buffer: lock error" );
X        exit( -1 );
X    }
X}
X
Xvoid
Xunlock( sem_id )
X    int sem_id;
X{
X    struct sembuf sembuf;
X
X    sembuf.sem_num = 0;
X    sembuf.sem_op = 1;
X    sembuf.sem_flg = 0;
X
X    if( semop( sem_id, &sembuf, 1 ) == -1 ){
X        fprintf( stderr, "internal error, lock id %d\n", sem_id );
X        perror( "buffer: unlock error" );
X        exit( -1 );
X    }
X}
X
Xvoid
Xremove_sem( sem_id )
X    int sem_id;
X{
X    if( sem_id == -1 )
X        return;
X
X    if( semctl( sem_id, 0, IPC_RMID, NULL ) == -1 )
X        perror( "buffer: internal error, failed to remove semaphore" );
X}
END_OF_FILE
if test 2585 -ne `wc -c <'sem.c'`; then
    echo shar: \"'sem.c'\" unpacked with wrong size!
fi
# end of 'sem.c'
fi
if test -f 'COPYING' -a "${1}" != "-c" ; then
  echo shar: Will not clobber existing file \"'COPYING'\"
else
echo shar: Extracting \"'COPYING'\" \(17982 characters\)
sed "s/^X//" >'COPYING' <<'END_OF_FILE'
X            GNU GENERAL PUBLIC LICENSE
X               Version 2, June 1991
X
X Copyright (C) 1989, 1991 Free Software Foundation, Inc.
X                          675 Mass Ave, Cambridge, MA 02139, USA
X Everyone is permitted to copy and distribute verbatim copies
X of this license document, but changing it is not allowed.
X
X                Preamble
X
X  The licenses for most software are designed to take away your
Xfreedom to share and change it.  By contrast, the GNU General Public
XLicense is intended to guarantee your freedom to share and change free
Xsoftware--to make sure the software is free for all its users.  This
XGeneral Public License applies to most of the Free Software
XFoundation's software and to any other program whose authors commit to
Xusing it.  (Some other Free Software Foundation software is covered by
Xthe GNU Library General Public License instead.)  You can apply it to
Xyour programs, too.
X
X  When we speak of free software, we are referring to freedom, not
Xprice.  Our General Public Licenses are designed to make sure that you
Xhave the freedom to distribute copies of free software (and charge for
Xthis service if you wish), that you receive source code or can get it
Xif you want it, that you can change the software or use pieces of it
Xin new free programs; and that you know you can do these things.
X
X  To protect your rights, we need to make restrictions that forbid
Xanyone to deny you these rights or to ask you to surrender the rights.
XThese restrictions translate to certain responsibilities for you if you
Xdistribute copies of the software, or if you modify it.
X
X  For example, if you distribute copies of such a program, whether
Xgratis or for a fee, you must give the recipients all the rights that
Xyou have.  You must make sure that they, too, receive or can get the
Xsource code.  And you must show them these terms so they know their
Xrights.
X
X  We protect your rights with two steps: (1) copyright the software, and
X(2) offer you this license which gives you legal permission to copy,
Xdistribute and/or modify the software.
X
X  Also, for each author's protection and ours, we want to make certain
Xthat everyone understands that there is no warranty for this free
Xsoftware.  If the software is modified by someone else and passed on, we
Xwant its recipients to know that what they have is not the original, so
Xthat any problems introduced by others will not reflect on the original
Xauthors' reputations.
X
X  Finally, any free program is threatened constantly by software
Xpatents.  We wish to avoid the danger that redistributors of a free
Xprogram will individually obtain patent licenses, in effect making the
Xprogram proprietary.  To prevent this, we have made it clear that any
Xpatent must be licensed for everyone's free use or not licensed at all.
X
X  The precise terms and conditions for copying, distribution and
Xmodification follow.
X
X            GNU GENERAL PUBLIC LICENSE
X   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
X
X  0. This License applies to any program or other work which contains
Xa notice placed by the copyright holder saying it may be distributed
Xunder the terms of this General Public License.  The "Program", below,
Xrefers to any such program or work, and a "work based on the Program"
Xmeans either the Program or any derivative work under copyright law:
Xthat is to say, a work containing the Program or a portion of it,
Xeither verbatim or with modifications and/or translated into another
Xlanguage.  (Hereinafter, translation is included without limitation in
Xthe term "modification".)  Each licensee is addressed as "you".
X
XActivities other than copying, distribution and modification are not
Xcovered by this License; they are outside its scope.  The act of
Xrunning the Program is not restricted, and the output from the Program
Xis covered only if its contents constitute a work based on the
XProgram (independent of having been made by running the Program).
XWhether that is true depends on what the Program does.
X
X  1. You may copy and distribute verbatim copies of the Program's
Xsource code as you receive it, in any medium, provided that you
Xconspicuously and appropriately publish on each copy an appropriate
Xcopyright notice and disclaimer of warranty; keep intact all the
Xnotices that refer to this License and to the absence of any warranty;
Xand give any other recipients of the Program a copy of this License
Xalong with the Program.
X
XYou may charge a fee for the physical act of transferring a copy, and
Xyou may at your option offer warranty protection in exchange for a fee.
X
X  2. You may modify your copy or copies of the Program or any portion
Xof it, thus forming a work based on the Program, and copy and
Xdistribute such modifications or work under the terms of Section 1
Xabove, provided that you also meet all of these conditions:
X
X    a) You must cause the modified files to carry prominent notices
X    stating that you changed the files and the date of any change.
X
X    b) You must cause any work that you distribute or publish, that in
X    whole or in part contains or is derived from the Program or any
X    part thereof, to be licensed as a whole at no charge to all third
X    parties under the terms of this License.
X
X    c) If the modified program normally reads commands interactively
X    when run, you must cause it, when started running for such
X    interactive use in the most ordinary way, to print or display an
X    announcement including an appropriate copyright notice and a
X    notice that there is no warranty (or else, saying that you provide
X    a warranty) and that users may redistribute the program under
X    these conditions, and telling the user how to view a copy of this
X    License.  (Exception: if the Program itself is interactive but
X    does not normally print such an announcement, your work based on
X    the Program is not required to print an announcement.)
X
XThese requirements apply to the modified work as a whole.  If
Xidentifiable sections of that work are not derived from the Program,
Xand can be reasonably considered independent and separate works in
Xthemselves, then this License, and its terms, do not apply to those
Xsections when you distribute them as separate works.  But when you
Xdistribute the same sections as part of a whole which is a work based
Xon the Program, the distribution of the whole must be on the terms of
Xthis License, whose permissions for other licensees extend to the
Xentire whole, and thus to each and every part regardless of who wrote it.
X
XThus, it is not the intent of this section to claim rights or contest
Xyour rights to work written entirely by you; rather, the intent is to
Xexercise the right to control the distribution of derivative or
Xcollective works based on the Program.
X
XIn addition, mere aggregation of another work not based on the Program
Xwith the Program (or with a work based on the Program) on a volume of
Xa storage or distribution medium does not bring the other work under
Xthe scope of this License.
X
X  3. You may copy and distribute the Program (or a work based on it,
Xunder Section 2) in object code or executable form under the terms of
XSections 1 and 2 above provided that you also do one of the following:
X
X    a) Accompany it with the complete corresponding machine-readable
X    source code, which must be distributed under the terms of Sections
X    1 and 2 above on a medium customarily used for software interchange; or,
X
X    b) Accompany it with a written offer, valid for at least three
X    years, to give any third party, for a charge no more than your
X    cost of physically performing source distribution, a complete
X    machine-readable copy of the corresponding source code, to be
X    distributed under the terms of Sections 1 and 2 above on a medium
X    customarily used for software interchange; or,
X
X    c) Accompany it with the information you received as to the offer
X    to distribute corresponding source code.  (This alternative is
X    allowed only for noncommercial distribution and only if you
X    received the program in object code or executable form with such
X    an offer, in accord with Subsection b above.)
X
XThe source code for a work means the preferred form of the work for
Xmaking modifications to it.  For an executable work, complete source
Xcode means all the source code for all modules it contains, plus any
Xassociated interface definition files, plus the scripts used to
Xcontrol compilation and installation of the executable.  However, as a
Xspecial exception, the source code distributed need not include
Xanything that is normally distributed (in either source or binary
Xform) with the major components (compiler, kernel, and so on) of the
Xoperating system on which the executable runs, unless that component
Xitself accompanies the executable.
X
XIf distribution of executable or object code is made by offering
Xaccess to copy from a designated place, then offering equivalent
Xaccess to copy the source code from the same place counts as
Xdistribution of the source code, even though third parties are not
Xcompelled to copy the source along with the object code.
X
X  4. You may not copy, modify, sublicense, or distribute the Program
Xexcept as expressly provided under this License.  Any attempt
Xotherwise to copy, modify, sublicense or distribute the Program is
Xvoid, and will automatically terminate your rights under this License.
XHowever, parties who have received copies, or rights, from you under
Xthis License will not have their licenses terminated so long as such
Xparties remain in full compliance.
X
X  5. You are not required to accept this License, since you have not
Xsigned it.  However, nothing else grants you permission to modify or
Xdistribute the Program or its derivative works.  These actions are
Xprohibited by law if you do not accept this License.  Therefore, by
Xmodifying or distributing the Program (or any work based on the
XProgram), you indicate your acceptance of this License to do so, and
Xall its terms and conditions for copying, distributing or modifying
Xthe Program or works based on it.
X
X  6. Each time you redistribute the Program (or any work based on the
XProgram), the recipient automatically receives a license from the
Xoriginal licensor to copy, distribute or modify the Program subject to
Xthese terms and conditions.  You may not impose any further
Xrestrictions on the recipients' exercise of the rights granted herein.
XYou are not responsible for enforcing compliance by third parties to
Xthis License.
X
X  7. If, as a consequence of a court judgment or allegation of patent
Xinfringement or for any other reason (not limited to patent issues),
Xconditions are imposed on you (whether by court order, agreement or
Xotherwise) that contradict the conditions of this License, they do not
Xexcuse you from the conditions of this License.  If you cannot
Xdistribute so as to satisfy simultaneously your obligations under this
XLicense and any other pertinent obligations, then as a consequence you
Xmay not distribute the Program at all.  For example, if a patent
Xlicense would not permit royalty-free redistribution of the Program by
Xall those who receive copies directly or indirectly through you, then
Xthe only way you could satisfy both it and this License would be to
Xrefrain entirely from distribution of the Program.
X
XIf any portion of this section is held invalid or unenforceable under
Xany particular circumstance, the balance of the section is intended to
Xapply and the section as a whole is intended to apply in other
Xcircumstances.
X
XIt is not the purpose of this section to induce you to infringe any
Xpatents or other property right claims or to contest validity of any
Xsuch claims; this section has the sole purpose of protecting the
Xintegrity of the free software distribution system, which is
Ximplemented by public license practices.  Many people have made
Xgenerous contributions to the wide range of software distributed
Xthrough that system in reliance on consistent application of that
Xsystem; it is up to the author/donor to decide if he or she is willing
Xto distribute software through any other system and a licensee cannot
Ximpose that choice.
X
XThis section is intended to make thoroughly clear what is believed to
Xbe a consequence of the rest of this License.
X
X  8. If the distribution and/or use of the Program is restricted in
Xcertain countries either by patents or by copyrighted interfaces, the
Xoriginal copyright holder who places the Program under this License
Xmay add an explicit geographical distribution limitation excluding
Xthose countries, so that distribution is permitted only in or among
Xcountries not thus excluded.  In such case, this License incorporates
Xthe limitation as if written in the body of this License.
X
X  9. The Free Software Foundation may publish revised and/or new versions
Xof the General Public License from time to time.  Such new versions will
Xbe similar in spirit to the present version, but may differ in detail to
Xaddress new problems or concerns.
X
XEach version is given a distinguishing version number.  If the Program
Xspecifies a version number of this License which applies to it and "any
Xlater version", you have the option of following the terms and conditions
Xeither of that version or of any later version published by the Free
XSoftware Foundation.  If the Program does not specify a version number of
Xthis License, you may choose any version ever published by the Free Software
XFoundation.
X
X  10. If you wish to incorporate parts of the Program into other free
Xprograms whose distribution conditions are different, write to the author
Xto ask for permission.  For software which is copyrighted by the Free
XSoftware Foundation, write to the Free Software Foundation; we sometimes
Xmake exceptions for this.  Our decision will be guided by the two goals
Xof preserving the free status of all derivatives of our free software and
Xof promoting the sharing and reuse of software generally.
X
X                NO WARRANTY
X
X  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
XFOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
XOTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
XPROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
XOR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
XMERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
XTO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
XPROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
XREPAIR OR CORRECTION.
X
X  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
XWILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
XREDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
XINCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
XOUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
XTO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
XYOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
XPROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
XPOSSIBILITY OF SUCH DAMAGES.
X
X             END OF TERMS AND CONDITIONS
X
X    Appendix: How to Apply These Terms to Your New Programs
X
X  If you develop a new program, and you want it to be of the greatest
Xpossible use to the public, the best way to achieve this is to make it
Xfree software which everyone can redistribute and change under these terms.
X
X  To do so, attach the following notices to the program.  It is safest
Xto attach them to the start of each source file to most effectively
Xconvey the exclusion of warranty; and each file should have at least
Xthe "copyright" line and a pointer to where the full notice is found.
X
X    <one line to give the program's name and a brief idea of what it does.>
X    Copyright (C) 19yy  <name of author>
X
X    This program is free software; you can redistribute it and/or modify
X    it under the terms of the GNU General Public License as published by
X    the Free Software Foundation; either version 2 of the License, or
X    (at your option) any later version.
X
X    This program is distributed in the hope that it will be useful,
X    but WITHOUT ANY WARRANTY; without even the implied warranty of
X    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
X    GNU General Public License for more details.
X
X    You should have received a copy of the GNU General Public License
X    along with this program; if not, write to the Free Software
X    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
X
XAlso add information on how to contact you by electronic and paper mail.
X
XIf the program is interactive, make it output a short notice like this
Xwhen it starts in an interactive mode:
X
X    Gnomovision version 69, Copyright (C) 19yy name of author
X    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
X    This is free software, and you are welcome to redistribute it
X    under certain conditions; type `show c' for details.
X
XThe hypothetical commands `show w' and `show c' should show the appropriate
Xparts of the General Public License.  Of course, the commands you use may
Xbe called something other than `show w' and `show c'; they could even be
Xmouse-clicks or menu items--whatever suits your program.
X
XYou should also get your employer (if you work as a programmer) or your
Xschool, if any, to sign a "copyright disclaimer" for the program, if
Xnecessary.  Here is a sample; alter the names:
X
X  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
X  `Gnomovision' (which makes passes at compilers) written by James Hacker.
X
X  <signature of Ty Coon>, 1 April 1989
X  Ty Coon, President of Vice
X
XThis General Public License does not permit incorporating your program into
Xproprietary programs.  If your program is a subroutine library, you may
Xconsider it more useful to permit linking proprietary applications with the
Xlibrary.  If this is what you want to do, use the GNU Library General
XPublic License instead of this License.
END_OF_FILE
if test 17982 -ne `wc -c <'COPYING'`; then
    echo shar: \"'COPYING'\" unpacked with wrong size!
fi
# end of 'COPYING'
fi
echo shar: End of shell archive.
exit 0

--
--
Lee McLoughlin.                          Phone: [phone] X 5085
Dept of Computing, Imperial College,     Fax: [phone]
180 Queens Gate, London, SW7 2BZ, UK.    Email: [e-mail]

exit 0 # Just in case...