#!%PerlProg%
#
# 3-way merge:
#
# merge3 prod.cnf sf.old s.tape f.tape sf.new [sf.kill]
#
# prod.cnf - the config file to use
# sf.old - input - old entries
# s.tape - input - student entries
# f.tape - input - staff entries
# sf.new - output - merged entries
# sf.kill - output - killed entries (optional)
#
# Files should be sorted on their id fields, which should appear first in
# each record.
#
# The prod.cnf file is read for merge information.  The merge info is read
# from left to right; the first non-empty field is taken, unless the 'C'
# selector is present and the entry has a "no_update" field, in which case
# the old field is used even if empty.
#
# The selectors are:
#   A - Add only if not present in old data.  Incompatible with O.
#   O - Use old info.  Incompatible with A.
#   C - conditional; use old if no_update
#   S - student info
#   F - staff info
#
# The assumption is made that if an entry appears in only one file,
# the entry should be copied as is into either the new or (for old entries)
# kill file.
#
# Copyright (c) 1985 Corporation for Research and Educational Networking
# Copyright (c) 1988 University of Illinois Board of Trustees, Steven
#		Dorner, and Paul Pomes
# All rights reserved.
#
# 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.
# 3. All advertising materials mentioning features or use of this software
#    must display the following acknowledgement:
#	This product includes software developed by the Corporation for
#	Research and Educational Networking (CREN), the University of
#	Illinois at Urbana, and their contributors.
# 4. Neither the name of CREN, the University nor the names of their
#    contributors may be used to endorse or promote products derived from
#    this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE TRUSTEES AND CONTRIBUTORS ``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 TRUSTEES OR CONTRIBUTORS 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.
#
# @(#)$Id: merge3,v 1.3 1995/01/11 00:05:11 p-pomes Exp $


$, = ", ";

if ($#ARGV<4 || $#ARGV>5)
{
  print STDERR "Usage: merge3 config sf.old s.tape f.tape sf.new [sf.kill]\n"; 
  exit 1;
}

($config,$oldFile,$studentFile,$staffFile,$newFile,$killFile) = @ARGV;

#
# let's find out any bad news right away
#
open(CONFIG,"<$config") || die "$config: $!\n";
open(STUDENTFILE,"<$studentFile") || die "$studentFile: $!\n";
open(STAFFFILE,"<$staffFile") || die "$staffFile: $!\n";
open(OLDFILE,"<$oldFile") || die "$oldFile: $!\n";
open(NEWFILE,">$newFile") || die "$newFile: $!\n";
if ($killFile ne "") {open(KILLFILE,">$killFile") || die "$killFile: $!\n";}

select((select(NEWFILE),$|=1)[0]);
select((select(KILLFILE),$|=1)[0]);

#
# parse the config file
#
while (<CONFIG>)
{
  chop;
  if (substr($_,0,1) eq "#") {next;}
  if (length==0) {next;}
  split(/:/);
  if (@_ < 2) {next;}
  $fMerge{$_[0]} = $_[4];
  if ($_[1] eq "no_update") {$nup = $_[0];}
}
@fids = sort(keys(%fMerge));

#
# Hoo, boy, here we go...
#
$student = (split(/[\t\n]/,$studentString=<STUDENTFILE>,2))[0];
$staff = (split(/[\t\n]/,$staffString=<STAFFFILE>,2))[0];
$old = (split(/[\t\n]/,$oldString=<OLDFILE>,2))[0];
if ($staff ne "" && $student ne "")
{
  $curId = ($student lt $staff) ? $student : $staff;
}
else
{
  $curId = ($student ne "") ? $student : $staff;
}

#
# keep going until we exhaust the student and staff files
#
while ($student ne "" || $staff ne "")
{
  #
  # toss out old entries until we come up to the one we're looking for
  #
  while ($old ne "" && $old lt $curId)
  {
    if ($killFile ne "") {print KILLFILE $oldString;}
    $old = (split(/[\t\n]/,$oldString=<OLDFILE>,2))[0];
  }
  
  #
  # copy entries until we come to the one we're looking for
  #
  while ($student ne "" && $student lt $curId)
  {
    print NEWFILE $studentString;
    $student = (split(/[\t\n]/,$studentString=<STUDENTFILE>,2))[0];
  }

  while ($staff ne "" && $staff lt $curId)
  {
    print NEWFILE $staffString;
    $staff = (split(/[\t\n]/,$staffString=<STAFFFILE>,2))[0];
  }
  
  #
  # copy into temp space
  #
  %oldFields = ($old ne $curId) ? () : &SplitFields($oldString);
  %studentFields = ($student ne $curId) ? () : &SplitFields($studentString);
  %staffFields = ($staff ne $curId) ? () : &SplitFields($staffString);
  
  #
  # now, go through all the fields
  #
  $resString = "";
  foreach $f (@fids)
  {
    if ($f eq "5") {next;}	# don't output id twice
    if ($f eq "42") {next;}	# if found on tape, don't output left field
    @selectors = split(//,$fMerge{$f});
    foreach (@selectors)
    {
      if (/C/ && $oldFields{$nup} ne "")
      {
        if ($oldFields{$f} ne "")
	{
	  $resString .= sprintf("\t%s:%s",$f,$oldFields{$f});
	}
	last;
      }
      elsif (/S/ && $student eq $curId)
      {
	if ($studentFields{$f})
	{
	  $resString .= sprintf("\t%s:%s",$f,$studentFields{$f});
	}
	last;
      }
      elsif (/F/ && $staff eq $curId)
      {
	if ($staffFields{$f})
	{
	  $resString .= sprintf("\t%s:%s",$f,$staffFields{$f});
	}
	last;
      }
      elsif (/O/ && $old eq $curId)
      {
	if ($oldFields{$f})
	{
	  $resString .= sprintf("\t%s:%s",$f,$oldFields{$f});
	}
	last;
      }
    }
  }
  if ($resString ne "") {print NEWFILE "$curId$resString\n";}
  
  #
  # time for the next ones...
  #
  if ($old eq $curId)
    {$old = (split(/[\t\n]/,$oldString=<OLDFILE>,2))[0];}
  if ($staff eq $curId)
    {$staff = (split(/[\t\n]/,$staffString=<STAFFFILE>,2))[0];}
  if ($student eq $curId)
    {$student = (split(/[\t\n]/,$studentString=<STUDENTFILE>,2))[0];}
  
  #
  # compute new "lowest of the low"
  if ($staff ne "" && $student ne "")
  {
    $curId = ($student lt $staff) ? $student : $staff;
  }
  else
  {
    $curId = ($student ne "") ? $student : $staff;
  }
}

#
# copy the rest of the old file
if ($oldString ne "" && $killFile ne "")
{
  print KILLFILE $oldString;
  while (<OLDFILE>) {print KILLFILE $_;}
}

sub SplitFields
{
  $_ = $_[0];
  if ($_ ne "")
  {
    chop;
    s/	([0-9]+):/	$1	/g;
    s/:/	/;
    %flds = split("\t");
  }
  else
  {
    ();
  }
}