#!/usr/bin/perl

#======================================================================

#                    A N T S I O . P L 

#                    doc: Fri Jun 19 19:22:51 1998

#                    dlm: Tue Nov 30 12:28:03 2021

#                    (c) 1998 A.M. Thurnherr

#                    uE-Info: 220 50 NIL 0 0 70 10 2 4 NIL ofnI

#======================================================================

# HISTORY:

#	Jun 19, 1998: - created

#	Dec 29, 1998: - added antsLineFlag and antsLinePrefix

#	Dec 30, 1998: - added -P)assthrough option handling, arg to &antsFlush()

#	Jan 02, 1999: - changed -P to -T and added -P)refix for [./fnr]

#	Feb 17, 1999: - added &antsReadFile()

#	Feb 25, 1999: - added &antsInfo()

#	Mar 11, 1999: - set undefined ret-vals of &antsBufOut() to NaN

#	Mar 12, 1999: - added FILE to &antsPrintHeaders()

#	Mar 14, 1999: - BUG ensured that $ants_[0] was defined when

#				    typical &antsBufFull was called on empty buffer

#				  - added &antsPostFlush()

#				  - added &antsSetR_()

#				  - BUG padding by &antsSet_() was broken

#	Mar 20, 1999: - added code to abort if file on cmdline does not exist

#				  - removed &antsReadFile()

#	Oct 31, 1999: - BUG when using -I

#	Dec 06, 1999: - made &antsInfo() respect -Q

#	Mar 07, 2000: - adapted to -M

#	Jul 31, 2000: - removed buffer auto growth unless $antsPadOut

#	Aug 21, 2000: - allow for in-line comments on -T

#	Aug 28, 2000: - added opt_Z to remove leading zeroes on output

#				  - added %P handling

#	Sep 03, 2000: - documentation

#	Sep 04, 2000: - ensure %PARAMS are not just whitespace strings

#	Oct 31, 2000: - added &antsReplaceParam()

#	Nov 07, 2000: - added &antsFileScanParam()

#	Nov 10, 2000: - made to ignore DOS EOF (BLOERKS!!!)

#	Nov 16, 2000: - added comment about antsIO() bypassing &antsBufOut()

#	Nov 17, 2000: - made -P override header PARAMs

#	Jan 16, 2001: - cosmetics

#	Feb 19, 2001: - added $antsNoHeaderCopy for [data]

#	Mar  8, 2001: - adapted to -G)range

#	Mar 18, 2001: - BUG: -G had selected NaNs

#	Mar 22, 2001: - added $antsNoEmbeddedHeaderCopy for [fields] [efields]

#	Mar 28, 2001: - mark header info of utils used in pipelines

#	Mar 31, 2001: - updated -G)range

#				  - adapted to -F)ields

#	Apr  3, 2001: - added appendfields

# 	Apr  5, 2001: - removed string interpolation from &antsOut()

#				  - added prependfields

#	May 15, 2001: - output NaN on undefined -F vals

#	Jun  4, 2001: - allowd %PARAMs on -F

#	Jun 19, 2001: - added pseudo param %FILE

#	Jul  9, 2001: - added Active ANTS stuff

#	Jul 10, 2001: - continued, split off &antsParseHeader()

#	Jul 11, 2001: - continued

#	Jul 13, 2001: - replace -F fields names on 1st use

#	Jul 16, 2001: - moved fchmod call to &antsPrintHeaders(), c.f. [Split]

#	Jul 19, 2001: - embedded error messages in pipeline

#				  - copy header on -ve -H

#	Jul 24, 2001: - BUG: set $antsNewLayout on -F

#				  - BUG: remove % from -F layout

#				  - moved fnr lookup for -G from [antsusage.pl]

#	Aug  1, 2001: - BUG: &antsIn() had not restored @ARGV on EOF

#	Aug  3, 2001: - added &antsFileScanLayout()

#	Aug  9, 2001: - BUG: $antsNewLayout was not set on prepend/append fields

#	Aug 10, 2001: - added $opt_G to &antsFileIn()

#	Aug 19, 2001: - BUG: &antsReplaceParam() re-written

#	Aug 29, 2001: - BUG: made -r into -f && -r

#	Oct 28, 2001: - BUG: handled antsLinePrefix on parseHeader

#	Nov 22, 2001: - added $antsParseHeader flag

#	Nov 28, 2001: - allowed %param in -G

#	Dec 30, 2001: - added &antsExit()

#	May 18, 2002: - added %BASENAME, %EXTN

#	May 20, 2002: - added $antsNewFile

#	Jun 22, 2002: - added $antsPadIn

#	Jan  6, 2003: - added $antsGrex (-G regex support)

#	Jan  8, 2003: - added &antsFileParams()

#	Mar  4, 2003: - added %RECNO

#	Apr 14, 2003: - BUG: antsReplaceParam() removed because in-stream

#						 %PARAMs are not generally handled correctly

#				  - BUG: antsFileScanParam() had returned the first

#						 value encountered, NOT the valid (last) one!!!

#	Apr 24, 2003: - BUG: added default $antsPadIn = 1 (required for

#						 [gamma_n])

#	May  8, 2003: - made antsFileIn() respect -N (for [gshear])

#	Jul  1, 2004: - BUG: $antsBufNFields was not set when an empty file

#						 with valid #ANTS#FIELDS# was read

#	Jul  9, 2004: - BUG: test of incompatible in-file field definitions

#						 did not work

#	Dec  5, 2004: - BUG: Jul 1 fix did not work correctly in cases where

#						 subsequent #ANTS#FIELDS# lines would shrink the

#						 number of fields; new fix was not debugged!

#	Jan 17, 2005: - removed path from active files and used perl -S

#	Feb  8, 2005: - made activation-status copy more portable (i.e.

#					independent of perl path)

#	Mar  7, 2005: - added %DIRNAME (& cleaned up %BASENAME %EXTN)

#	Nov  8, 2005: - changed -T to -P, -Z => -T, added -Z

#	Nov 17, 2005: - BUG: antsPreFlush() flushed one too few ([fmedian])

#				  - BUG: antsFlagged was not set correctly any more

#	Nov 18, 2005: - finally allowed %PARAMs bounds in -G

#	Nov 21, 2005: - BUG: %PARAM bounds in -G had broken regexp capability

#	Dec  7, 2005: - BUG: embedded layout overrode @antsFName if $antsNewLayout

#				  - replaced @antsFName by @antsLayout{In,Out}

#	Dec  8, 2005: - Version 3.2 (see [HISTORY])

#	Dec 12, 2005: - disable output padding in &antsOut() if new layout

#	Dec 14, 2005: - made &antsAddParams() set %P

#				  - removed &antsReplaceParam()

#	Dec 20, 2005: - BUG: empty field names in Layout replaced by undef

#				  - $# is buggy => implemented opt_M without $#

#	Dec 23, 2005: - replaced defined(@array) (c.f. perlfunc(1))

#                 - BUG: -F did not work ok when @antsNewLayout was set

#   Dec 29, 2005: - added $PARAMSonly to avoid output duplication on -F%param

#   Dec 30, 2005: - changed &antsFileIn() EOF return

#   Jan  3, 2006: - BUG: pseudo %PARAMs (e.g. BASENAME) were not set

#                        on EOF when buffer is not full

#                 - changed %FILE to %FILENAME

#                 - added support for -S)elect

#   Jan  4, 2006: - BUG: empty strings were not output as NaN

#   Jan  9, 2006: - removed line flagging code

#   Jan 12, 2006: - replaced old -H)eader skip support with new -H)ead

#   Jan 13, 2006: - new [antsexprs.pl]

#                 - removed -G handling (now done as -S)

#                 - renamed -T)rim to -C)anonical

#                 - removed -Z)ap handling

#   Jan 14, 2006: - continued removing -G

#   Jan 31, 2006: - BUG: selecting last field per record with -I produced

#                        an extraneous empty line

#   May 18, 2006: - BUG: set pseudo-params before -S test, to allow e.g.

#                        -S %RECNO==3 to work

#                 - BUG: set %RECNO on partially full buffer

#                 - added %LINENO pseudo param

#   Jun 27, 2006: - BUG: added formal param @ to allow antsOut(NaN) to be

#                        used in list -w

#				  - changed semantics of antsPadOut()

#   Jul  1, 2006: - Version 3.3 [HISTORY]

#	Jul 10, 2006: - removed fchmod (now in perl chmod)

#	Jul 21, 2006: - removed obsolete code

#	Jul 22, 2006: - shuffled &antsOut() to allow for -H0

#	Jul 23, 2006: - BUG: -F%PARAM did not work any more

#	Jul 28, 2006: - BUG: pseudo-params were set during header parsing of

#						 an empty file

#	Jul 31, 2006: - BUG: @antsLayout was not set on 0-record files

#				  - code cleanup

#	Aug 24, 2006: - added $antsIgnoreInputParams

#	Aug 28, 2006: - made antsIgnoreInputParams into eva'ed expr for [bindata]

#	Oct 26, 2006: - allowed for empty lines in &antsFileScanParams()

#	Nov 10, 2006: - suppressed copying of layout even if embedded headers

#					are copied

#	Dec 17, 2007: - modified behavior of antsIgnoreInputParams (see NOTES below)

#	Jan 16, 2007: - re-implemented changes to -P mandated by Dec 14, 2006

#				    changes to [antsusage.pl]

#	May 31, 2007: - added support for -G)eographic coord format

#	Nov 14, 2007: - maded -G work with %PARAMS

#				  - BUG: %FILENAME (& others) not set on %PARAMS-only files

#	Nov 15, 2007: - BUG: -G had never worked correctly when selecting fields

#	Feb  8, 2008: - moved number output formatting to fmtNum() [antsutils.pl]

#	Mar 26, 2008: - modified/extended -F behavior

#	Mar 28, 2008: - fiddled

#	Apr 15, 2008: - BUG: pseudo params were not set during header parsing

#						 => e.g. %RECNO could not be used in ded addr-expr

#	May  1, 2008: - BUG: embedded header copy also copied embedded layout

#						 re-definitions

#	May 22, 2008: - BUG: $antsPadOut = 0 did not suppress padding as intended

#						 in presence of layout or new layout => add option of

#						 setting it to -1

#	Jul 11, 2008: - BUG: file-name-related pseudo %PARAMs did not work

#						 correctly for input files without extensions

#				  - added %FILENAME -> %PATHNAME

#	Jul 21, 2008: - fiddled with antsInfo()

#	Jul 23, 2008: - added code to allow deleting %PARAMs by setting them

#					to undef in [list]

#	Jul 29, 2008: - BUG: removed code to strip leading/trailing spaces from

#						 %PARAMs (before, a %PARAM containing just spaces

#						 was deleted on an NCode/listNC combo --- there is

#						 an example in [ubtest/NCode.TF]

#	Jun 10, 2009: - added duplicate-output-field sanity check

#	Aug  1, 2009: - BUG: duplicate unnamed output files generated error

#	Aug 23, 2009: - V4.0: added &antsAddDeps

#	Aug 25, 2009: - BUG: '-' was added as a dep for STDIN

#	Aug 27, 2009: - added pseudo %PARAM %DEPS

#	Oct  3, 2009: - added $antsAllowEmbeddedLayoutChange

#	Oct 12, 2009: - changed antsAddDeps() to ignore empty dependencies

#	Oct 13, 2009: - removed antsAddDeps() defaults

#	Oct 15, 2009: - replaced \n by \\n in antsAddParams(); primarily for listNC

#	Nov  3, 2009: - BUG: <> dependencies were not set when $antsParseHeader was set to 0

#	Nov  6, 2009: - BUG: stdin had sometimes produced empty dep

#	Aug 15, 2010: - turned error on duplicate output fields into warning

#	Aug 28, 2010: - moved dependency checks from [list] to here

#	Oct 18, 2010: - disabled dependency checks for files in other directories

#	Oct 19, 2010: - implemented &antsOut('EOF') to clear all static vars & other stuff to

#				    allow a single utility to output different ANTS files (used in

#				    LADCPproc)

#	Apr 28, 2011: - added code to make all nans lowercase to antsIn()

#	May 20, 2011: - BUG: %LINENO had not been reset between files any more

#	May 22, 2011: - adapted to new antsCompileEditExpr()

#	May 24: 2011: - BUG: forgot '$' in a variable (where???)

#	Jul 28, 2011: - disabled adding of new deps on -D

#	Apr 11, 2012: - improved layout-change error message

#	Apr 26, 2012: - BUG: antsFileScanParam() was not properly anchored (%start_date matched %BT.start_date)

#	Jul 20, 2014: - adapted antsFileScanParam() to :: convention

#	Jul 22, 2014: - BUG: antsPadIn was done after handling -S & -N

#				  - removed antsPadIn flag (made it always be true)

#	Aug  7, 2014: - allow optional % in param name in &antsFileScanParam()

#	Oct 29, 2014: - implemented abbreviated Layout and %PARAM definitions

#	Sep 27, 2015: - BUG: antsDeps() accumulate with multiple input files; solution is to make sure that

#						 antsCheckDeps() is called whenever a new input file has been read for the first

#						 time (as in [list]), because antsCheckDeps() deletes the dependencies after

#						 checking

#	Jan 15, 2016: - BUG: antsCheckDeps() cannot delete the dependencies after checking because,

#						 otherwise, dependencies are not inherited => presumably, Sep 27 bug fix has been

#						 reversed

#	Sep 13, 2016: - modified &antsAddParams to make more flexible

#	Mar 10, 2017: - BUG: antsCheckDeps() used ctime instead of mtime!!!

#	Apr  5, 2017: - BUG: stale file mtime dependency info was not printed correctly

#	Apr 23, 2018: - BUG: @antsLayout was not kept up-to-date when layout-changes are allowed

#	Apr 10, 2019: - disabled dependency warnings

#	Oct 14, 2021: - changed nan to NaN, to make gnuplot work nicely again

#	Nov 30, 2021: - finally made -F not croak on division-by-zero, etc.

#				  - BUG: some NaNs were still nans

# HISTORY END

# GENERAL NOTES:

#	- %P was named without an ants-prefix because associative arrays

#	  are rare (and perl supports multiple name spaces for the

#	  different variable types) and to facilitate its use in

#	  [list]

#	- copying of embedded (i.e. not appearing at start) headers is

#	  required e.g. for subsample -i ... | list %some-param

# ABBREVIATED LAYOUT & PARAM DEFINITIONS

#	- # definition [definition [...]]

#	- definition := field_name | %PARAM_def

#	- field_name := {string}

#	- %PARAM_def := string{string|num}

#	- implemented in October 2014 in order to make ANTS format easier to use for others

#	- abbreviated and full headers must not be used together

#	- abbreviated field definitions are additive (rather than replacing, as in the full headers)

# $antsIngoreInputParams:

#	- is eval'ed first time antsIn() is called (usually while parsing header)

#	- if it evaluates to TRUE, all input %PARAMS are ignored (even if it would

#	  later eval to FALSE)

#	- during header parsing, @ARGV only contains additional file arguments,

#	  i.e. setting $antsIgnoreInputParams = '@ARGV>0' before antsUsage() is

#	  called ignores all input %PARAMs if there is more than 1 file argument

#======================================================================

# Default Behaviour 

#======================================================================

# Flags

$antsFixedFormat = 0;						# remove leading & trailing stuff

$antsParseHeader = 1;						# parse header on &antsUsage()

$antsIgnoreInputParams = 0;					# ignore %PARAMs

$antsAllowEmbeddedLayoutChange = 0;			# disallow layount changes

# Standard Fixed Size Buffer

sub antsBufFull()							# default buffer full

    {return $#ants_+1 == $antsBufSize;}   

sub antsBufOut($)                           # default constructor

    {return $ants_[$ants_][$_[0]]; }

# Setup Size 1 Buffer

$antsBufSize = 1;							# default

$antsBufSkip = 1;

#======================================================================

# Interface

#======================================================================

sub antsInstallBufFull($)

{

	eval "sub antsBufFull() { $_[0] }";

	croak($@) if ($@);

	&antsReCompile();

}

sub antsInstallBufOut($)

{

	eval "sub antsBufOut(\$) { my(\$fnr)=\@_; $_[0] }";

	croak($@) if ($@);

	&antsReCompile();

}

sub antsActivateOut()

{

	$antsActiveHeader = "#!/usr/bin/perl -S list\n" unless ($opt_Q);

}

#----------------------------------------------------------------------

# antsCheckDeps([filename]):

#	- call only after header has been parsed

#	- by default, tests current <> file

#----------------------------------------------------------------------

{ my($warned) = 1;									# disable dependency warning

  sub antsCheckDeps()

  {

#	  print(STDERR "checking dependencies of file $infile (deps = @antsDeps)\n");

	  return unless (@antsDeps);					# no dependency info

	  return if ($opt_D);							# suppressed by user

	  my($infile) = @_ ? $_[0] : $ARGV; 			# default: check current input

	  my($indir) = ($infile =~ m{^(.*)/[^/]*$});

	  return if defined($indir) && $indir ne '.';	# not in current directory

	  my(@stat) = stat($infile);					# get time

	  return unless (@stat);						# happens on stdin?

	  my($mtimef) = 9; my($mtime) = $stat[$mtimef];

	  for (my($d)=0; $d<=$#antsDeps; $d++) {

		  @stat = stat($antsDeps[$d]);

		  if (@stat) {

			  croak("$0: <$infile> ($mtime) is stale with respect to <$antsDeps[$d]> ($stat[$mtimef])\n")

				  unless ($stat[$mtimef] <= $mtime);

		  } elsif (!$warned) {

			  &antsInfo("WARNING: dependency $antsDeps[$d] (&, possibly, others) not found");

			  $warned = 1;

		  }

	  }

#	  undef(@antsDeps);								# don't check again; BUG: 01/15/2016

  }

} # static scope

sub antsParseHeader()

{

	return if ($antsFixedFormat || !$antsParseHeader);

	$antsDoParseHeader = 1;						# glorks!

	my($success) = &antsIn();

	&antsCheckDeps();

	return $success;

}

#----------------------------------------------------------------------

sub def_abbrev($)

{

	my($def) = @_;

	if ($def =~ /^\{(\w+)\}$/) {

		push(@Layout,$1);

	} else {

		my($name,$val) = ($def =~ /(\w+)\{([^\}]+)\}/);

		$P{$name} = $val;

	}

}

sub antsReCompile()								# re-compile with funs

{ eval '

sub antsIn()

{

	local(@Layout);

	undef(@Layout);								# needed, but unclear why

	undef($antsNewFile);						# assume no new file

	unless ($antsHeaderParsed || $antsDoParseHeader) {

		for (my($i)=0; $i<=$#ARGV; $i++) {		# check file params

			open($ARGV[$i]),croak("$0: $ARGV[$i]: $!\n")

				unless (-f $ARGV[$i] && -r $ARGV[$i]);

	    }

		&antsAddDeps($ARGV,@ARGV);				# <> files

		$antsCurHeader =~ s/\]/\] |/			# mark as pipeline

			unless (-t 0);

	    $antsHeaderParsed = 1;

	}

	my(@tempARGV);								# temporily remove non-file args

	if ($antsDoParseHeader) {

		my($ai) = $#ARGV;

		while ($ai >= 0 && -f $ARGV[$ai]) { $ai-- }

#		print(STDERR "before: @ARGV\n");

		push(@tempARGV,splice(@ARGV,0,$ai+1));

#		print(STDERR "after: @ARGV\n");

		if ($#ARGV < 0 && -t 0) {					# donot wait on stdin

			push(@ARGV,@tempARGV);

			$antsDoParseHeader=0;

			return 0;

		}

	}

	splice(@ants_,0,$antsBufSkip);					# shift buffers

	IN: until ($#ants_>=0 && &antsBufFull()) {		# fill buffer; NEEDS RECOMPILE

		if (defined($antsPeekBuffer)) {				# from header parsing

			$_ = $antsPeekBuffer;

			$antsPeekBuffer = undef;

		} else {

			unless ($_ = <>) {						# get next record

				# EOF before buffer is full (can be partially filled)

				unshift(@ARGV,@tempARGV);			# restore ARGV list

				@antsLayout = @Layout if (@Layout);	# set last defined layout

				$antsBufNFields = @antsLayout		# adjust buffer width

					if (@antsLayout > $antsBufNFields);

				my($lastFile) = $P{PATHNAME};

				$P{PATHNAME} = $ARGV;				# set pseudo %PARAMs

				($P{DIRNAME},$P{FILENAME}) =

					($ARGV =~ m{^(.*)/([^/]+)$});

				unless (defined($P{DIRNAME})) {

					$P{DIRNAME} = ".";

					$P{FILENAME} = $P{PATHNAME};

				}

				($P{BASENAME},$P{EXTN}) =

					($P{FILENAME} =~ m{^([^\.]+)\.(.+)$});

				unless (defined($P{EXTN})) {

					$P{BASENAME} = $P{FILENAME};

					$P{EXTN} = "";

				}

				$P{DEPS} = "@antsDeps";

				return 0 if ($antsDoParseHeader);	# empty file!!!

				$P{RECNO} = -1						# set pseudo %PARAMs

					unless defined($P{RECNO});

	    		$P{RECNO}++;

			    $P{LINENO} = ($ARGV eq $lastFile) ? $P{LINENO}+1 : 0;

				return 0;							# return EOF

			}

		}

		next IN if (length == 1 && ord == 26);		# handle MS-DOG EOF

		&antsActivateOut(),next IN					# copy activation status

			if (m{^#![^\s]*/perl\s.*list$});

		exit(1) if (/^#ANTS#ERROR#/);				# error in pipeline

		if (/^#ANTS#PARAMS# ([^\{]+)\{([^\}]*)\}/) {

			if (eval($antsIgnoreInputParams)) {		# eval only 1st time

				$antsIgnoreInputParams = 1;

				next IN;

			}

			do {

				if ($2 eq "") {

					delete($P{$1});

				} else {

					$P{$1} = $2;

				}

			} while ($\' =~ m/ ([^\{]+)\{([^\}]*)\}/);

		} elsif (/^#ANTS#DEPS# \{([^\}]*)\}/) {		# handle dependencies

			do { push(@antsDeps,$1); }

				while ($\' =~ m/ \{([^\}]*)\}/);

		} elsif (/^#ANTS# \[[^\]]*\] [^|]/) {		# pipe-head => restart dependencies

			undef(@antsDeps);

		} elsif (/^#ANTS#FIELDS# \{([^\}]*)\}/) {	# handle layout

			undef(@Layout);

			do {

				push(@Layout,$1 eq "" ? undef : $1);

			} while ($\' =~ m/ \{([^\}]*)\}/);

		} elsif (/^# (\{\w+\}|\w+\{[^\}]+\})+/) {		# ABBREVIATED DEFINITIONS

			my($match) = $1; my($rem) = $\';

			do {

				def_abbrev($match);

				($match,$rem) = ($rem =~ /(\{\w+\}|\w+\{[^\}]+\})(.*)/);

			} while ($match);

		}

		if (!($opt_Q || $antsNoHeaderCopy) && /^#ANTS#/) {	# handle headers

			if (defined($antsHeadersPrinted)) {		# embedded headers

# The following is somewhat subtle because it must prevent embedded

# layout definitions to be copied 1) even if embedded headers are requested

# (because otherwise there will be embedded-layout-change errors) 2) but not

# if there has not been a layout defined already (ubtest common_opts);

				print unless ($antsNoEmbeddedHeaderCopy ||

								(/^#ANTS#FIELDS#/ && @antsLayout));

			} else {

				$antsOldHeaders .= $_;

			}

			next IN;

		}

		if (/^#/) {								# handle non-header comments

			&antsPrintHeaders(STDOUT,@antsNewLayout),print if ($opt_P);

			next IN;

		}

		next IN if /^\s*$/;						# skip empty lines

		unless ($antsFixedFormat) {

			s/^\s+//;							# strip leading space

			s/#.*$// unless ($opt_P);			# strip trailing comments

			s/\s+$//;							# strip trailing space

		}

		# DONE WITH HEADER PARSING

		# Handle Layout changes:

		#	- only allow when $antsAllowEmbeddedLayoutChange is set

		#	- ensure that antsLayout always contains up-to-date Layout

		if (!$antsAllowEmbeddedLayoutChange && @Layout && @antsLayout && ("@Layout" ne "@antsLayout")) {

			my(@OL) = @antsLayout;

			my(@NL) = @Layout;

			while ($OL[0] eq $NL[0]) {

				shift(@OL); shift(@NL);

			}

			croak("$0: embedded layout change when reading file $ARGV <@OL[0..3] ...> -> <@NL[0..3] ...>")

		}

		@antsLayout = @Layout if (@Layout);

		$P{RECNO} = -1 unless defined($P{RECNO});	# set pseudo %PARAMs

		$P{LINENO} = -1 unless defined($P{LINENO});

		$P{DEPS} = "@antsDeps";

		my($lastFile) = $P{PATHNAME};

		$P{PATHNAME} = $ARGV;		    

		($P{DIRNAME},$P{FILENAME}) =

			($ARGV =~ m{^(.*)/([^/]+)$});

		unless (defined($P{DIRNAME})) {

			$P{DIRNAME} = ".";

			$P{FILENAME} = $P{PATHNAME};

		}

		($P{BASENAME},$P{EXTN}) =

			($P{FILENAME} =~ m{^([^\.]+)\.(.+)$});