package ExtUtils::F77;

use Config;

=head1 NAME

ExtUtils::F77 - Simple interface to F77 libs

=head1 DESCRIPTION

This module tries to figure out how to link C programs with
Fortran subroutines on your system. Basically one must add a list
of Fortran runtime libraries. The problem is their location
and name varies with each OS/compiler combination!

This module tries to implement a simple  
'rule-of-thumb' database for various flavours of UNIX systems.
A simple self-documenting Perl database of knowledge/code
for figuring out how to link for various combinations of OS and
compiler is embedded in the modules Perl code. Please help 
save the world by sending database entries for
your system to kgb@aaoepp.aao.gov.au

The library list which the module returns 
can be explicitly overridden by setting the environment 
variable F77LIBS, e.g.

  % setenv F77LIBS "-lfoo -lbar"
  % perl Makefile.PL
  ...

=cut

$VERSION = "1.13";

# Database starts here. Basically we have a large hash specifying
# entries for each os/compiler combination. Entries can be code refs
# in which case they are executed and the returned value used. This
# allows us to be quite smart.

# Hash key convention is uppercase first letter of
# hash keys. First key is usually the name of the architecture as
# returned by Config (modulo ucfirst()).

%F77config=();

### SunOS (use this as a template for new entries) ###

# Code to figure out and return link-string for this architecture
# Returns false if it can't find anything sensible.

$F77config{Sunos}{F77}{Link} = sub {  
       $dir = find_highest_SC("/usr/lang/SC*");
       return "" unless $dir; # Failure
       print "$Pkg: Found Fortran latest version lib dir $dir\n";
       return "-L$dir -lF77 -lm";
};

# Whether symbols (subroutine names etc.) have trailing underscores 
# (true/false)

$F77config{Sunos}{F77}{Trail_} = 1; 

# Name of default compiler - corresponds to one of the above keys

$F77config{Sunos}{DEFAULT} = 'F77'; 

# Program to run to actually compile stuff

$F77config{Sunos}{F77}{Compiler} = 'f77';

# Associated compiler flags

$F77config{Sunos}{F77}{Cflags} = '-O';

############ Rest of database is here ############ 

### Solaris ###

$F77config{Solaris}{F77}{Link} = sub {
    my $NSPATH = "";
    $NSPATH = $ENV{'LD_LIBRARY_PATH'} if defined $ENV{'LD_LIBRARY_PATH'};
#find the SUNWspro entry of nonstandard inst. in LD_LIBRARY_PATH
    $NSPATH =~ /\:.*SUNWspro(\/|\:|\b)/;
    $NSPATH = $& if $&;
    $NSPATH =~ /.*SUNWspro(\/|\:|\b)/;
    $NSPATH = $&;
    $NSPATH =~ /SUNWspro/;
    $NSPATH = $`;
    $NSPATH =~ s/://gi;
    $NSPATH = "/opt/" unless $NSPATH;
    print "$Pkg: Found non-standard F77 path:--->$NSPATH\n" if $NSPATH ne
"/opt/";
       $dir = find_highest_SC("$NSPATH/SUNWspro/SC*/lib");
       return "" unless $dir; # Failure
       print "$Pkg: Found Fortran latest version lib dir $dir\n";
       return "-L$dir -lF77 -lM77 -lsunmath -lm";
};


$F77config{Solaris}{F77}{Trail_} = 1;
$F77config{Solaris}{F77}{Compiler} = 'f77';
$F77config{Solaris}{F77}{Cflags} = '-O';
$F77config{Solaris}{DEFAULT} = 'F77';

### Generic GNU-77 or F2C system ###

$F77config{Generic}{G77}{Link} = sub {
    my @libs = ('g2c', 'f2c');
    my ($dir, $lib, $test);
    foreach $test (@libs) {
      $dir = `g77 -print-file-name=lib$test.a`;
      chomp $dir;
      # Note that -print-file-name returns just the library name
      # if it cant be found - make sure that we only accept the
      # directory if it returns a proper path (or matches a /)
      if (defined $dir && $dir ne "lib$test.a") {
        $lib = $test; # Found an existing library
        last; 
      }
    }

    if( defined $dir  && defined $lib) {
        $dir =~ s,/lib$lib.a$,,;
    } else {
        $dir = "/usr/local/lib";
        $lib = "f2c";
    }    
    return( "-L$dir -L/usr/lib -l$lib -lm" );
};
$F77config{Generic}{G77}{Trail_} = 1;
$F77config{Generic}{G77}{Compiler} = find_in_path('g77','f77','fort77');
$F77config{Generic}{G77}{Cflags} = '-O';
$F77config{Generic}{DEFAULT} = 'G77';
$F77config{Generic}{F2c}     = $F77config{Generic}{G77};

### cygwin ###
#"-lg2c -lm";
# needed this on my cygwin system to get things working properly
sub getcyglink {
   return join ' ', map {my $lp = `g77 -print-file-name=lib$_.a`;
			$lp =~ s|/[^/]+$||;
			 $lp =~ s|L([a-z,A-Z]):|L//$1|g;
			 "-L$lp -l$_"} qw/g2c m/;
}

$F77config{Cygwin}{G77}{Trail_} = 1;
$F77config{Cygwin}{G77}{Compiler} = 'g77';
$F77config{Cygwin}{G77}{Cflags} = '-O';
$F77config{Cygwin}{G77}{Link}	= \&getcyglink;
$F77config{Cygwin}{DEFAULT}	= 'G77';

### Linux ###

$F77config{Linux}{G77}     = $F77config{Generic}{G77};
$F77config{Linux}{F2c}     = $F77config{Generic}{G77};
$F77config{Linux}{DEFAULT} = 'G77';

### DEC OSF/1 ###

$F77config{Dec_osf}{F77}{Link}   = "-L/usr/lib -lUfor -lfor -lFutil -lm -lots -lc";
$F77config{Dec_osf}{F77}{Trail_} = 1;
$F77config{Dec_osf}{F77}{Compiler} = 'f77';
$F77config{Dec_osf}{F77}{Cflags} = '-O';
$F77config{Dec_osf}{DEFAULT}     = 'F77';

### HP/UX ###

$F77config{Hpux}{F77}{Link}   = "-L/usr/lib -lcl -lm";
$F77config{Hpux}{F77}{Trail_} = 0;
$F77config{Hpux}{F77}{Compiler} = 'f77';
$F77config{Hpux}{F77}{Cflags} = '-O';
$F77config{Hpux}{DEFAULT}     = 'F77';

### IRIX ###

# From: Ovidiu Toader <ovi@physics.utoronto.ca>
# For an SGI running IRIX 6.4 or higher (probably lower than 6.4 also)
# there is a new abi, -64, which produces 64 bit executables. This is no
# longer an experimental feature and I am using it exclusively without any
# problem. The code below is what I use instead of original IRIX section
# in the ExtUtils::F77 package. It adds the -64 flag and it is supposed to
# provide the same functionality as the old code for a non -64 abi. 

if (ucfirst($Config{'osname'}) eq "Irix")
{
  my ($cflags,$mips,$default_abi,$abi,$mips_dir,$libs);
  $cflags = $Config{cc};
  ($mips) = ($cflags =~ /(-mips\d)/g);
  $mips = "" if ! defined($mips);
  $mips_dir = $mips;$mips_dir =~ s/-//g;
  $default_abi = $Config{osvers} >= 6.4 ? "-n32" : "-o32";
 GET_ABI:
  {
    # -32 seems to be synonymous for -o32 (CS)
    $abi = "-o32",last GET_ABI if $cflags =~ /-o?32/;
    $abi = "-n32",last GET_ABI if $cflags =~ /-n32/;
    $abi = "-64",last GET_ABI if $cflags =~ /-64/;
    $abi = $default_abi;
  }
  if ( $abi eq "-64" ){
    $libs = ( (-r "/usr/lib64/$mips_dir") && (-d _) && (-x _) ) ?
	"-L/usr/lib64/$mips_dir" : "";
    $libs .=  " -L/usr/lib64 -lftn -lm";
  }
  if ( $abi eq "-n32" ){
    $libs = ( (-r "/usr/lib32/$mips_dir") && (-d _) && (-x _) ) ?
	"-L/usr/lib32/$mips_dir" : "";
    $libs .=  " -L/usr/lib32 -lftn -lm";
  }
  if ( $abi eq "-o32" ){
    $libs = "-L/usr/lib -lF77 -lI77 -lU77 -lisam -lm";
  }
  $F77config{Irix}{F77}{Cflags}   = "$abi $mips";
  $F77config{Irix}{F77}{Link}     = "$libs";
  $F77config{Irix}{F77}{Trail_}   = 1;
  $F77config{Irix}{F77}{Compiler} = "f77 $abi";
  $F77config{Irix}{DEFAULT}       = 'F77';
}

### AIX ###

$F77config{Aix}{F77}{Link}   = "-L/usr/lib -lxlf90 -lxlf -lc -lm";
$F77config{Aix}{F77}{Trail_} = 0;
$F77config{Aix}{DEFAULT}     = 'F77';

### FreeBSD ###

$F77config{Freebsd}{F77}{Trail_} = 1;
$F77config{Freebsd}{F77}{Link}   = '-L/usr/lib -lf2c -lm';
$F77config{Freebsd}{DEFAULT}     = 'F77';

### VMS ###

$F77config{VMS}{Fortran}{Trail_} = 0;
$F77config{VMS}{Fortran}{Link}   = ' ';         # <---need this space!
$F77config{VMS}{DEFAULT}     = 'Fortran';
$F77config{VMS}{Fortran}{Compiler} = 'Fortran';

############ End of database is here ############ 

=head1 SYNOPSIS

  use ExtUtils::F77;               # Automatic guess 
  use ExtUtils::F77 qw(sunos);     # Specify system
  use ExtUtils::F77 qw(linux g77); # Specify system and compiler
  $fortranlibs = ExtUtils::F77->runtime;

=cut

# Package variables

$Runtime = "-LSNAFU -lwontwork";
$RuntimeOK = 0;
$Trail_  = 1;
$Pkg   = "";
$Compiler = "";
$Cflags = "";

sub get; # See below

# All the figuring out occurs during import - this is because
# a lot of the answers depend on a lot of the guesswork.

sub import {
   $Pkg    = shift;
   my $system   = ucfirst(shift);  # Set package variables
   my $compiler = ucfirst(shift);

   # Guesses if system/compiler not specified.

   $system   = ucfirst $Config{'osname'} unless $system;
   $system = 'Cygwin' if $system =~ /Cygwin/;
   $compiler = get $F77config{$system}{DEFAULT} unless $compiler;

   print "$Pkg: Using system=$system compiler=$compiler\n";
   
   if (defined($ENV{F77LIBS})) {
      print "Overriding Fortran libs from value of enviroment variable F77LIBS = $ENV{F77LIBS}\n";
      $Runtime = $ENV{F77LIBS};
   }
   else {
      
     # Try this combination

     if (defined( $F77config{$system} )){
     	my $flibs = get ($F77config{$system}{$compiler}{Link});
        if ($flibs ne "") {
     	   $Runtime = $flibs . gcclibs();
	   $Runtime =~ s|L([a-z,A-Z]):|L//$1|g if $^O =~ /cygwin/i;
           $Runtime = ' ' if $^O eq 'VMS';  # <-- need this space!
	   print "Runtime: $Runtime\n";
           $ok = 1;
     	   $ok = validate_libs($Runtime) if $flibs ne "";
	}
     }else {
     	$Runtime = $ok = "";
     }

     # If it doesn't work try Generic + GNU77

     unless (defined($Runtime) && $ok) {
     	print <<"EOD";
$Pkg: Unable to guess and/or validate system/compiler configuration
$Pkg: Will try system=Generic Compiler=G77
EOD
    	 $system   = "Generic";
    	 $compiler = "G77";
    	 my $flibs = get ($F77config{$system}{$compiler}{Link});
    	 $Runtime =  $flibs. gcclibs();
    	 $ok = validate_libs($Runtime) if $flibs ne "";
    	 print "$Pkg: Well that didn't appear to validate. Well I will try it anyway.\n"
    	      unless $Runtime && $ok;
       }
 
      $RuntimeOK = $ok;
      
   } # Not overriding   

   # Now get the misc info for the methods.
      
   if (defined( $F77config{$system}{$compiler}{Trail_} )){
      $Trail_  = get $F77config{$system}{$compiler}{Trail_};  
   }
   else{ 
      print << "EOD";
$Pkg: There does not appear to be any configuration info about
$Pkg: names with trailing underscores for system $system. Will assume
$Pkg: F77 names have trailing underscores.
EOD
      $Trail_ = 1;
   }
  
   if (defined( $F77config{$system}{$compiler}{Compiler} )) {
	$Compiler = $F77config{$system}{$compiler}{Compiler};
   } else {
	print << "EOD";
$Pkg: There does not appear to be any configuration info about
$Pkg: the F77 compiler name. Will assume 'f77'.
EOD
	$Compiler = 'f77';
   }
print "$Pkg: Compiler: $Compiler\n";

   if (defined( $F77config{$system}{$compiler}{Cflags} )) {
	$Cflags = $F77config{$system}{$compiler}{Cflags};
   } else {
	print << "EOD";
$Pkg: There does not appear to be any configuration info about
$Pkg: the options for the F77 compiler. Will assume none
$Pkg: necessary.
EOD
	$Cflags = '';
   }

   print "$Pkg: Cflags: $Cflags\n";
   
} # End of import ()

=head1 METHODS

The following methods are provided:

=over 4

=item * B<runtime>

Returns a list of F77 runtime libraries.

  $fortranlibs = ExtUtils::F77->runtime;

=item * B<runtimeok>

Returns TRUE only if runtime libraries have been found successfully.

=item * B<trail_>

Returns true if F77 names have trailing underscores.

=item * B<compiler>

Returns command to execute the compiler (e.g. 'f77').

=item * B<cflags>

Returns compiler flags.

=item * B<testcompiler>

Test to see if compiler actually works.

=back

More methods  will probably be added in the future.

=cut
	
sub runtime { return $Runtime; }
sub runtimeok { return $RuntimeOK; }
sub trail_  { return $Trail_; }
sub compiler { return $Compiler; }
sub cflags  { return $Cflags; }

### Minor internal utility routines ###

# Get hash entry, evaluating code references

sub get { ref($_[0]) eq "CODE" ? &{$_[0]} : $_[0] };

# Test if any files exist matching glob

sub any_exists {
    my @glob = glob(shift);
    return scalar(@glob);
}

# Find highest version number of SCN.N(.N) directories
# (Nasty SunOS/Solaris naming scheme for F77 libs]

sub find_highest_SC {
    print "$Pkg: Scanning for $_[0]\n";
    my @glob = glob(shift);
    my %n=();
    for (@glob) {
      #print "Found $_\n";
       if ( m|/SC(\d)\.(\d)/?.*$| ) {
           $n{$_} = $1 *100 + $2 * 10;
       }
       if ( m|/SC(\d)\.(\d)\.(\d)/?.*$| ) {
           $n{$_} = $1 *100 + $2 * 10 + $3;
       }
    }
    my @sorted_dirs = grep {-f "$_/libF77.a"} sort {$n{$a} <=> $n{$b}} @glob;

    return pop @sorted_dirs; # Highest N
}
     
# Validate a string of form "-Ldir -lfoo -lbar"

sub validate_libs {
   print "$Pkg: Validating $_[0]   ";
   my @args = split(' ',shift());
   my $pat;
   my $ret = 1;

   # Create list of directories to search (with common defaults)

   my @path = ();     
   for (@args, "/usr/lib", "/lib") { 
      push @path, $1 if /^-L(.+)$/ && -d $1;
   }

   # Search directories

   for (@args) {      
      next if /^-L/;
      next if $_ eq "-lm"; # Ignore this common guy
      if (/^-l(.+)$/) {
         $pat = join(" ", map {$_."/lib".$1.".*"} @path); # Join dirs + file
         #print "Checking for $pat\n";
         unless (any_exists($pat)) {
            print "\n$Pkg:    Unable to find library $_" ;
            $ret = 0;
         }
       }
   }
   print $ret ? "[ok]\n" : "\n";
   return $ret;
}


sub testcompiler {
 
    my $file = "/tmp/testf77$$";
    my $ret;
    open(OUT,">$file.f");
    print OUT "      print *, 'Hello World'\n";
    print OUT "      end\n";
    close(OUT);
    print "Compiling the test Fortran program...\n";
    system "$Compiler $Cflags $file.f -o ${file}_exe";
    print "Executing the test program...\n";
    if (`${file}_exe` ne " Hello World\n") {
       print "Test of Fortran Compiler FAILED. \n";
       print "Do not know how to compile Fortran on your system\n";
       $ret=0;
    }
    else{
       print "Congratulations you seem to have a working f77!\n";
       $ret=1;
    }
    unlink("${file}_exe"); unlink("$file.f"); unlink("$file.o") if -e "$file.o";
    return $ret;
};

# Return gcc libs (e.g. -L/usr/local/lib/gcc-lib/sparc-sun-sunos4.1.3_U1/2.7.0 -lgcc)

sub gcclibs {
   my $isgcc = $Config{'cc'} eq 'gcc';
   if (!$isgcc && $^O ne 'VMS') {
      print "Checking for gcc in disguise:\n";
      $isgcc = 1 if $Config{gccversion};
      my $string;
      if ($isgcc) {
        $string = "Compiler is gcc version $Config{gccversion}";
        $string .= "\n" unless $string =~ /\n$/;
      } else {
        $string = "Not gcc\n";
      }
      print $string;
   }
   if ($isgcc) {
       $gccdir = `gcc -print-libgcc-file-name`; chomp $gccdir;
       $gccdir =~ s/\/libgcc.a//;
       return " -L$gccdir -lgcc";   
   }else{
       return "";
   }
}

# Try and find a program in the users PATH

sub find_in_path {
   my @names = @_;
   my @path = split(":",$ENV{PATH});
   my ($name,$dir);
   for $name (@names) {
      for $dir (@path) {
         if (-x $dir."/$name") {
	    print "Found compiler $name\n";
	    return $name;
	  }
      }
   }
   return '' if $^O eq 'VMS';
   die "Unable to find a fortran compiler using names: ".join(" ",@names);
}


=head1 AUTHOR

Karl Glazebrook (kgb@aaoepp.aao.GOV.AU).

=cut


1; # Return true