## -*- mode: Perl -*-
##
## Copyright (c) 2012, 2013, 2015, 2016 The University of Utah
## All rights reserved.
##
## This file is distributed under the University of Illinois Open Source
## License.  See the file COPYING for details.

###############################################################################

package creduce_utils;

use warnings;

use Exporter::Lite;
use File::Spec;
use File::Which;

@EXPORT      = qw($DEBUG $OK $STOP $ERROR
		  find_external_program
		  runit nprocs
                  run_clang_delta
		  $replace_cont $matched replace_aux
		  read_file write_file
                  );

$DEBUG = 0;

$OK = 999999;
$STOP = 111333;
$ERROR = 223334;

sub find_external_program($$) {
    my ($configured_path, $program_name) = @_;
    # $configured_path is the pathname that was found at configure time.
    # If it seems OK, use it.
    # Otherwise, try looking in the user's path for $program_name.
    if (File::Spec->file_name_is_absolute ($configured_path)
	&& -e $configured_path
	&& -f $configured_path
	&& -x $configured_path) {
	return $configured_path;
    }
    return File::Which::which ($program_name);
}

sub runit ($) {
    (my $cmd) = @_;
    my $res = system("$cmd");
    return 0 if $res == 0;
    return $? >> 8;
}

sub run_clang_delta ($) {
    (my $cmd) = @_;
    if ((system "$cmd") != 0) {
        my $res = $? >> 8;
        if ($res == 255) {
            return -1;
        }
        elsif ($res == 1) {
            return -2;
        }
        else {
            return -3;
        }
    }
    return ($? >> 8);
}

# utility code to help us replace the nth occurrence of a pattern
$replace_cont = 0;
$matched = 0;
sub replace_aux ($$$) {
    my ($index,$original,$replacement) = @_;
    $replace_cont++;
    $matched = 1;
    return ($replace_cont == $index) ? $replacement : $original;
}

sub read_file ($) {
    (my $cfile) = @_;
    open INF, "<$cfile" or die;
    my $prog = "";
    while (my $line = <INF>) {
	$prog .= $line;
    }
    close INF;
    return $prog;
}

sub write_file ($$) {
    (my $cfile, my $prog) = @_;
    open OUTF, ">$cfile" or die;
    print OUTF $prog;
    close OUTF;
}

# attempt to find number of real cores, not hyperthreaded ones
sub ncpus () {
    my $OS = $^O;
    if ($OS eq "linux") {
	my $cores;
	my $sockets;
	open INF, "lscpu |";
	while (my $line = <INF>) {
	    chomp $line;
	    $cores = $1 if ($line =~ /Core\(s\) per socket:\s+([0-9]+)\s*$/);
	    $sockets = $1 if ($line =~ /Socket\(s\):\s+([0-9]+)\s*$/);
	}
	close INF;
	return ($cores * $sockets) if (defined($cores) && defined($sockets));
    }
    if ($OS eq "darwin") {
	my $cpus;
	open INF, "sysctl hw |";
	while (my $line = <INF>) {
	    chomp $line;
	    $cpus = $1 if ($line =~ /hw.physicalcpu: ([0-9]+)$/);
	}
	close INF;
	return $cpus if defined $cpus;
    }
    if ($OS eq "MSWin32") {
	# TODO
    }
    # Load and use the Sys::CPU module if available, don't complain otherwise
    # we try this last since it will count hyperthreads not cores
    return Sys::CPU::cpu_count() if (eval { require Sys::CPU; });
    return 1;
}

# here we're pretty conservative about the number of parallel
# processes to use; if the user has some big iron she can specify a
# higher number using -n
sub nprocs () {
    my $cpus = ncpus();
    die unless ($cpus >= 1);
    return $cpus if ($cpus <= 2);
    return $cpus - 1 if ($cpus <= 4);
    return 4;
}

1;
