Added all remaining gists.

read_off.pl/README.md

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+A little project to learn the basics of Perl. A Perl script that reads a 3D model in the OFF file format and spits it's data to standard output.

read_off.pl/read_off.pl

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+#! /usr/bin/env perl
+use 5.010;
+use strict;
+use warnings;
+
+my $status = 0;
+
+foreach my $arg (0 .. $#ARGV){
+    say "---------------------------------------------------------------------";
+    say "FILE: $ARGV[$arg]";
+    say "---------------------------------------------------------------------";
+    $status = &read_off_file($ARGV[$arg]);
+}
+
+exit $status;
+
+##########################
+# SUBROUTINE DEFINITIONS #
+##########################
+
+sub read_off_file {
+    return unless defined wantarray;
+
+    # Local variable definitions.
+    my $v_ind = 0;
+    my $f_ind = 0;
+    my $status = 0;
+    my $meta_read = 0;
+
+    my $arg = shift @_;
+
+    open (my $file, '<', $arg) or die "$arg: $!";
+    my $row = <$file>;
+    chomp $row;
+
+    # Check if the first line in the file matches the "OFF" string. If it
+    # doesn't then this file is not a valid OFF file.
+    if(not $row =~ /OFF/){
+        say "$arg is not an OFF file.";
+        $status = 1;
+        last;
+    }else{
+        while($row = <$file>){
+            chomp $row;
+            # Remove leading and trailing whitespace.
+            $row =~ s/^\s+|\s+$//g;
+        
+            if(not $meta_read and $row =~ /^(((\d+)(\s+)){2})(\d+)$/){
+                # If the line is exactly three integers separated by arbitrary
+                # whitespace then it is the number of vertices, faces and edges.
+                my ($num_v, $num_f, $num_e) = split(/\s+/, $row);
+                say "Number of vertices: $num_v";
+                say "Number of faces: $num_f";
+                say "Number of edges: $num_e";
+                $meta_read = 1;
+
+            }elsif($row =~ /^(((\-?)(\d+)(\.(\d+))?(\s+)){2})((\-?)(\d+)(\.(\d+))?)$/){
+                # If the line has three numbers (integer or floating point)
+                # surrounded by arbitrary whitespace then it is a vertex.
+                my ($x, $y, $z) = split(/\s+/, $row);
+                say "Vertex #$v_ind: ($x, $y, $z)";
+                $v_ind = $v_ind + 1;
+
+            }elsif($row =~ /(\d+)(((\s+)(\d+)){3,})/){
+                # If the line has one integer followed by at least three or more
+                # integers, all of them separated by arbitrary whitespace, then
+                # it is a polygon.
+                my @face = split(/\s+/, $row);
+                print "Face $f_ind: Num vertices = $face[0] - ";
+                print "v::$face[$_] " foreach 1 .. $#face;
+                print "\n";
+                $f_ind = $f_ind + 1;
+            }elsif($row =~ /^(\s*)#(.*)/ or $row =~ /^(s*)$/){
+                say "Skipping comment or empty line.";
+            }else{
+                say "Unrecognized line.";
+            }
+        }
+    }
+
+    close $file;
+    
+    return $status;
+}