initial sketch

3 files changed, 358 insertions, 0 deletions

diff --git a/lib/Image/PNM.pm b/lib/Image/PNM.pm
index e69de29..31d4c93 100644
--- a/lib/Image/PNM.pm
+++ b/lib/Image/PNM.pm
@@ -0,0 +1,139 @@
+package Image::PNM;
+use strict;
+use warnings;
+
+sub new {
+    my $class = shift;
+    my ($data) = @_;
+
+    my $self = bless {}, $class;
+
+    if (ref $data) {
+        $self->_parse_string($data);
+    }
+    elsif ($data) {
+        $self->_parse_file($data);
+    }
+    else {
+        $self->{w}      = 1;
+        $self->{h}      = 1;
+        $self->{max}    = 1;
+        $self->{pixels} = [[0]];
+    }
+
+    return $self;
+}
+
+sub as_string {
+    my $self = shift;
+    my ($format) = @_;
+
+    my $method = "_as_string_$format";
+    die "Unknown format $format"
+        unless $self->can($method);
+
+    return $self->$method;
+}
+
+sub _as_string_P3 {
+    my $self = shift;
+
+    my $data = <<HEADER;
+P3
+$self->{w} $self->{h}
+$self->{max}
+HEADER
+
+    for my $row (@{ $self->{pixels} }) {
+        $data .= join(' ', map { join(' ', @$_) } @$row) . "\n";
+    }
+
+    return $data;
+}
+
+sub _parse_string {
+    my $self = shift;
+    my ($string) = @_;
+
+    return $self->_parse_pnm(sub {
+        my ($line, $rest) = split /\n/, $string, 2;
+        return unless length($line) || length($rest);
+        $string = $rest;
+        return "$line\n";
+    });
+}
+
+sub _parse_file {
+    my $self = shift;
+    my ($filename) = @_;
+
+    open my $fh, '<', $filename
+        or die "Couldn't open $filename for reading: $!";
+
+    return $self->_parse_pnm(sub { scalar <$fh> });
+}
+
+sub _parse_pnm {
+    my $self = shift;
+    my ($next_line) = @_;
+
+    my $next_line_nocomments = sub {
+        my $line;
+        while (!length($line)) {
+            $line = $next_line->();
+            return unless defined($line);
+            $line =~ s/#.*//s;
+        }
+        return $line;
+    };
+
+    chomp(my $format = $next_line_nocomments->());
+    chomp(my $dimensions = $next_line_nocomments->());
+
+    my ($w, $h) = $dimensions =~ /^([0-9]+)\s+([0-9]+)$/;
+    die "Invalid dimensions: $dimensions"
+        unless $w && $h;
+    $self->{w} = $w;
+    $self->{h} = $h;
+
+    my $method = "_parse_pnm_$format";
+    die "Don't know how to parse PNM files of format $format"
+        unless $self->can($method);
+    return $self->$method($next_line_nocomments);
+}
+
+sub _parse_pnm_P3 {
+    my $self = shift;
+    my ($next_line) = @_;
+
+    chomp (my $max = $next_line->());
+    die "Invalid max color value: $max"
+        unless $max =~ /^[0-9]+$/ && $max > 0;
+    $self->{max} = $max;
+
+    my @words;
+    my $next_word = sub {
+        if (!@words) {
+            chomp(my $line = $next_line->());
+            @words = split ' ', $line;
+        }
+        my $word = shift @words;
+        die "Invalid color: $word" unless $word =~ /^[0-9]+$/;
+        return $word;
+    };
+
+    $self->{pixels} = [];
+    for my $i (1..$self->{w}) {
+        my $row = [];
+        for my $j (1..$self->{h}) {
+            push @$row, [
+                $next_word->(),
+                $next_word->(),
+                $next_word->(),
+            ];
+        }
+        push @{ $self->{pixels} }, $row;
+    }
+}
+
+1;
diff --git a/t/P3.t b/t/P3.t
new file mode 100644
index 0000000..5712ace
--- /dev/null
+++ b/t/P3.t
@@ -0,0 +1,23 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use Test::More;
+
+use Image::PNM;
+
+my $image = Image::PNM->new('t/data/P3.pnm');
+is($image->as_string('P3'), <<IMAGE);
+P3
+8 8
+255
+255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
+255 255 255 255 255 255 255 255 255 0 84 255 0 84 255 255 255 255 255 255 255 255 255 255
+255 255 255 255 255 255 0 0 0 255 255 255 255 255 255 0 0 0 255 255 255 255 255 255
+255 255 255 0 0 0 255 255 255 255 255 255 255 255 255 255 255 255 0 0 0 255 255 255
+255 255 255 0 0 0 255 0 0 255 0 0 255 0 0 255 0 0 0 0 0 255 255 255
+255 255 255 0 0 0 255 255 255 255 255 255 255 255 255 255 255 255 0 0 0 255 255 255
+255 255 255 0 0 0 255 255 255 255 255 255 255 255 255 255 255 255 0 0 0 255 255 255
+255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 255
+IMAGE
+
+done_testing;
diff --git a/t/data/P3.pnm b/t/data/P3.pnm
new file mode 100644
index 0000000..df64d54
--- /dev/null
+++ b/t/data/P3.pnm
@@ -0,0 +1,196 @@
+P3
+# CREATOR: GIMP PNM Filter Version 1.1
+8 8
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+0
+84
+255
+0
+84
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+0
+0
+0
+255
+255
+255
+255
+255
+255
+0
+0
+0
+255
+255
+255
+255
+255
+255
+255
+255
+255
+0
+0
+0
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+0
+0
+0
+255
+255
+255
+255
+255
+255
+0
+0
+0
+255
+0
+0
+255
+0
+0
+255
+0
+0
+255
+0
+0
+0
+0
+0
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+255
+255
+255
+255
+255
+0
+0
+0
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+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+0
+0
+0
+255
+255
+255
+255
+255
+255
+0
+0
+0
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+255
+0
+0
+0
+255
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+255