start of a BMP file structure dumper

diff --git a/fileformatdocs/bmpdump.pl b/fileformatdocs/bmpdump.pl
new file mode 100644 (file)
index 0000000..8dce821
--- /dev/null
+++ b/fileformatdocs/bmpdump.pl
@@ -0,0 +1,65 @@
+#!perl
+use strict;
+use Getopt::Long;
+
+my $dumpall = 0;
+my $image = 0;
+GetOptions(dumpall => \$dumpall,
+          image => \$image);
+
+my $file = shift
+  or die "Usage: $0 filename\n";
+
+open my $fh, "<", $file
+  or die "$0: cannot open '$file': $!\n";
+
+binmode $fh;
+
+my $filehead;
+read($fh, $filehead, 14) == 14
+  or die "Could not read file header: $!\n";
+my ($h_type, $h_size, $res1, $res2, $h_offset)
+  = unpack("A2VvvV", $filehead);
+
+$h_type eq "BM"
+  or die "Not a BMP file - no BM signature\n";
+
+print <<EOS;
+File header:
+  Type: $h_type
+  Size: $h_size
+  Res1: $res1
+  Res2: $res2
+  Offset: $h_offset
+EOS
+
+my $bmi;
+read($fh, $bmi, 40) == 40
+  or die "Could not read BITMAPINFO\n";
+
+my ($i_size, $i_width, $i_height, $i_planes, $i_bits, $i_compress, $i_size_img, $i_xppm, $i_yppm, $clr_used, $clr_imp) =
+  unpack("VVVvvVVVVVV", $bmi);
+printf <<EOS,
+Bitmapinfo:
+  biSize: %d
+  biWidth: %d
+  biHeight: %d
+  biPlanes: %d
+  biBitCount: %d
+  biCompression: %d
+  biSizeImage: %d
+  biXPelsPerMeter: %d
+  biYPelsPerMeter: %d
+  biClrUsed: %d
+  biClrImportant: %d
+EOS
+  $i_size, $i_width, $i_height, $i_planes, $i_bits, $i_compress, $i_size_img, $i_xppm, $i_yppm, $clr_used, $clr_imp;
+
+$i_size < 40
+  and die "biSize too small\n";
+
+if ($i_size > 40) {
+  my $extra_head;
+  read($fh, $extra_head, $i_size - 40) == $i_size - 40
+    or die "Failed to read rest of header\n";
+}