Committing my thoughts on .an1 to posterity in code form.

diff --git a/gpsbabel/intdoc/SA2003_an1_dump.pl b/gpsbabel/intdoc/SA2003_an1_dump.pl
new file mode 100644 (file)
index 0000000..acf497d
--- /dev/null
+++ b/gpsbabel/intdoc/SA2003_an1_dump.pl
@@ -0,0 +1,135 @@
+#!/usr/bin/perl
+
+=pod
+
+  This script reads a DeLorme Street Atlas 2003 .an1 (drawing) file 
+  and prints various pertinent data from it.  Anything with a variable 
+  name starting with "unk" or "magic" or "zero" is probably something 
+  we don't yet understand.  Suggestions as to what some of these fields 
+  mean are welcome.  The author disclaims any liability arising from 
+  the use of any information contained within this script. 
+
+    Copyright (C) 2005 Ronald L. Parker (babelan1perl@parkrrrr.com)
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111 USA
+
+=cut
+
+# Convert a longword to a latitude or longitude
+sub decode {
+   my $foo = shift;
+
+   my $deg = (0x80000000-$foo)/(0x800000);
+   sprintf( "%d %06.3f", $deg, 60*($deg-int($deg)));
+}
+
+
+# read a data structure from the input file.  
+sub shiftunpack {
+
+   my $pattern = shift;
+   my @result = unpack( $pattern, $file );
+   my $str = pack( $pattern, @result );
+   $file = substr( $file, length( $str ));
+   @result;
+}
+
+sub skip_bytes {
+   my $count = shift;
+   $file = substr( $file, $count );
+}
+
+# read file
+undef $/;
+$file = <>;
+
+# read file header
+($magic, $unk1 ) = shiftunpack( 'ss' );
+
+print <<END;
+MAGIC   $magic
+
+END
+
+# read bitmap info
+($bitmapcount) = shiftunpack( 'l' );
+
+while ( $bitmapcount ) {
+  ($rec_type) = shiftunpack( 's' );
+  if ( $rec_type == 0x4c49 ) { # 'IL'
+    # I don't know what this structure is, but it appears twice in my test files.
+    ($unk10101, $unke, $unkc, $unk18_1, $unk18_2, $unkneg1_1,
+     $unk20, $unkneg1_2, $unkneg1_3) = shiftunpack( 'lsssslsll');
+  }
+  elsif ( $rec_type == 0x4d42 ) { # 'BM'
+    # This is a standard BMP file, documented in MSDN.
+    # BITMAPFILEHEADER
+    ($fhsize, $res_0_1, $res_0_2, $bitoffset) = shiftunpack( 'lssl' );
+    # BITMAPINFOHEADER
+    ($bmisize, $width, $height, $planes, $bpp, $compression, 
+     $size, $xppm, $yppm, $colused, $colimprt ) = shiftunpack( 'lllssllllll');
+    # palette
+    $palettesize = $bitoffset - $bmisize - 14; # 14 bytes in BMFH, including the 'BM'
+    skip_bytes( $palettesize );
+    # image
+    skip_bytes( $size );
+  }
+  else {
+    # image information - the 'type' we read was actually the low word of the hotspot X coord.
+    ($hotspotxhi, $hotspoty, $unk1, $unk2, $unk3, $unk4, $unk5, $name ) = 
+          shiftunpack( 'sllllllC/A*' );
+    $hotspotx = $rec_type + 0x10000*$hotspotxhi;
+    print( "Image: $hotspotx $hotspoty   $name\n" );
+    $bitmapcount--; 
+  }
+} 
+
+# waypoint information
+
+($magic, $wptcount) = shiftunpack( 'sl' );
+
+print( "$wptcount waypoints\n" );
+while ( $wptcount ) {
+  ($magic, $unk0, $lat, $lon, $unk1, $unk2, $unk3, $unk4, $unk5, $serial,
+   $unk6s, $unk7s, $unk8, $unk9, $unk10s, $name, $font, $unk11l, $unk11h, 
+   $unk12l, $unk12h, $unk13l, $unk13h, $unk14l, $unk14h, $unk15, $unk16, $fontsize, $unk17,
+   $unk18, $unk19, $unk20, $unk21, $unk22 ) = 
+   shiftunpack( 'slllsllsssssllss/A*s/A*sssssssslllllllll' );
+  $lat = decode( $lat );
+  $lon = decode( $lon );
+  print ( "$lat   $lon   $serial  $name\n" );
+  $wptcount--;
+} 
+
+# line information
+($magic, $linecount ) = shiftunpack( 'sl' );
+print ( "$linecount lines\n" );
+while ( $linecount ) {
+  print "--- start line ---\n";
+  ($magic, $unk1, $unk2, $unk3, $unk4, $unk5l, $unk6, $unk7, $unk8l, $unk9l,
+   $unk10_3, $unk11_0, $unk12_0, $unk13_0, $unk14s, $pointcount ) = 
+    shiftunpack( 'sllsslssllllllsl' );
+       # unk10_3 might be a count that counts $unkXX_0
+  while ( $pointcount ) {
+    ($magic, $unk0, $lat, $lon, $unk0s ) = shiftunpack( 'sllls' );
+    $lat = decode( $lat );
+    $lon = decode( $lon );
+    print "  $lat   $lon\n";
+    $pointcount--;
+  }
+  print "--- end line ---\n";
+  $linecount--;
+}
+