Add a utils.HexDump library

Be a bit more robust about dealing with data corruption

src/apple2disk/dos33disk.py

@@ -1,9 +1,7 @@
 import applesoft
 import bitstring
 import disk as disklib
-import string
-
-PRINTABLE = set(string.letters + string.digits + string.punctuation + ' ')
+import utils
 
 class FileType(object):
     def __init__(self, short_type, long_type, parser=None):
@@ -227,7 +225,11 @@ class Dos33Disk(disklib.Disk):
                 #print "XXX found a sparse sector?"
                 continue
             (t, s) = ts
-            fds = FileDataSector.fromSector(self.ReadSector(t, s), entry.FileName())
+            try:
+                fds = FileDataSector.fromSector(self.ReadSector(t, s), entry.FileName())
+            except disklib.IOError, e:
+                print "%s: Failed to read File data sector: %s" % (entry, e)
+                continue
             contents.append(fds.data)
 
         return File(entry, contents)
@@ -276,8 +278,11 @@ class File(object):
         self.catalog_entry = catalog_entry
 
         self.contents = contents
+        self.parsed_contents = None
         parser = catalog_entry.file_type.parser
         if parser:
-            self.parsed_contents = parser(contents)
-        else:
-            self.parsed_contents = None
+            try:
+                self.parsed_contents = parser(contents)
+            except Exception:
+                print "Failed to parse file %s" % self.catalog_entry
+                print utils.HexDump(contents.tobytes())

src/apple2disk/utils.py

@@ -0,0 +1,17 @@
+import string
+
+PRINTABLE = set(string.letters + string.digits + string.punctuation + ' ')
+
+def HexDump(data):
+    line = []
+    for idx, b in enumerate(data):
+        if idx % 8 == 0:
+            print '$%02x:  ' % idx,
+        print "%02x" % ord(b),
+        if b in PRINTABLE:
+            line.append(b)
+        else:
+            line.append('.')
+        if (idx + 1) % 8 == 0:
+            print "    %s" % ''.join(line)
+            line = []