Initial import

ebook_converter/ebooks/mobi/reader/containers.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python2
+# vim:fileencoding=utf-8
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+__license__ = 'GPL v3'
+__copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
+
+from struct import unpack_from, error
+
+from calibre.utils.imghdr import what
+
+
+def find_imgtype(data):
+    return what(None, data) or 'unknown'
+
+
+class Container(object):
+
+    def __init__(self, data):
+        self.is_image_container = False
+        self.resource_index = 0
+
+        if len(data) > 60 and data[48:52] == b'EXTH':
+            length, num_items = unpack_from(b'>LL', data, 52)
+            pos = 60
+            while pos < 60 + length - 8:
+                try:
+                    idx, size = unpack_from(b'>LL', data, pos)
+                except error:
+                    break
+                pos += 8
+                size -= 8
+                if size < 0:
+                    break
+                if idx == 539:
+                    self.is_image_container = data[pos:pos+size] == b'application/image'
+                    break
+                pos += size
+
+    def load_image(self, data):
+        self.resource_index += 1
+        if self.is_image_container:
+            data = data[12:]
+            imgtype = find_imgtype(data)
+            if imgtype != 'unknown':
+                return data, imgtype
+        return None, None
+
+