Initial import

ebook_converter/ebooks/compression/palmdoc.py

@@ -0,0 +1,96 @@
+#!/usr/bin/env  python2
+# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+__license__   = 'GPL v3'
+__copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
+
+import io
+from struct import pack
+
+from calibre.constants import plugins
+from polyglot.builtins import range
+cPalmdoc = plugins['cPalmdoc'][0]
+if not cPalmdoc:
+    raise RuntimeError(('Failed to load required cPalmdoc module: '
+            '%s')%plugins['cPalmdoc'][1])
+
+
+def decompress_doc(data):
+    return cPalmdoc.decompress(data)
+
+
+def compress_doc(data):
+    return cPalmdoc.compress(data) if data else b''
+
+
+def py_compress_doc(data):
+    out = io.BytesIO()
+    i = 0
+    ldata = len(data)
+    while i < ldata:
+        if i > 10 and (ldata - i) > 10:
+            chunk = b''
+            match = -1
+            for j in range(10, 2, -1):
+                chunk = data[i:i+j]
+                try:
+                    match = data.rindex(chunk, 0, i)
+                except ValueError:
+                    continue
+                if (i - match) <= 2047:
+                    break
+                match = -1
+            if match >= 0:
+                n = len(chunk)
+                m = i - match
+                code = 0x8000 + ((m << 3) & 0x3ff8) + (n - 3)
+                out.write(pack('>H', code))
+                i += n
+                continue
+        ch = data[i:i+1]
+        och = ord(ch)
+        i += 1
+        if ch == b' ' and (i + 1) < ldata:
+            onch = ord(data[i:i+1])
+            if onch >= 0x40 and onch < 0x80:
+                out.write(pack('>B', onch ^ 0x80))
+                i += 1
+                continue
+        if och == 0 or (och > 8 and och < 0x80):
+            out.write(ch)
+        else:
+            j = i
+            binseq = [ch]
+            while j < ldata and len(binseq) < 8:
+                ch = data[j:j+1]
+                och = ord(ch)
+                if och == 0 or (och > 8 and och < 0x80):
+                    break
+                binseq.append(ch)
+                j += 1
+            out.write(pack('>B', len(binseq)))
+            out.write(b''.join(binseq))
+            i += len(binseq) - 1
+    return out.getvalue()
+
+
+def find_tests():
+    import unittest
+
+    class Test(unittest.TestCase):
+
+        def test_palmdoc_compression(self):
+            for test in [
+                b'abc\x03\x04\x05\x06ms',  # Test binary writing
+                b'a b c \xfed ',  # Test encoding of spaces
+                b'0123456789axyz2bxyz2cdfgfo9iuyerh',
+                b'0123456789asd0123456789asd|yyzzxxffhhjjkk',
+                (b'ciewacnaq eiu743 r787q 0w%  ; sa fd\xef\ffdxosac wocjp acoiecowei '
+                b'owaic jociowapjcivcjpoivjporeivjpoavca; p9aw8743y6r74%$^$^%8 ')
+            ]:
+                x = compress_doc(test)
+                self.assertEqual(py_compress_doc(test), x)
+                self.assertEqual(decompress_doc(x), test)
+
+    return unittest.defaultTestLoader.loadTestsFromTestCase(Test)