Merge pull request #146 from psd-tools/v1.8.30

workaround for reading malformed psd files

CHANGES.rst

@@ -1,3 +1,8 @@
+1.8.30 (2019-09-24)
+-------------------
+
+- [psd] workaround for reading less-than-4-byte int in malformed psd files.
+
 1.8.29 (2019-09-10)
 -------------------
 

src/psd_tools/psd/base.py

@@ -351,7 +351,11 @@ class ShortIntegerElement(IntegerElement):
 
     @classmethod
     def read(cls, fp, **kwargs):
-        return cls(read_fmt('H2x', fp)[0])
+        try:
+            return cls(read_fmt('H2x', fp)[0])
+        except AssertionError as e:
+            logger.error(e)
+        return cls(read_fmt('H', fp)[0])
 
     def write(self, fp, **kwargs):
         return write_fmt(fp, 'H2x', self.value)
@@ -367,7 +371,11 @@ class ByteElement(IntegerElement):
 
     @classmethod
     def read(cls, fp, **kwargs):
-        return cls(read_fmt('B3x', fp)[0])
+        try:
+            return cls(read_fmt('B3x', fp)[0])
+        except AssertionError as e:
+            logger.error(e)
+        return cls(read_fmt('B', fp)[0])
 
     def write(self, fp, **kwargs):
         return write_fmt(fp, 'B3x', self.value)
@@ -384,7 +392,11 @@ class BooleanElement(IntegerElement):
 
     @classmethod
     def read(cls, fp, **kwargs):
-        return cls(read_fmt('?3x', fp)[0])
+        try:
+            return cls(read_fmt('?3x', fp)[0])
+        except AssertionError as e:
+            logger.error(e)
+        return cls(read_fmt('?', fp)[0])
 
     def write(self, fp, **kwargs):
         return write_fmt(fp, '?3x', self.value)

src/psd_tools/utils.py

@@ -32,8 +32,12 @@ def read_fmt(fmt, fp):
     fmt = str(">" + fmt)
     fmt_size = struct.calcsize(fmt)
     data = fp.read(fmt_size)
-    assert len(data
-               ) == fmt_size, 'read=%d, expected=%d' % (len(data), fmt_size)
+    try:
+        assert len(data
+                   ) == fmt_size, 'read=%d, expected=%d' % (len(data), fmt_size)
+    except:
+        fp.seek(-len(data), 1)
+        raise
     return struct.unpack(fmt, data)
 
 

src/psd_tools/version.py

@@ -1 +1 @@
-__version__ = '1.8.29'
+__version__ = '1.8.30'

tests/psd_tools/psd/test_base.py

@@ -50,6 +50,17 @@ def test_numbers(kls, fixture):
     assert hash(value) == hash(fixture)
 
 
+@pytest.mark.parametrize(
+    'kls, fixture', [
+        (ByteElement, b'\x01\x00'),
+        (ShortIntegerElement, b'\x00\x01'),
+        (BooleanElement, b'\x00\x01'),
+    ]
+)
+def test_malformed_numbers(kls, fixture):
+    kls.frombytes(fixture)
+
+
 def test_boolean():
     value = BooleanElement(True)
     assert value.value is True