img: add _ShortIfdEntry._parse_value()

Steve Canny · Steve Canny · commit a41f9ecdeab6 · 2014-02-27T12:08:36.000-08:00
diff --git a/docx/image/tiff.py b/docx/image/tiff.py
@@ -278,6 +278,16 @@ class _ShortIfdEntry(_IfdEntry):
     """
     IFD entry expressed as a short (2-byte) integer
     """
+    @classmethod
+    def _parse_value(cls, stream_rdr, offset, value_count, value_offset):
+        """
+        Return the short int value contained in the *value_offset* field of
+        this entry. Only supports single values at present.
+        """
+        if value_count == 1:
+            return stream_rdr.read_short(offset, 8)
+        else:
+            return 'Multi-value short integer NOT IMPLEMENTED'
 
 
 class _LongIfdEntry(_IfdEntry):
diff --git a/tests/image/test_tiff.py b/tests/image/test_tiff.py
@@ -14,7 +14,8 @@
 from docx.image.constants import MIME_TYPE, TIFF_TAG
 from docx.image.helpers import BIG_ENDIAN, LITTLE_ENDIAN, StreamReader
 from docx.image.tiff import (
-    _IfdEntries, _IfdEntry, _IfdEntryFactory, _IfdParser, Tiff, _TiffParser
+    _IfdEntries, _IfdEntry, _IfdEntryFactory, _IfdParser, _ShortIfdEntry,
+    Tiff, _TiffParser
 )
 
 from ..unitutil import (
@@ -414,3 +415,12 @@ def _parse_value_(self, request, value_):
     @pytest.fixture
     def value_(self, request):
         return loose_mock(request)
+
+
+class Describe_ShortIfdEntry(object):
+
+    def it_can_parse_a_short_int_IFD_entry(self):
+        bytes_ = b'foobaroo\x00\x2A'
+        stream_rdr = StreamReader(BytesIO(bytes_), BIG_ENDIAN)
+        val = _ShortIfdEntry._parse_value(stream_rdr, 0, 1, None)
+        assert val == 42
