Fix reading some RDC compressed pages

Author: jonashaag

doc/source/whatsnew/v1.5.0.rst

@@ -813,6 +813,7 @@ I/O
 - Bug in :func:`read_excel` when reading a ``.ods`` file with newlines between xml elements (:issue:`45598`)
 - Bug in :func:`read_parquet` when ``engine="fastparquet"`` where the file was not closed on error (:issue:`46555`)
 - :meth:`to_html` now excludes the ``border`` attribute from ``<table>`` elements when ``border`` keyword is set to ``False``.
+- Bug in :func:`read_sas` with certain types of compressed SAS7BDAT files (:issue:`35545`)
 -
 
 Period

pandas/io/sas/sas7bdat.py

@@ -424,7 +424,9 @@ def _process_page_meta(self) -> bool:
     def _read_page_header(self):
         bit_offset = self._page_bit_offset
         tx = const.page_type_offset + bit_offset
-        self._current_page_type = self._read_int(tx, const.page_type_length)
+        self._current_page_type = (
+            self.read_int(tx, const.page_type_length) & const.page_type_mask
+        )
         tx = const.block_count_offset + bit_offset
         self._current_page_block_count = self._read_int(tx, const.block_count_length)
         tx = const.subheader_count_offset + bit_offset

pandas/io/sas/sas_constants.py

@@ -53,6 +53,7 @@
 block_count_length = 2
 subheader_count_offset = 4
 subheader_count_length = 2
+page_type_mask = 3840
 page_meta_type = 0
 page_data_type = 256
 page_amd_type = 1024