Update the changes in the files modified from CPython

Author: rhpvorderman

src/isal/igzip.py

@@ -9,11 +9,7 @@
 # Changes compared to CPython:
 # - Subclassed GzipFile to IGzipFile. Methods that included calls to zlib have
 #   been overwritten with the same methods, but now calling to isal_zlib.
-# - _GzipReader uses a igzip_lib.IgzipDecompressor. This Decompressor is
-#   derived from the BZ2Decompressor as such it does not produce an unconsumed
-#   tail but keeps the read data internally. This prevents unnecessary copying
-#   of data. To accomodate this, the read method has been rewritten.
-# - _GzipReader._add_read_data uses isal_zlib.crc32 instead of zlib.crc32.
+# - _GzipReader is implemented in C in isal_zlib and allows dropping the GIL.
 # - Gzip.compress does not use a GzipFile to compress in memory, but creates a
 #   simple header using _create_simple_gzip_header and compresses the data with
 #   igzip_lib.compress using the DECOMP_GZIP_NO_HDR flag. This change was

src/isal/isal_zlibmodule.c

@@ -14,14 +14,13 @@ Changes compared to CPython:
 - Zlib to ISA-L conversion functions were included.
 - All compression and checksum functions from zlib replaced with ISA-L
   compatible functions.
-- No locks in Compress and Decompress objects. These were deemed unnecessary
-  as the ISA-L functions do not allocate memory, unlike the zlib
-  counterparts.
 - zlib.compress also has a 'wbits' argument. This change was included in
   Python 3.11. It allows for faster gzip compression by using
   isal_zlib.compress(data, wbits=31).
 - Argument parsers were written using th CPython API rather than argument
   clinic.
+- Created a GzipReader class that implements gzip reading in C, reducing a lot
+  of overhead compared to the gzip.py:_GzipReader class.
 */
 
 #include "isal_shared.h"