small refatoring aound the block decompression

Author: danielhrisca

src/asammdf/blocks/mdf_v4.py

@@ -24,15 +24,9 @@
 from typing import BinaryIO, Final, Literal, TYPE_CHECKING
 from zipfile import ZIP_DEFLATED, ZipFile
 
-try:
-    from isal.isal_zlib import decompress as zlib_decompress
-except ImportError:
-    from zlib import decompress as zlib_decompress
-
 import canmatrix
 from canmatrix.canmatrix import CanMatrix
 from lz4.frame import compress as lz_compress
-from lz4.frame import decompress as lz_decompress
 import numpy as np
 from numpy import (
     arange,
@@ -69,7 +63,6 @@
     TypeIs,
     Unpack,
 )
-from zstd import decompress as zstd_decompress
 
 from .. import tool
 from ..signal import InvalidationArray, Signal
@@ -104,6 +97,7 @@
     CONVERT,
     count_channel_groups,
     DataBlockInfo,
+    DECOMPRESS_FUNC_MAP,
     extract_display_names,
     extract_encryption_information,
     extract_xml_comment,
@@ -192,18 +186,6 @@
 SORT_STEPS: Final = 102
 
 
-DECOMPRESS_FUNC_MAP = {
-    # data block type
-    v4c.DT_BLOCK: lambda x: x,
-    v4c.DZ_BLOCK_DEFLATE: zlib_decompress,
-    v4c.DZ_BLOCK_TRANSPOSED: zlib_decompress,
-    v4c.DZ_BLOCK_LZ: lz_decompress,
-    v4c.DZ_BLOCK_LZ_TRANSPOSED: lz_decompress,
-    v4c.DZ_BLOCK_ZSTD:zstd_decompress,
-    v4c.DZ_BLOCK_ZSTD_TRANSPOSED: zstd_decompress,
-}
-
-
 logger = logging.getLogger("asammdf")
 
 __all__ = ["MDF4"]

src/asammdf/blocks/utils.py

@@ -47,6 +47,13 @@
 from .options import GLOBAL_OPTIONS
 from .types import StrPath
 
+try: 
+    from isal.isal_zlib import decompress as zlib_decompress
+except ImportError:
+    from zlib import decompress as zlib_decompress
+from lz4.frame import decompress as lz_decompress
+from zstd import decompress as zstd_decompress
+
 try:
     from cchardet import detect
 except:
@@ -136,9 +143,19 @@ def __init__(self, *args: object) -> None:
 MDF4_VERSIONS: Final[tuple[LiteralString, ...]] = ("4.00", "4.10", "4.11", "4.20", "4.30")
 SUPPORTED_VERSIONS: Final = MDF2_VERSIONS + MDF3_VERSIONS + MDF4_VERSIONS
 
-
 ALLOWED_MATLAB_CHARS: Final = set(string.ascii_letters + string.digits + "_")
 
+DECOMPRESS_FUNC_MAP = {
+    # data block type
+    v4c.DT_BLOCK: lambda x: x,
+    v4c.DZ_BLOCK_DEFLATE: zlib_decompress,
+    v4c.DZ_BLOCK_TRANSPOSED: zlib_decompress,
+    v4c.DZ_BLOCK_LZ: lz_decompress,
+    v4c.DZ_BLOCK_LZ_TRANSPOSED: lz_decompress,
+    v4c.DZ_BLOCK_ZSTD:zstd_decompress,
+    v4c.DZ_BLOCK_ZSTD_TRANSPOSED: zstd_decompress,
+}
+
 
 class MdfException(Exception):
     """MDF Exception class."""

src/asammdf/mdf.py

@@ -16,6 +16,7 @@
 import re
 from shutil import copy, move
 import sys
+import tempfile
 from tempfile import gettempdir, mkdtemp
 from traceback import format_exc
 from types import TracebackType
@@ -25,29 +26,16 @@
 import zipfile
 
 from canmatrix import CanMatrix
-import numpy as np
-from numpy.typing import NDArray
-import pandas as pd
-from pandas import DataFrame
-from typing_extensions import Any, LiteralString, Never, overload, TypedDict, Unpack
-
-try:
-    from deflate import zlib_decompress
-    def decompress(data, bufsize):
-        return zlib_decompress(data, originalsize=bufsize)
-except ImportError:
-    try: 
-        from isal.isal_zlib import decompress
-    except ImportError:
-        from zlib import decompress
-import tempfile
-
 from lz4.frame import compress as lz_compress
-from lz4.frame import decompress as lz_decompress
+import numpy as np
 from numpy import (
     frombuffer,
     uint8,
 )
+from numpy.typing import NDArray
+import pandas as pd
+from pandas import DataFrame
+from typing_extensions import Any, LiteralString, Never, overload, TypedDict, Unpack
 
 from . import tool
 from .blocks import mdf_v2, mdf_v3, mdf_v4
@@ -83,6 +71,7 @@ def decompress(data, bufsize):
     csv_bytearray2hex,
     csv_int2hex,
     DataBlockInfo,
+    DECOMPRESS_FUNC_MAP,
     downcast,
     FileLike,
     Fragment,
@@ -1498,11 +1487,12 @@ def _cut_inplace(
                 seek(address)
                 new_data: bytes | memoryview[int] = read(typing.cast(int, compressed_size))
 
-                match block_type:
-                    case v4c.DZ_BLOCK_DEFLATE:
-                        new_data = decompress(new_data, bufsize=original_size)
-                    case v4c.DZ_BLOCK_TRANSPOSED:
-                        new_data = decompress(new_data, bufsize=original_size)
+                if block_type:
+                    decompress = DECOMPRESS_FUNC_MAP[block_type]
+                    new_data = decompress(new_data)
+
+                    if block_type % 2 == 0:
+                        # tranposed data
                         cols = typing.cast(int, param)
                         lines = original_size // cols
                         matrix_size = lines * cols
@@ -1518,9 +1508,6 @@ def _cut_inplace(
                         else:
                             new_data = frombuffer(new_data, dtype=uint8).reshape((cols, lines)).T.ravel().tobytes()
 
-                    case v4c.DZ_BLOCK_LZ:
-                        new_data = lz_decompress(new_data)
-
                 if block_limit is not None:
                     new_data = new_data[:block_limit]