zlib.py

ofrak.core.zlib

ZlibCompressionLevelAnalyzer (Analyzer)

analyze(self, resource, config=None) async

Analyze a resource for to extract specific ResourceAttributes.

Users should not call this method directly; rather, they should run Resource.run or Resource.analyze.

Parameters:

Name	Type	Description	Default
resource	Resource	The resource that is being analyzed	required
config		Optional config for analyzing. If an implementation provides a default, this default will always be used when config would otherwise be None. Note that a copy of the default config will be passed, so the default config values cannot be modified persistently by a component run.	None

Returns:

Type	Description
ZlibData	The analysis results

Source code in ofrak/core/zlib.py

async def analyze(self, resource: Resource, config=None) -> ZlibData:
    zlib_data = await resource.get_data(Range(0, 2))
    flevel = zlib_data[-1]
    if flevel == 0x01:
        compression_level = 1
    elif flevel == 0x5E:
        compression_level = 2
    elif flevel == 0x9C:
        compression_level = 6
    elif flevel == 0xDA:
        compression_level = 7
    else:
        compression_level = 6
    return ZlibData(compression_level)

ZlibData (GenericBinary) dataclass

ZlibData(compression_level: int)

ZlibPacker (Packer)

Pack a binary with zlib

pack(self, resource, config=None) async

Pack the given resource.

Users should not call this method directly; rather, they should run Resource.run or Resource.pack.

Parameters:

Name	Type	Description	Default
resource	Resource		required
config		Optional config for packing. If an implementation provides a default, this default will always be used when config would otherwise be None. Note that a copy of the default config will be passed, so the default config values cannot be modified persistently by a component run.	None

Source code in ofrak/core/zlib.py

async def pack(self, resource: Resource, config=None):
    zlib_view = await resource.view_as(ZlibData)
    compression_level = zlib_view.compression_level
    zlib_child = await zlib_view.get_child()
    zlib_data = await zlib_child.resource.get_data()
    zlib_compressed = zlib.compress(zlib_data, compression_level)

    original_zlib_size = await zlib_view.resource.get_data_length()
    resource.queue_patch(Range(0, original_zlib_size), zlib_compressed)

ZlibUnpacker (Unpacker)

Decompress a blob of zlib data

unpack(self, resource, config=None) async

Unpack the given resource.

Users should not call this method directly; rather, they should run Resource.run or Resource.unpack.

Parameters:

Name	Type	Description	Default
resource	Resource	The resource that is being unpacked	required
config		Optional config for unpacking. If an implementation provides a default, this default will always be used when config would otherwise be None. Note that a copy of the default config will be passed, so the default config values cannot be modified persistently by a component run.	None

Source code in ofrak/core/zlib.py

async def unpack(self, resource: Resource, config=None):
    zlib_data = await resource.get_data()
    zlib_uncompressed_data = zlib.decompress(zlib_data)
    await resource.create_child(
        tags=(GenericBinary,),
        data=zlib_uncompressed_data,
    )