lzma.py

ofrak.core.lzma

LzmaData (GenericBinary)

An lzma binary blob.

LzmaPacker (Packer)

Pack data into a compressed LZMA | XZ file.

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/lzma.py

async def pack(self, resource: Resource, config=None):
    lzma_format, tag = await self._get_lzma_format_and_tag(resource)
    lzma_file: Union[XzData, LzmaData] = await resource.view_as(tag)

    lzma_child = await lzma_file.get_child()
    lzma_compressed = lzma.compress(await lzma_child.resource.get_data(), lzma_format)

    original_size = await lzma_file.resource.get_data_length()
    resource.queue_patch(Range(0, original_size), lzma_compressed)

LzmaUnpacker (Unpacker)

Unpack (decompress) an LZMA | XZ file.

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/lzma.py

async def unpack(self, resource: Resource, config=None):
    file_data = BytesIO(await resource.get_data())

    format = lzma.FORMAT_AUTO

    if resource.has_tag(XzData):
        format = lzma.FORMAT_XZ
    elif resource.has_tag(LzmaData):
        format = lzma.FORMAT_ALONE

    lzma_entry_data = None
    compressed_data = file_data.read()

    try:
        lzma_entry_data = lzma.decompress(compressed_data, format)
    except lzma.LZMAError:
        LOGGER.info("Initial LZMA decompression failed. Trying with null bytes stripped")
        lzma_entry_data = lzma.decompress(compressed_data.rstrip(b"\x00"), format)

    if lzma_entry_data is not None:
        await resource.create_child(
            tags=(GenericBinary,),
            data=lzma_entry_data,
        )
    else:
        raise lzma.LZMAError("Decompressed LZMA data is null")

XzData (GenericBinary)

An xz binary blob.