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python-rsrcfork
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Refactor rsrcfork.compress to prepare for 'dcmp' (1) support

This commit is contained in:
dgelessus 2019-08-22 01:12:29 +02:00
parent 3d444bda10
commit acd056973e
1 changed files with 26 additions and 14 deletions
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40
rsrcfork/compress.py
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@ -163,23 +163,11 @@ def _read_variable_length_integer(data: bytes, position: int) -> typing.Tuple[in
return int.from_bytes(data[position:position+1], "big", signed=True), 1
def _decompress_application(data: bytes, decompressed_length: int, *, debug: bool=False) -> bytes:
working_buffer_fractional_size, expansion_buffer_size, dcmp_id, reserved = STRUCT_COMPRESSED_APPLICATION_HEADER.unpack_from(data)
if debug:
print(f"Working buffer fractional size: {working_buffer_fractional_size} (=> {len(data) * 256 / working_buffer_fractional_size})")
print(f"Expansion buffer size: {expansion_buffer_size}")
if dcmp_id != 0:
raise DecompressError(f"Unsupported 'dcmp' ID: {dcmp_id}, expected 0")
if reserved != 0:
raise DecompressError(f"Reserved field should be 0, not 0x{reserved:>04x}")
def _decompress_application_0(data: bytes, decompressed_length: int, *, debug: bool=False) -> bytes:
prev_literals = []
decompressed = b""
i = STRUCT_COMPRESSED_APPLICATION_HEADER.size
i = 0
while i < len(data):
byte = data[i]
@ -432,6 +420,30 @@ def _decompress_application(data: bytes, decompressed_length: int, *, debug: boo
return decompressed
def _decompress_application_1(data: bytes, decompressed_length: int, *, debug: bool=False) -> bytes:
raise NotImplementedError("'dcmp' (1) decompression not supported yet")
def _decompress_application(data: bytes, decompressed_length: int, *, debug: bool=False) -> bytes:
working_buffer_fractional_size, expansion_buffer_size, dcmp_id, reserved = STRUCT_COMPRESSED_APPLICATION_HEADER.unpack_from(data)
if debug:
print(f"Working buffer fractional size: {working_buffer_fractional_size} (=> {len(data) * 256 / working_buffer_fractional_size})")
print(f"Expansion buffer size: {expansion_buffer_size}")
if dcmp_id == 0:
decompress_func = _decompress_application_0
elif dcmp_id == 1:
decompress_func = _decompress_application_1
else:
raise DecompressError(f"Unsupported 'dcmp' ID: {dcmp_id}, expected 0 or 1")
if reserved != 0:
raise DecompressError(f"Reserved field should be 0, not 0x{reserved:>04x}")
return decompress_func(data[STRUCT_COMPRESSED_APPLICATION_HEADER.size:], decompressed_length, debug=debug)
def _decompress_system_untagged(data: bytes, decompressed_length: int, table: typing.Sequence[bytes], *, debug: bool=False) -> bytes:
parts = []
i = 0