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Add legacy decompression to TXP2File (#105)

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seth 2025-11-12 19:28:09 -06:00 committed by GitHub
parent 5de55fef39
commit 48d5a12380
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GPG Key ID: B5690EEEBB952194
1 changed files with 63 additions and 1 deletions
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64
bemani/format/afp/container.py
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@ -372,6 +372,68 @@ class TXP2File(TrackedCoverage, VerboseOutput):
flags3=flags3,
)
def decompress_legacy(self, texture_offset: int, texture_length: int, name: str) -> bytes:
# Get size, round up to nearest power of 4
decomp_len, comp_len = struct.unpack(
">II",
self.data[texture_offset : (texture_offset + 8)],
)
self.add_coverage(texture_offset, 8)
self.vprint(
f" {name}, length: {texture_length}, offset: {hex(texture_offset)}, deflated_size: {comp_len}, inflated_size: {decomp_len}"
)
if comp_len != (texture_length - 8):
raise Exception("We got an incorrect length for lz texture!")
decomp_len = (decomp_len + 3) & (~3)
# Get the data offset.
lz_data_offset = texture_offset + 8
comp = self.data[lz_data_offset : (lz_data_offset + comp_len)]
self.add_coverage(lz_data_offset, comp_len)
# This takes forever, so skip it if we're pretending.
if comp_len == 0:
data_len = min(decomp_len, texture_length - 8)
return self.data[lz_data_offset : (lz_data_offset + data_len)]
decomp = bytearray()
window = [0] * 4096
comp_i, window_i = 0, 4078
control = 0
while comp_i < comp_len:
control = comp[comp_i]
comp_i += 1
i = 0
while i < 8 and len(decomp) < decomp_len:
if (control & 0x01) != 0:
if comp_i >= comp_len:
return decomp
decomp.append(comp[comp_i])
window[window_i] = comp[comp_i]
window_i += 1
comp_i += 1
window_i &= 0xfff
else:
slide_off = (((comp[comp_i + 1] & 0xf0) << 4) | comp[comp_i]) & 0xfff
slide_len = (comp[comp_i + 1] & 0x0f) + 3
comp_i += 2
if (len(decomp) + slide_len) > decomp_len:
slide_len = decomp_len - len(decomp)
while slide_len > 0:
decomp.append(window[slide_off])
window[window_i] = window[slide_off]
window_i += 1
slide_off += 1
window_i &= 0xfff
slide_off &= 0xfff
slide_len -= 1
control >>= 1
i += 1
return decomp
def __parse(self, verbose: bool) -> None:
# First, check the signature
if self.data[0:4] == b"2PXT":
@ -437,7 +499,7 @@ class TXP2File(TrackedCoverage, VerboseOutput):
if name_offset != 0 and texture_offset != 0:
lz_data: Optional[bytes] = None
if self.legacy_lz:
raise Exception("We don't support legacy lz mode!")
raw_data = self.decompress_legacy(texture_offset, texture_length, name)
elif self.modern_lz:
# Get size, round up to nearest power of 4
inflated_size, deflated_size = struct.unpack(