Renamed decompressed_files/ to out/
Fised a lot of logic Set starting bit to 0x800, since that's after a big blank space in files, is the method bit we are expecting (0x0B) every time, and works to decomp all files (wow!)
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2
.gitignore
vendored
2
.gitignore
vendored
@@ -1,6 +1,6 @@
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# Project Specific
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bin_extract/*
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decompressed_files/*
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out/*
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bzz_mudule.py
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# Byte-compiled / optimized / DLL files
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178
main.py
178
main.py
@@ -1,171 +1,166 @@
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import os
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from bitarray import bitarray
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from pathlib import Path
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class BZZCompressor:
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def decompress(self, input_file_path) -> bytes:
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def decompress(self, input_file_path, input_file, output_folder="out/") -> bytes:
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data = bitarray(endian="big")
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output_buffer = bitarray(endian="big")
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output_buffer = bytearray()
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index = 0x800
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# read the input file
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try:
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with open(input_file_path, "rb") as input_file:
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with open(f"{input_file_path}/{input_file}", "rb") as input_file:
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data.fromfile(input_file)
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data = data.tobytes()
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except IOError:
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print("Could not open input file...")
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raise
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if len(data) > 9:
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# Getting our method, this is likely imprecise, since I'm one dealing with one method type, but it gets what I want
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method = data[0:8] | bitarray("00001010")
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method = data[index]
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# We move on to the next byte in data
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del data[0:8]
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index = index + 1
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# Gathering variables based on the method according to https://problemkaputt.de/psxspx-cdrom-file-compression-bzz.htm
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# Note: bin(int)[2:].zfill(8) converts a number to an 8-bit binary string
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# `>> 3` is the same as dividing by 8
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shifter = (method >> 3) & bitarray(bin(0x03)[2:].zfill(8))
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len_bits = (method & bitarray(bin(0x07)[2:].zfill(8))) ^ bitarray(
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bin(0x07)[2:].zfill(8)
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)
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shifter = (method >> 3) & 0x03
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len_bits = (method & 0x07) ^ 0x07
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# The bin() function only returns the second half of the byte, so we pad the byte
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len_mask = bitarray(bin((1 << int(len_bits.to01(), 2)) - 1)[2:].zfill(8))
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len_mask = 1 << len_bits
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threshold = len_mask >> 1
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if int(threshold.to01(), 2) > 0x07:
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threshold = bitarray(bin(0x13).zfill(8))
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if threshold > 0x07:
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threshold = 0x13
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len_table = []
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for i in range(int(len_mask.to01(), 2)):
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if i > int(threshold.to01(), 2):
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len_table.append(
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(i - int(threshold.to01(), 2) << int(shifter.to01(), 2))
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+ int(threshold.to01(), 2)
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+ 3
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)
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for i in range(len_mask):
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if i > threshold:
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len_table.append((i - threshold << shifter) + threshold + 3)
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else:
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len_table.append(i + 3)
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num_flags = bitarray(bin(int(data[0:24].to01(), 2) + 1)[2:].zfill(24))
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del data[0:24]
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temp_flags = ""
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print(f"Method: {method.tobytes()}")
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print(f"Shifter: {shifter.tobytes()}")
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print(f"Len Bits: {len_bits.tobytes()}")
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print(f"Len Mask: {len_mask.tobytes()}")
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print(f"Threshold: {threshold.tobytes()}")
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for item in data[index : index + 3]:
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temp_flags += bin(item)[2:].zfill(8)
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num_flags = int(temp_flags, 2) + 1
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index = index + 3
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print(f"Method: {hex(method)}")
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print(f"Shifter: {shifter}")
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print(f"Len Bits: {bin(len_bits)}")
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print(f"Len Mask: {bin(len_mask)}")
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print(f"Threshold: {threshold}")
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print(f"Len Table: {len_table}")
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print(f"Num Flags: {num_flags.tobytes()}")
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print(f"Num Flags: {bin(num_flags)}")
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# Adding 0x100 here means the bitarray is a length of 9, and the first item is always 1
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# This means that later, when we need to gather more flag bits, we aren't losing any data, or
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# hitting an index out of bounds error
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flag_bits = bitarray(bin(int(data[0:8].to01(), 2) + 0x100)[2:])
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del data[0:8]
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flag_bits = bitarray(bin(data[index] + 0x100)[2:])
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index = index + 1
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print(f"Starting flag_bits: {flag_bits}")
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while int(num_flags.to01(), 2) > 0:
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while num_flags > 0:
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carry = flag_bits[-1]
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flag_bits = flag_bits >> 1
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if len(flag_bits) > 8 and flag_bits[0] == 0:
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flag_bits = flag_bits[1:]
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print(f"Carry: {carry}")
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print(f"Flag Bits: {flag_bits}")
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# if we are down to only 0 bits, we are out of file-driven data
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# Here we collect more flag bits and re-iterate the loop
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if len(flag_bits.to01()) == 0:
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flag_bits = bitarray(bin(int(data[0:8].to01(), 2) + 0x100)[2:])
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del data[0:8]
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if int(flag_bits.to01(), 2) == 0x00:
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flag_bits = bitarray(bin(data[index] + 0x100)[2:])
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index = index + 1
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continue
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# Carry means the next byte is raw data, no weird placement or indexing
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if carry:
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if len(data) == 0:
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print("Error processing file. Reached of data stream early.")
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try:
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output_buffer.append(data[index])
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index = index + 1
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except IndexError:
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print(output_buffer)
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print(
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f"Error processing file. Reached of data stream early. Index: {index}"
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)
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return
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output_buffer.append(data[0:8])
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del data[0:8]
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# If Carry is 0, then we are doing actual decompression. This is the tricky part
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else:
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# This shouldn't happen
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if len(data) <= 8:
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if len(data) <= index + 1:
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print("Error processing file. Reached of data stream early.")
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return
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# This is "temp" in our documentation
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distance_data = data[0:16]
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del data[0:16]
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temp = ""
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for item in data[index : index + 2]:
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temp = temp + bin(item)[2:].zfill(8)
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distance_data = int(temp, 2)
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index = index + 2
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# length here is the length of the data we are copying.
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# We multiply by 8 since we are working with bits instead of bytes
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length = (
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len_table[
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int(
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(
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distance_data
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& bitarray(
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bin(int(len_mask.to01(), 2))[2:].zfill(16)
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)
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).to01(),
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2,
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)
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]
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* 8
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)
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length = len_table[(distance_data & len_mask) - 1]
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# Displacement is how far back in the existing output_buffer we are
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# looking to copy from. We multiply by 8 since we are working with bits and not bytes
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displacement = (
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int((distance_data >> int(len_bits.to01(), 2)).to01(), 2) * 8
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)
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displacement = distance_data >> len_bits
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# This shouldn't happen
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if displacement <= 0:
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print(
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"Error processing file. Displacement was less than or equal to 0"
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f"Error processing file. Displacement was less than or equal to 0.\n"
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+ f"Distance Data: {distance_data}. Displacement: {displacement}. Index: {hex(index)}"
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)
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return
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print(f"Output Buffer Size (in bits): {len(output_buffer)}")
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print(f"Distance Data: {distance_data.tobytes()}")
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print(f"Displacement (in bits): {displacement}")
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print(f"Length (in bits): {length}")
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print(f"Output Buffer Size {len(output_buffer)}")
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print(f"Distance Data: {distance_data}")
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print(f"Displacement: {displacement}")
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print(f"Length: {length}")
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# Here we copy bit by bit from earlier in the output buffer.
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# we use this instead of index slicing since the slice could lead to
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# data we are currently copying into the buffer
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start_index = len(output_buffer) - displacement
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copy_index = len(output_buffer) - displacement
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# If start index is less than 0, we'll be checking something like output_buffer[-2]
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# or smth, which will have an IndexOutOfBounds exception
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if start_index < 0:
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if copy_index < 0:
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print(output_buffer)
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print("Error decompressing file. Start Index was out of range.")
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return
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for i in range(length):
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output_buffer.append(output_buffer[start_index + i])
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output_buffer.append(output_buffer[copy_index + i])
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num_flags = bitarray(bin(int(num_flags.to01(), 2) - 1)[2:].zfill(24))
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num_flags = num_flags - 1
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if len(data) > 0:
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output_buffer.append(
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bitarray(data.to01() + "0".join("" for i in range(8 - len(data))))
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)
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if len(data) > index:
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for item in data[index:]:
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output_buffer.append(item)
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else:
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# If the file is less than 9 bits, it's just output
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for i in data:
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output_buffer.append(i)
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out_data = b"".join(output_buffer.tobytes())
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# This handoff is so I can change buffer logic without breaking write-out logic
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out_data = output_buffer
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try:
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if "bin_extract" in input_file_path[0:11]:
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@@ -174,20 +169,35 @@ class BZZCompressor:
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output_file_path = input_file_path
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if "/" in output_file_path:
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output_file_name = output_file_path.split("/")[-1]
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output_file_name = output_file_path.split("/")[-1] + ".file"
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else:
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output_file_name = output_file_path
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output_file_name = output_file_path + ".file"
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# TODO: Create file path, if it doesn't exist
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with open(
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f"decompressed_files/{output_file_name[:4]}.file", "wb"
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) as outfile:
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with open(f"{output_folder}/{output_file_name}", "wb") as outfile:
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outfile.write(out_data)
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print(f"File {output_file_name} saved successfully!")
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except IOError:
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print(f"Unable to write file for {input_file_path}")
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except IOError as e:
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print(
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f"Unable to write file for {input_file_path}/{input_file}. Error: {e}"
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)
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compressor = BZZCompressor()
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if __name__ == "__main__":
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compressor = BZZCompressor()
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compressor.decompress("bin_extract/level/mc/mccave01.bzz")
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for dirpath, dirnames, filenames in os.walk("./bin_extract"):
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print(f"{dirpath} | {', '.join(filenames)}")
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for file in filenames:
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if file[-4:] == ".bzz":
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output_folder_path = Path(f"out/{'/'.join(dirpath.split("/")[2:])}")
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output_folder_path.mkdir(parents=True, exist_ok=True)
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try:
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compressor.decompress(dirpath, file, output_folder_path)
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except Exception as e:
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print(
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f"Error while decompressing {output_folder_path}/{file}. Error: {e}"
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)
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continue
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