Ковыряем deSPIRIA

[e2e4]

декомпрессор для cpr проде работает, правда как упаковать обратно не ясно, ну не селен я в програмировании

Код:

import struct
import sys

def lzss_decompress(data: bytes) -> bytes:
    print("  [LZSS] Checking input length...")
    if len(data) < 5:
        raise ValueError("LZSS input is too short")

    target_size = struct.unpack_from("<I", data, 0)[0]
    print(f"  [LZSS] Target size from header: {target_size} bytes")
    if target_size <= 0:
        raise ValueError(f"Invalid LZSS decompressed size: {target_size}")

    ring = bytearray(4096)
    ring_pos = 0xFEE
    src_pos = 4
    out = bytearray()

    print("  [LZSS] Starting decompression loop...")
    while src_pos < len(data) and len(out) < target_size:
        flags = data[src_pos]
        src_pos += 1

        for bit in range(8):
            if flags & (1 << bit):
                # Literal byte
                if src_pos >= len(data):
                    raise ValueError("Truncated LZSS literal")

                value = data[src_pos]
                src_pos += 1

                out.append(value)
                ring[ring_pos] = value
                ring_pos = (ring_pos + 1) & 0xFFF
            else:
                # Two-byte back-reference
                if src_pos + 1 >= len(data):
                    raise ValueError("Truncated LZSS back-reference")

                b0 = data[src_pos]
                b1 = data[src_pos + 1]
                src_pos += 2

                offset = b0 | ((b1 & 0xF0) << 4)
                length = (b1 & 0x0F) + 3

                for i in range(length):
                    value = ring[(offset + i) & 0xFFF]
                    out.append(value)
                    ring[ring_pos] = value
                    ring_pos = (ring_pos + 1) & 0xFFF

                    if len(out) >= target_size:
                        break

            if len(out) >= target_size:
                break

    if len(out) != target_size:
        raise ValueError(
            f"LZSS stream ended at {len(out):,} bytes; expected {target_size:,}"
        )

    return bytes(out)

def main():
    print("=== LZSS Decompressor started ===")
    if len(sys.argv) < 3:
        print("Usage: python lzss_decompress.py <input.cpr> <output.bin>")
        sys.exit(1)

    input_path = sys.argv[1]
    output_path = sys.argv[2]

    print(f"[MAIN] Input: {input_path}")
    print(f"[MAIN] Output: {output_path}")

    try:
        with open(input_path, "rb") as f:
            data = f.read()
        print(f"[MAIN] Read {len(data)} bytes from input file")
    except FileNotFoundError:
        print(f"ERROR: Input file not found: {input_path}", file=sys.stderr)
        sys.exit(1)
    except Exception as e:
        print(f"ERROR reading file: {e}", file=sys.stderr)
        sys.exit(1)

    try:
        decompressed = lzss_decompress(data)
        print(f"[MAIN] Decompressed to {len(decompressed)} bytes")
    except ValueError as e:
        print(f"LZSS decompression error: {e}", file=sys.stderr)
        sys.exit(1)
    except Exception as e:
        print(f"Unexpected error during decompression: {e}", file=sys.stderr)
        sys.exit(1)

    try:
        with open(output_path, "wb") as f:
            f.write(decompressed)
        print(f"[MAIN] Wrote {len(decompressed)} bytes to output file")
        print("=== Done ===")
    except Exception as e:
        print(f"Error writing output file: {e}", file=sys.stderr)
        sys.exit(1)

if __name__ == "__main__":
    main()