decodeLiteral

    fn decodeLiteral(
        self: *Decode,
        reader: *Reader,
        /// `CircularBuffer` or `std.compress.lzma2.AccumBuffer`.
        buffer: anytype,
        decoder: *RangeDecoder,
        n_read: *u64,
    ) !u8 {
        const def_prev_byte = 0;
        const prev_byte = @as(usize, buffer.lastOr(def_prev_byte));

        var result: usize = 1;
        const lit_state = ((buffer.len & ((@as(usize, 1) << self.properties.lp) - 1)) << self.properties.lc) +
            (prev_byte >> (8 - self.properties.lc));
        const probs = try self.literal_probs.get(lit_state);

        if (self.state >= 7) {
            var match_byte = @as(usize, try buffer.lastN(self.rep[0] + 1));

            while (result < 0x100) {
                const match_bit = (match_byte >> 7) & 1;
                match_byte <<= 1;
                const bit = @intFromBool(try decoder.decodeBit(
                    reader,
                    &probs[((@as(usize, 1) + match_bit) << 8) + result],
                    n_read,
                ));
                result = (result << 1) ^ bit;
                if (match_bit != bit) {
                    break;
                }
            }
        }

        while (result < 0x100) {
            result = (result << 1) ^ @intFromBool(try decoder.decodeBit(reader, &probs[result], n_read));
        }

        return @truncate(result - 0x100);
    }