def __init__(self, rom: NintendoDSRom):
self.rom = rom
data = rom.iconBanner
self.version = read_u16(data, 0x0)
assert len(data) == ICON_BANNER_SIZE
assert self.version == 1 # EoS should always use version 1
self.checksum = read_u16(data, 0x2)
self.icon = Icon(read_bytes(data, 0x20, 0x200),
read_bytes(data, 0x220, 0x20))
self.title_japanese = read_bytes(
data, 0x240, 0x100).decode('UTF-16LE').rstrip('\x00')
self.title_english = read_bytes(
data, 0x340, 0x100).decode('UTF-16LE').rstrip('\x00')
self.title_french = read_bytes(data, 0x440,
0x100).decode('UTF-16LE').rstrip('\x00')
self.title_german = read_bytes(data, 0x540,
0x100).decode('UTF-16LE').rstrip('\x00')
self.title_italian = read_bytes(
data, 0x640, 0x100).decode('UTF-16LE').rstrip('\x00')
self.title_spanish = read_bytes(
data, 0x740, 0x100).decode('UTF-16LE').rstrip('\x00')
def _look_ahead_two_int_sequence(self):
seq = bytearray(NRL_LOOKAHEAD_COPY_BYTES_MAX_BYTES * 4)
seq_len = 0
# If the repeat counter reaches NRL_MIN_SEQ_LEN, the sequence ends NRL_MIN_SEQ_LEN entries before that
repeat_counter = 0
previous_ints_at_pos = 0x1000000 # Impossible "null" value for now
nc = self.cursor
while True:
ints_at_pos = read_bytes(self.uncompressed_data, nc, 4)
if ints_at_pos == previous_ints_at_pos:
repeat_counter += 1
else:
repeat_counter = 0
previous_ints_at_pos = ints_at_pos
seq[seq_len * 4:(seq_len * 4) + 4] = ints_at_pos
if repeat_counter > NRL_MIN_SEQ_LEN:
seq_len -= NRL_MIN_SEQ_LEN
break
if seq_len + 1 >= NRL_LOOKAHEAD_COPY_BYTES_MAX_BYTES or nc >= self.length_input:
break
seq_len += 1
nc += 4
return seq_len, seq[:seq_len * 4]
def _read(self) -> bytes:
"""Reads 4 bytes and increases cursor"""
if self.cursor + 4 > self.length_input:
raise ValueError("BMA Layer NRL Compressor: Reached EOF while reading data.")
oc = self.cursor
self.cursor += 4
return read_bytes(self.uncompressed_data, oc, 4)
def _look_ahead_repeats(self, data: bytes):
"""Look how often the 4 byte pattern in the input data repeats, up to NRL_LOOKAHEAD_MAX_BYTES"""
nc = self.cursor
repeats = 0
while read_bytes(self.uncompressed_data, nc, 4) == data and \
repeats < NRL_LOOKAHEAD_ZERO_MAX_BYTES and \
nc < self.length_input:
repeats += 1
nc += 4
return repeats
def matches(cls, data: bytes, byte_offset=0):
"""Check if the given data stream is a At3px container"""
return read_bytes(data, byte_offset, 5) == b'AT3PX'
def matches(cls, data: bytes, byte_offset=0):
"""Check if the given data is a At4pn container"""
return read_bytes(data, byte_offset, 5) == b'AT4PN'
def matches(cls, data: bytes, byte_offset=0):
"""Check if the given data stream has the magic string for MD files."""
return read_bytes(data, byte_offset, 4) == b'MD\0\0'
def matches(cls, data: bytes, byte_offset: int = 0) -> bool:
"""Check if the given data is a container of its type"""
return read_bytes(data, byte_offset,
len(cls.magic_word())) == cls.magic_word()
def matches(cls, data: bytes, byte_offset=0):
"""Check if the given data stream is a Sir0 container"""
return read_bytes(data, byte_offset, 4) == b'SIR0'