tbxi/tbxi/bootinfo_build.py
2019-05-25 10:05:06 +08:00

78 lines
2.2 KiB
Python

from os import path
import re
import zlib
try:
from .fast_lzss import compress
except ImportError:
from .slow_lzss import compress
from . import dispatcher
def append_checksum(binary):
cksum = ('\r\\ h# %08X' % zlib.adler32(binary)).encode('ascii')
binary.extend(cksum)
def build(src):
try:
with open(path.join(src, 'Bootscript'), 'rb') as f:
booter = bytearray(f.read().replace(b'\n', b'\r'))
except (NotADirectoryError, FileNotFoundError):
raise dispatcher.WrongFormat
constants = dict()
constant_spans = dict()
for m in re.finditer(rb'h#\s+([A-Fa-f0-9]+)\s+constant\s+([-\w]+)', booter):
key = m.group(2).decode('ascii')
val = int(m.group(1), 16)
constants[key] = val
constant_spans[key] = m.span(1)
booter.append(4) # EOT
for f in ['elf-offset', 'elf-size']:
assert f in constants
if 'elf-offset' in constants:
# special case: pad according to residual info in script
booter.extend(b'\0' * (constants['elf-offset'] - len(booter)))
constants['elf-offset'] = len(booter)
booter.extend(dispatcher.build_path(path.join(src, 'MacOS.elf')))
constants['elf-size'] = len(booter) - constants['elf-offset']
if 'lzss-offset' in constants:
base = 'lzss'
else:
base = 'parcels'
if base + '-offset' in constants:
constants[base + '-offset'] = len(booter)
for attempt in ['MacROM', 'Parcels']:
try:
data = dispatcher.build_path(path.join(src, attempt))
except:
pass
else:
break
else:
raise FileNotFoundError
if not data.startswith(b'prcl'): data = compress(data)
booter.extend(data)
constants[base + '-size'] = len(booter) - constants[base + '-offset']
constants['info-size'] = len(booter)
for key, (start, stop) in reversed(sorted(constant_spans.items())):
insert = ('%X' % constants[key]).zfill(stop - start).encode('ascii')
assert start + len(insert) == stop
booter[start:stop] = insert
append_checksum(booter)
return bytes(booter)