mbirth/gcd-parser
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Small optimisations.

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This commit is contained in:
Markus Birth 2018-10-18 00:57:30 +02:00
parent 02daff44b5
commit 4aa3e39d7d
Signed by: mbirth
GPG Key ID: A9928D7A098C3A9A
1 changed files with 11 additions and 2 deletions
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13
grmn/gcd.py
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@ -12,6 +12,9 @@ DEFAULT_ALIGN = 0x1000 # second padding block pads until 0x1000
# first 0x1000 Bytes: GCD_SIG > 0x0001 > 0x0002 > 0x0003 > 0x0005 > 0x0001 > 0x0002 # first 0x1000 Bytes: GCD_SIG > 0x0001 > 0x0002 > 0x0003 > 0x0005 > 0x0001 > 0x0002
# then: 0x0001 > ( 0x0006 > 0x0007 > 0x???? > 0x0001 ... ) > 0xffff # then: 0x0001 > ( 0x0006 > 0x0007 > 0x???? > 0x0001 ... ) > 0xffff
class ParseException(Exception):
pass
class Gcd: class Gcd:
def __init__(self, filename: str=None): def __init__(self, filename: str=None):
self.filename = filename self.filename = filename
@ -26,12 +29,12 @@ class Gcd:
with open(self.filename, "rb") as f: with open(self.filename, "rb") as f:
sig = f.read(8) sig = f.read(8)
if sig != GCD_SIG: if sig != GCD_SIG:
raise Exception("Signature mismatch ({}, should be {})!".format(repr(sig), repr(GCD_SIG))) raise ParseException("Signature mismatch ({}, should be {})!".format(repr(sig), repr(GCD_SIG)))
while True: while True:
cur_offset = f.tell() cur_offset = f.tell()
header = f.read(4) header = f.read(4)
tlv = TLV.factory(header, offset=cur_offset) tlv = TLV.factory(header, offset=cur_offset)
self.struct.append(tlv) self.add_tlv(tlv)
if tlv.type_id == 0xFFFF: if tlv.type_id == 0xFFFF:
# End of file reached # End of file reached
break break
@ -44,7 +47,13 @@ class Gcd:
tlv.set_tlv6(last_tlv6) tlv.set_tlv6(last_tlv6)
f.close() f.close()
def add_tlv(self, new_tlv: TLV):
self.struct.append(new_tlv)
def print_struct(self): def print_struct(self):
"""
Prints the structure of the parsed GCD file
"""
last_tlv = 0xffff last_tlv = 0xffff
tlv_count = 0 tlv_count = 0
tlv_length = 0 tlv_length = 0