def read(self, count):
end = self.inputpos + count
if end > len(self.input):
raise StructError('unpack str size too short for format')
s = self.input[self.inputpos:end]
self.inputpos = end
return s
def accept_obj_arg(self):
try:
w_obj = self.args_w[self.args_index]
except IndexError:
raise StructError("struct format requires more arguments")
self.args_index += 1
return w_obj
def unpack_pascal(fmtiter, count):
if count == 0:
raise StructError("bad '0p' in struct format")
data = fmtiter.read(count)
end = 1 + ord(data[0])
if end > count:
end = count
fmtiter.appendobj(data[1:end])
def pack_int(fmtiter):
method = getattr(fmtiter, accept_method)
value = method()
if check_range:
if value < min or value > max:
raise StructError(errormsg)
if fmtiter.bigendian:
for i in unroll_revrange_size:
x = (value >> (8 * i)) & 0xff
fmtiter.result.append(chr(x))
else:
for i in unroll_revrange_size:
fmtiter.result.append(chr(value & 0xff))
value >>= 8
def pack_pascal(fmtiter, count):
string = fmtiter.accept_str_arg()
prefix = len(string)
if prefix >= count:
prefix = count - 1
if prefix < 0:
raise StructError("bad '0p' in struct format")
if prefix > 255:
prefixchar = '\xff'
else:
prefixchar = chr(prefix)
fmtiter.result.append(prefixchar)
fmtiter.result.append_slice(string, 0, prefix)
fmtiter.result.append_multiple_char('\x00', count - (1 + prefix))
def pack_pascal(fmtiter, count):
string = fmtiter.accept_str_arg()
prefix = len(string)
if prefix >= count:
prefix = count - 1
if prefix < 0:
raise StructError("bad '0p' in struct format")
if prefix > 255:
prefixchar = '\xff'
else:
prefixchar = chr(prefix)
fmtiter.result.append(prefixchar)
fmtiter.result += string[:prefix]
for i in range(1 + prefix, count):
fmtiter.result.append('\x00')
def pack_unichar(fmtiter):
unistr = fmtiter.accept_unicode_arg()
if len(unistr) != 1:
raise StructError("expected a unicode string of length 1")
c = unistr[0] # string->char conversion for the annotator
unichar.pack_unichar(c, fmtiter.result)
def finished(self):
if self.inputpos != len(self.input):
raise StructError('unpack str size too long for format')
def align(self, mask):
pad = (-self.totalsize) & mask
try:
self.totalsize = ovfcheck(self.totalsize + pad)
except OverflowError:
raise StructError("total struct size too long")
def operate(self, fmtdesc, repetitions):
try:
size = ovfcheck(fmtdesc.size * repetitions)
self.totalsize = ovfcheck(self.totalsize + size)
except OverflowError:
raise StructError("total struct size too long")
def interpret(self, fmt):
# decode the byte order, size and alignment based on the 1st char
table = unroll_native_fmtdescs
self.bigendian = native_is_bigendian
index = 0
if len(fmt) > 0:
c = fmt[0]
index = 1
if c == '@':
pass
elif c == '=':
table = unroll_standard_fmtdescs
elif c == '<':
table = unroll_standard_fmtdescs
self.bigendian = False
elif c == '>' or c == '!':
table = unroll_standard_fmtdescs
self.bigendian = True
else:
index = 0
# interpret the format string,
# calling self.operate() for each format unit
while index < len(fmt):
c = fmt[index]
index += 1
if c.isspace():
continue
if c.isdigit():
repetitions = ord(c) - ord('0')
while True:
if index == len(fmt):
raise StructError("incomplete struct format")
c = fmt[index]
index += 1
if not c.isdigit():
break
try:
repetitions = ovfcheck(repetitions * 10)
repetitions = ovfcheck(repetitions +
(ord(c) - ord('0')))
except OverflowError:
raise StructError("overflow in item count")
assert repetitions >= 0
else:
repetitions = 1
for fmtdesc in table:
if c == fmtdesc.fmtchar:
if self._operate_is_specialized_:
if fmtdesc.alignment > 1:
self.align(fmtdesc.mask)
self.operate(fmtdesc, repetitions)
break
else:
raise StructError("bad char in struct format")
if not self._operate_is_specialized_:
if fmtdesc.alignment > 1:
self.align(fmtdesc.mask)
self.operate(fmtdesc, repetitions)
self.finished()
def finished(self):
if self.args_index != len(self.args_w):
raise StructError("too many arguments for struct format")
def pack_char(fmtiter):
string = fmtiter.accept_str_arg()
if len(string) != 1:
raise StructError("expected a string of length 1")
c = string[0] # string->char conversion for the annotator
fmtiter.result.append(c)
