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# Implement (a subset of) Sun XDR -- RFC1014.
import struct
Long = type(0L)
class Packer:
def init(self):
self.reset()
return self
def reset(self):
self.buf = ''
def get_buf(self):
return self.buf
def pack_uint(self, x):
self.buf = self.buf + \
(chr(int(x>>24 & 0xff)) + chr(int(x>>16 & 0xff)) + \
chr(int(x>>8 & 0xff)) + chr(int(x & 0xff)))
if struct.pack('l', 1) == '\0\0\0\1':
def pack_uint(self, x):
if type(x) == Long:
x = int((x + 0x80000000L) % 0x100000000L \
- 0x80000000L)
self.buf = self.buf + struct.pack('l', x)
pack_int = pack_uint
pack_enum = pack_int
def pack_bool(self, x):
if x: self.buf = self.buf + '\0\0\0\1'
else: self.buf = self.buf + '\0\0\0\0'
def pack_uhyper(self, x):
self.pack_uint(int(x>>32 & 0xffffffff))
self.pack_uint(int(x & 0xffffffff))
pack_hyper = pack_uhyper
def pack_fstring(self, n, s):
if n < 0:
raise ValueError, 'fstring size must be nonnegative'
n = ((n+3)/4)*4
data = s[:n]
data = data + (n - len(data)) * '\0'
self.buf = self.buf + data
pack_fopaque = pack_fstring
def pack_string(self, s):
n = len(s)
self.pack_uint(n)
self.pack_fstring(n, s)
pack_opaque = pack_string
def pack_list(self, list, pack_item):
for item in list:
self.pack_uint(1)
pack_item(list)
self.pack_uint(0)
class Unpacker:
def init(self, data):
self.reset(data)
return self
def reset(self, data):
self.buf = data
self.pos = 0
def done(self):
if self.pos < len(self.buf):
raise RuntimeError, 'unextracted data remains'
def unpack_uint(self):
i = self.pos
self.pos = j = i+4
data = self.buf[i:j]
x = long(ord(data[0]))<<24 | ord(data[1])<<16 | \
ord(data[2])<<8 | ord(data[3])
# Return a Python long only if the value is not representable
# as a nonnegative Python int
if x < 0x80000000L: x = int(x)
return x
if struct.unpack('l', '\0\0\0\1') == 1:
def unpack_uint(self):
i = self.pos
self.pos = j = i+4
return struct.unpack('l', self.buf[i:j])
def unpack_int(self):
x = self.unpack_uint()
if x >= 0x80000000L: x = x - 0x100000000L
return int(x)
unpack_enum = unpack_int
unpack_bool = unpack_int
def unpack_uhyper(self):
hi = self.unpack_uint()
lo = self.unpack_uint()
return long(hi)<<32 | lo
def unpack_hyper(self):
x = self.unpack_uhyper()
if x >= 0x8000000000000000L: x = x - 0x10000000000000000L
return x
def unpack_fstring(self, n):
if n < 0:
raise ValueError, 'fstring size must be nonnegative'
i = self.pos
j = i + (n+3)/4*4
if j > len(self.buf):
raise RuntimeError, 'buffer overrun'
self.pos = j
return self.buf[i:i+n]
unpack_fopaque = unpack_fstring
def unpack_string(self):
n = self.unpack_uint()
return self.unpack_fstring(n)
unpack_opaque = unpack_string
def unpack_list(self, unpack_item):
list = []
while 1:
x = self.unpack_uint()
if not x: break
if x <> 1:
raise RuntimeError, \
'0 or 1 expected, got ' + `x`
list.append(unpack_item())
return list
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