Edit File: xdr.py
# Implement (a subset of) Sun XDR -- RFC1014. try: import struct except ImportError: struct = None Long = type(0L) class Packer: def __init__(self): self.reset() 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 and 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_float(self, x): # XXX self.buf = self.buf + struct.pack('f', x) def pack_double(self, x): # XXX self.buf = self.buf + struct.pack('d', x) 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(item) self.pack_uint(0) def pack_farray(self, n, list, pack_item): if len(list) <> n: raise ValueError, 'wrong array size' for item in list: pack_item(item) def pack_array(self, list, pack_item): n = len(list) self.pack_uint(n) self.pack_farray(n, list, pack_item) class Unpacker: def __init__(self, data): self.reset(data) 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] if len(data) < 4: raise EOFError 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 and struct.unpack('l', '\0\0\0\1') == 1: def unpack_uint(self): i = self.pos self.pos = j = i+4 data = self.buf[i:j] if len(data) < 4: raise EOFError return struct.unpack('l', data) 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_float(self): # XXX i = self.pos self.pos = j = i+4 data = self.buf[i:j] if len(data) < 4: raise EOFError return struct.unpack('f', data)[0] def unpack_double(self): # XXX i = self.pos self.pos = j = i+8 data = self.buf[i:j] if len(data) < 8: raise EOFError return struct.unpack('d', data)[0] 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 EOFError 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 x == 0: break if x <> 1: raise RuntimeError, '0 or 1 expected, got %r' % (x, ) item = unpack_item() list.append(item) return list def unpack_farray(self, n, unpack_item): list = [] for i in range(n): list.append(unpack_item()) return list def unpack_array(self, unpack_item): n = self.unpack_uint() return self.unpack_farray(n, unpack_item)