1 # Implement (a subset of) Sun XDR -- RFC1014. 2 3 4 try: 5 import struct 6 except ImportError: 7 struct = None 8 9 10 Long = type(0L) 11 12 13 class Packer: 14 15 def __init__(self): 16 self.reset() 17 18 def reset(self): 19 self.buf = '' 20 21 def get_buf(self): 22 return self.buf 23 24 def pack_uint(self, x): 25 self.buf = self.buf + \ 26 (chr(int(x>>24 & 0xff)) + chr(int(x>>16 & 0xff)) + \ 27 chr(int(x>>8 & 0xff)) + chr(int(x & 0xff))) 28 if struct and struct.pack('l', 1) == '\0\0\0\1': 29 def pack_uint(self, x): 30 if type(x) == Long: 31 x = int((x + 0x80000000L) % 0x100000000L \ 32 - 0x80000000L) 33 self.buf = self.buf + struct.pack('l', x) 34 35 pack_int = pack_uint 36 37 pack_enum = pack_int 38 39 def pack_bool(self, x): 40 if x: self.buf = self.buf + '\0\0\0\1' 41 else: self.buf = self.buf + '\0\0\0\0' 42 43 def pack_uhyper(self, x): 44 self.pack_uint(int(x>>32 & 0xffffffff)) 45 self.pack_uint(int(x & 0xffffffff)) 46 47 pack_hyper = pack_uhyper 48 49 def pack_float(self, x): 50 # XXX 51 self.buf = self.buf + struct.pack('f', x) 52 53 def pack_double(self, x): 54 # XXX 55 self.buf = self.buf + struct.pack('d', x) 56 57 def pack_fstring(self, n, s): 58 if n < 0: 59 raise ValueError, 'fstring size must be nonnegative' 60 n = ((n + 3)//4)*4 61 data = s[:n] 62 data = data + (n - len(data)) * '\0' 63 self.buf = self.buf + data 64 65 pack_fopaque = pack_fstring 66 67 def pack_string(self, s): 68 n = len(s) 69 self.pack_uint(n) 70 self.pack_fstring(n, s) 71 72 pack_opaque = pack_string 73 74 def pack_list(self, list, pack_item): 75 for item in list: 76 self.pack_uint(1) 77 pack_item(item) 78 self.pack_uint(0) 79 80 def pack_farray(self, n, list, pack_item): 81 if len(list) <> n: 82 raise ValueError, 'wrong array size' 83 for item in list: 84 pack_item(item) 85 86 def pack_array(self, list, pack_item): 87 n = len(list) 88 self.pack_uint(n) 89 self.pack_farray(n, list, pack_item) 90 91 92 class Unpacker: 93 94 def __init__(self, data): 95 self.reset(data) 96 97 def reset(self, data): 98 self.buf = data 99 self.pos = 0 100 101 def done(self): 102 if self.pos < len(self.buf): 103 raise RuntimeError, 'unextracted data remains' 104 105 def unpack_uint(self): 106 i = self.pos 107 self.pos = j = i+4 108 data = self.buf[i:j] 109 if len(data) < 4: 110 raise EOFError 111 x = long(ord(data[0]))<<24 | ord(data[1])<<16 | \ 112 ord(data[2])<<8 | ord(data[3]) 113 # Return a Python long only if the value is not representable 114 # as a nonnegative Python int 115 if x < 0x80000000L: x = int(x) 116 return x 117 if struct and struct.unpack('l', '\0\0\0\1') == 1: 118 def unpack_uint(self): 119 i = self.pos 120 self.pos = j = i+4 121 data = self.buf[i:j] 122 if len(data) < 4: 123 raise EOFError 124 return struct.unpack('l', data) 125 126 def unpack_int(self): 127 x = self.unpack_uint() 128 if x >= 0x80000000L: x = x - 0x100000000L 129 return int(x) 130 131 unpack_enum = unpack_int 132 133 unpack_bool = unpack_int 134 135 def unpack_uhyper(self): 136 hi = self.unpack_uint() 137 lo = self.unpack_uint() 138 return long(hi)<<32 | lo 139 140 def unpack_hyper(self): 141 x = self.unpack_uhyper() 142 if x >= 0x8000000000000000L: x = x - 0x10000000000000000L 143 return x 144 145 def unpack_float(self): 146 # XXX 147 i = self.pos 148 self.pos = j = i+4 149 data = self.buf[i:j] 150 if len(data) < 4: 151 raise EOFError 152 return struct.unpack('f', data)[0] 153 154 def unpack_double(self): 155 # XXX 156 i = self.pos 157 self.pos = j = i+8 158 data = self.buf[i:j] 159 if len(data) < 8: 160 raise EOFError 161 return struct.unpack('d', data)[0] 162 163 def unpack_fstring(self, n): 164 if n < 0: 165 raise ValueError, 'fstring size must be nonnegative' 166 i = self.pos 167 j = i + (n+3)//4*4 168 if j > len(self.buf): 169 raise EOFError 170 self.pos = j 171 return self.buf[i:i+n] 172 173 unpack_fopaque = unpack_fstring 174 175 def unpack_string(self): 176 n = self.unpack_uint() 177 return self.unpack_fstring(n) 178 179 unpack_opaque = unpack_string 180 181 def unpack_list(self, unpack_item): 182 list = [] 183 while 1: 184 x = self.unpack_uint() 185 if x == 0: break 186 if x <> 1: 187 raise RuntimeError, '0 or 1 expected, got %r' % (x, ) 188 item = unpack_item() 189 list.append(item) 190 return list 191 192 def unpack_farray(self, n, unpack_item): 193 list = [] 194 for i in range(n): 195 list.append(unpack_item()) 196 return list 197 198 def unpack_array(self, unpack_item): 199 n = self.unpack_uint() 200 return self.unpack_farray(n, unpack_item) 201
