26 class encoder(object):
27 def __init__(self, *, backrefs=True):
28 self.backrefs = backrefs
35 return bytes([(sec << 3) | pri])
37 def writetag(self, dst, pri, sec, datum):
38 dst.write(self.enctag(pri, sec))
42 if datum is not None and id(datum) not in self.reftab:
43 self.reftab[id(datum)] = ref
53 while (x > 0) or (b & 0x40) != 0:
61 while x < -1 or (b & 0x40) == 0:
69 def writestr(dst, text):
70 dst.write(text.encode("utf-8"))
73 def dumpseq(self, dst, seq):
76 dst.write(self.enctag(T_END, 0))
78 def dumpmap(self, dst, val):
79 for k, v in val.items():
82 dst.write(self.enctag(T_END, 0))
84 def dump(self, dst, datum):
85 ref = self.reftab.get(id(datum))
87 dst.write(self.enctag(T_INT, INT_REF))
88 dst.write(self.encint(ref))
91 self.writetag(dst, T_NIL, 0, None)
93 self.writetag(dst, T_NIL, NIL_FALSE, None)
95 self.writetag(dst, T_NIL, NIL_TRUE, None)
96 elif isinstance(datum, int):
97 self.writetag(dst, T_INT, 0, None)
98 dst.write(self.encint(datum))
99 elif isinstance(datum, str):
100 self.writetag(dst, T_STR, 0, datum)
101 self.writestr(dst, datum)
102 elif isinstance(datum, (bytes, bytearray)):
103 self.writetag(dst, T_BIT, 0, datum)
104 dst.write(self.encint(len(datum)))
106 elif isinstance(datum, data.symbol):
108 self.writetag(dst, T_STR, STR_SYM, datum)
109 self.writestr(dst, datum.name)
111 nsref = self.nstab.get(datum.ns)
113 nsref = self.writetag(dst, T_SYM, 0, datum)
115 self.writestr(dst, datum.ns)
116 self.writestr(dst, datum.name)
117 if nsref is not None:
118 self.nstab[datum.ns] = nsref
120 self.writetag(dst, T_SYM, 0, datum)
122 dst.write(self.encint(nsref))
123 self.writestr(dst, datum.name)
124 elif isinstance(datum, list):
125 self.writetag(dst, T_CON, CON_SEQ, datum)
126 self.dumpseq(dst, datum)
127 elif isinstance(datum, set):
128 self.writetag(dst, T_CON, CON_SET, datum)
129 self.dumpseq(dst, datum)
130 elif isinstance(datum, dict):
131 self.writetag(dst, T_CON, CON_MAP, datum)
132 self.dumpmap(dst, datum)
133 elif isinstance(datum, data.obj):
134 self.writetag(dst, T_CON, CON_OBJ, datum)
135 self.dump(dst, getattr(type(datum), "typename", None))
136 self.dumpmap(dst, datum.__dict__)
138 raise ValueError("unsupported object type: " + repr(datum))
140 def dump(dst, datum):
141 encoder().dump(dst, datum)
144 class fmterror(Exception):
147 class eoferror(fmterror):
149 super().__init__("unexpected end-of-data")
151 class referror(fmterror):
153 super().__init__("bad backref")
155 class namedtype(type):
158 class decoder(object):
176 ret += (b & 0x7f) << p
192 return buf.decode("utf-8")
194 def loadsym(self, fp):
197 nsref = self.loadint(fp)
198 if not 0 <= nsref < len(self.reftab):
199 raise fmterror("illegal namespace ref: " + str(nsref))
200 nssym = self.reftab[nsref]
201 if not isinstance(nssym, data.symbol):
202 raise fmterror("illegal namespace ref: " + str(nsref))
205 ns = self.loadstr(fp)
206 nm = self.loadstr(fp)
207 ret = data.symbol.get(ns, nm)
210 def loadlist(self, fp, buf):
215 buf.append(self.loadtagged(fp, tag))
217 def loadmap(self, fp, buf):
222 key = self.loadtagged(fp, tag)
226 buf[key] = self.loadtagged(fp, tag)
228 def loadobj(self, fp, ref=False):
230 refid = len(self.reftab)
231 self.reftab.append(None)
233 typ = self.namedtypes.get(nm)
235 typ = self.namedtypes[nm] = namedtype(str(nm), (data.obj, object), {})
239 self.reftab[refid] = ret
241 # print(">", nm, hex(st))
242 ret.__dict__.update(self.loadmap(fp, {}))
243 # print("<", nm, hex(fp.tell()), hex(st))
246 def addref(self, obj):
247 self.reftab.append(obj)
250 def loadtagged(self, fp, tag):
251 pri, sec = (tag & 0x7), (tag & 0xf8) >> 3
253 raise fmterror("unexpected end-tag")
256 idx = self.loadint(fp)
257 if not 0 <= idx < len(self.reftab):
259 # print(idx, self.reftab[idx], hex(fp.tell()))
260 return self.reftab[idx]
261 return self.addref(self.loadint(fp))
263 ret = self.addref(self.loadstr(fp))
265 return data.symbol.get("", ret)
268 ln = self.loadint(fp)
269 ret = self.addref(fp.read(ln))
275 return self.addref(True)
276 elif sec == NIL_FALSE:
277 return self.addref(False)
278 return self.addref(None)
280 return self.addref(self.loadsym(fp))
283 return self.loadmap(fp, self.addref({}))
285 return self.loadobj(fp, ref=True)
287 return self.loadlist(fp, self.addref([]))
289 raise fmterror("unknown primary: " + str(pri))
293 return self.loadtagged(fp, tag)