support for complex numbers

for more information, see https://pre-commit.ci

Author: chillenb

cbor2/_decoder.py

@@ -623,6 +623,21 @@ def decode_sharedref(self) -> Any:
         else:
             return shared
 
+    def decode_complex(self) -> complex:
+        # Semantic tag 43000
+        inputval = self._decode(immutable=True, unshared=True)
+        try:
+            value = complex(*inputval)
+        except TypeError as exc:
+            if not isinstance(inputval, tuple):
+                raise CBORDecodeValueError(
+                    "error decoding complex: input value was not a tuple"
+                ) from None
+
+            raise CBORDecodeValueError("error decoding complex") from exc
+
+        return self.set_shareable(value)
+
     def decode_rational(self) -> Fraction:
         # Semantic tag 30
         from fractions import Fraction
@@ -780,6 +795,7 @@ def decode_float64(self) -> float:
     260: CBORDecoder.decode_ipaddress,
     261: CBORDecoder.decode_ipnetwork,
     1004: CBORDecoder.decode_date_string,
+    43000: CBORDecoder.decode_complex,
     55799: CBORDecoder.decode_self_describe_cbor,
 }
 

cbor2/_encoder.py

@@ -614,6 +614,11 @@ def encode_float(self, value: float) -> None:
         else:
             self._fp_write(struct.pack(">Bd", 0xFB, value))
 
+    def encode_complex(self, value: complex) -> None:
+        # Semantic tag 43000
+        with self.disable_value_sharing():
+            self.encode_semantic(CBORTag(43000, [value.real, value.imag]))
+
     def encode_minimal_float(self, value: float) -> None:
         # Handle special values efficiently
         if math.isnan(value):
@@ -652,6 +657,7 @@ def encode_undefined(self, value: UndefinedType) -> None:
     str: CBOREncoder.encode_string,
     int: CBOREncoder.encode_int,
     float: CBOREncoder.encode_float,
+    complex: CBOREncoder.encode_complex,
     ("decimal", "Decimal"): CBOREncoder.encode_decimal,
     bool: CBOREncoder.encode_boolean,
     type(None): CBOREncoder.encode_none,

docs/usage.rst

@@ -99,6 +99,7 @@ Tag   Semantics                                Python type(s)
 258   Set of unique items                      set
 260   Network address                          :class:`ipaddress.IPv4Address` (or IPv6)
 261   Network prefix                           :class:`ipaddress.IPv4Network` (or IPv6)
+43000 Single complex number                    complex
 55799 Self-Described CBOR                      object
 ===== ======================================== ====================================================
 

docs/versionhistory.rst

@@ -9,6 +9,8 @@ This library adheres to `Semantic Versioning <https://semver.org/>`_.
 
 - Dropped support for Python 3.8
   (#247 <https://github.com/agronholm/cbor2/pull/247>_; PR by @hugovk)
+- Added complex number support (tag 43000)
+  (#249 <https://github.com/agronholm/cbor2/pull/249>_; PR by @chillenb)
 
 **5.6.5** (2024-10-09)
 

source/decoder.c

@@ -55,6 +55,7 @@ static PyObject * CBORDecoder_decode_epoch_date(CBORDecoderObject *);
 static PyObject * CBORDecoder_decode_date_string(CBORDecoderObject *);
 static PyObject * CBORDecoder_decode_fraction(CBORDecoderObject *);
 static PyObject * CBORDecoder_decode_bigfloat(CBORDecoderObject *);
+static PyObject * CBORDecoder_decode_complex(CBORDecoderObject *);
 static PyObject * CBORDecoder_decode_rational(CBORDecoderObject *);
 static PyObject * CBORDecoder_decode_regexp(CBORDecoderObject *);
 static PyObject * CBORDecoder_decode_uuid(CBORDecoderObject *);
@@ -1172,6 +1173,7 @@ decode_semantic(CBORDecoderObject *self, uint8_t subtype)
             case 260:   ret = CBORDecoder_decode_ipaddress(self);       break;
             case 261:   ret = CBORDecoder_decode_ipnetwork(self);       break;
             case 1004:  ret = CBORDecoder_decode_date_string(self);     break;
+            case 43000: ret = CBORDecoder_decode_complex(self);         break;
             case 55799: ret = CBORDecoder_decode_self_describe_cbor(self);
                 break;
 
@@ -1636,6 +1638,34 @@ CBORDecoder_decode_sharedref(CBORDecoderObject *self)
     return ret;
 }
 
+// CBORDecoder.decode_complex(self)
+static PyObject *
+CBORDecoder_decode_complex(CBORDecoderObject *self)
+{
+    // semantic type 43000
+    PyObject *real, *imag, *ret = NULL;
+    payload_t = decode(self, DECODE_IMMUTABLE | DECODE_UNSHARED);
+    if (payload_t) {
+        if (PyTuple_CheckExact(payload_t) && PyTuple_GET_SIZE(payload_t) == 2) {
+            real = PyTuple_GET_ITEM(payload_t, 0);
+            imag = PyTuple_GET_ITEM(payload_t, 1);
+            f(PyFloat_CheckExact(real) && PyFloat_CheckExact(imag)) {
+                ret = PyComplex_FromDoubles(PyFloat_AS_DOUBLE(real), PyFloat_AS_DOUBLE(imag));
+            } else {
+                PyErr_Format(
+                    _CBOR2_CBORDecodeValueError,
+                                "Incorrect tag 43000 payload: does not contain two floats");
+            }
+        } else {
+            PyErr_Format(
+                _CBOR2_CBORDecodeValueError,
+                            "Incorrect tag 43000 payload: not an array of length 2");
+            }
+        Py_DECREF(payload_t);
+    }
+    set_shareable(self, ret);
+    return ret;
+}
 
 // CBORDecoder.decode_rational(self)
 static PyObject *
@@ -2159,6 +2189,8 @@ static PyMethodDef CBORDecoder_methods[] = {
         "decode a fractional number from the input"},
     {"decode_rational", (PyCFunction) CBORDecoder_decode_rational, METH_NOARGS,
         "decode a rational value from the input"},
+    {"decode_complex", (PyCFunction) CBORDecoder_decode_complex, METH_NOARGS,
+        "decode a complex value from the input"},
     {"decode_bigfloat", (PyCFunction) CBORDecoder_decode_bigfloat, METH_NOARGS,
         "decode a large floating-point value from the input"},
     {"decode_regexp", (PyCFunction) CBORDecoder_decode_regexp, METH_NOARGS,

source/encoder.c

@@ -1362,6 +1362,36 @@ CBOREncoder_encode_rational(CBOREncoderObject *self, PyObject *value)
     return ret;
 }
 
+// CBOREncoder.encode_complex(self, value)
+static PyObject *
+CBOREncoder_encode_complex(CBOREncoderObject *self, PyObject *value)
+{
+    // semantic type 43000
+    PyObject *tuple, *real, *imag, *ret = NULL;
+    bool sharing;
+
+    real = PyObject_GetAttr(value, _CBOR2_str_real);
+    if (real) {
+        imag = PyObject_GetAttr(value, _CBOR2_str_imag);
+        if (imag) {
+            tuple = PyTuple_Pack(2, real, imag);
+            if (tuple) {
+                sharing = self->value_sharing;
+                self->value_sharing = false;
+                if (encode_semantic(self, 43000, tuple) == 0) {
+                    Py_INCREF(Py_None);
+                    ret = Py_None;
+                }
+                self->value_sharing = sharing;
+                Py_DECREF(tuple);
+            }
+            Py_DECREF(imag);
+        }
+        Py_DECREF(real);
+    }
+    return ret;
+}
+
 
 // CBOREncoder.encode_regexp(self, value)
 static PyObject *
@@ -2118,6 +2148,8 @@ static PyMethodDef CBOREncoder_methods[] = {
         "encode the specified integer *value* to the output"},
     {"encode_float", (PyCFunction) CBOREncoder_encode_float, METH_O,
         "encode the specified floating-point *value* to the output"},
+    {"encode_complex", (PyCFunction) CBOREncoder_encode_complex, METH_O,
+        "encode the specified complex *value* to the output"},
     {"encode_boolean", (PyCFunction) CBOREncoder_encode_boolean, METH_O,
         "encode the specified boolean *value* to the output"},
     {"encode_none", (PyCFunction) CBOREncoder_encode_none, METH_O,

source/module.c

@@ -621,6 +621,7 @@ PyObject *_CBOR2_str_FrozenDict = NULL;
 PyObject *_CBOR2_str_fromordinal = NULL;
 PyObject *_CBOR2_str_getvalue = NULL;
 PyObject *_CBOR2_str_groups = NULL;
+PyObject *_CBOR2_str_imag = NULL;
 PyObject *_CBOR2_str_ip_address = NULL;
 PyObject *_CBOR2_str_ip_network = NULL;
 PyObject *_CBOR2_str_is_infinite = NULL;
@@ -637,6 +638,7 @@ PyObject *_CBOR2_str_parsestr = NULL;
 PyObject *_CBOR2_str_pattern = NULL;
 PyObject *_CBOR2_str_prefixlen = NULL;
 PyObject *_CBOR2_str_read = NULL;
+PyObject *_CBOR2_str_real = NULL;
 PyObject *_CBOR2_str_s = NULL;
 PyObject *_CBOR2_str_timestamp = NULL;
 PyObject *_CBOR2_str_toordinal = NULL;
@@ -955,6 +957,7 @@ PyInit__cbor2(void)
     INTERN_STRING(fromordinal);
     INTERN_STRING(getvalue);
     INTERN_STRING(groups);
+    INTERN_STRING(imag);
     INTERN_STRING(ip_address);
     INTERN_STRING(ip_network);
     INTERN_STRING(is_infinite);
@@ -971,6 +974,7 @@ PyInit__cbor2(void)
     INTERN_STRING(pattern);
     INTERN_STRING(prefixlen);
     INTERN_STRING(read);
+    INTERN_STRING(real);
     INTERN_STRING(s);
     INTERN_STRING(timestamp);
     INTERN_STRING(toordinal);

source/module.h

@@ -53,6 +53,7 @@ extern PyObject *_CBOR2_str_FrozenDict;
 extern PyObject *_CBOR2_str_fromordinal;
 extern PyObject *_CBOR2_str_getvalue;
 extern PyObject *_CBOR2_str_groups;
+extern PyObject *_CBOR2_str_imag;
 extern PyObject *_CBOR2_str_ip_address;
 extern PyObject *_CBOR2_str_ip_network;
 extern PyObject *_CBOR2_str_is_infinite;
@@ -69,6 +70,7 @@ extern PyObject *_CBOR2_str_parsestr;
 extern PyObject *_CBOR2_str_pattern;
 extern PyObject *_CBOR2_str_prefixlen;
 extern PyObject *_CBOR2_str_read;
+extern PyObject *_CBOR2_str_real;
 extern PyObject *_CBOR2_str_s;
 extern PyObject *_CBOR2_str_timestamp;
 extern PyObject *_CBOR2_str_toordinal;

tests/test_decoder.py

@@ -539,6 +539,35 @@ def test_bigfloat(impl):
     assert decoded == Decimal("1.5")
 
 
+@pytest.mark.parametrize(
+    "payload, expected",
+    [
+        ("d9a7f882f90000f90000", 0.0j),
+        ("d9a7f882fb0000000000000000fb0000000000000000", 0.0j),
+        ("d9a7f882f98000f98000", -0.0j),
+        ("d9a7f882f90000f93c00", 1.0j),
+        ("d9a7f882fb0000000000000000fb3ff199999999999a", 1.1j),
+        ("d9a7f882f93e00f93e00", 1.5 + 1.5j),
+        ("d9a7f882f97bfff97bff", 65504.0 + 65504.0j),
+        ("d9a7f882fa47c35000fa47c35000", 100000.0 + 100000.0j),
+        ("fa7f7fffff", 3.4028234663852886e38),
+        ("d9a7f882f90000fb7e37e43c8800759c", 1.0e300j),
+        ("d9a7f882f90000f90001", 5.960464477539063e-8j),
+        ("d9a7f882f90000f90400", 0.00006103515625j),
+        ("d9a7f882f90000f9c400", -4.0j),
+        ("d9a7f882f90000fbc010666666666666", -4.1j),
+        ("d9a7f882f90000f97c00", complex(0.0, float("inf"))),
+        ("d9a7f882f97c00f90000", complex(float("inf"), 0.0)),
+        ("d9a7f882f90000f9fc00", complex(0.0, float("-inf"))),
+        ("d9a7f882f90000fa7f800000", complex(0.0, float("inf"))),
+        ("d9a7f882f90000faff800000", complex(0.0, float("-inf"))),
+    ],
+)
+def test_complex(impl, payload, expected):
+    decoded = impl.loads(unhexlify(payload))
+    assert decoded == expected
+
+
 def test_rational(impl):
     decoded = impl.loads(unhexlify("d81e820205"))
     assert decoded == Fraction(2, 5)

tests/test_encoder.py

@@ -324,6 +324,22 @@ def test_decimal(impl, value, expected):
     assert impl.dumps(value) == expected
 
 
+@pytest.mark.parametrize(
+    "value, expected",
+    [
+        (3.1 + 2.1j, "d9a7f882fb4008cccccccccccdfb4000cccccccccccd"),
+        (1.0e300j, "d9a7f882fb0000000000000000fb7e37e43c8800759c"),
+        (0.0j, "d9a7f882fb0000000000000000fb0000000000000000"),
+        (complex(float("inf"), float("inf")), "d9a7f882f97c00f97c00"),
+        (complex(float("inf"), 0.0), "d9a7f882f97c00fb0000000000000000"),
+        (complex(float("nan"), float("inf")), "d9a7f882f97e00f97c00"),
+    ],
+)
+def test_complex(impl, value, expected):
+    expected = unhexlify(expected)
+    assert impl.dumps(value) == expected
+
+
 def test_rational(impl):
     expected = unhexlify("d81e820205")
     assert impl.dumps(Fraction(2, 5)) == expected