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Issue #1023290: Added API for the conversion of longs to bytes and vice-versa.
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Alexandre Vassalotti
parent
a28e7028f9
commit
c36c3789de
4 changed files with 497 additions and 0 deletions
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@ -4296,6 +4296,201 @@ long_is_finite(PyObject *v)
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}
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#endif
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PyDoc_STRVAR(long_to_bytes_doc,
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"int.to_bytes(length, byteorder, *, signed=False) -> bytes\n\
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\n\
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Return an array of bytes representing an integer.\n\
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\n\
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The integer is represented using length bytes. An OverflowError is\n\
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raised if the integer is not representable with the given number of\n\
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bytes.\n\
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\n\
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The byteorder argument determines the byte order used to represent the\n\
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integer. If byteorder is 'big', the most significant byte is at the\n\
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beginning of the byte array. If byteorder is 'little', the most\n\
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significant byte is at the end of the byte array. To request the native\n\
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byte order of the host system, use `sys.byteorder' as the byte order value.\n\
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\n\
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The signed keyword-only argument determines whether two's complement is\n\
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used to represent the integer. If signed is False and a negative integer\n\
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is given, an OverflowError is raised.");
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static PyObject *
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long_to_bytes(PyLongObject *v, PyObject *args, PyObject *kwds)
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{
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PyObject *byteorder_str;
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PyObject *is_signed_obj = NULL;
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Py_ssize_t length;
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int little_endian;
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int is_signed;
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PyObject *bytes;
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static PyObject *little_str = NULL, *big_str = NULL;
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static char *kwlist[] = {"length", "byteorder", "signed", NULL};
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if (!PyArg_ParseTupleAndKeywords(args, kwds, "nO|O:to_bytes", kwlist,
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&length, &byteorder_str,
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&is_signed_obj))
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return NULL;
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if (args != NULL && Py_SIZE(args) > 2) {
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PyErr_SetString(PyExc_TypeError,
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"'signed' is a keyword-only argument");
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return NULL;
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}
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if (little_str == NULL) {
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little_str = PyUnicode_InternFromString("little");
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big_str = PyUnicode_InternFromString("big");
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if (little_str == NULL || big_str == NULL)
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return NULL;
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}
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if (PyObject_RichCompareBool(byteorder_str, little_str, Py_EQ))
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little_endian = 1;
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else if (PyObject_RichCompareBool(byteorder_str, big_str, Py_EQ))
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little_endian = 0;
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else {
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PyErr_SetString(PyExc_ValueError,
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"byteorder must be either 'little' or 'big'");
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return NULL;
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}
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if (is_signed_obj != NULL) {
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int cmp = PyObject_IsTrue(is_signed_obj);
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if (cmp < 0)
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return NULL;
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is_signed = cmp ? 1 : 0;
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}
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else {
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/* If the signed argument was omitted, use False as the
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default. */
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is_signed = 0;
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}
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if (length < 0) {
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PyErr_SetString(PyExc_ValueError,
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"length argument must be non-negative");
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return NULL;
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}
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bytes = PyBytes_FromStringAndSize(NULL, length);
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if (bytes == NULL)
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return NULL;
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if (_PyLong_AsByteArray(v, (unsigned char *)PyBytes_AS_STRING(bytes),
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length, little_endian, is_signed) < 0) {
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Py_DECREF(bytes);
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return NULL;
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}
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return bytes;
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}
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PyDoc_STRVAR(long_from_bytes_doc,
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"int.from_bytes(bytes, byteorder, *, signed=False) -> int\n\
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\n\
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Return the integer represented by the given array of bytes.\n\
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\n\
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The bytes argument must either support the buffer protocol or be an\n\
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iterable object producing bytes. Bytes and bytearray are examples of\n\
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built-in objects that support the buffer protocol.\n\
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\n\
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The byteorder argument determines the byte order used to represent the\n\
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integer. If byteorder is 'big', the most significant byte is at the\n\
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beginning of the byte array. If byteorder is 'little', the most\n\
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significant byte is at the end of the byte array. To request the native\n\
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byte order of the host system, use `sys.byteorder' as the byte order value.\n\
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\n\
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The signed keyword-only argument indicates whether two's complement is\n\
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used to represent the integer.");
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static PyObject *
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long_from_bytes(PyTypeObject *type, PyObject *args, PyObject *kwds)
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{
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PyObject *byteorder_str;
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PyObject *is_signed_obj = NULL;
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int little_endian;
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int is_signed;
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PyObject *obj;
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PyObject *bytes;
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PyObject *long_obj;
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static PyObject *little_str = NULL, *big_str = NULL;
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static char *kwlist[] = {"bytes", "byteorder", "signed", NULL};
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if (!PyArg_ParseTupleAndKeywords(args, kwds, "OO|O:from_bytes", kwlist,
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&obj, &byteorder_str,
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&is_signed_obj))
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return NULL;
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if (args != NULL && Py_SIZE(args) > 2) {
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PyErr_SetString(PyExc_TypeError,
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"'signed' is a keyword-only argument");
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return NULL;
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}
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if (little_str == NULL) {
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little_str = PyUnicode_InternFromString("little");
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big_str = PyUnicode_InternFromString("big");
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if (little_str == NULL || big_str == NULL)
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return NULL;
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}
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if (PyObject_RichCompareBool(byteorder_str, little_str, Py_EQ))
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little_endian = 1;
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else if (PyObject_RichCompareBool(byteorder_str, big_str, Py_EQ))
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little_endian = 0;
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else {
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PyErr_SetString(PyExc_ValueError,
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"byteorder must be either 'little' or 'big'");
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return NULL;
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}
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if (is_signed_obj != NULL) {
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int cmp = PyObject_IsTrue(is_signed_obj);
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if (cmp < 0)
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return NULL;
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is_signed = cmp ? 1 : 0;
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}
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else {
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/* If the signed argument was omitted, use False as the
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default. */
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is_signed = 0;
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}
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bytes = PyObject_Bytes(obj);
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if (bytes == NULL)
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return NULL;
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long_obj = _PyLong_FromByteArray(
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(unsigned char *)PyBytes_AS_STRING(bytes), Py_SIZE(bytes),
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little_endian, is_signed);
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Py_DECREF(bytes);
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/* If from_bytes() was used on subclass, allocate new subclass
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* instance, initialize it with decoded long value and return it.
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*/
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if (type != &PyLong_Type && PyType_IsSubtype(type, &PyLong_Type)) {
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PyLongObject *newobj;
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int i;
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Py_ssize_t n = ABS(Py_SIZE(long_obj));
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newobj = (PyLongObject *)type->tp_alloc(type, n);
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if (newobj == NULL) {
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Py_DECREF(long_obj);
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return NULL;
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}
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assert(PyLong_Check(newobj));
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Py_SIZE(newobj) = Py_SIZE(long_obj);
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for (i = 0; i < n; i++) {
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newobj->ob_digit[i] =
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((PyLongObject *)long_obj)->ob_digit[i];
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}
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Py_DECREF(long_obj);
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return (PyObject *)newobj;
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}
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return long_obj;
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}
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static PyMethodDef long_methods[] = {
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{"conjugate", (PyCFunction)long_long, METH_NOARGS,
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"Returns self, the complex conjugate of any int."},
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@ -4305,6 +4500,10 @@ static PyMethodDef long_methods[] = {
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{"is_finite", (PyCFunction)long_is_finite, METH_NOARGS,
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"Returns always True."},
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#endif
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{"to_bytes", (PyCFunction)long_to_bytes,
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METH_VARARGS|METH_KEYWORDS, long_to_bytes_doc},
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{"from_bytes", (PyCFunction)long_from_bytes,
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METH_VARARGS|METH_KEYWORDS|METH_CLASS, long_from_bytes_doc},
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{"__trunc__", (PyCFunction)long_long, METH_NOARGS,
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"Truncating an Integral returns itself."},
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{"__floor__", (PyCFunction)long_long, METH_NOARGS,
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