[Python-checkins] r64438 - in python/trunk: Lib/test/test_builtin.py Misc/NEWS Objects/floatobject.c

[Christian Tismer]

Good to see you alive, again

Von meinem iTouch gesendet

On 21.06.2008, at 02:39, "raymond.hettinger" <python- 
checkins at python.org> wrote:

> Author: raymond.hettinger
> Date: Sat Jun 21 08:39:53 2008
> New Revision: 64438
>
> Log:
> Issue 3008: hex/oct/bin can show floats exactly.
>
> Modified:
>   python/trunk/Lib/test/test_builtin.py
>   python/trunk/Misc/NEWS
>   python/trunk/Objects/floatobject.c
>
> Modified: python/trunk/Lib/test/test_builtin.py
> === 
> === 
> === 
> =====================================================================
> --- python/trunk/Lib/test/test_builtin.py    (original)
> +++ python/trunk/Lib/test/test_builtin.py    Sat Jun 21 08:39:53 2008
> @@ -631,6 +631,15 @@
>         self.assertEqual(hex(-16), '-0x10')
>         self.assertEqual(hex(-16L), '-0x10L')
>         self.assertRaises(TypeError, hex, {})
> +        self.assertEqual(hex(3.125), '0x19 * 2.0 ** -3')
> +        self.assertEqual(hex(0.0), '0x0 * 2.0 ** 0')
> +        for sv in float('nan'), float('inf'), float('-inf'):
> +            self.assertEqual(hex(sv), repr(sv))
> +        for i in range(100):
> +            x = random.expovariate(.05)
> +            self.assertEqual(eval(hex(x)), x, (x, hex(x), eval(hex 
> (x))))
> +            self.assertEqual(eval(hex(-x)), -x)
> +            self.assertEqual(hex(-x), ('-' + hex(x)))
>
>     def test_id(self):
>         id(None)
> @@ -914,6 +923,15 @@
>         self.assertEqual(oct(-100), '-0144')
>         self.assertEqual(oct(-100L), '-0144L')
>         self.assertRaises(TypeError, oct, ())
> +        self.assertEqual(oct(3.125), '031 * 2.0 ** -3')
> +        self.assertEqual(oct(0.0), '0 * 2.0 ** 0')
> +        for sv in float('nan'), float('inf'), float('-inf'):
> +            self.assertEqual(oct(sv), repr(sv))
> +        for i in range(100):
> +            x = random.expovariate(.05)
> +            self.assertEqual(eval(oct(x)), x)
> +            self.assertEqual(eval(oct(-x)), -x)
> +            self.assertEqual(oct(-x), ('-' + oct(x)))
>
>     def write_testfile(self):
>         # NB the first 4 lines are also used to test input and  
> raw_input, below
> @@ -1466,6 +1484,15 @@
>         self.assertEqual(bin(2**65-1), '0b' + '1' * 65)
>         self.assertEqual(bin(-(2**65)), '-0b1' + '0' * 65)
>         self.assertEqual(bin(-(2**65-1)), '-0b' + '1' * 65)
> +        self.assertEqual(bin(3.125), '0b11001 * 2.0 ** -3')
> +        self.assertEqual(bin(0.0), '0b0 * 2.0 ** 0')
> +        for sv in float('nan'), float('inf'), float('-inf'):
> +            self.assertEqual(bin(sv), repr(sv))
> +        for i in range(100):
> +            x = random.expovariate(.05)
> +            self.assertEqual(eval(bin(x)), x)
> +            self.assertEqual(eval(bin(-x)), -x)
> +            self.assertEqual(bin(-x), ('-' + bin(x)))
>
> class TestSorted(unittest.TestCase):
>
>
> Modified: python/trunk/Misc/NEWS
> === 
> === 
> === 
> =====================================================================
> --- python/trunk/Misc/NEWS    (original)
> +++ python/trunk/Misc/NEWS    Sat Jun 21 08:39:53 2008
> @@ -17,6 +17,9 @@
>   slice(None, 10, -1).indices(10) returns (9, 9, -1) instead of (9,
>   10, -1).
>
> +- Issue 3008: hex(), oct(), and bin() can now create exact reprs
> +  for floats.
> +
> - Make bin() implementation parallel oct() and hex().
>
>
>
> Modified: python/trunk/Objects/floatobject.c
> === 
> === 
> === 
> =====================================================================
> --- python/trunk/Objects/floatobject.c    (original)
> +++ python/trunk/Objects/floatobject.c    Sat Jun 21 08:39:53 2008
> @@ -1204,6 +1204,62 @@
> ">>> (-.25).as_integer_ratio()\n"
> "(-1, 4)");
>
> +static PyObject *
> +_float_to_base(PyFloatObject *v, unaryfunc int_to_base)
> +{
> +    PyObject *mant, *conv, *result;
> +    double x, fr;
> +    int i, exp, n;
> +    char *conv_str;
> +
> +    CONVERT_TO_DOUBLE(((PyObject *)v), x);
> +    if (!Py_IS_FINITE(x))
> +        return PyObject_Repr((PyObject *)v);
> +    fr = frexp(x, &exp);
> +    for (i=0; i<300 && fr != floor(fr) ; i++) {
> +        fr *= 2.0;
> +        exp--;
> +    }
> +    mant = PyLong_FromDouble(floor(fr));
> +    if (mant == NULL)
> +        return NULL;
> +    conv = int_to_base(mant);
> +    Py_DECREF(mant);
> +    if (conv== NULL)
> +        return NULL;
> +    n = PyString_GET_SIZE(conv);
> +    conv_str = PyString_AS_STRING(conv);
> +    /* Remove the trailing 'L' if present */
> +    if (n && conv_str[n-1] == 'L') {
> +        PyObject *newconv = PySequence_GetSlice(conv, 0, -1);
> +        Py_DECREF(conv);
> +        if (newconv == NULL)
> +            return NULL;
> +        conv = newconv;
> +        conv_str = PyString_AS_STRING(conv);
> +    }
> +    result = PyString_FromFormat("%s * 2.0 ** %d", conv_str, exp);
> +    Py_DECREF(conv);
> +    return result;
> +}
> +
> +static PyObject *
> +float_hex(PyFloatObject *v)
> +{
> +    return _float_to_base(v, PyLong_Type.tp_as_number->nb_hex);
> +}
> +
> +static PyObject *
> +float_oct(PyFloatObject *v)
> +{
> +    return _float_to_base(v, PyLong_Type.tp_as_number->nb_oct);
> +}
> +
> +static PyObject *
> +float_bin(PyFloatObject *v)
> +{
> +    return _float_to_base(v, PyLong_Type.tp_as_number->nb_bin);
> +}
>
> static PyObject *
> float_subtype_new(PyTypeObject *type, PyObject *args, PyObject *kwds);
> @@ -1490,8 +1546,8 @@
>    float_trunc,    /*nb_int*/
>    float_trunc,    /*nb_long*/
>    float_float,    /*nb_float*/
> -    0,        /* nb_oct */
> -    0,        /* nb_hex */
> +    (unaryfunc)float_oct,        /* nb_oct */
> +    (unaryfunc)float_hex,        /* nb_hex */
>    0,        /* nb_inplace_add */
>    0,        /* nb_inplace_subtract */
>    0,        /* nb_inplace_multiply */
> @@ -1507,6 +1563,8 @@
>    float_div,    /* nb_true_divide */
>    0,        /* nb_inplace_floor_divide */
>    0,        /* nb_inplace_true_divide */
> +    0,        /* nb_index */
> +    (unaryfunc)float_bin,        /* nb_bin */
> };
>
> PyTypeObject PyFloat_Type = {
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