From ad476dab097c3a0701faf035974c7c1f4b916396 Mon Sep 17 00:00:00 2001 From: Mark Dickinson Date: Thu, 23 Apr 2009 19:14:16 +0000 Subject: [PATCH] Issue #5816: Simplify code for parsing and printing of complex numbers. nans and infs are no longer given special treatment; as a result, repr(complex(z)) recovers z for any complex number z. --- Lib/test/test_complex.py | 65 +++++++-- Misc/NEWS | 3 + Objects/complexobject.c | 308 +++++++++++++-------------------------- Python/pystrtod.c | 23 +-- 4 files changed, 168 insertions(+), 231 deletions(-) diff --git a/Lib/test/test_complex.py b/Lib/test/test_complex.py index ab3c1d1d2da..836360a107b 100644 --- a/Lib/test/test_complex.py +++ b/Lib/test/test_complex.py @@ -2,7 +2,7 @@ import unittest, os from test import support from random import random -from math import atan2 +from math import atan2, isnan, copysign INF = float("inf") NAN = float("nan") @@ -37,6 +37,29 @@ class ComplexTest(unittest.TestCase): # check that relative difference < eps self.assert_(abs((x-y)/y) < eps) + def assertFloatsAreIdentical(self, x, y): + """assert that floats x and y are identical, in the sense that: + (1) both x and y are nans, or + (2) both x and y are infinities, with the same sign, or + (3) both x and y are zeros, with the same sign, or + (4) x and y are both finite and nonzero, and x == y + + """ + msg = 'floats {!r} and {!r} are not identical' + + if isnan(x) or isnan(y): + if isnan(x) and isnan(y): + return + elif x == y: + if x != 0.0: + return + # both zero; check that signs match + elif copysign(1.0, x) == copysign(1.0, y): + return + else: + msg += ': zeros have different signs' + self.fail(msg.format(x, y)) + def assertClose(self, x, y, eps=1e-9): """Return true iff complexes x and y "are close\"""" self.assertCloseAbs(x.real, y.real, eps) @@ -202,6 +225,8 @@ class ComplexTest(unittest.TestCase): self.assertAlmostEqual(complex("+1"), +1) self.assertAlmostEqual(complex("(1+2j)"), 1+2j) self.assertAlmostEqual(complex("(1.3+2.2j)"), 1.3+2.2j) + self.assertAlmostEqual(complex("3.14+1J"), 3.14+1j) + self.assertAlmostEqual(complex(" ( +3.14-6J )"), 3.14-6j) class complex2(complex): pass self.assertAlmostEqual(complex(complex2(1+1j)), 1+1j) @@ -229,8 +254,6 @@ class ComplexTest(unittest.TestCase): self.assertRaises(TypeError, complex, "1", "1") self.assertRaises(TypeError, complex, 1, "1") - self.assertEqual(complex(" 3.14+J "), 3.14+1j) - # SF bug 543840: complex(string) accepts strings with \0 # Fixed in 2.3. self.assertRaises(ValueError, complex, '1+1j\0j') @@ -254,6 +277,11 @@ class ComplexTest(unittest.TestCase): self.assertRaises(ValueError, complex, "(1+2j)123") self.assertRaises(ValueError, complex, "1"*500) self.assertRaises(ValueError, complex, "x") + self.assertRaises(ValueError, complex, "J") + self.assertRaises(ValueError, complex, "1j+2") + self.assertRaises(ValueError, complex, "1e1ej") + self.assertRaises(ValueError, complex, "1e++1ej") + self.assertRaises(ValueError, complex, ")1+2j(") class EvilExc(Exception): pass @@ -318,17 +346,17 @@ class ComplexTest(unittest.TestCase): self.assertEqual(-6j,complex(repr(-6j))) self.assertEqual(6j,complex(repr(6j))) - self.assertEqual(repr(complex(1., INF)), "(1+inf*j)") - self.assertEqual(repr(complex(1., -INF)), "(1-inf*j)") + self.assertEqual(repr(complex(1., INF)), "(1+infj)") + self.assertEqual(repr(complex(1., -INF)), "(1-infj)") self.assertEqual(repr(complex(INF, 1)), "(inf+1j)") - self.assertEqual(repr(complex(-INF, INF)), "(-inf+inf*j)") + self.assertEqual(repr(complex(-INF, INF)), "(-inf+infj)") self.assertEqual(repr(complex(NAN, 1)), "(nan+1j)") - self.assertEqual(repr(complex(1, NAN)), "(1+nan*j)") - self.assertEqual(repr(complex(NAN, NAN)), "(nan+nan*j)") + self.assertEqual(repr(complex(1, NAN)), "(1+nanj)") + self.assertEqual(repr(complex(NAN, NAN)), "(nan+nanj)") - self.assertEqual(repr(complex(0, INF)), "inf*j") - self.assertEqual(repr(complex(0, -INF)), "-inf*j") - self.assertEqual(repr(complex(0, NAN)), "nan*j") + self.assertEqual(repr(complex(0, INF)), "infj") + self.assertEqual(repr(complex(0, -INF)), "-infj") + self.assertEqual(repr(complex(0, NAN)), "nanj") def test_neg(self): self.assertEqual(-(1+6j), -1-6j) @@ -367,6 +395,21 @@ class ComplexTest(unittest.TestCase): self.assertEquals(atan2(z1.imag, -1.), atan2(0., -1.)) self.assertEquals(atan2(z2.imag, -1.), atan2(-0., -1.)) + @unittest.skipUnless(float.__getformat__("double").startswith("IEEE"), + "test requires IEEE 754 doubles") + def test_repr_roundtrip(self): + # complex(repr(z)) should recover z exactly, even for complex numbers + # involving an infinity, nan, or negative zero + vals = [0.0, 1e-200, 0.0123, 3.1415, 1e50, INF, NAN] + vals += [-v for v in vals] + for x in vals: + for y in vals: + z = complex(x, y) + roundtrip = complex(repr(z)) + self.assertFloatsAreIdentical(z.real, roundtrip.real) + self.assertFloatsAreIdentical(z.imag, roundtrip.imag) + + def test_main(): support.run_unittest(ComplexTest) diff --git a/Misc/NEWS b/Misc/NEWS index c69672f0fc9..f4ffbb761ca 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -12,6 +12,9 @@ What's New in Python 3.1 beta 1? Core and Builtins ----------------- +- Issue #5816: complex(repr(z)) now recovers z exactly, even when + z involves nans, infs or negative zeros. + - Issue #3166: Make long -> float (and int -> float) conversions correctly rounded. diff --git a/Objects/complexobject.c b/Objects/complexobject.c index 721db8f514e..27765adf74a 100644 --- a/Objects/complexobject.c +++ b/Objects/complexobject.c @@ -332,99 +332,64 @@ complex_dealloc(PyObject *op) static PyObject * complex_format(PyComplexObject *v, char format_code) { - PyObject *result = NULL; - Py_ssize_t len; + PyObject *result = NULL; + Py_ssize_t len; - /* If these are non-NULL, they'll need to be freed. */ - char *pre = NULL; - char *pim = NULL; - char *buf = NULL; + /* If these are non-NULL, they'll need to be freed. */ + char *pre = NULL; + char *im = NULL; + char *buf = NULL; - /* These do not need to be freed. They're either aliases for pim - and pre, or pointers to constants. */ - char *re = NULL; - char *im = NULL; - char *lead = ""; - char *tail = ""; + /* These do not need to be freed. re is either an alias + for pre or a pointer to a constant. lead and tail + are pointers to constants. */ + char *re = NULL; + char *lead = ""; + char *tail = ""; + if (v->cval.real == 0. && copysign(1.0, v->cval.real)==1.0) { + re = ""; + im = PyOS_double_to_string(v->cval.imag, format_code, + 0, 0, NULL); + if (!im) { + PyErr_NoMemory(); + goto done; + } + } else { + /* Format imaginary part with sign, real part without */ + pre = PyOS_double_to_string(v->cval.real, format_code, + 0, 0, NULL); + if (!pre) { + PyErr_NoMemory(); + goto done; + } + re = pre; - if (v->cval.real == 0.) { - re = ""; - if (!Py_IS_FINITE(v->cval.imag)) { - if (Py_IS_NAN(v->cval.imag)) - im = "nan*"; - else if (copysign(1, v->cval.imag) == 1) - im = "inf*"; - else - im = "-inf*"; - } - else { - pim = PyOS_double_to_string(v->cval.imag, format_code, - 0, 0, NULL); - if (!pim) { - PyErr_NoMemory(); - goto done; - } - im = pim; - } - } else { - /* Format imaginary part with sign, real part without */ - if (!Py_IS_FINITE(v->cval.real)) { - if (Py_IS_NAN(v->cval.real)) - re = "nan"; - /* else if (copysign(1, v->cval.real) == 1) */ - else if (v->cval.real > 0) - re = "inf"; - else - re = "-inf"; - } - else { - pre = PyOS_double_to_string(v->cval.real, format_code, - 0, 0, NULL); - if (!pre) { - PyErr_NoMemory(); - goto done; - } - re = pre; - } + im = PyOS_double_to_string(v->cval.imag, format_code, + 0, Py_DTSF_SIGN, NULL); + if (!im) { + PyErr_NoMemory(); + goto done; + } + lead = "("; + tail = ")"; + } + /* Alloc the final buffer. Add one for the "j" in the format string, + and one for the trailing zero. */ + len = strlen(lead) + strlen(re) + strlen(im) + strlen(tail) + 2; + buf = PyMem_Malloc(len); + if (!buf) { + PyErr_NoMemory(); + goto done; + } + PyOS_snprintf(buf, len, "%s%s%sj%s", lead, re, im, tail); + result = PyUnicode_FromString(buf); + done: + PyMem_Free(im); + PyMem_Free(pre); + PyMem_Free(buf); - if (!Py_IS_FINITE(v->cval.imag)) { - if (Py_IS_NAN(v->cval.imag)) - im = "+nan*"; - /* else if (copysign(1, v->cval.imag) == 1) */ - else if (v->cval.imag > 0) - im = "+inf*"; - else - im = "-inf*"; - } - else { - pim = PyOS_double_to_string(v->cval.imag, format_code, - 0, Py_DTSF_SIGN, NULL); - if (!pim) { - PyErr_NoMemory(); - goto done; - } - im = pim; - } - lead = "("; - tail = ")"; - } - /* Alloc the final buffer. Add one for the "j" in the format string, and - one for the trailing zero. */ - len = strlen(lead) + strlen(re) + strlen(im) + strlen(tail) + 2; - buf = PyMem_Malloc(len); - if (!buf) { - PyErr_NoMemory(); - goto done; - } - PyOS_snprintf(buf, len, "%s%s%sj%s", lead, re, im, tail); - result = PyUnicode_FromString(buf); -done: - PyMem_Free(pim); - PyMem_Free(pre); - PyMem_Free(buf); - - return result; + return result; } static PyObject * @@ -757,11 +722,7 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v) const char *s, *start; char *end; double x=0.0, y=0.0, z; - int got_re=0, got_im=0, got_bracket=0, done=0; - int digit_or_dot; - int sw_error=0; - int sign; - char buffer[256]; /* For errors */ + int got_bracket=0; char s_buffer[256]; Py_ssize_t len; @@ -785,16 +746,13 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v) return NULL; } + errno = 0; + /* position on first nonblank */ start = s; while (*s && isspace(Py_CHARMASK(*s))) s++; - if (s[0] == '\0') { - PyErr_SetString(PyExc_ValueError, - "complex() arg is an empty string"); - return NULL; - } - if (s[0] == '(') { + if (*s == '(') { /* Skip over possible bracket from repr(). */ got_bracket = 1; s++; @@ -802,120 +760,50 @@ complex_subtype_from_string(PyTypeObject *type, PyObject *v) s++; } - z = -1.0; - sign = 1; - do { - - switch (*s) { - - case '\0': - if (s-start != len) { - PyErr_SetString( - PyExc_ValueError, - "complex() arg contains a null byte"); - return NULL; - } - if(!done) sw_error=1; - break; - - case ')': - if (!got_bracket || !(got_re || got_im)) { - sw_error=1; - break; - } - got_bracket=0; - done=1; - s++; - while (*s && isspace(Py_CHARMASK(*s))) - s++; - if (*s) sw_error=1; - break; - - case '-': - sign = -1; - /* Fallthrough */ - case '+': - if (done) sw_error=1; - s++; - if ( *s=='\0'||*s=='+'||*s=='-'||*s==')'|| - isspace(Py_CHARMASK(*s)) ) sw_error=1; - break; - - case 'J': - case 'j': - if (got_im || done) { - sw_error = 1; - break; - } - if (z<0.0) { - y=sign; - } - else{ - y=sign*z; - } - got_im=1; - s++; - if (*s!='+' && *s!='-' ) - done=1; - break; - - default: - if (isspace(Py_CHARMASK(*s))) { - while (*s && isspace(Py_CHARMASK(*s))) - s++; - if (*s && *s != ')') - sw_error=1; - else - done = 1; - break; - } - digit_or_dot = - (*s=='.' || isdigit(Py_CHARMASK(*s))); - if (done||!digit_or_dot) { - sw_error=1; - break; - } - errno = 0; - PyFPE_START_PROTECT("strtod", return 0) - z = PyOS_ascii_strtod(s, &end) ; - PyFPE_END_PROTECT(z) - if (errno != 0) { - PyOS_snprintf(buffer, sizeof(buffer), - "float() out of range: %.150s", s); - PyErr_SetString( - PyExc_ValueError, - buffer); - return NULL; - } - s=end; - if (*s=='J' || *s=='j') { - - break; - } - if (got_re) { - sw_error=1; - break; - } - - /* accept a real part */ - x=sign*z; - got_re=1; - if (got_im) done=1; - z = -1.0; - sign = 1; - break; - - } /* end of switch */ - - } while (s - start < len && !sw_error); - - if (sw_error || got_bracket) { - PyErr_SetString(PyExc_ValueError, - "complex() arg is a malformed string"); - return NULL; + /* get float---might be real or imaginary part */ + z = PyOS_ascii_strtod(s, &end); + if (end == s) + goto error; + s = end; + if (*s == '+' || *s == '-') { + /* we've got a real part *and* an imaginary part */ + x = z; + y = PyOS_ascii_strtod(s, &end); + if (end == s || !(*end == 'j' || *end == 'J')) + goto error; + s = ++end; } + else if (*s == 'j' || *s == 'J') { + /* no real part; z was the imaginary part */ + s++; + y = z; + } + else + /* no imaginary part */ + x = z; + + /* trailing whitespace and closing bracket */ + while (*s && isspace(Py_CHARMASK(*s))) + s++; + if (got_bracket && *s == ')') { + got_bracket = 0; + s++; + while (*s && isspace(Py_CHARMASK(*s))) + s++; + } + /* we should now be at the end of the string */ + if (s-start != len || got_bracket) + goto error; return complex_subtype_from_doubles(type, x, y); + + error: + /* check for PyOS_ascii_strtod failure due to lack of memory */ + if (errno == ENOMEM) + return PyErr_NoMemory(); + PyErr_SetString(PyExc_ValueError, + "complex() arg is a malformed string"); + return NULL; } static PyObject * diff --git a/Python/pystrtod.c b/Python/pystrtod.c index 95fbd891520..002714f7c29 100644 --- a/Python/pystrtod.c +++ b/Python/pystrtod.c @@ -630,8 +630,9 @@ PyAPI_FUNC(char *) PyOS_double_to_string(double val, } p = result; - /* Never add sign for nan/inf, even if asked. */ - if (flags & Py_DTSF_SIGN && buf[0] != '-' && t == Py_DTST_FINITE) + /* Add sign when requested. It's convenient (esp. when formatting + complex numbers) to include a sign even for inf and nan. */ + if (flags & Py_DTSF_SIGN && buf[0] != '-') *p++ = '+'; strcpy(p, buf); @@ -733,6 +734,10 @@ format_float_short(double d, char format_code, so convert Infinity to inf and NaN to nan, and ignore sign of nan. Then return. */ + /* ignore the actual sign of a nan */ + if (digits[0] == 'n' || digits[0] == 'N') + sign = 0; + /* We only need 5 bytes to hold the result "+inf\0" . */ bufsize = 5; /* Used later in an assert. */ buf = (char *)PyMem_Malloc(bufsize); @@ -742,13 +747,13 @@ format_float_short(double d, char format_code, } p = buf; + if (sign == 1) { + *p++ = '-'; + } + else if (always_add_sign) { + *p++ = '+'; + } if (digits[0] == 'i' || digits[0] == 'I') { - if (sign == 1) { - *p++ = '-'; - } - else if (always_add_sign) { - *p++ = '+'; - } strncpy(p, float_strings[OFS_INF], 3); p += 3; @@ -756,8 +761,6 @@ format_float_short(double d, char format_code, *type = Py_DTST_INFINITE; } else if (digits[0] == 'n' || digits[0] == 'N') { - /* note that we *never* add a sign for a nan, - even if one has explicitly been requested */ strncpy(p, float_strings[OFS_NAN], 3); p += 3;