From 3b83549ea0b0c3e8d1919925a8875052e13367cf Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Sat, 5 Jan 2008 00:59:59 +0000 Subject: [PATCH] Patch #1725 by Mark Dickinson, fixes incorrect conversion of -1e1000 and adds errors for -0x. --- Lib/test/test_builtin.py | 6 ++++ Lib/test/test_float.py | 7 ++++ Python/pystrtod.c | 74 ++++++++++++++++++++++++++++------------ 3 files changed, 65 insertions(+), 22 deletions(-) diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py index c5a1cc3fb21..255fb969611 100644 --- a/Lib/test/test_builtin.py +++ b/Lib/test/test_builtin.py @@ -619,6 +619,11 @@ class BuiltinTest(unittest.TestCase): self.assertEqual(float(" 3.14 "), 3.14) self.assertRaises(ValueError, float, " 0x3.1 ") self.assertRaises(ValueError, float, " -0x3.p-1 ") + self.assertRaises(ValueError, float, " +0x3.p-1 ") + self.assertRaises(ValueError, float, "++3.14") + self.assertRaises(ValueError, float, "+-3.14") + self.assertRaises(ValueError, float, "-+3.14") + self.assertRaises(ValueError, float, "--3.14") if have_unicode: self.assertEqual(float(unicode(" 3.14 ")), 3.14) self.assertEqual(float(unicode(" \u0663.\u0661\u0664 ",'raw-unicode-escape')), 3.14) @@ -648,6 +653,7 @@ class BuiltinTest(unittest.TestCase): self.assertRaises(ValueError, float, " -3,14 ") self.assertRaises(ValueError, float, " 0x3.1 ") self.assertRaises(ValueError, float, " -0x3.p-1 ") + self.assertRaises(ValueError, float, " +0x3.p-1 ") self.assertEqual(float(" 25.e-1 "), 2.5) self.assertEqual(fcmp(float(" .25e-1 "), .025), 0) diff --git a/Lib/test/test_float.py b/Lib/test/test_float.py index 11f169054a9..9d330403aa9 100644 --- a/Lib/test/test_float.py +++ b/Lib/test/test_float.py @@ -121,6 +121,13 @@ class IEEEFormatTestCase(unittest.TestCase): self.assertEquals(pos_pos(), neg_pos()) self.assertEquals(pos_neg(), neg_neg()) + if float.__getformat__("double").startswith("IEEE"): + def test_underflow_sign(self): + import math + # check that -1e-1000 gives -0.0, not 0.0 + self.assertEquals(math.atan2(-1e-1000, -1), math.atan2(-0.0, -1)) + self.assertEquals(math.atan2(float('-1e-1000'), -1), + math.atan2(-0.0, -1)) class ReprTestCase(unittest.TestCase): def test_repr(self): diff --git a/Python/pystrtod.c b/Python/pystrtod.c index 6c19b45fd26..14fb84ba715 100644 --- a/Python/pystrtod.c +++ b/Python/pystrtod.c @@ -48,6 +48,8 @@ PyOS_ascii_strtod(const char *nptr, char **endptr) size_t decimal_point_len; const char *p, *decimal_point_pos; const char *end = NULL; /* Silence gcc */ + const char *digits_pos = NULL; + int negate = 0; assert(nptr != NULL); @@ -60,18 +62,41 @@ PyOS_ascii_strtod(const char *nptr, char **endptr) assert(decimal_point_len != 0); decimal_point_pos = NULL; + + /* We process any leading whitespace and the optional sign manually, + then pass the remainder to the system strtod. This ensures that + the result of an underflow has the correct sign. (bug #1725) */ + + p = nptr; + /* Skip leading space */ + while (ISSPACE(*p)) + p++; + + /* Process leading sign, if present */ + if (*p == '-') { + negate = 1; + p++; + } else if (*p == '+') { + p++; + } + + /* What's left should begin with a digit, a decimal point, or one of + the letters i, I, n, N. It should not begin with 0x or 0X */ + if ((!ISDIGIT(*p) && + *p != '.' && *p != 'i' && *p != 'I' && *p != 'n' && *p != 'N') + || + (*p == '0' && (p[1] == 'x' || p[1] == 'X'))) + { + if (endptr) + *endptr = (char*)nptr; + errno = EINVAL; + return val; + } + digits_pos = p; + if (decimal_point[0] != '.' || decimal_point[1] != 0) { - p = nptr; - /* Skip leading space */ - while (ISSPACE(*p)) - p++; - - /* Skip leading optional sign */ - if (*p == '+' || *p == '-') - p++; - while (ISDIGIT(*p)) p++; @@ -93,7 +118,8 @@ PyOS_ascii_strtod(const char *nptr, char **endptr) else if (strncmp(p, decimal_point, decimal_point_len) == 0) { /* Python bug #1417699 */ - *endptr = (char*)nptr; + if (endptr) + *endptr = (char*)nptr; errno = EINVAL; return val; } @@ -109,7 +135,8 @@ PyOS_ascii_strtod(const char *nptr, char **endptr) char *copy, *c; /* We need to convert the '.' to the locale specific decimal point */ - copy = (char *)PyMem_MALLOC(end - nptr + 1 + decimal_point_len); + copy = (char *)PyMem_MALLOC(end - digits_pos + + 1 + decimal_point_len); if (copy == NULL) { if (endptr) *endptr = (char *)nptr; @@ -118,8 +145,8 @@ PyOS_ascii_strtod(const char *nptr, char **endptr) } c = copy; - memcpy(c, nptr, decimal_point_pos - nptr); - c += decimal_point_pos - nptr; + memcpy(c, digits_pos, decimal_point_pos - digits_pos); + c += decimal_point_pos - digits_pos; memcpy(c, decimal_point, decimal_point_len); c += decimal_point_len; memcpy(c, decimal_point_pos + 1, end - (decimal_point_pos + 1)); @@ -131,24 +158,27 @@ PyOS_ascii_strtod(const char *nptr, char **endptr) if (fail_pos) { if (fail_pos > decimal_point_pos) - fail_pos = (char *)nptr + (fail_pos - copy) - (decimal_point_len - 1); + fail_pos = (char *)digits_pos + + (fail_pos - copy) - + (decimal_point_len - 1); else - fail_pos = (char *)nptr + (fail_pos - copy); + fail_pos = (char *)digits_pos + + (fail_pos - copy); } PyMem_FREE(copy); } else { - unsigned i = 0; - if (nptr[i] == '-') - i++; - if (nptr[i] == '0' && (nptr[i+1] == 'x' || nptr[i+1] == 'X')) - fail_pos = (char*)nptr; - else - val = strtod(nptr, &fail_pos); + val = strtod(digits_pos, &fail_pos); } + if (fail_pos == digits_pos) + fail_pos = (char *)nptr; + + if (negate && fail_pos != nptr) + val = -val; + if (endptr) *endptr = fail_pos;