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author	Thiago Macieira <thiago.macieira@intel.com>	2012-09-11 13:36:54 (GMT)
committer	The Qt Project <gerrit-noreply@qt-project.org>	2013-01-05 13:45:53 (GMT)
commit	f31ff453c3f03ffae21ec9bcd64e9cd93547e6d2 (patch)
tree	d1ea50c22f491b81630281e6ea077026834d32d9 /doc/src/snippets/qt-namespace/main.cpp
parent	b36bf7507c02f0e3cf32abda49e295fdd94a4848 (diff)
download	Qt-f31ff453c3f03ffae21ec9bcd64e9cd93547e6d2.zip Qt-f31ff453c3f03ffae21ec9bcd64e9cd93547e6d2.tar.gz Qt-f31ff453c3f03ffae21ec9bcd64e9cd93547e6d2.tar.bz2

Fix thread-safety of qt_ignore_sigpipe

The testAndSet operation would mean another thread could see the value of 1 and proceed to write(2)/sendto(2) before SIGPIPE had been ignored. If the pipe or socket were already closed by then, a SIGPIPE would be delivered to the application with its default action: terminate. (cherry-picked from qtbase commit 3f970c20f9afd5c9a1cc14d7f69882e13f6aaf1b) Change-Id: I62dc8f5fa14c1dd453d13e4053c642bd78fbc468 Reviewed-by: Qt Doc Bot <qt_docbot@qt-project.org> Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com> Reviewed-by: Shane Kearns <shane.kearns@accenture.com> Reviewed-by: Peter Hartmann <phartmann@rim.com>

Diffstat (limited to 'doc/src/snippets/qt-namespace/main.cpp')

0 files changed, 0 insertions, 0 deletions

/* -*- Mode: C; c-file-style: "python" -*- */ #include <Python.h> #include <locale.h> /** * PyOS_ascii_strtod: * @nptr: the string to convert to a numeric value. * @endptr: if non-%NULL, it returns the character after * the last character used in the conversion. * * Converts a string to a #gdouble value. * This function behaves like the standard strtod() function * does in the C locale. It does this without actually * changing the current locale, since that would not be * thread-safe. * * This function is typically used when reading configuration * files or other non-user input that should be locale independent. * To handle input from the user you should normally use the * locale-sensitive system strtod() function. * * If the correct value would cause overflow, plus or minus %HUGE_VAL * is returned (according to the sign of the value), and %ERANGE is * stored in %errno. If the correct value would cause underflow, * zero is returned and %ERANGE is stored in %errno. * If memory allocation fails, %ENOMEM is stored in %errno. * * This function resets %errno before calling strtod() so that * you can reliably detect overflow and underflow. * * Return value: the #gdouble value. **/ /* Use system strtod; since strtod is locale aware, we may have to first fix the decimal separator. Note that unlike _Py_dg_strtod, the system strtod may not always give correctly rounded results. */ /* Case-insensitive string match used for nan and inf detection; t should be lower-case. Returns 1 for a successful match, 0 otherwise. */ static int case_insensitive_match(const char *s, const char *t) { while(*t && Py_TOLOWER(*s) == *t) { s++; t++; } return *t ? 0 : 1; } double PyOS_ascii_strtod(const char *nptr, char **endptr) { char *fail_pos; double val = -1.0; struct lconv *locale_data; const char *decimal_point; 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); fail_pos = NULL; locale_data = localeconv(); decimal_point = locale_data->decimal_point; decimal_point_len = strlen(decimal_point); assert(decimal_point_len != 0); decimal_point_pos = NULL; /* Set errno to zero, so that we can distinguish zero results and underflows */ errno = 0; /* 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 (Py_ISSPACE(*p)) p++; /* Process leading sign, if present */ if (*p == '-') { negate = 1; p++; } else if (*p == '+') { p++; } /* Parse infinities and nans */ if (*p == 'i' || *p == 'I') { if (case_insensitive_match(p+1, "nf")) { val = Py_HUGE_VAL; if (case_insensitive_match(p+3, "inity")) fail_pos = (char *)p+8; else fail_pos = (char *)p+3; goto got_val; } else goto invalid_string; } #ifdef Py_NAN if (*p == 'n' || *p == 'N') { if (case_insensitive_match(p+1, "an")) { val = Py_NAN; fail_pos = (char *)p+3; goto got_val; } else goto invalid_string; } #endif /* Some platform strtods accept hex floats; Python shouldn't (at the moment), so we check explicitly for strings starting with '0x'. */ if (*p == '0' && (*(p+1) == 'x' || *(p+1) == 'X')) goto invalid_string; /* Check that what's left begins with a digit or decimal point */ if (!Py_ISDIGIT(*p) && *p != '.') goto invalid_string; digits_pos = p; if (decimal_point[0] != '.' || decimal_point[1] != 0) { /* Look for a '.' in the input; if present, it'll need to be swapped for the current locale's decimal point before we call strtod. On the other hand, if we find the current locale's decimal point then the input is invalid. */ while (Py_ISDIGIT(*p)) p++; if (*p == '.') { decimal_point_pos = p++; /* locate end of number */ while (Py_ISDIGIT(*p)) p++; if (*p == 'e' || *p == 'E') p++; if (*p == '+' || *p == '-') p++; while (Py_ISDIGIT(*p)) p++; end = p; } else if (strncmp(p, decimal_point, decimal_point_len) == 0) /* Python bug #1417699 */ goto invalid_string; /* For the other cases, we need not convert the decimal point */ } if (decimal_point_pos) { char *copy, *c; /* Create a copy of the input, with the '.' converted to the locale-specific decimal point */ copy = (char *)PyMem_MALLOC(end - digits_pos + 1 + decimal_point_len); if (copy == NULL) { if (endptr) *endptr = (char *)nptr; errno = ENOMEM; return val; } c = copy; 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)); c += end - (decimal_point_pos + 1); *c = 0; val = strtod(copy, &fail_pos); if (fail_pos) { if (fail_pos > decimal_point_pos) fail_pos = (char *)digits_pos + (fail_pos - copy) - (decimal_point_len - 1); else fail_pos = (char *)digits_pos + (fail_pos - copy); } PyMem_FREE(copy); } else { val = strtod(digits_pos, &fail_pos); } if (fail_pos == digits_pos) goto invalid_string; got_val: if (negate && fail_pos != nptr) val = -val; if (endptr) *endptr = fail_pos; return val; invalid_string: if (endptr) *endptr = (char*)nptr; errno = EINVAL; return -1.0; } double PyOS_ascii_atof(const char *nptr) { return PyOS_ascii_strtod(nptr, NULL); } /* Given a string that may have a decimal point in the current locale, change it back to a dot. Since the string cannot get longer, no need for a maximum buffer size parameter. */ Py_LOCAL_INLINE(void) change_decimal_from_locale_to_dot(char* buffer) { struct lconv *locale_data = localeconv(); const char *decimal_point = locale_data->decimal_point; if (decimal_point[0] != '.' || decimal_point[1] != 0) { size_t decimal_point_len = strlen(decimal_point); if (*buffer == '+' || *buffer == '-') buffer++; while (Py_ISDIGIT(*buffer)) buffer++; if (strncmp(buffer, decimal_point, decimal_point_len) == 0) { *buffer = '.'; buffer++; if (decimal_point_len > 1) { /* buffer needs to get smaller */ size_t rest_len = strlen(buffer + (decimal_point_len - 1)); memmove(buffer, buffer + (decimal_point_len - 1), rest_len); buffer[rest_len] = 0; } } } } Py_LOCAL_INLINE(void) ensure_sign(char* buffer, size_t buf_size) { size_t len; if (buffer[0] == '-') /* Already have a sign. */ return; /* Include the trailing 0 byte. */ len = strlen(buffer)+1; if (len >= buf_size+1) /* No room for the sign, don't do anything. */ return; memmove(buffer+1, buffer, len); buffer[0] = '+'; } /* From the C99 standard, section 7.19.6: The exponent always contains at least two digits, and only as many more digits as necessary to represent the exponent. */ #define MIN_EXPONENT_DIGITS 2 /* Ensure that any exponent, if present, is at least MIN_EXPONENT_DIGITS in length. */ Py_LOCAL_INLINE(void) ensure_minimum_exponent_length(char* buffer, size_t buf_size) { char *p = strpbrk(buffer, "eE"); if (p && (*(p + 1) == '-' || *(p + 1) == '+')) { char *start = p + 2; int exponent_digit_cnt = 0; int leading_zero_cnt = 0; int in_leading_zeros = 1; int significant_digit_cnt; /* Skip over the exponent and the sign. */ p += 2; /* Find the end of the exponent, keeping track of leading zeros. */ while (*p && Py_ISDIGIT(*p)) { if (in_leading_zeros && *p == '0') ++leading_zero_cnt; if (*p != '0') in_leading_zeros = 0; ++p; ++exponent_digit_cnt; } significant_digit_cnt = exponent_digit_cnt - leading_zero_cnt; if (exponent_digit_cnt == MIN_EXPONENT_DIGITS) { /* If there are 2 exactly digits, we're done, regardless of what they contain */ } else if (exponent_digit_cnt > MIN_EXPONENT_DIGITS) { int extra_zeros_cnt; /* There are more than 2 digits in the exponent. See if we can delete some of the leading zeros */ if (significant_digit_cnt < MIN_EXPONENT_DIGITS) significant_digit_cnt = MIN_EXPONENT_DIGITS; extra_zeros_cnt = exponent_digit_cnt - significant_digit_cnt; /* Delete extra_zeros_cnt worth of characters from the front of the exponent */ assert(extra_zeros_cnt >= 0); /* Add one to significant_digit_cnt to copy the trailing 0 byte, thus setting the length */ memmove(start, start + extra_zeros_cnt, significant_digit_cnt + 1); } else { /* If there are fewer than 2 digits, add zeros until there are 2, if there's enough room */ int zeros = MIN_EXPONENT_DIGITS - exponent_digit_cnt; if (start + zeros + exponent_digit_cnt + 1 < buffer + buf_size) { memmove(start + zeros, start, exponent_digit_cnt + 1); memset(start, '0', zeros); } } } } /* Remove trailing zeros after the decimal point from a numeric string; also remove the decimal point if all digits following it are zero. The numeric string must end in '\0', and should not have any leading or trailing whitespace. Assumes that the decimal point is '.'. */ Py_LOCAL_INLINE(void) remove_trailing_zeros(char *buffer) { char *old_fraction_end, *new_fraction_end, *end, *p; p = buffer; if (*p == '-' || *p == '+') /* Skip leading sign, if present */ ++p; while (Py_ISDIGIT(*p)) ++p; /* if there's no decimal point there's nothing to do */ if (*p++ != '.') return; /* scan any digits after the point */ while (Py_ISDIGIT(*p)) ++p; old_fraction_end = p; /* scan up to ending '\0' */ while (*p != '\0') p++; /* +1 to make sure that we move the null byte as well */ end = p+1; /* scan back from fraction_end, looking for removable zeros */ p = old_fraction_end; while (*(p-1) == '0') --p; /* and remove point if we've got that far */ if (*(p-1) == '.') --p; new_fraction_end = p; memmove(new_fraction_end, old_fraction_end, end-old_fraction_end); } /* Ensure that buffer has a decimal point in it. The decimal point will not be in the current locale, it will always be '.'. Don't add a decimal point if an exponent is present. Also, convert to exponential notation where adding a '.0' would produce too many significant digits (see issue 5864). Returns a pointer to the fixed buffer, or NULL on failure. */ Py_LOCAL_INLINE(char *) ensure_decimal_point(char* buffer, size_t buf_size, int precision) { int digit_count, insert_count = 0, convert_to_exp = 0; char* chars_to_insert, *digits_start; /* search for the first non-digit character */ char *p = buffer; if (*p == '-' || *p == '+') /* Skip leading sign, if present. I think this could only ever be '-', but it can't hurt to check for both. */ ++p; digits_start = p; while (*p && Py_ISDIGIT(*p)) ++p; digit_count = Py_SAFE_DOWNCAST(p - digits_start, Py_ssize_t, int); if (*p == '.') { if (Py_ISDIGIT(*(p+1))) { /* Nothing to do, we already have a decimal point and a digit after it */ } else { /* We have a decimal point, but no following digit. Insert a zero after the decimal. */ /* can't ever get here via PyOS_double_to_string */ assert(precision == -1); ++p; chars_to_insert = "0"; insert_count = 1; } } else if (!(*p == 'e' || *p == 'E')) { /* Don't add ".0" if we have an exponent. */ if (digit_count == precision) { /* issue 5864: don't add a trailing .0 in the case where the '%g'-formatted result already has as many significant digits as were requested. Switch to exponential notation instead. */ convert_to_exp = 1; /* no exponent, no point, and we shouldn't land here for infs and nans, so we must be at the end of the string. */ assert(*p == '\0'); } else { assert(precision == -1 || digit_count < precision); chars_to_insert = ".0"; insert_count = 2; } } if (insert_count) { size_t buf_len = strlen(buffer); if (buf_len + insert_count + 1 >= buf_size) { /* If there is not enough room in the buffer for the additional text, just skip it. It's not worth generating an error over. */ } else { memmove(p + insert_count, p, buffer + strlen(buffer) - p + 1); memcpy(p, chars_to_insert, insert_count); } } if (convert_to_exp) { int written; size_t buf_avail; p = digits_start; /* insert decimal point */ assert(digit_count >= 1); memmove(p+2, p+1, digit_count); /* safe, but overwrites nul */ p[1] = '.'; p += digit_count+1; assert(p <= buf_size+buffer); buf_avail = buf_size+buffer-p; if (buf_avail == 0) return NULL; /* Add exponent. It's okay to use lower case 'e': we only arrive here as a result of using the empty format code or repr/str builtins and those never want an upper case 'E' */ written = PyOS_snprintf(p, buf_avail, "e%+.02d", digit_count-1); if (!(0 <= written && written < Py_SAFE_DOWNCAST(buf_avail, size_t, int))) /* output truncated, or something else bad happened */ return NULL; remove_trailing_zeros(buffer); } return buffer; } /* see FORMATBUFLEN in unicodeobject.c */ #define FLOAT_FORMATBUFLEN 120 /** * _PyOS_ascii_formatd: * @buffer: A buffer to place the resulting string in * @buf_size: The length of the buffer. * @format: The printf()-style format to use for the * code to use for converting. * @d: The #gdouble to convert * * Converts a #gdouble to a string, using the '.' as * decimal point. To format the number you pass in * a printf()-style format string. Allowed conversion * specifiers are 'e', 'E', 'f', 'F', 'g', 'G', and 'Z'. * * 'Z' is the same as 'g', except it always has a decimal and * at least one digit after the decimal. * * Return value: The pointer to the buffer with the converted string. * On failure returns NULL but does not set any Python exception. **/ /* DEPRECATED, will be deleted in 2.8 and 3.2 */ PyAPI_FUNC(char *) PyOS_ascii_formatd(char *buffer, size_t buf_size, const char *format, double d) { char format_char; size_t format_len = strlen(format); /* Issue 2264: code 'Z' requires copying the format. 'Z' is 'g', but also with at least one character past the decimal. */ char tmp_format[FLOAT_FORMATBUFLEN]; if (PyErr_WarnEx(PyExc_DeprecationWarning, "PyOS_ascii_formatd is deprecated, " "use PyOS_double_to_string instead", 1) < 0) return NULL; /* The last character in the format string must be the format char */ format_char = format[format_len - 1]; if (format[0] != '%') return NULL; /* I'm not sure why this test is here. It's ensuring that the format string after the first character doesn't have a single quote, a lowercase l, or a percent. This is the reverse of the commented-out test about 10 lines ago. */ if (strpbrk(format + 1, "'l%")) return NULL; /* Also curious about this function is that it accepts format strings like "%xg", which are invalid for floats. In general, the interface to this function is not very good, but changing it is difficult because it's a public API. */ if (!(format_char == 'e' || format_char == 'E' || format_char == 'f' || format_char == 'F' || format_char == 'g' || format_char == 'G' || format_char == 'Z')) return NULL; /* Map 'Z' format_char to 'g', by copying the format string and replacing the final char with a 'g' */ if (format_char == 'Z') { if (format_len + 1 >= sizeof(tmp_format)) { /* The format won't fit in our copy. Error out. In practice, this will never happen and will be detected by returning NULL */ return NULL; } strcpy(tmp_format, format); tmp_format[format_len - 1] = 'g'; format = tmp_format; } /* Have PyOS_snprintf do the hard work */ PyOS_snprintf(buffer, buf_size, format, d); /* Do various fixups on the return string */ /* Get the current locale, and find the decimal point string. Convert that string back to a dot. */ change_decimal_from_locale_to_dot(buffer); /* If an exponent exists, ensure that the exponent is at least MIN_EXPONENT_DIGITS digits, providing the buffer is large enough for the extra zeros. Also, if there are more than MIN_EXPONENT_DIGITS, remove as many zeros as possible until we get back to MIN_EXPONENT_DIGITS */ ensure_minimum_exponent_length(buffer, buf_size); /* If format_char is 'Z', make sure we have at least one character after the decimal point (and make sure we have a decimal point); also switch to exponential notation in some edge cases where the extra character would produce more significant digits that we really want. */ if (format_char == 'Z') buffer = ensure_decimal_point(buffer, buf_size, -1); return buffer; } /* Precisions used by repr() and str(), respectively. The repr() precision (17 significant decimal digits) is the minimal number that is guaranteed to have enough precision so that if the number is read back in the exact same binary value is recreated. This is true for IEEE floating point by design, and also happens to work for all other modern hardware. The str() precision (12 significant decimal digits) is chosen so that in most cases, the rounding noise created by various operations is suppressed, while giving plenty of precision for practical use. */ PyAPI_FUNC(void) _PyOS_double_to_string(char *buf, size_t buf_len, double val, char format_code, int precision, int flags, int *ptype) { char format[32]; int t; int upper = 0; if (buf_len < 1) { assert(0); /* There's no way to signal this error. Just return. */ return; } buf[0] = 0; /* Validate format_code, and map upper and lower case */ switch (format_code) { case 'e': /* exponent */ case 'f': /* fixed */ case 'g': /* general */ break; case 'E': upper = 1; format_code = 'e'; break; case 'F': upper = 1; format_code = 'f'; break; case 'G': upper = 1; format_code = 'g'; break; case 'r': /* repr format */ /* Supplied precision is unused, must be 0. */ if (precision != 0) return; /* The repr() precision (17 significant decimal digits) is the minimal number that is guaranteed to have enough precision so that if the number is read back in the exact same binary value is recreated. This is true for IEEE floating point by design, and also happens to work for all other modern hardware. */ precision = 17; format_code = 'g'; break; default: assert(0); return; } /* Check for buf too small to fit "-inf". Other buffer too small conditions are dealt with when converting or formatting finite numbers. */ if (buf_len < 5) { assert(0); return; } /* Handle nan and inf. */ if (Py_IS_NAN(val)) { strcpy(buf, "nan"); t = Py_DTST_NAN; } else if (Py_IS_INFINITY(val)) { if (copysign(1., val) == 1.) strcpy(buf, "inf"); else strcpy(buf, "-inf"); t = Py_DTST_INFINITE; } else { t = Py_DTST_FINITE; /* Build the format string. */ PyOS_snprintf(format, sizeof(format), "%%%s.%i%c", (flags & Py_DTSF_ALT ? "#" : ""), precision, format_code); /* Have PyOS_snprintf do the hard work. */ PyOS_snprintf(buf, buf_len, format, val); /* Do various fixups on the return string */ /* Get the current locale, and find the decimal point string. Convert that string back to a dot. */ change_decimal_from_locale_to_dot(buf); /* If an exponent exists, ensure that the exponent is at least MIN_EXPONENT_DIGITS digits, providing the buffer is large enough for the extra zeros. Also, if there are more than MIN_EXPONENT_DIGITS, remove as many zeros as possible until we get back to MIN_EXPONENT_DIGITS */ ensure_minimum_exponent_length(buf, buf_len); /* Possibly make sure we have at least one character after the decimal point (and make sure we have a decimal point). */ if (flags & Py_DTSF_ADD_DOT_0) buf = ensure_decimal_point(buf, buf_len, precision); } /* Add the sign if asked and the result isn't negative. */ if (flags & Py_DTSF_SIGN && buf[0] != '-') ensure_sign(buf, buf_len); if (upper) { /* Convert to upper case. */ char *p; for (p = buf; *p; p++) *p = Py_TOUPPER(*p); } if (ptype) *ptype = t; } PyAPI_FUNC(char *) PyOS_double_to_string(double val, char format_code, int precision, int flags, int *ptype) { char buf[128]; Py_ssize_t len; char *result; _PyOS_double_to_string(buf, sizeof(buf), val, format_code, precision, flags, ptype); len = strlen(buf); if (len == 0) { PyErr_BadInternalCall(); return NULL; } /* Add 1 for the trailing 0 byte. */ result = PyMem_Malloc(len + 1); if (result == NULL) { PyErr_NoMemory(); return NULL; } strcpy(result, buf); return result; }


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