/src/utils/python/python26/Python/pystrtod.c
C | 490 lines | 278 code | 65 blank | 147 comment | 147 complexity | 3a0853f47bb37e5bf9766fac780522b4 MD5 | raw file
- /* -*- Mode: C; c-file-style: "python" -*- */
- #include <Python.h>
- #include <locale.h>
- /* ascii character tests (as opposed to locale tests) */
- #define ISSPACE(c) ((c) == ' ' || (c) == '\f' || (c) == '\n' || \
- (c) == '\r' || (c) == '\t' || (c) == '\v')
- #define ISDIGIT(c) ((c) >= '0' && (c) <= '9')
- /**
- * 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.
- **/
- 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;
- /* 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)
- {
- while (ISDIGIT(*p))
- p++;
- if (*p == '.')
- {
- decimal_point_pos = p++;
- while (ISDIGIT(*p))
- p++;
- if (*p == 'e' || *p == 'E')
- p++;
- if (*p == '+' || *p == '-')
- p++;
- while (ISDIGIT(*p))
- p++;
- end = p;
- }
- else if (strncmp(p, decimal_point, decimal_point_len) == 0)
- {
- /* Python bug #1417699 */
- if (endptr)
- *endptr = (char*)nptr;
- errno = EINVAL;
- return val;
- }
- /* For the other cases, we need not convert the decimal
- point */
- }
- /* Set errno to zero, so that we can distinguish zero results
- and underflows */
- errno = 0;
- if (decimal_point_pos)
- {
- char *copy, *c;
- /* We need to convert the '.' 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)
- fail_pos = (char *)nptr;
- if (negate && fail_pos != nptr)
- val = -val;
- if (endptr)
- *endptr = fail_pos;
- return val;
- }
- /* 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 (isdigit(Py_CHARMASK(*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;
- }
- }
- }
- }
- /* 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_minumim_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 && isdigit(Py_CHARMASK(*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);
- }
- }
- }
- }
- /* Ensure that buffer has a decimal point in it. The decimal point
- will not be in the current locale, it will always be '.' */
- Py_LOCAL_INLINE(void)
- ensure_decimal_point(char* buffer, size_t buf_size)
- {
- int insert_count = 0;
- char* chars_to_insert;
- /* 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;
- while (*p && isdigit(Py_CHARMASK(*p)))
- ++p;
- if (*p == '.') {
- if (isdigit(Py_CHARMASK(*(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. */
- ++p;
- chars_to_insert = "0";
- insert_count = 1;
- }
- }
- else {
- 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);
- }
- }
- }
- /* Add the locale specific grouping characters to buffer. Note
- that any decimal point (if it's present) in buffer is already
- locale-specific. Return 0 on error, else 1. */
- Py_LOCAL_INLINE(int)
- add_thousands_grouping(char* buffer, size_t buf_size)
- {
- Py_ssize_t len = strlen(buffer);
- struct lconv *locale_data = localeconv();
- const char *decimal_point = locale_data->decimal_point;
- /* Find the decimal point, if any. We're only concerned
- about the characters to the left of the decimal when
- adding grouping. */
- char *p = strstr(buffer, decimal_point);
- if (!p) {
- /* No decimal, use the entire string. */
- /* If any exponent, adjust p. */
- p = strpbrk(buffer, "eE");
- if (!p)
- /* No exponent and no decimal. Use the entire
- string. */
- p = buffer + len;
- }
- /* At this point, p points just past the right-most character we
- want to format. We need to add the grouping string for the
- characters between buffer and p. */
- return _PyString_InsertThousandsGrouping(buffer, len, p-buffer,
- buf_size, NULL, 1);
- }
- /* 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 'n'.
- *
- * 'n' is the same as 'g', except it uses the current locale.
- * '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.
- **/
- char *
- PyOS_ascii_formatd(char *buffer,
- size_t buf_size,
- const char *format,
- double d)
- {
- char format_char;
- size_t format_len = strlen(format);
- /* For type 'n', we need to make a copy of the format string, because
- we're going to modify 'n' -> 'g', and format is const char*, so we
- can't modify it directly. FLOAT_FORMATBUFLEN should be longer than
- we ever need this to be. There's an upcoming check to ensure it's
- big enough. */
- /* 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];
- /* 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 == 'n' || format_char == 'Z'))
- return NULL;
- /* Map 'n' or 'Z' format_char to 'g', by copying the format string and
- replacing the final char with a 'g' */
- if (format_char == 'n' || 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. Do not do this if using the
- 'n' (number) format code, since we want to keep the localized
- decimal point in that case. */
- if (format_char != 'n')
- 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_minumim_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). */
- if (format_char == 'Z')
- ensure_decimal_point(buffer, buf_size);
- /* If format_char is 'n', add the thousands grouping. */
- if (format_char == 'n')
- if (!add_thousands_grouping(buffer, buf_size))
- return NULL;
- return buffer;
- }
- double
- PyOS_ascii_atof(const char *nptr)
- {
- return PyOS_ascii_strtod(nptr, NULL);
- }