Function parse_iso_8601_datetime

numpy/core/src/multiarray/datetime_strings.c:221–753

* Parses (almost) standard ISO 8601 date strings. The differences are: * * + The date "20100312" is parsed as the year 20100312, not as * equivalent to "2010-03-12". The '-' in the dates are not optional. * + Only seconds may have a decimal point, with up to 18 digits after it * (maximum attoseconds precision). * + Either a 'T' as in ISO 8601 or a ' ' may be used to separate * the dat

 * Returns 0 on success, -1 on failure.
 */
NPY_NO_EXPORT int
parse_iso_8601_datetime(char const *str, Py_ssize_t len,
                    NPY_DATETIMEUNIT unit,
                    NPY_CASTING casting,
                    npy_datetimestruct *out,
                    NPY_DATETIMEUNIT *out_bestunit,
                    npy_bool *out_special)
{
    int year_leap = 0;
    int i, numdigits;
    char const *substr;
    Py_ssize_t sublen;
    NPY_DATETIMEUNIT bestunit;

    /* Initialize the output to all zeros */
    memset(out, 0, sizeof(npy_datetimestruct));
    out->month = 1;
    out->day = 1;

    /*
     * Convert the empty string and case-variants of "NaT" to not-a-time.
     * Tried to use PyOS_stricmp, but that function appears to be broken,
     * not even matching the strcmp function signature as it should.
     */
    if (len <= 0 || (len == 3 &&
                        tolower(str[0]) == 'n' &&
                        tolower(str[1]) == 'a' &&
                        tolower(str[2]) == 't')) {
        out->year = NPY_DATETIME_NAT;

        /*
         * Indicate that this was a special value, and
         * recommend generic units.
         */
        if (out_bestunit != NULL) {
            *out_bestunit = NPY_FR_GENERIC;
        }
        if (out_special != NULL) {
            *out_special = 1;
        }

        return 0;
    }

    if (unit == NPY_FR_GENERIC) {
        PyErr_SetString(PyExc_ValueError,
                    "Cannot create a NumPy datetime other than NaT "
                    "with generic units");
        return -1;
    }

    /*
     * The string "today" means take today's date in local time, and
     * convert it to a date representation. This date representation, if
     * forced into a time unit, will be at midnight UTC.
     * This is perhaps a little weird, but done so that the
     * 'datetime64[D]' type produces the date you expect, rather than
     * switching to an adjacent day depending on the current time and your