Function parse_datetime_unit_from_string

numpy/core/src/multiarray/datetime.c:1716–1775

* Converts a substring given by 'str' and 'len' into * a date time unit enum value. The 'metastr' parameter * is used for error messages, and may be NULL. * * Returns NPY_DATETIMEUNIT on success, NPY_FR_ERROR on failure. */

 * Returns NPY_DATETIMEUNIT on success, NPY_FR_ERROR on failure.
 */
NPY_NO_EXPORT NPY_DATETIMEUNIT
parse_datetime_unit_from_string(char const *str, Py_ssize_t len, char const *metastr)
{
    /* Use switch statements so the compiler can make it fast */
    if (len == 1) {
        switch (str[0]) {
            case 'Y':
                return NPY_FR_Y;
            case 'M':
                return NPY_FR_M;
            case 'W':
                return NPY_FR_W;
            case 'D':
                return NPY_FR_D;
            case 'h':
                return NPY_FR_h;
            case 'm':
                return NPY_FR_m;
            case 's':
                return NPY_FR_s;
        }
    }
    /* All the two-letter units are variants of seconds */
    else if (len == 2 && str[1] == 's') {
        switch (str[0]) {
            case 'm':
                return NPY_FR_ms;
            case 'u':
                return NPY_FR_us;
            case 'n':
                return NPY_FR_ns;
            case 'p':
                return NPY_FR_ps;
            case 'f':
                return NPY_FR_fs;
            case 'a':
                return NPY_FR_as;
        }
    }
    else if (len == 3 && !strncmp(str, "\xce\xbcs", 3)) {
        /* greek small letter mu, utf8-encoded */
        return NPY_FR_us;
    }
    else if (len == 7 && !strncmp(str, "generic", 7)) {
        return NPY_FR_GENERIC;
    }

    /* If nothing matched, it's an error */
    if (metastr == NULL) {
        PyErr_Format(PyExc_TypeError,
                "Invalid datetime unit \"%s\" in metadata",
                str);
    }
    else {
        PyErr_Format(PyExc_TypeError,
                "Invalid datetime unit in metadata string \"%s\"",
                metastr);
    }