Function str_to_int64

numpy/core/src/multiarray/textreading/str_to_int.h:19–96

* The following two string conversion functions are largely equivalent * in Pandas. They are in the header file here, to ensure they can be easily * inline in the other function. * Unlike pandas, pass in end-pointer (do not rely on \0) and return 0 or -1. * * The actual functions are defined using macro templating below. */

 * The actual functions are defined using macro templating below.
 */
NPY_FINLINE int
str_to_int64(
        const Py_UCS4 *p_item, const Py_UCS4 *p_end,
        int64_t int_min, int64_t int_max, int64_t *result)
{
    const Py_UCS4 *p = (const Py_UCS4 *)p_item;
    bool isneg = 0;
    int64_t number = 0;

    // Skip leading spaces.
    while (Py_UNICODE_ISSPACE(*p)) {
        ++p;
    }

    // Handle sign.
    if (*p == '-') {
        isneg = true;
        ++p;
    }
    else if (*p == '+') {
        p++;
    }

    // Check that there is a first digit.
    if (!isdigit(*p)) {
        return -1;
    }

    if (isneg) {
        // If number is greater than pre_min, at least one more digit
        // can be processed without overflowing.
        int dig_pre_min = -(int_min % 10);
        int64_t pre_min = int_min / 10;

        // Process the digits.
        int d = *p;
        while (isdigit(d)) {
            if ((number > pre_min) || ((number == pre_min) && (d - '0' <= dig_pre_min))) {
                number = number * 10 - (d - '0');
                d = *++p;
            }
            else {
                return -1;
            }
        }
    }
    else {
        // If number is less than pre_max, at least one more digit
        // can be processed without overflowing.
        int64_t pre_max = int_max / 10;
        int dig_pre_max = int_max % 10;

        // Process the digits.
        int d = *p;
        while (isdigit(d)) {
            if ((number < pre_max) || ((number == pre_max) && (d - '0' <= dig_pre_max))) {
                number = number * 10 + (d - '0');
                d = *++p;