int H3_EXPORT()

in src/h3lib/lib/h3Index.c [85:118]

• 25 lines of code
• 14 McCabe index (conditional complexity)

int H3_EXPORT(h3IsValid)(H3Index h) {
    if (H3_GET_HIGH_BIT(h) != 0) return 0;

    if (H3_GET_MODE(h) != H3_HEXAGON_MODE) return 0;

    if (H3_GET_RESERVED_BITS(h) != 0) return 0;

    int baseCell = H3_GET_BASE_CELL(h);
    if (baseCell < 0 || baseCell >= NUM_BASE_CELLS) return 0;

    int res = H3_GET_RESOLUTION(h);
    if (res < 0 || res > MAX_H3_RES) return 0;

    bool foundFirstNonZeroDigit = false;
    for (int r = 1; r <= res; r++) {
        Direction digit = H3_GET_INDEX_DIGIT(h, r);

        if (!foundFirstNonZeroDigit && digit != CENTER_DIGIT) {
            foundFirstNonZeroDigit = true;
            if (_isBaseCellPentagon(baseCell) && digit == K_AXES_DIGIT) {
                return 0;
            }
        }

        if (digit < CENTER_DIGIT || digit >= NUM_DIGITS) return 0;
    }

    for (int r = res + 1; r <= MAX_H3_RES; r++) {
        Direction digit = H3_GET_INDEX_DIGIT(h, r);
        if (digit != INVALID_DIGIT) return 0;
    }

    return 1;
}