Method ensure_capacity

src/fl/stl/deque.h:24–53

    static const fl::size kInitialCapacity = 8;

    void ensure_capacity(fl::size min_capacity) {
        if (mCapacity >= min_capacity) {
            return;
        }

        fl::size new_capacity = mCapacity == 0 ? kInitialCapacity : mCapacity * 2;
        while (new_capacity < min_capacity) {
            new_capacity *= 2;
        }

        T* new_data = static_cast<T*>(mResource->allocate(new_capacity * sizeof(T)));
        if (!new_data) {
            return; // Allocation failed
        }

        // Copy existing elements to new buffer in linear order
        for (fl::size i = 0; i < mSize; ++i) {
            fl::size old_idx = (mFront + i) % mCapacity;
            new (&new_data[i]) T(fl::move(mData[old_idx]));
            mData[old_idx].~T();
        }

        if (mData) {
            mResource->deallocate(mData, mCapacity * sizeof(T));
        }

        mData = new_data;
        mCapacity = new_capacity;
        mFront = 0; // Reset front to 0 after reallocation
    }

    fl::size get_index(fl::size logical_index) const {
        return (mFront + logical_index) % mCapacity;