size()

template<typename T , typename StoragePolicy , typename ConcurrencyPolicy = SingleThreadedPolicy, typename AccessPattern = QueueAccess>

size_t MayaFlux::Memory::RingBuffer< T, StoragePolicy, ConcurrencyPolicy, AccessPattern >::size ( ) const

inlinenoexcept

Get approximate element count.

Returns

Number of elements in buffer

For LockFreePolicy, value may be stale due to concurrent modification. Use for debugging/monitoring only, not for critical logic.

Definition at line 1053 of file RingBuffer.hpp.

    {
        const size_t cap = m_storage.capacity();
 
        if constexpr (is_mpsc) {
            auto claim = m_state.claim_index.load(std::memory_order_acquire);
            auto read = m_state.read_index.load(std::memory_order_acquire);
            return (claim - read) & (cap - 1);
        } else if constexpr (is_lock_free) {
            auto write = m_state.write_index.load(std::memory_order_acquire);
            auto read = m_state.read_index.load(std::memory_order_acquire);
            return (write >= read) ? (write - read) : (cap - read + write);
        } else {
            return (m_state.write_index >= m_state.read_index)
                ? (m_state.write_index - m_state.read_index)
                : (cap - m_state.read_index + m_state.write_index);
        }
    }

References MayaFlux::Memory::RingBuffer< T, StoragePolicy, ConcurrencyPolicy, AccessPattern >::is_lock_free, MayaFlux::Memory::RingBuffer< T, StoragePolicy, ConcurrencyPolicy, AccessPattern >::is_mpsc, MayaFlux::Memory::RingBuffer< T, StoragePolicy, ConcurrencyPolicy, AccessPattern >::m_state, and MayaFlux::Memory::RingBuffer< T, StoragePolicy, ConcurrencyPolicy, AccessPattern >::m_storage.

Referenced by MayaFlux::Memory::RingBuffer< T, StoragePolicy, ConcurrencyPolicy, AccessPattern >::linearized_view(), MayaFlux::Memory::RingBuffer< T, StoragePolicy, ConcurrencyPolicy, AccessPattern >::linearized_view_mut(), and MayaFlux::Memory::RingBuffer< T, StoragePolicy, ConcurrencyPolicy, AccessPattern >::peek_oldest().

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