RingBuffer.h

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#ifndef IMT_BASE_CORE_UTIL_RINGBUFFER_H
#define IMT_BASE_CORE_UTIL_RINGBUFFER_H
 
#include <array>
#include <Imt.Base.Core.Diagnostics/Diagnostics.h>
#include <Imt.Base.Core.Platform/Platform.h>
 
namespace imt {
namespace base {
namespace core {
namespace util {
 
template<typename ElementType, uint16_t BufferSize>
class RingBuffer final {
 
    // There must always be a gap between in and out position.
    // Therefore a buffer of size 0 or 1 does not work
    static_assert(BufferSize > 1, "Buffer size less than 2 elements");
 
public:
 
    using ValueType = ElementType;
 
    static constexpr uint16_t SIZE {BufferSize}; // AXIVION Line AutosarC++19_03-M0.1.4: field will be reference in the projects
 
    RingBuffer() = default;
 
    void push(ValueType const& newValue) {
        m_buf[m_inPos] = newValue;
        m_inPos = (m_inPos + 1) % BufferSize;
    }
 
    ValueType const& top() const {
        // check for invalid address space access
        ASSERT_DEBUG(m_outPos < BufferSize);
        return m_buf[m_outPos];
    }
 
    ValueType const& top(uint16_t const offset) const {
        uint16_t const index {static_cast<uint16_t>((m_outPos + offset) % BufferSize)};
        // check for invalid address space access
        ASSERT_DEBUG(index < BufferSize);
        return m_buf[index];
    }
 
    ValueType& top() {
        // check for invalid address space access
        ASSERT_DEBUG(m_outPos < BufferSize);
        return m_buf[m_outPos];
    }
 
    ValueType& top(uint16_t const offset) {
        uint16_t const index {static_cast<uint16_t>((m_outPos + offset) % BufferSize)};
        // check for invalid address space access
        ASSERT_DEBUG(index < BufferSize);
        return m_buf[index];
    }
 
    ValueType pop() {
        // Calculate index of the position to return
        uint16_t const pos {m_outPos};
        // Calculate next output position
        m_outPos = (m_outPos + 1) % BufferSize;
        // check for invalid address space access
        ASSERT_DEBUG(pos < BufferSize);
        return m_buf[pos];
    }
 
    ValueType const& bottom() const {
        uint16_t const inPos {m_inPos}; // copy m_inPos to prevent race conditions (irq/tasking)
        uint16_t const index {(inPos > 0) ? static_cast<uint16_t>((inPos - 1) % BufferSize) : static_cast<uint16_t>(BufferSize - 1)};
        // check for invalid address space access
        ASSERT_DEBUG(index < BufferSize);
        return m_buf[index];
    }
 
    ValueType const& bottomAndClearAll() {
        uint16_t const inPos {m_inPos}; // copy m_inPos to prevent race conditions (irq/tasking)
        uint16_t const index {(inPos > 0) ? static_cast<uint16_t>((inPos - 1) % BufferSize) : static_cast<uint16_t>(BufferSize - 1)};
        m_outPos = m_inPos;
        // check for invalid address space access
        ASSERT_DEBUG(index < BufferSize);
        return m_buf[index];
    }
 
    ValueType const& bottom(uint16_t const offset) const {
        uint16_t const index {static_cast<uint16_t>((((BufferSize - 1) + m_inPos) - offset) % BufferSize)};
        // check for invalid address space access
        ASSERT_DEBUG(index < BufferSize);
        return m_buf[index];
    }
 
    bool isEmpty() const {
        return m_inPos == m_outPos;
    }
 
    bool isFull() const {
        return getSizeUsed() == (BufferSize - 1);
    }
 
    uint16_t getSizeUsed() const {
        uint16_t const inPos {m_inPos};   // copy m_inPos to prevent race conditions (irq/tasking)
        uint16_t const outPos {m_outPos}; // copy m_outPos to prevent race conditions (irq/tasking)
        return (inPos >= outPos) ? (inPos - outPos) : (BufferSize - (outPos - inPos));
    }
 
private:
 
    uint16_t m_inPos {0U};
    uint16_t m_outPos {0U};
    std::array<ValueType, BufferSize> m_buf {};
};
 
} // namespace util
} // namespace core
} // namespace base
} // namespace imt
 
#endif // IMT_BASE_CORE_UTIL_RINGBUFFER_H