circular_buffer.h

Go to the documentation of this file.

#pragma once
 
#include "fl/math_macros.h"
#include "fl/namespace.h"
#include "fl/scoped_array.h"
#include "fl/stdint.h" // For standard integer types
 
namespace fl {
 
// TODO:
// ERROR bit to indicate over flow.
 
template <typename T> class CircularBuffer {
  public:
    CircularBuffer(fl::size capacity)
        : mCapacity(capacity + 1), mHead(0),
          mTail(0) { // Extra space for distinguishing full/empty
        mBuffer.reset(new T[mCapacity]);
    }
 
    CircularBuffer(const CircularBuffer &) = delete;
    CircularBuffer &operator=(const CircularBuffer &) = delete;
 
    bool push_back(const T &value) {
        if (full()) {
            mTail = increment(mTail); // Overwrite the oldest element
        }
        mBuffer[mHead] = value;
        mHead = increment(mHead);
        return true;
    }
 
    bool pop_front(T *dst = nullptr) {
        if (empty()) {
            return false;
        }
        if (dst) {
            *dst = mBuffer[mTail];
        }
        mTail = increment(mTail);
        return true;
    }
 
    bool push_front(const T &value) {
        if (full()) {
            mHead = decrement(mHead); // Overwrite the oldest element
        }
        mTail = decrement(mTail);
        mBuffer[mTail] = value;
        return true;
    }
 
    bool pop_back(T *dst = nullptr) {
        if (empty()) {
            return false;
        }
        mHead = decrement(mHead);
        if (dst) {
            *dst = mBuffer[mHead];
        }
        return true;
    }
 
    T &front() { return mBuffer[mTail]; }
 
    const T &front() const { return mBuffer[mTail]; }
 
    T &back() { return mBuffer[(mHead + mCapacity - 1) % mCapacity]; }
 
    const T &back() const {
        return mBuffer[(mHead + mCapacity - 1) % mCapacity];
    }
 
    T &operator[](fl::size index) { return mBuffer[(mTail + index) % mCapacity]; }
 
    const T &operator[](fl::size index) const {
        return mBuffer[(mTail + index) % mCapacity];
    }
 
    fl::size size() const { return (mHead + mCapacity - mTail) % mCapacity; }
 
    fl::size capacity() const { return mCapacity - 1; }
 
    bool empty() const { return mHead == mTail; }
 
    bool full() const { return increment(mHead) == mTail; }
 
    void clear() { mHead = mTail = 0; }
 
  private:
    fl::size increment(fl::size index) const { return (index + 1) % mCapacity; }
 
    fl::size decrement(fl::size index) const {
        return (index + mCapacity - 1) % mCapacity;
    }
 
    fl::scoped_array<T> mBuffer;
    fl::size mCapacity;
    fl::size mHead;
    fl::size mTail;
};
 
} // namespace fl