将包含循环缓冲区的类添加到 Vector

Question

我正在尝试创建一个充满类对象的向量，并且类对象包含循环缓冲区作为它们的成员之一。我遇到了这个错误：

In file included from .pio/libdeps/teensy40/Vector/src/Vector.h:95:0,
                 from src/main.cpp:2:
.pio/libdeps/teensy40/Vector/src/Vector/VectorDefinitions.h: In instantiation of 'void Vector<T>::push_back(const T&) [with T = Node]':
src/main.cpp:25:27:   required from here
.pio/libdeps/teensy40/Vector/src/Vector/VectorDefinitions.h:162:22: error: use of deleted function 'Node& Node::operator=(const Node&)'
     values_[size_++] = value;
                      ^
src/main.cpp:5:7: note: 'Node& Node::operator=(const Node&)' is implicitly deleted because the default definition would be ill-formed:
 class Node
       ^
src/main.cpp:5:7: error: use of deleted function 'CircularBuffer<T, S, IT>& CircularBuffer<T, S, IT>::operator=(const CircularBuffer<T, S, IT>&) [with T = long unsigned int; unsigned int S = 100u; IT = unsigned char]'
In file included from src/main.cpp:3:0:
.pio/libdeps/teensy40/CircularBuffer/CircularBuffer.h:64:18: note: declared here
  CircularBuffer& operator=(const CircularBuffer&) = delete;
                  ^
*** [.pio/build/teensy40/src/main.cpp.o] Error 1
======================================== [FAILED] Took 0.99 seconds ========================================

我创建了一个程序，它是我可以复制错误的最少代码：

#include <Arduino.h>
#include <Vector.h>
#include <CircularBuffer.h>

class Node
{
  CircularBuffer<uint32_t, 100> RTTSamplesBuffer;
};

// Vector to hold the nodes we currently have saved
Vector<Node> Nodes;
// This stuff is used in setup to make the vector not use dynamic allocation
// This version of the Vector library is special for arduino so it is not
// dynamically allocating the vector to prevent filling the controllers memory
const int NODE_COUNT_MAX = 20;
Node storage_array[NODE_COUNT_MAX];

void setup()
{
  Serial.begin(115200);
  // Point the vector to it's storage location.
  Nodes.setStorage(storage_array);

  while (!Serial)
    ;

  // Create Node I want to add to the vector
  Node testNode;

  // Try and add the Node to the vector.
  Nodes.push_back(testNode);

  while (1)
    ;
}

void loop()
{
  // put your main code here, to run repeatedly:
}

我使用this 库作为向量，因为它与Arduino 兼容并且不会填满内存，我使用this 库作为循环缓冲区。谢谢！

Answer 1

看循环缓冲区的代码：

    CircularBuffer(const CircularBuffer&) = delete;
    CircularBuffer(CircularBuffer&&) = delete;
    CircularBuffer& operator=(const CircularBuffer&) = delete;
    CircularBuffer& operator=(CircularBuffer&&) = delete;

这意味着循环缓冲区一旦分配，就不能以任何方式移动或复制。它保持在原来的位置，这也适用于将其中之一作为成员的任何类型。

添加一个间接级别，以便 CircularBuffers 只被引用，而不是被复制，这将使您摆脱困境。

大概是这样的：

class Node
{
  using buffer_type = CircularBuffer<uint32_t, 100>;

  buffer_type* RTTSamplesBuffer = nullptr;

public:
  set_buffer(buffer_type* b) {
    RTTSamplesBuffer = b;
  }
};

const int NODE_COUNT_MAX = 20;
Node storage_array[NODE_COUNT_MAX];
Node::buffer_type buffers[NODE_COUNT_MAX];

void setup()
{
  for(int i=0; i<NODE_COUNT_MAX; ++i) {
    storage_array[i].set_buffer(&buffers[i]);
  }

  // ...
}

通常，这就是“应该”对 0/3/5 规则进行大量讨论的地方。但是，只要这些是指向全局分配对象的指针，就不是绝对必要的。