Question

所以我正在尝试制作一个缓冲区类。该缓冲区类包含一个大小为384 * 4的巨大缓冲区。该计划是针对每个收到的UDP数据报，大小为384，调用缓冲区类并返回一个指向应将数据报写入位置的指针。

将有另一个侦听器指针，RtAudio播放将从该侦听器指向。 [聆听部分并不完全相关，因为我在写入缓冲区时仍然遇到问题]

当我尝试调用server _-> getPointer（）（如下所示）时，出现“异常抛出：写访问冲突。这是nullptr。”被抛出。请帮我！！告诉我是否还有其他需要提供的东西。

Buffer.h

#pragma once

#ifndef BUFFER_H
#define BUFFER_H



class Buffer {
private:
    int bufferSize = 192 * 2; // one frame takes 2 Byte [int16]
    int nBuffers = 4;

    int *buffer_ = nullptr;

    int* writerPointer = nullptr;
    int* listenerPointer = nullptr;

    int writerCounter = 0;
    int listenerCounter = 0;

    int* tempW = nullptr;
    int* tempL = nullptr;

public:
    Buffer();
    ~Buffer();
    int* getWriterPointer();
    int* getlistenerPointer();
    int * getPointer();
};

#endif // !BUFFER_H

Buffer.cpp

#include"Buffer.h"
#include <iostream>


Buffer::Buffer() {
    buffer_ = reinterpret_cast<int*>(malloc(bufferSize*nBuffers));
    memset(buffer_, (int)5, bufferSize*nBuffers);

    std::cout << "new Buffer" << bufferSize * nBuffers << std::endl;
    listenerPointer = buffer_;
    writerPointer = buffer_;
    std::cout << "HERE " << *buffer_ << std::endl;
    std::cout << "new Buffer" << bufferSize * nBuffers << " pointer a " << listenerPointer << " pointer b " << writerPointer << std::endl;
}

Buffer::~Buffer() {
    delete buffer_;
}

...

//For teting purposes
int* Buffer::getPointer(){
    bufferSize = 192 * 2;
    std::cout << "get pointer asdfasdf::" << writerCounter << std::endl;
    std::cout << "pointer's position offset: " << writerCounter - 1 << std::endl;

    if (writerCounter == nBuffers - 1) {
        writerCounter = 0;
        return writerPointer + (bufferSize*(nBuffers - 1));
    }
    else {
        writerCounter += 1;
        return writerPointer + (bufferSize*(writerCounter - 1));
    }
}

main.cpp

#include <iostream>
#include "Buffer.h"


int main()
{
    std::cout << "Hello World!\n"; 
    Buffer *buffer_ = new Buffer();

    buffer_->getPointer();


}

Answer 1

查找协议部分的“零复制”。

您遇到的问题是，在您尝试使用它时，指针实际上是一个nullptr。您需要检查来自malloc的退货：

buffer_ = reinterpret_cast<int*>(malloc(bufferSize*nBuffers))
if(buffer_) ...

但是，将buffer_ = reinterpret_cast<int*>(malloc(bufferSize*nBuffers));更改为buffer_ = new int[bufferSize*nBuffers];，对于每个malloc，您需要一个free。对于每一个new，您都需要一个delete-请勿混用。

此外，malloc分配字节，但是int通常为4或8个字节，因此您需要将大小乘以sizeof(int)以获得正确的大小。忘记malloc和free并使用new和delete。

这是删除数组的方法：

Buffer::~Buffer() {
    delete[] buffer_; // delete array
}

引发异常：写访问冲突。这是nullptr

1 个答案: