Question

我正在尝试写入文件，然后将大量的短数据读取到文件中。我的写入成功，但是在读取时，在文件结束前很久的读取过程中，在看似随机的点上rdstate出现问题。这是我当前代码的最小可运行代码段：

#include <fstream>
#include <iostream>
int main(int argc, char** argv)
{
    short * inData = new short[512 * 512 * 361];
    //fill with dummy data
    for (int z = 0; z < 361; z++)
    {
        for (int y = 0; y < 512; y++)
        {
            for (int x = 0; x < 512; x++)
            {
                inData[x + y * x + z * y * x] = x + y + z;
            }
        }
    }

    //write file
    {
        std::ofstream outfile("data.bin", std::ios::out, std::ios::binary);
        if (outfile.is_open())
        {
            //header
            char buffer[10] = "vol_v1.00";
            outfile.write(buffer, 10);
            //dimensions
            int dims[] = { 512,512,361 };
            outfile.write(reinterpret_cast<char*>(dims), std::streamsize(3 * sizeof(int)));
            //spacing
            double spacing[] = { 0.412,0.412,1 };
            outfile.write(reinterpret_cast<char*>(spacing), std::streamsize(3 * sizeof(double)));
            //data
            outfile.write(reinterpret_cast<const char*>(&inData[0]), sizeof(inData[0]) * dims[0] * dims[1] * dims[2]);
            std::cout << "write finished with rdstate:  " << outfile.rdstate() << std::endl;
        }
    }

    short * outData = new short[512 * 512 * 361];
    //read file
    {
        std::ifstream infile("data.bin", std::ios::in, std::ios::binary);
        if (infile.is_open())
        {
            // get length of file:
            infile.seekg(0, infile.end);
            long length = infile.tellg();
            infile.seekg(0, infile.beg);
            std::cout << "file length: " << length << std::endl;

            //header
            char buffer[10];
            infile.read(reinterpret_cast<char*>(buffer), 10);
            std::string header(buffer);

            //dimensions
            int* dims = new int[3];
            infile.read(reinterpret_cast<char*>(dims), std::streamsize(3 * sizeof(int)));

            //spacing
            double* spacing = new double[3];
            infile.read(reinterpret_cast<char*>(spacing), std::streamsize(3 * sizeof(double)));

            infile.read(reinterpret_cast<char*>(&outData[0]), std::streamsize(sizeof(outData[0]) * dims[0] * dims[1] * dims[2]));
            std::cout << "ending pointer pos: " << infile.tellg() << std::endl;
            std::cout << "read finished with rdstate:  " << infile.rdstate() << std::endl;
        }
    }
    free(outData);
    free(inData);

    system("PAUSE");
    return 0;
}

我还有其他尝试读取大块的尝试，但是为了简洁起见，这里只做了单个大块，因为问题似乎相同。但是对于大块数据，将读取数十万个值的数据，然后以坏位失败。

Answer 1

对fstream的两次调用不正确。如所写，它仍然可以在VS2015中进行编译，但未正确设置两个标志（写和二进制），从而导致上述流错误。下面是正确的读写二进制文件的调用：

std::ofstream outfile("data.bin", std::ofstream::out | std::ofstream::binary);

std::ifstream infile("data.bin", std::ofstream::in | std::ofstream::binary);

将大量短裤存储/加载到二进制文件

1 个答案: