读取二进制数据而不重新解释\u cast

只是因为在我写程序读取二进制STL文件之前,我从未读过二进制文件。我用 ifstream

主要功能:

std::ifstream in (cmdline[1].c_str(), std::ios::binary);

in.seekg(80, std::ifstream::beg); //skip header

int numTriangle;
in.read (reinterpret_cast<char*>(&numTriangle), sizeof(int)); //determine number of triangles
//create triangle data type and read data
triangle* t = new triangle();
for (int i = 0; i < numTriangle; ++i)  {
    in.read(reinterpret_cast<char*>(t), triangle::size);
    std::cout << *t;  // there's an opertor<< for triangle
}
delete t;

in.close(); //close file read from

//attempt to get the right size of a class without structure padding
#pragma pack(push)
#pragma pack(1)

//standard STL triangle data structure
struct triangle {
public:
    float n[3]; //normals, 4*3=12 bytes

    float x[3]; //first point of the triangle, 4*3=12 bytes
    float y[3]; //second point of the triangle, 4*3=12 bytes
    float z[3]; //third point of the triangle, 4*3=12 bytes

    long int a; //attributes, 2 bytes

    static const int size = 12+12+12+12+2; //sum of member variables
    //static const int size = sizeof(n) + sizeof(x) + sizeof(y) + sizeof(z) + sizeof(a);
};
#pragma pack(pop)