Outputting large structures to HD - visual-c++

Question

I have an array of a large structure that I am trying to output to hard drive. I seem to be able to write to hard drive just fine (though it's difficult to verify by looking at the binary data), however when I try to read it back, I always end up with a garbled mess. Any ideas what I'm doing wrong?
here's the structure configuration:
class xyz
{
public:
double x, y, z;
};
class trianglePackage
{
public:
int score;
int position;
xyz contactCoordinates;
xyz normalVector;
xyz locatorOffset;
};
class quadanglesOutput
{
public:
int locator1position, locator2position, locator3position, locator4position;
xyz centroid;
int surfaceAreaScore;
int centroidDifferance1Score;
int centroidDifferance2Score;
int minDistance1Score;
int minDistance2Score;
int totalLocatorScore;
int totalHullScore;
int totalScore;
double surfaceArea;
double centroidDifferance1;
double centroidDifferance2;
double minDistance1;
double minDistance2;
int hull;
trianglePackage locator1, locator2, locator3, locator4;
};
and here are the read/write functions I'm using:
void outputQuadangleOutput(quadanglesOutput* output, string description, param parameters)
{
string outputName = parameters.fileName + " " + description + ".bin";
cout << "Output " << outputName.c_str() << "...";
ofstream output2;
output2.open(outputName.c_str());
output2.write(reinterpret_cast<char*>(output), streamsize(parameters.topXlist * sizeof(quadanglesOutput)));
output2.close();
cout << "done" << endl;
}
void readIn(quadanglesOutput* pointer, param parameters, string description)
{
string fileName = parameters.fileName + " " + description + ".bin";
cout << "openining " << fileName << "...";
ifstream readFile;
readFile.open(fileName.c_str());
readFile.read(reinterpret_cast<char*>(pointer), (parameters.topXlist * sizeof(quadanglesOutput)));
readFile.close();
cout << "done" << endl;
}
Typically the arrays of structures are about 100 in length, but usually only about the first 25 read back correctly, everything else is default uninitialized data.
I'm 99% sure that it's something wrong with my code, however is there a possibility it has something to do with four byte alignment?
Thanks.

Answer 1

It may be an issue with byte alignment, use pragma.
try wrap classes around with
#PRAGMA PACK PUSH(1)
....
#PRAGMA PACK POP
or
#PRAGMA PACK(1)
struct{
..
}
Try those as well:
Force binary flag for the stream.
ios_base::binary
readFile.open(fileName.c_str(), ios_base::binary);
Try to flush the the stream.
stream.write(...)
stream.flush()
//i know that close() should flush it.
UPDATE:
Everything works for me:
#include <iostream>
#include <fstream>
#include <string>
#include <stdlib.h>
using namespace std;
#pragma pack(1)
class xyz
{
public:
double x, y, z;
};
#pragma pack(1)
class trianglePackage
{
public:
int score;
int position;
xyz contactCoordinates;
xyz normalVector;
xyz locatorOffset;
};
#pragma pack(1)
class quadanglesOutput
{
public:
int locator1position, locator2position, locator3position, locator4position;
xyz centroid;
int surfaceAreaScore;
int centroidDifferance1Score;
int centroidDifferance2Score;
int minDistance1Score;
int minDistance2Score;
int totalLocatorScore;
int totalHullScore;
int totalScore;
double surfaceArea;
double centroidDifferance1;
double centroidDifferance2;
double minDistance1;
double minDistance2;
int hull;
trianglePackage locator1, locator2, locator3, locator4;
};
class param
{
public:
string fileName;
int topXlist;
};
void outputQuadangleOutput(quadanglesOutput* output, string description, param parameters)
{
string outputName = parameters.fileName + " " + description + ".bin";
cout << "Output " << outputName.c_str() << "...";
ofstream output2;
output2.open(outputName.c_str());
output2.write(reinterpret_cast<char*>(output), streamsize(parameters.topXlist * sizeof(quadanglesOutput)));
output2.close();
cout << "done" << endl;
}
void readIn(quadanglesOutput* pointer, param parameters, string description)
{
string fileName = parameters.fileName + " " + description + ".bin";
cout << "openining " << fileName << "...";
ifstream readFile;
readFile.open(fileName.c_str());
readFile.read(reinterpret_cast<char*>(pointer), (parameters.topXlist * sizeof(quadanglesOutput)));
readFile.close();
cout << "done" << endl;
}
int main(int argc, char *argv[])
{
quadanglesOutput a = {0};
cout<<"total score:"<<a.totalScore<<endl;
cout<<"locator position:"<<a.totalScore<<endl;
cout<<"locator position:"<<a.locator1.position<<endl;
cout<<"locator position:"<<a.locator2.normalVector.y <<endl;
cout<<"sizeof quadangsomething:"<<sizeof(quadanglesOutput)<<endl;
a.totalScore=1;
a.locator1.position=333445;
a.locator2.normalVector.y = 999.3224;
cout<<"total score:"<<a.totalScore<<endl;
cout<<"locator position:"<<a.locator1.position<<endl;
cout<<"locator position:"<<a.locator2.normalVector.y <<endl;
param p = {"C:/", 1};
outputQuadangleOutput(&a, "file1", p);
quadanglesOutput *b = new quadanglesOutput();
readIn(b, p, "file1");
cout<<"new total score:"<<b->totalScore<<endl;
cout<<"new locator position:"<<b->locator1.position<<endl;
cout<<"new locator position:"<<b->locator2.normalVector.y <<endl;
delete b;
string asdf;
cin>>asdf;
};
OUTPUT:
total score:0
locator position:0
locator2.normalVector.y :0
sizeof quadangsomething:436
total score:1
locator position:333445
locator2.normalVector.y :999.322
Output C:/ file1.bin...done
openining C:/ file1.bin...done
new total score:1
new locator position:333445
new locator2.normalVector.y :999.322
without pragma it's still correct but you can see the difference in size:
sizeof quadangsomething:440
But packing it is good when sending structures over network.
Because here system alligns it always in the same fashion.