Loading and Saving Binary Data

JoeC

I have successfully saved and re-loaded binary data but I am having
some trouble with some data:

I wrote a binary graphics object and it takes data in a BYTE form.
Here is the data I have and how I save then load it:

static BYTE bits [] =
{0xff,0xff, 0x00,0x00, 0x7f,0xfe, 0x7f,0xfe,
0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe, 0x7e,0x7e,
0x7e,0x7e, 0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe,
0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe, 0x00,0x00};

graphics gr(bits);

std::ofstream f("box.bin", ios::out | ios::binary);
gr.save(f);
f.close();

std::ifstream f("box.bin", ios::in | ios::binary);
gr.load(f);
f.close();
void graphics::load(std::ifstream& f){
bitData.clear();
for(int lp = 0; lp != size; lp++){
f.read((char*)&bitData[lp],sizeof(BYTE));
}
}

void graphics::save(std::ofstream& f){
for(int lp = 0; lp != size; lp++){
f.write((char*)&bitData[lp], sizeof(BYTE));
}
}

Nov 20 '07 #1

red floyd

JoeC wrote:

I have successfully saved and re-loaded binary data but I am having
some trouble with some data:

That's nice. Would you mind being a bit more specific? What trouble
are you having? What are you expecting?

Post a minimal *COMPILABLE* example that exhibits the behavior in
question. Note that your fragment below is not a compilable example.

I wrote a binary graphics object and it takes data in a BYTE form.
Here is the data I have and how I save then load it:

BYTE undefined.

static BYTE bits [] =
{0xff,0xff, 0x00,0x00, 0x7f,0xfe, 0x7f,0xfe,
0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe, 0x7e,0x7e,
0x7e,0x7e, 0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe,
0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe, 0x00,0x00};

graphics undefined.

graphics gr(bits);

std::ofstream f("box.bin", ios::out | ios::binary);
gr.save(f);
f.close();

std::ifstream f("box.bin", ios::in | ios::binary);
gr.load(f);
f.close();
void graphics::load(std::ifstream& f){

bitData and size undefined.

bitData.clear();
for(int lp = 0; lp != size; lp++){
f.read((char*)&bitData[lp],sizeof(BYTE));

no error checking on istream::read().

}
}

void graphics::save(std::ofstream& f){

see comments for load.

for(int lp = 0; lp != size; lp++){
f.write((char*)&bitData[lp], sizeof(BYTE));
}
}

Nov 20 '07 #2

JoeC

On Nov 19, 10:41 pm, red floyd <no.s...@here.dudewrote:

JoeC wrote:

I have successfully saved and re-loaded binary data but I am having
some trouble with some data:

That's nice. Would you mind being a bit more specific? What trouble
are you having? What are you expecting?

Post a minimal *COMPILABLE* example that exhibits the behavior in
question. Note that your fragment below is not a compilable example.

I wrote a binary graphics object and it takes data in a BYTE form.
Here is the data I have and how I save then load it:

BYTE undefined.

static BYTE bits [] =
{0xff,0xff, 0x00,0x00, 0x7f,0xfe, 0x7f,0xfe,
0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe, 0x7e,0x7e,
0x7e,0x7e, 0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe,
0x7f,0xfe, 0x7f,0xfe, 0x7f,0xfe, 0x00,0x00};

graphics undefined.

graphics gr(bits);

std::ofstream f("box.bin", ios::out | ios::binary);
gr.save(f);
f.close();

std::ifstream f("box.bin", ios::in | ios::binary);
gr.load(f);
f.close();

void graphics::load(std::ifstream& f){

bitData and size undefined.

bitData.clear();
for(int lp = 0; lp != size; lp++){
f.read((char*)&bitData[lp],sizeof(BYTE));

no error checking on istream::read().

}
}
void graphics::save(std::ofstream& f){

see comments for load.

for(int lp = 0; lp != size; lp++){
f.write((char*)&bitData[lp], sizeof(BYTE));
}
}

The program compiles and runs. It seems to save data, it create the
file and seems to be about the right size but I can't seem to get the
data to load. That is I save the graphics then when I load it it does
not display the saved shape. This is the only relieve5t cone and it
does not seem to be wrong it just doesn't load.

Nov 20 '07 #3