C / C++ / MFC

<br />
char* buffer = new char[settings.getAccessesToSimulate()];<br />
char* fname = settings.getFileName();<br />
<br />
ifstream binFile(fname, ios::in|ios::binary);<br />
<br />
if(!binFile)<br />
{<br />
   //handle error code<br />
}<br />
<br />
binFile.read(buffer,settings.getAccessesToSimulate());<br />
<br />
binFile.close();<br />
<br />

Mustafa Ismail Mustafa wrote:

After this little beauty runs, I get buffer = "gsA" which is incorrect since I'm giving it 1000 characters to read. Opening the file manually (in windows, not linux where its supposed to be) shows me that there's an NUL right after those three characters (they're actually hex).

48 65 6C 6C 6F 00 48 65 6C 6C 6F

int fd = open(fname, O_RDONLY);
const int nBytesRead = read(fd, buffer, 1000);
close(fd);

int fd = _open(fname, _O_RDONLY|_O_BINARY);
const int nBytesRead = _read(fd, buffer, 1000);
_close(fd);

binFile.read(buffer, 1000);
std::cout << binFile.gcount() << std::endl;

Mustafa Ismail Mustafa wrote:

After restarting the computer, things worked perfectly

Stuart Dootson wrote:

Don't you hate computers sometimes

Mustafa Ismail Mustafa wrote:

A different binary file, is being read and this time, I need to clump every 4 bytes into one structure and this structure would be a member in an array of its type. Suggestions?

1. Does the file have the same endian-ness as the computer you're working on?
2. Do you know how many elements the array has?
3. What format is the 'structure' you talk about?

• Interpreting the file byte-by-byte, to read into the structure
• Read the file a structure (four bytes at a time), assuming that the structure can be represented as four contiguous bytes in memory. I'd use #pragma pack to do that, with a static assert[^] to ensure that the structure really takes up four bytes in memory. If endian-ness is an issue, then you can reverse bytes at this point.
• Read the whole array in, if you know how many members it has. To ensure that padding doesn't get in the way, you could read in the correct number of bytes (sizeof structure * element_count), then use a byte pointer to step through the bytes, casting the pointer to a structure pointer when accessing the bytes

Luc Pattyn wrote:

when the data is binary, there are no delimiters by default

Luc Pattyn wrote:

AFAIK writing a char array to the console in C++ is considered a string operation, so it will stop at the first NULL, interpret every NEWLINE, TAB, etc.

Luc Pattyn wrote:

Not sure what sizeof is supposed to do on a char*.

Mustafa Ismail Mustafa wrote:

cout << hex << buffer[i] << endl

Luc Pattyn [Forum Guidelines] [My Articles]

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Fixturized forever.

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Luc Pattyn wrote:

f you want to see its numeric value, you must do something to it, as a minimum cast it to an int.

Mustafa Ismail Mustafa wrote:

When reading a binary file, and you have no clue what the delimeter...

Mustafa Ismail Mustafa wrote:

Is there a single function that can do that...

DavidCrow wrote:

Taken at face value, these two seem to be a bit contradictory.

DavidCrow wrote:

Do what? Read the entire file into a buffer?