Question

I have loads of c++ classes that reads data from a file stream. The functions looks like this.

bool LoadFromFile(class ifstream &file);

I’m creating a new function to read from memory instead of a file. So I googled around and a istringstream seems to do the trick without any modifications to the code.

bool LoadFromData(class istringstream &file);

Now my question is. I need to construct this stream to read from a char array. The string is not null-terminated, it’s pure binary data and I got a integer with the size. I tried assigning it to a string and creating a stream from a string, however the string terminates after a null character.. and the data is copied.

int size;
char *data;
string s = *data;

How do I create a string from a char array pointer without copying the data + specifying the size of the pointer data? Do you know any other solution than a stringstream?

Answer 1

Write an own basic_streambuf class! More details.. (This way you could work on the current memory.)

To create string from pointer and size: string str(data,data+size); (it will copy the data).

On more thing: you should rewrite your functions to based on istream:

bool LoadFromStream(istream &is);

In this way you could do the followings, because both istringstream and ifstream based on istream (later this function could also supports tcp streams…):

ifstream file;
istringstream sstream;

LoadFromStream(file);
LoadFromStream(sstream);