Using basic_istream& get( basic_streambuf....

[DeveloperDave]

Hi,

Using C++ I am trying to read x number of characters up to a delimiter
character and store them in a istringstream.

I am using the ifstream class to open a file.
Looking at the API I noticed a 'get' operator that took a reference to
a basic_streambuf as a parameter.
see http://www.cppreference.com/wiki/io...ww.cppreference.com/wiki/io/basic_istream/get

Anyway I was wondering is it possible to create a istringstream and
then get the underlying basic_streambuf, and pass it into this get
method.

I am struggling with the syntax, so if this is possible and someone
has an example I would appreciate it.

Cheers

 

[DeveloperDave]

I should mention I've tried:

<code>
ifstream inputStream(filename.c_str(), ios_base::in);
while(inputStream.good())
{
istringstream buffer;
stringbuf* stringBuffer = buffer.rdbuf();
streambuf* streamBuffer = stringBuffer;

inputStream.get(*streamBuffer, ',');
cout << "Got: " << buffer.str() << endl;
}
</code>

This compiles, but unfortunately doesn't seem to find the delimiter
character.

 

[Vaclav Haisman]

DeveloperDave wrote, On 26.1.2011 18:36:

I should mention I've tried:

<code>
ifstream inputStream(filename.c_str(), ios_base::in);
while(inputStream.good())
{
istringstream buffer;
stringbuf* stringBuffer = buffer.rdbuf();
streambuf* streamBuffer = stringBuffer;

inputStream.get(*streamBuffer, ',');

You are insterting the read characters into a streambuf of input buffer,
which IMHO does not make much sense.

cout << "Got: " << buffer.str() << endl;
}
</code>

This compiles, but unfortunately doesn't seem to find the delimiter
character.

I have tried the following and it works as I would expect:

stringstream iss ("abc,efg,klm");
ostringstream oss;
streambuf * sb = oss.rdbuf ();
iss.get (*sb, ',');
cout << oss.str ();

It prints "abc".

 

[Vaclav Haisman]

Vaclav Haisman wrote, On 26.1.2011 19:37:

DeveloperDave wrote, On 26.1.2011 18:36:
You are insterting the read characters into a streambuf of input buffer,
which IMHO does not make much sense.

I have tried the following and it works as I would expect:

stringstream iss ("abc,efg,klm");
ostringstream oss;
streambuf * sb = oss.rdbuf ();
iss.get (*sb, ',');
cout << oss.str ();

It prints "abc".

I was probably too quick with the reply. If you want to do more input with
the piece that you read into the streambuf, you can use stringstream instead
of istringstream:

istringstream iss ("abc,efg,klm");
stringstream oss;
streambuf * sb = oss.rdbuf ();
iss.get (*sb, ',');
cout << oss.str () << " ";
string s;
getline (oss, s);
cout << s;

This prints "abc abc".

 

[DeveloperDave]

Vaclav Haisman wrote, On 26.1.2011 19:37:










I was probably too quick with the reply. If you want to do more input with
the piece that you read into the streambuf, you can use stringstream instead
of istringstream:

istringstream iss ("abc,efg,klm");
stringstream oss;
streambuf * sb = oss.rdbuf ();
iss.get (*sb, ',');
cout << oss.str () << " ";
string s;
getline (oss, s);
cout << s;

This prints "abc abc".

Thanks that works perfectly. I can see how I should be using that
class and method now.

Cheers