[Octave-bug-tracker] [bug #51871] loading '-ascii' format files is slow

[Dan Sebald]

Follow-up Comment #35, bug #51871 (project octave):

I guess somewhere in that getline_alleol() would need to be a clearing of the
string str, but I'm wondering if we could avoid the clearing of the string str
and instead reuse it's current contents until it is necessary to expand it. 
Say something like below.  The idea is to overwrite the existing buffer until
it is necessary to expand it.  Then, at the end of the current line I've put a
0x0D EOL character in place so that subsequent routines which extract floating
point data will end at the EOL.  That's the general idea.  I wonder if that
would be more efficient than clearing the string buffer and continually using
push_pack to expand it.


istream& getline_alleol (istream& is, string& str) {
    int c;
    int i;
    int strsize = str.size();

    for (i=0; i < strsize; i++) {
        c = is.get ();
        if (c == EOF || c == 0x0A)
            break;
        elseif (c == 0x0D) {
            if ((c = is.peek ()) != EOF) {
                 if (c == 0x0A)
                     is.ignore ();
            }
            break;
        } else
            str.replace (i,  1,  &c);
    }

    if (i == strsize) {
        while ((c = is.get ()) != EOF) {
            if (c == 0x0A)
                break;
            elseif (c == 0x0D) {
                if ((c = is.peek ()) != EOF) {
                    if (c == 0x0A)
                         is.ignore ();
                }
                break;
            } else
                str.push_back(c);
        }
       str.push_back (i,  1, 1, 0x0D);
    } else
       str.replace (i,  1, 1, 0x0D);

    return is;
}



    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?51871>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/