Inkscapestream: Incredible speed up for writing of strings

This tremendously speeds up saving long strings which previously
had to do "n!" lookups (where n is the number of chars) as
Glib::ustring::operator[] has to iterate over all preceding
unichars in each iteration to find the requested unichar.

A file with a CDATA section of ~1 MB saves in a few milliseconds now,
previously it didn't finish even after some minutes.

Fixed bugs:
  - https://bugs.launchpad.net/inkscape/+bug/1793877

1 files changed, 3 insertions, 2 deletions

diff --git a/src/io/inkscapestream.cpp b/src/io/inkscapestream.cpp
index dcfc662ca..3042ecff7 100644
--- a/src/io/inkscapestream.cpp
+++ b/src/io/inkscapestream.cpp
@@ -501,8 +501,9 @@ Writer &BasicWriter::writeChar(char ch)
  */ 
 Writer &BasicWriter::writeUString(Glib::ustring &str)
 {
-    for (int i=0; i< (int)str.size(); i++)
-        put(str[i]);
+    for (auto it = str.begin(); it != str.end(); it++) {
+        put(*it);
+    }
     return *this;
 }