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https://gitlab.gnome.org/GNOME/gparted
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Simplified cleanup_cursor() implementation
I hit this performance bug when I cloneda 40G NTFS partition. The actual copy was done in under 11 minutes. After that I was shocked to find that gparted would spend over 12 minutes in cleanup_cursor, pegging a CPU core. (On a quad core desktop...) Simply replacing the ustring with std::string would reduce the time to about 1.5 minutes. Still bad. Also, I didn't want to lose UTF8 awareness. So I rewrote the algorithm in 'streaming mode'. This has the (potential) drawback that locale conversions are done, but performs well and - IMHO - is a lot more readable. On a minor note: this implementation correctly handles backspaces at the start of a line.
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51
src/Utils.cc
51
src/Utils.cc
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@ -422,34 +422,33 @@ Glib::ustring Utils::trim( const Glib::ustring & src, const Glib::ustring & c /*
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Glib::ustring Utils::cleanup_cursor( const Glib::ustring & text )
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{
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//Clean up text for commands that use cursoring to display progress.
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Glib::ustring str = text;
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//remove backspace '\b' and delete previous character. Used in mke2fs output.
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for ( unsigned int index = str .find( "\b" ) ; index < str .length() ; index = str .find( "\b" ) ) {
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if ( index > 0 )
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str .erase( index - 1, 2 ) ;
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else
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str .erase( index, 1 ) ;
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std::istringstream in(text);
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std::ostringstream out;
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char ch;
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std::streampos startofline = out.tellp();
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while (in.get(ch))
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{
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switch(ch)
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{
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case '\r':
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if ('\n' != in.peek()) // for windows CRLF
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out.seekp(startofline);
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else
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out.put(ch);
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break;
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case '\b':
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if (out.tellp() > startofline)
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out.seekp(out.tellp()-1ll);
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break;
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default:
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out.put(ch);
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}
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if (ch == '\n')
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startofline = out.tellp();
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}
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//Remove carriage return and line up to previous line feed. Used in ntfsclone output.
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//NOTE: Normal linux line end is line feed. DOS uses CR + LF.
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for ( unsigned int index1 = str .find( "\r") ; index1 < str .length() ; index1 = str .find( "\r" ) )
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{
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//Only process if next character is not a LF.
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if ( str .at(index1 + 1) != '\n')
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{
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//find point to start erase from.
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unsigned int index2 = str .rfind( "\n", index1 ) ;
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//find end point to erase up to.
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unsigned int index3 = str .find( "\n", index1 ) ;
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unsigned int index4 = str .rfind( "\r", index3 ) ;
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//perform erase if indices are valid
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if ( ( index2 <= index1 ) && ( index4 > index2 ) && ( index4 < str .length() ) )
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str .erase( index2 + 1, index4 - index2 ) ;
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}
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}
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return str;
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return out.str();
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}
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Glib::ustring Utils::get_lang()
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