[KPhotoAlbum] Bug in image cache size computation

Henner Zeller h.zeller at acm.org
Sun Sep 27 02:40:46 CEST 2015


On 26 September 2015 at 16:55, Robert Krawitz <rlk at alum.mit.edu> wrote:
> The number of items in the image cache is computed incorrectly if the
> image cache size is 2048 MB or greater; it's effectively zero due to
> signedness problems.  Performance is much better with this fix.
>
> Also, why the hard upper limit of 4096 MB?  I have 16 GB of RAM in my
> laptop, and might as well take advantage of it.
>
> diff --git a/Viewer/ImageDisplay.cpp b/Viewer/ImageDisplay.cpp
> index 1775efb..77be9a9 100644
> --- a/Viewer/ImageDisplay.cpp
> +++ b/Viewer/ImageDisplay.cpp
> @@ -567,7 +567,7 @@ void Viewer::ImageDisplay::setImageList( const DB::FileNameList& list )
>
>  void Viewer::ImageDisplay::updatePreload()
>  {
> -    const int cacheSize = ( Settings::SettingsData::instance()->viewerCacheSize() * 1024 * 1024 ) / (width()*height()*4);
> +    const int cacheSize = (int) ((long long) ( Settings::SettingsData::instance()->viewerCacheSize() * 1024ll * 1024ll ) / (width()*height()*4));

fyi, it is a good idea to have long constants with uppercase L,
because the lowercase l is easily confused with a 1 (one) (Don't ask
me how I know :) ).

So I suggest 1024ll -> 1024LL

-h

>      bool cacheFull = (m_cache.count() > cacheSize);
>
>      int incr = ( m_forward ? 1 : -1 );
>
>
> --
> Robert Krawitz                                     <rlk at alum.mit.edu>
>
> ***  MIT Engineers   A Proud Tradition   http://mitathletics.com  ***
> Member of the League for Programming Freedom  --  http://ProgFree.org
> Project lead for Gutenprint   --    http://gimp-print.sourceforge.net
>
> "Linux doesn't dictate how I work, I dictate how Linux works."
> --Eric Crampton
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