Added some useful filtering functions.
Added some useful filtering functions.

ruschelp/cortex-vfx,ruschelp/cortex-vfx,code-google-com/cortex-vfx,ruschelp/cortex-vfx,code-google-com/cortex-vfx,code-google-com/cortex-vfx,code-google-com/cortex-vfx