code: public String removeSiteRoot(String resourcename) {
  
          String siteRoot = getAdjustedSiteRoot(m_siteRoot, resourcename);
          if ((siteRoot == m_siteRoot)
              && resourcename.startsWith(siteRoot)
              && ((resourcename.length() == siteRoot.length()) || (resourcename.charAt(siteRoot.length()) == '/'))) {
              resourcename = resourcename.substring(siteRoot.length());
          }
          if (resourcename.length() == 0) {
              // input was a site root folder without trailing slash
              resourcename = "/";
          }
          return resourcename;
      }
docs: Removes the current site root prefix from the absolute path in the resource name,
  that is adjusts the resource name for the current site root.<p>
  
  If the resource name does not start with the current site root,
  it is left untouched.<p>
  
  @param resourcename the resource name
  
  @return the resource name adjusted for the current site root
  
  @see #getSitePath(CmsResource)