private static String doGetFullPath()

in src/main/java/org/apache/commons/io/FilenameUtils.java [267:290]


    private static String doGetFullPath(final String fileName, final boolean includeSeparator) {
        if (fileName == null) {
            return null;
        }
        final int prefix = getPrefixLength(fileName);
        if (prefix < 0) {
            return null;
        }
        if (prefix >= fileName.length()) {
            if (includeSeparator) {
                return getPrefix(fileName);  // add end slash if necessary
            }
            return fileName;
        }
        final int index = indexOfLastSeparator(fileName);
        if (index < 0) {
            return fileName.substring(0, prefix);
        }
        int end = index + (includeSeparator ?  1 : 0);
        if (end == 0) {
            end++;
        }
        return fileName.substring(0, end);
    }