Convert alternate charset names (eg utf8) to normalized name (eg UTF-8).
@param s the charset to normalize
@param offset the offset in the charset
@param length the length of the charset in the input param
@return the normalized charset (or null if not found)
Convert alternate charset names (eg utf8) to normalized name (eg UTF-8).
@param s the charset to normalize @param offset the offset in the charset @param length the length of the charset in the input param @return the normalized charset (or null if not found)