src/org/kocakosm/pitaya/charset/UTF8.java
public static boolean canEncode(String str, int off, int len)
	{
		return canEncode(str.substring(off, off + len));
	}
public static boolean canEncode(String str, int off, int len)
	{
		return canEncode(str.substring(off, off + len));
	}
Returns whether the specified range in the given {@code String} can
be encoded into UTF-8.

@param str the input {@code String}.
@param off the start index, inclusive.
@param len the number of characters to test.

@return whether the specified range in {@code str} can be encoded
into UTF-8.

@throws NullPointerException if {@code str} is {@code null}.
@throws IndexOutOfBoundsException if {@code off} or {@code len} is
negative or if {@code off + len} is greater than {@code str}'s
length.