public static double getEntropy(@Nullable String text) {
		if (text == null || text.isEmpty())
			return 0;
		Char2IntMap charCountMap = new Char2IntArrayMap(64);
		for (char c : text.toCharArray())
			charCountMap.mergeInt(c, 1, Integer::sum);
		int length = text.length();
		final double[] entropy = {0.0};
		charCountMap.values().forEach(value -> {
			double freq = ((double) value) / length;
			entropy[0] -= freq * (Math.log(freq) / Math.log(2));
		});
		return entropy[0];
	}
@param text
		Input text.

@return Entropy of the characters in the text.
recaf-core/src/main/java/software/coley/recaf/util/StringUtil.java