public static int[] indicesOf(@Nonnull String input, char c) {
		IntList list = new IntArrayList(5);
		int i = -1;
		do {
			i = input.indexOf(c, i);
			if (i >= 0) {
				list.add(i);
				i++;
			}
		} while (i >= 0);
		return list.toArray(EMPTY_INT_ARRAY);
	}
@param input
		Some text to search.
@param c
		Char to get index of in the input string.

@return Array of indices in the input string where the char exists.
recaf-core/src/main/java/software/coley/recaf/util/StringUtil.java