generating strings from name and surname

I have a requirement to generate strings from names and surname. To give more detail: The generated string length can not exceed 11.

For the string "Leo Messi" I can directly generate "Leo Messi" but

For "Cristiano ronaldo" as you see the length exceeds 11, I should generate something like "C. Ronaldo", "Christiano R."

Another example "Diego Armando Maradona" I can generate "D. Maradona", "A. Maradona", "Diego A. M." and so on...

I must find a good algorithm to generate these kind of strings that doesn't exceeds length 11. What is your opinion. Is there any library that I can use for this purpose?