a-rubyist-rusting-part-4-7.rs

#![feature(libc)]
#![feature(cstr_memory)]
extern crate libc;

use std::ffi::CString;
use std::mem;

#[repr(C)]
pub struct RubyArray {
  len: libc::size_t,
  data: *const libc::c_void,
}

impl RubyArray {
  fn from_vec<T>(vec: Vec<T>) -> RubyArray {
    let array = RubyArray { 
      data: vec.as_ptr() as *const libc::c_void, 
      len: vec.len() as libc::size_t };
    mem::forget(vec);
    array
  }
}

#[no_mangle]
pub extern fn number_to_char_array() -> RubyArray {
  let mut utf_chars: Vec<*const libc::c_char> = vec![];

  for i in 33..126 {
    let maybe_char: Option<char> = std::char::from_u32(i);
    utf_chars.push(CString::new(maybe_char.unwrap().to_string()).unwrap().into_ptr());
  }

  RubyArray::from_vec(utf_chars)
}