You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: parse.rs
    path of file: ./repos/ruffle/wstr/src
    
    the code of the file until where you have to start completion: use core::fmt;
use core::num::Wrapping;

use super::WStr;

/// Analog of [`core::str::FromStr`], but for Ruffle's &[`WStr`].
pub trait FromWStr: Sized {
    type Err;

    fn from_wstr(s: &WStr) -> Result<Self, Self::Err>;
}

/// Error returned by [`Integer::from_str_radix`].
#[derive(Debug)]
pub struct ParseNumError(());

impl fmt::Display for ParseNumError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
   
    
fn parse_special_floats(s: &WStr) -> Option<f64> {
    let nan = WStr::from_units(b"NaN");
    let inf = WStr::from_units(b"inf");

    let slice = match s.len() {
        3 if s == nan => return Some(f64::NAN),
        3 if s == inf => return Some(f64::INFINITY),
        4 => &s[1..],
        _ => return None,
    };

    let is_nan = if slice == nan {
        true
    } else if slice == inf {
        false
    } else {
        return None;
    };
    let is_neg = match u8::try_from(s.at(0)) {
        Ok(b'+') => false,
        Ok(b'-') => true,
        _ => return None,
    };

    Some(match (is_nan, is_neg) {
        (false, false) => f64::INFINITY,
        (false, true) => f64::NEG_INFINITY,
        (true, _) => f64::NAN,
    })
}