pub fn encode(input: &str) -> Result<String, ()> {
    let mut output = String::new();
    let mut unicode = Vec::<char>::new(); // Non-basic code points (the ones we need to encode).
    for c in input.chars() {
        if c.is_ascii() {
            // All basic code points appearing in the extended string are
            // represented literally at the beginning of the basic string, in their
            // original order, followed by a delimiter if (and only if) the number
            // of basic code points is nonzero.
            output.push(c);
        } else {
            unicode.push(c); // Perhaps store the index to make below faster
        }
    }

    let basic_len = output.len() as u32;

    if !output.is_empty() {
        output.push(DELIMITER);
    }

    if unicode.is_empty() {
        return Ok(output);
    }

    // "Insertion unsort coding" encodes the non-basic code points as deltas,
    // and processes the code points in numerical order rather than in order
    // of appearance, which typically results in smaller deltas.
    unicode.sort_by(|a, b| b.cmp(&a));
    unicode.dedup();

    if *unicode.last().unwrap() < INITIAL_N {
        // If the input contains a non-basic code point < n then fail
        panic!("the input contains a non-basic code point < n");
    }

    let mut last_char = INITIAL_N as u32; // The first non-ASCII code point.
    let mut bias = INITIAL_BIAS;
    let mut delta = 0;
    let mut h = basic_len;

    //while h < input.len() {
    while let Some(c) = unicode.pop() {
        // The minimum {non-basic} code point >= n in the input
        let cur_char = c as u32;

        // println!("next code point to insert is {:X}", m as u32);

        // The deltas are represented as "generalized variable-length integers",
        // which use basic code points to represent nonnegative integers.
        delta += (cur_char - last_char) * (h + 1); // TODO fail on overflow

        // TODO We can remove this `c in input` loop, all it does is move the delta along.
        for c in input.chars() {
            let c = c as u32;
            if c < cur_char {
                delta += 1; // TODO Fail on overflow
            }

            // We found the current unicode character, so lets encode it.
            if c == cur_char {
                // print!("needed delta is {}, encodes as ", delta);

                let mut q = delta;
                let mut k = BASE;
                loop {
                    assert!(!(bias < k && k < (bias + TMIN)));
                    let t = if k <= bias {
                        TMIN
                    } else if k >= bias + TMAX {
                        TMAX
                    } else {
                        k - bias
                    };

                    if q < t {
                        break;
                    }

                    // TODO Check that this value will always fit into a u8.
                    // output the code point for digit t + ((q - t) mod (base - t))
                    let output_c = to_char((t + ((q - t) % (BASE - t))) as u8);
                    output.push(output_c);
                    // print!("{}", output_c);

                    q = (q - t) / (BASE - t);
                    k += BASE;
                }

                // print!("{}", to_char(q as u8));

                // Output the last digit for cur_char.
                output.push(to_char(q as u8));

                bias = adapt(delta, h + 1, h == basic_len);

                // println!();
                // println!("bias becomes {}", bias);

                delta = 0;
                h += 1;
            }
        }

        delta += 1;
        last_char = cur_char + 1;
    }

    // println!("output is \"{}\"", output);

    Ok(output)
}
// Encodes a string into punycode.
Encodes a string into punycode.
Encodes a string into punycode .
pub fn encode(input: &str) -> Result<String, ()> {
    let mut output = String::new();
    let mut unicode = Vec::<char>::new(); // Non-basic code points (the ones we need to encode).
    for c in input.chars() {
        if c.is_ascii() {
            // All basic code points appearing in the extended string are
            // represented literally at the beginning of the basic string, in their
            // original order, followed by a delimiter if (and only if) the number
            // of basic code points is nonzero.
            output.push(c);
        } else {
            unicode.push(c); // Perhaps store the index to make below faster
        }
    }
    let basic_len = output.len() as u32;
    if !output.is_empty() {
        output.push(DELIMITER);
    }
    if unicode.is_empty() {
        return Ok(output);
    }
    // "Insertion unsort coding" encodes the non-basic code points as deltas,
    // and processes the code points in numerical order rather than in order
    // of appearance, which typically results in smaller deltas.
    unicode.sort_by(|a, b| b.cmp(&a));
    unicode.dedup();
    if *unicode.last().unwrap() < INITIAL_N {
        // If the input contains a non-basic code point < n then fail
        panic!("the input contains a non-basic code point < n");
    }
    let mut last_char = INITIAL_N as u32; // The first non-ASCII code point.
    let mut bias = INITIAL_BIAS;
    let mut delta = 0;
    let mut h = basic_len;
    //while h < input.len() {
    while let Some(c) = unicode.pop() {
        // The minimum {non-basic} code point >= n in the input
        let cur_char = c as u32;
        // println!("next code point to insert is {:X}", m as u32);
        // The deltas are represented as "generalized variable-length integers",
        // which use basic code points to represent nonnegative integers.
        delta += (cur_char - last_char) * (h + 1); // TODO fail on overflow
        // TODO We can remove this `c in input` loop, all it does is move the delta along.
        for c in input.chars() {
            let c = c as u32;
            if c < cur_char {
                delta += 1; // TODO Fail on overflow
            }
            // We found the current unicode character, so lets encode it.
            if c == cur_char {
                // print!("needed delta is {}, encodes as ", delta);
                let mut q = delta;
                let mut k = BASE;
                loop {
                    assert!(!(bias < k && k < (bias + TMIN)));
                    let t = if k <= bias {
                        TMIN
                    } else if k >= bias + TMAX {
                        TMAX
                    } else {
                        k - bias
                    };
                    if q < t {
                        break;
                    }
                    // TODO Check that this value will always fit into a u8.
                    // output the code point for digit t + ((q - t) mod (base - t))
                    let output_c = to_char((t + ((q - t) % (BASE - t))) as u8);
                    output.push(output_c);
                    // print!("{}", output_c);
                    q = (q - t) / (BASE - t);
                    k += BASE;
                }
                // print!("{}", to_char(q as u8));
                // Output the last digit for cur_char.
                output.push(to_char(q as u8));
                bias = adapt(delta, h + 1, h == basic_len);
                // println!();
                // println!("bias becomes {}", bias);
                delta = 0;
                h += 1;
            }
        }
        delta += 1;
        last_char = cur_char + 1;
    }
    // println!("output is \"{}\"", output);
    Ok(output)
}
pub fn encode ( input : & str ) -> Result < String , ( ) > { let mut output = String :: new ( ) ; let mut unicode = Vec :: < char > :: new ( ) ; // Non-basic code points (the ones we need to encode). for c in input . chars ( ) { if c . is_ascii ( ) { // All basic code points appearing in the extended string are // represented literally at the beginning of the basic string, in their // original order, followed by a delimiter if (and only if) the number // of basic code points is nonzero. output . push ( c ) ; } else { unicode . push ( c ) ; // Perhaps store the index to make below faster } } let basic_len = output . len ( ) as u32 ; if ! output . is_empty ( ) { output . push ( DELIMITER ) ; } if unicode . is_empty ( ) { return Ok ( output ) ; } // "Insertion unsort coding" encodes the non-basic code points as deltas, // and processes the code points in numerical order rather than in order // of appearance, which typically results in smaller deltas. unicode . sort_by ( | a , b | b . cmp ( & a ) ) ; unicode . dedup ( ) ; if * unicode . last ( ) . unwrap ( ) < INITIAL_N { // If the input contains a non-basic code point < n then fail panic ! ( " " ) ; } let mut last_char = INITIAL_N as u32 ; // The first non-ASCII code point. let mut bias = INITIAL_BIAS ; let mut delta = 0 ; let mut h = basic_len ; //while h < input.len() { while let Some ( c ) = unicode . pop ( ) { // The minimum {non-basic} code point >= n in the input let cur_char = c as u32 ; // println!("next code point to insert is {:X}", m as u32); // The deltas are represented as "generalized variable-length integers", // which use basic code points to represent nonnegative integers. delta += ( cur_char - last_char ) * ( h + 1 ) ; // TODO fail on overflow // TODO We can remove this `c in input` loop, all it does is move the delta along. for c in input . chars ( ) { let c = c as u32 ; if c < cur_char { delta += 1 ; // TODO Fail on overflow } // We found the current unicode character, so lets encode it. if c == cur_char { // print!("needed delta is {}, encodes as ", delta); let mut q = delta ; let mut k = BASE ; loop { assert ! ( ( bias k k ( bias TMIN ) ) ) ; let t = if k <= bias { TMIN } else if k >= bias + TMAX { TMAX } else { k - bias } ; if q < t { break ; } // TODO Check that this value will always fit into a u8. // output the code point for digit t + ((q - t) mod (base - t)) let output_c = to_char ( ( t + ( ( q - t ) % ( BASE - t ) ) ) as u8 ) ; output . push ( output_c ) ; // print!("{}", output_c); q = ( q - t ) / ( BASE - t ) ; k += BASE ; } // print!("{}", to_char(q as u8)); // Output the last digit for cur_char. output . push ( to_char ( q as u8 ) ) ; bias = adapt ( delta , h + 1 , h == basic_len ) ; // println!(); // println!("bias becomes {}", bias); delta = 0 ; h += 1 ; } } delta += 1 ; last_char = cur_char + 1 ; } // println!("output is \"{}\"", output); Ok ( output ) }
Encodes a string into punycode.
Encodes a string into punycode .
input
&str