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use serde::{Deserialize, Serialize};
use std::fmt;
/// A UTF-16 encoded, growable string.
///
/// # Examples
///
/// let mut string16 = String16::from("Übung");
/// string16.push('ä');
#[derive(Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct String16 {
utf16: Vec<u16>,
}
impl String16 {
/// Creates a new empty `String16`.
pub fn new() -> Self {
String16 { utf16: vec![] }
}
/// Returns the length of this `String16`, in bytes.
///
/// # Examples
///
/// Basic usage:
///
/// let a = String16::from("Übung");
///
/// assert_eq!(a.len(), 5);
#[inline]
pub fn len(&self) -> usize {
self.utf16.len()
}
/// Returns a slice of [`u16`]s bytes that were attempted to convert to a `String`.
pub fn as_bytes(&self) -> &[u16] {
&self.utf16
}
/// Returns a mutable slice of [`u16`]s bytes that were attempted to convert to a `String`.
pub fn as_bytes_mut(&mut self) -> &mut [u16] {
&mut self.utf16
}
/// Inserts a string slice into this `String16` at a byte position.
pub fn insert_str(&mut self, idx: usize, string: &str) {
let mut counter = idx;
for u in string.encode_utf16() {
self.utf16.insert(counter, u);
counter += 1;
}
}
/// Appends a given char onto the end of this `String16`.
pub fn push(&mut self, ch: char) {
let mut buf = [0; 2];
for part in ch.encode_utf16(&mut buf) {
self.utf16.push(*part)
}
}
/// Removes a [`char`] from this `String16` at a byte position and returns it.
pub fn remove(&mut self, idx: usize) {
self.utf16.remove(idx);
}
/// Returns `true` if this `String16` has a length of zero, and `false` otherwise.
pub fn is_empty(&self) -> bool {
self.utf16.is_empty()
}
/// Returns `true` if this `String16` ends with the given string slice, or `false` otherwise.
pub fn ends_with(&self, pat: &str) -> bool {
self.as_string().ends_with(pat)
}
/// Truncates this `String16`, removing all contents.
pub fn clear(&mut self) {
self.utf16.clear()
}
/// Returns a string part begins with the `start`and ends with the `end` index.
pub fn get_string(&self, start: usize, end: usize) -> Option<String> {
self.utf16.get(start..end).map(String::from_utf16_lossy)
}
/// Converts the `String16` value to a String.
pub fn as_string(&self) -> String {
String::from_utf16_lossy(&self.utf16)
}
}
impl From<&str> for String16 {
fn from(s: &str) -> Self {
String16 {
utf16: s.encode_utf16().collect(),
}
}
}
impl From<String> for String16 {
fn from(string: String) -> Self {
String16 {
utf16: string.encode_utf16().collect(),
}
}
}
impl fmt::Debug for String16 {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "String16 {}", self.as_string())
}
}
impl fmt::Display for String16 {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.as_string())
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn from_string() {
let string16 = String16::from(String::from("Übung"));
assert_eq!(string16.len(), 5);
let string16 = String16::from(String::from("World"));
assert_eq!(string16.len(), 5);
}
#[test]
fn from_str() {
let string16 = String16::from("Übung");
assert_eq!(string16.len(), 5);
let string16 = String16::from("World");
assert_eq!(string16.len(), 5);
}
#[test]
fn push() {
// Single-u16 encoded char
let mut string16 = String16::from("Fo");
string16.push('o');
assert_eq!(string16, String16::from("Foo"));
// Two-u16 encoded char
let mut string16 = String16::from("Bar");
string16.push('𝕊');
assert_eq!(string16, String16::from("Bar𝕊"));
}
}