Add function for utf-16 compression (#9)

* Add method for compressing to utf-16

* Format

* Use std::char::from_u32

* Format

src/compress.rs

@@ -97,6 +97,14 @@ pub fn compress_str(input: &str) -> Vec<u32> {
     compress(input, 16, |n| n)
 }
 
+#[inline]
+pub fn compress_to_utf16(input: &str) -> String {
+    let buf = compress(input, 15, |n| n + 32);
+    buf.iter()
+        .map(|i| std::char::from_u32(*i).unwrap())
+        .collect()
+}
+
 #[inline]
 pub fn compress_uri(data: &str) -> Vec<u32> {
     compress(&data, 6, |n| {

src/lib.rs

@@ -10,6 +10,7 @@ pub use crate::{
     compress::{
         compress,
         compress_str,
+        compress_to_utf16,
         compress_uri,
     },
     decompress::{

tests/common_legacy.rs

@@ -1,5 +1,6 @@
 use lz_string::{
     compress_str,
+    compress_to_utf16,
     compress_uri,
     decompress_str,
     decompress_uri,
@@ -29,6 +30,12 @@ pub fn compress_red() {
     assert_eq!(str_to_u32_vec("ᎅ〦䀀"), compressed);
 }
 
+#[test]
+pub fn compress_red_to_utf16() {
+    let compressed = compress_to_utf16(&RED_STR);
+    assert_eq!("\u{9e2}䰩䠠".to_string(), compressed);
+}
+
 #[test]
 pub fn compress_repeat() {
     let data = "aaaaabaaaaacaaaaadaaaaaeaaaaa";