Add comment on UTF-16 surrogates

ChrisDenton · ChrisDenton · commit ae03f898eb94 · 2024-04-08T11:42:16.000Z
diff --git a/library/std/src/sys/pal/windows/api.rs b/library/std/src/sys/pal/windows/api.rs
@@ -73,6 +73,8 @@ pub const fn utf16_len(s: &str) -> usize {
             n => n as usize,
         };
         i += utf8_len;
+        // Note that UTF-16 surrogates (U+D800 to U+DFFF) are not encodable as UTF-8,
+        // so (unlike with WTF-8) we don't have to worry about how they'll get re-encoded.
         len += if utf8_len < 4 { 1 } else { 2 };
     }
     len

Original file line number	Diff line number	Diff line change
`@@ -73,6 +73,8 @@ pub const fn utf16_len(s: &str) -> usize {`
`73`	`73`	`n => n as usize,`
`74`	`74`	`};`
`75`	`75`	`i += utf8_len;`
	`76`	`+ // Note that UTF-16 surrogates (U+D800 to U+DFFF) are not encodable as UTF-8,`
	`77`	`+ // so (unlike with WTF-8) we don't have to worry about how they'll get re-encoded.`
`76`	`78`	`len += if utf8_len < 4 { 1 } else { 2 };`
`77`	`79`	`}`
`78`	`80`	`len`