Add comment on UTF-16 surrogates

ChrisDenton · ChrisDenton · commit 78ff007512ab · 2024-04-09T20:20:32.000Z
diff --git a/std/src/sys/pal/windows/api.rs b/std/src/sys/pal/windows/api.rs
@@ -68,6 +68,8 @@ 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
`@@ -68,6 +68,8 @@ pub const fn utf16_len(s: &str) -> usize {`
`68`	`68`	`n => n as usize,`
`69`	`69`	`};`
`70`	`70`	`i += utf8_len;`
	`71`	`+ // Note that UTF-16 surrogates (U+D800 to U+DFFF) are not encodable as UTF-8,`
	`72`	`+ // so (unlike with WTF-8) we don't have to worry about how they'll get re-encoded.`
`71`	`73`	`len += if utf8_len < 4 { 1 } else { 2 };`
`72`	`74`	`}`
`73`	`75`	`len`