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Diffstat (limited to 'lib/smol_str/src/lib.rs')
| -rw-r--r-- | lib/smol_str/src/lib.rs | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/lib/smol_str/src/lib.rs b/lib/smol_str/src/lib.rs index b76c1c7d14..c592cb25d2 100644 --- a/lib/smol_str/src/lib.rs +++ b/lib/smol_str/src/lib.rs @@ -721,7 +721,8 @@ impl StrExt for str { fn to_lowercase_smolstr(&self) -> SmolStr { let len = self.len(); if len <= INLINE_CAP { - let (buf, rest) = inline_convert_while_ascii(self, u8::to_ascii_lowercase); + // SAFETY: `to_ascii_lowercase` always converts ASCII to ASCII + let (buf, rest) = unsafe { inline_convert_while_ascii(self, u8::to_ascii_lowercase) }; from_buf_and_chars(buf, len - rest.len(), rest.chars().flat_map(|c| c.to_lowercase())) } else { self.to_lowercase().into() @@ -732,7 +733,8 @@ impl StrExt for str { fn to_uppercase_smolstr(&self) -> SmolStr { let len = self.len(); if len <= INLINE_CAP { - let (buf, rest) = inline_convert_while_ascii(self, u8::to_ascii_uppercase); + // SAFETY: `to_ascii_uppercase` always converts ASCII to ASCII + let (buf, rest) = unsafe { inline_convert_while_ascii(self, u8::to_ascii_uppercase) }; from_buf_and_chars(buf, len - rest.len(), rest.chars().flat_map(|c| c.to_uppercase())) } else { self.to_uppercase().into() @@ -848,8 +850,13 @@ unsafe fn replacen_1_ascii(src: &str, mut map: impl FnMut(&u8) -> u8) -> SmolStr } /// Inline version of std fn `convert_while_ascii`. `s` must have len <= 23. +/// +/// # Safety +/// +/// If the input to `convert` is valid ASCII (<= 0x7F), +/// then the output must be as well. #[inline] -fn inline_convert_while_ascii(s: &str, convert: fn(&u8) -> u8) -> ([u8; INLINE_CAP], &str) { +unsafe fn inline_convert_while_ascii(s: &str, convert: fn(&u8) -> u8) -> ([u8; INLINE_CAP], &str) { // Process the input in chunks of 16 bytes to enable auto-vectorization. // Previously the chunk size depended on the size of `usize`, // but on 32-bit platforms with sse or neon is also the better choice. |