Unnamed repository; edit this file 'description' to name the repository.
| -rw-r--r-- | lib/smol_str/src/lib.rs | 47 | ||||
| -rw-r--r-- | lib/smol_str/tests/test.rs | 14 |
2 files changed, 56 insertions, 5 deletions
diff --git a/lib/smol_str/src/lib.rs b/lib/smol_str/src/lib.rs index 375a4a5b6b..9afe2a932c 100644 --- a/lib/smol_str/src/lib.rs +++ b/lib/smol_str/src/lib.rs @@ -592,6 +592,22 @@ pub trait StrExt: private::Sealed { /// See [`str::to_ascii_uppercase`]. #[must_use = "this returns a new SmolStr without modifying the original"] fn to_ascii_uppercase_smolstr(&self) -> SmolStr; + + /// Replaces all matches of a &str with another &str returning a new [`SmolStr`], + /// potentially without allocating. + /// + /// See [`str::replace`]. + // TODO: Use `Pattern` when stable. + #[must_use = "this returns a new SmolStr without modifying the original"] + fn replace_smolstr(&self, from: &str, to: &str) -> SmolStr; + + /// Replaces first N matches of a &str with another &str returning a new [`SmolStr`], + /// potentially without allocating. + /// + /// See [`str::replacen`]. + // TODO: Use `Pattern` when stable. + #[must_use = "this returns a new SmolStr without modifying the original"] + fn replacen_smolstr(&self, from: &str, to: &str, count: usize) -> SmolStr; } impl StrExt for str { @@ -614,6 +630,24 @@ impl StrExt for str { fn to_ascii_uppercase_smolstr(&self) -> SmolStr { SmolStr::from_char_iter(self.chars().map(|c| c.to_ascii_uppercase())) } + + #[inline] + fn replace_smolstr(&self, from: &str, to: &str) -> SmolStr { + self.replacen_smolstr(from, to, usize::MAX) + } + + #[inline] + fn replacen_smolstr(&self, from: &str, to: &str, count: usize) -> SmolStr { + let mut result = Writer::new(); + let mut last_end = 0; + for (start, part) in self.match_indices(from).take(count) { + result.push_str(unsafe { self.get_unchecked(last_end..start) }); + result.push_str(to); + last_end = start + part.len(); + } + result.push_str(unsafe { self.get_unchecked(last_end..self.len()) }); + SmolStr::from(result) + } } mod private { @@ -651,10 +685,8 @@ impl Writer { len: 0, } } -} -impl fmt::Write for Writer { - fn write_str(&mut self, s: &str) -> fmt::Result { + fn push_str(&mut self, s: &str) { // if currently on the stack if self.len <= INLINE_CAP { let old_len = self.len; @@ -663,8 +695,7 @@ impl fmt::Write for Writer { // if the new length will fit on the stack (even if it fills it entirely) if self.len <= INLINE_CAP { self.inline[old_len..self.len].copy_from_slice(s.as_bytes()); - - return Ok(()); // skip the heap push below + return; // skip the heap push below } self.heap.reserve(self.len); @@ -678,7 +709,13 @@ impl fmt::Write for Writer { } self.heap.push_str(s); + } +} +impl fmt::Write for Writer { + #[inline] + fn write_str(&mut self, s: &str) -> fmt::Result { + self.push_str(s); Ok(()) } } diff --git a/lib/smol_str/tests/test.rs b/lib/smol_str/tests/test.rs index 11b7df710a..655f30cbb0 100644 --- a/lib/smol_str/tests/test.rs +++ b/lib/smol_str/tests/test.rs @@ -312,4 +312,18 @@ mod test_str_ext { assert_eq!(uppercase, "AßΔC"); assert!(!uppercase.is_heap_allocated()); } + + #[test] + fn replace() { + let result = "foo_bar_baz".replace_smolstr("ba", "do"); + assert_eq!(result, "foo_dor_doz"); + assert!(!result.is_heap_allocated()); + } + + #[test] + fn replacen() { + let result = "foo_bar_baz".replacen_smolstr("ba", "do", 1); + assert_eq!(result, "foo_dor_baz"); + assert!(!result.is_heap_allocated()); + } } |