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SmolStrBuilder::push
| -rw-r--r-- | lib/smol_str/src/lib.rs | 27 | ||||
| -rw-r--r-- | lib/smol_str/tests/test.rs | 35 |
2 files changed, 57 insertions, 5 deletions
diff --git a/lib/smol_str/src/lib.rs b/lib/smol_str/src/lib.rs index cc8612ee45..9cc21ec780 100644 --- a/lib/smol_str/src/lib.rs +++ b/lib/smol_str/src/lib.rs @@ -744,9 +744,30 @@ impl SmolStrBuilder { }) } + /// Appends the given [`char`] to the end of `self`'s buffer. + pub fn push(&mut self, c: char) { + match self { + SmolStrBuilder::Inline { len, buf } => { + let char_len = c.len_utf8(); + let new_len = *len + char_len; + if new_len <= INLINE_CAP { + c.encode_utf8(&mut buf[*len..]); + *len += char_len; + } else { + let mut heap = String::with_capacity(new_len); + // copy existing inline bytes over to the heap + // SAFETY: inline data is guaranteed to be valid utf8 for `old_len` bytes + unsafe { heap.as_mut_vec().extend_from_slice(buf) }; + heap.push(c); + *self = SmolStrBuilder::Heap(heap); + } + } + SmolStrBuilder::Heap(h) => h.push(c), + } + } + /// Appends a given string slice onto the end of `self`'s buffer. pub fn push_str(&mut self, s: &str) { - // if currently on the stack match self { Self::Inline { len, buf } => { let old_len = *len; @@ -762,9 +783,7 @@ impl SmolStrBuilder { // copy existing inline bytes over to the heap // SAFETY: inline data is guaranteed to be valid utf8 for `old_len` bytes - unsafe { - heap.as_mut_vec().extend_from_slice(&buf[..old_len]); - } + unsafe { heap.as_mut_vec().extend_from_slice(&buf[..old_len]) }; heap.push_str(s); *self = SmolStrBuilder::Heap(heap); } diff --git a/lib/smol_str/tests/test.rs b/lib/smol_str/tests/test.rs index 22b9df2afd..81bccf106e 100644 --- a/lib/smol_str/tests/test.rs +++ b/lib/smol_str/tests/test.rs @@ -256,7 +256,7 @@ fn test_to_smolstr() { } } #[test] -fn test_builder() { +fn test_builder_push_str() { //empty let builder = SmolStrBuilder::new(); assert_eq!("", builder.finish()); @@ -292,6 +292,39 @@ fn test_builder() { assert_eq!("a".repeat(46), s); } +#[test] +fn test_builder_push() { + //empty + let builder = SmolStrBuilder::new(); + assert_eq!("", builder.finish()); + + // inline push + let mut builder = SmolStrBuilder::new(); + builder.push('a'); + builder.push('b'); + let s = builder.finish(); + assert!(!s.is_heap_allocated()); + assert_eq!("ab", s); + + // inline max push + let mut builder = SmolStrBuilder::new(); + for _ in 0..23 { + builder.push('a'); + } + let s = builder.finish(); + assert!(!s.is_heap_allocated()); + assert_eq!("a".repeat(23), s); + + // heap push + let mut builder = SmolStrBuilder::new(); + for _ in 0..24 { + builder.push('a'); + } + let s = builder.finish(); + assert!(s.is_heap_allocated()); + assert_eq!("a".repeat(24), s); +} + #[cfg(test)] mod test_str_ext { use smol_str::StrExt; |