Struct re2::string::StringWrapper

pub struct StringWrapper(/* private fields */);

Handle to a heap-allocated C++ std::string.

This is used as an output for some string search methods such as RE2::extract() which need to allocate memory dynamically. The same instance can be provided to multiple calls in order to avoid allocating a new string upon each call, and Self::as_mut_view() and Self::resize() can be used to modify the contents in between calls.

This object “owns” its string data, and upon destruction, this object will deallocate the underlying std::string data as well. Use Self::as_view() to extract a view of the underlying data in order to copy it elsewhere.

Implementations

impl StringWrapper

pub const fn blank() -> Self

Generate an instance without allocating any memory dynamically.

 let s = re2::string::StringWrapper::blank();
 assert_eq!(unsafe { s.as_view().as_str() }, "");

pub fn from_view(s: StringView<'_>) -> Self

Generate an instance which copies the bytes from the argument s.

 let s = re2::string::StringWrapper::from_view("asdf".into());
 assert_eq!(unsafe { s.as_view().as_str() }, "asdf");

pub fn as_view(&self) -> StringView<'_>

Generate a read-only view of the dynamically allocated memory.

 let s = re2::string::StringWrapper::from_view("asdf".into());
 assert_eq!(unsafe { s.as_view().as_str() }, "asdf");

pub fn as_mut_view(&mut self) -> StringMut<'_>

Generate a mutable view of the dynamically allocated memory.

 let mut s = re2::string::StringWrapper::from_view("asdf".into());
 s.as_mut_view().as_mut_slice()[2] = b'e';
 assert_eq!(unsafe { s.as_view().as_str() }, "asef");

pub fn resize(&mut self, len: usize)

Resize the underlying std::string storage.

If the new length is larger than the old, this method will pad the result with null bytes.

 let mut s = re2::string::StringWrapper::from_view("asdf".into());
 assert_eq!(unsafe { s.as_view().as_str() }, "asdf");
 s.resize(2);
 assert_eq!(unsafe { s.as_view().as_str() }, "as");
 s.resize(6);
 assert_eq!(unsafe { s.as_view().as_str() }, "as\0\0\0\0");
 s.resize(0);
 assert_eq!(unsafe { s.as_view().as_str() }, "");

pub fn clear(&mut self)

Deallocate the underlying string storage.

This method is idempotent and can be called multiple times in a row.

 let mut s = re2::string::StringWrapper::from_view("asdf".into());
 assert_eq!(unsafe { s.as_view().as_str() }, "asdf");
 s.clear();
 assert_eq!(unsafe { s.as_view().as_str() }, "");

Trait Implementations

impl Debug for StringWrapper

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for StringWrapper

fn drop(&mut self)

Executes the destructor for this type.