Enum cfixed_string::CFixedString

pub enum CFixedString {
    Local {
        s: [c_char; 512],
        len: usize,
    },
    Heap {
        s: CString,
        len: usize,
    },
}

This is a C String abstractions that presents a CStr like interface for interop purposes but tries to be little nicer by avoiding heap allocations if the string is within the generous bounds (512 bytes) of the statically sized buffer. Strings over this limit will be heap allocated, but the interface outside of this abstraction remains the same.

Variants

Local

Fields of Local

s: [c_char; 512]len: usize

Heap

Fields of Heap

s: CStringlen: usize

Implementations

impl CFixedString

pub fn new() -> Self

Creates an empty CFixedString, this is intended to be used with write! or the fmt::Write trait

pub fn from_str<S: AsRef<str>>(s: S) -> Self

Create from str

pub fn as_ptr(&self) -> *const c_char

Returns the pointer to be passed down to the C code

pub fn is_allocated(&self) -> bool

Returns true if the string has been heap allocated

pub fn to_string(&self) -> Cow<'_, str>

Converts a CFixedString into a Cow<str>.

This function will calculate the length of this string (which normally requires a linear amount of work to be done) and then return the resulting slice as a Cow<str>, replacing any invalid UTF-8 sequences with U+FFFD REPLACEMENT CHARACTER. If there are no invalid UTF-8 sequences, this will merely return a borrowed slice.

pub unsafe fn as_str(&self) -> &str

Convert back to str. Unsafe as it uses from_utf8_unchecked

Trait Implementations

impl AsRef<CStr> for CFixedString

fn as_ref(&self) -> &CStr

Performs the conversion.

impl AsRef<str> for CFixedString

fn as_ref(&self) -> &str

Performs the conversion.

impl Borrow<CStr> for CFixedString

fn borrow(&self) -> &CStr

Immutably borrows from an owned value.

impl Borrow<str> for CFixedString

fn borrow(&self) -> &str

Immutably borrows from an owned value.

impl Deref for CFixedString

type Target = CStr

The resulting type after dereferencing.

fn deref(&self) -> &CStr

Dereferences the value.

impl<'a> From<&'a str> for CFixedString

fn from(s: &'a str) -> Self

Performs the conversion.

impl From<CFixedString> for String

fn from(s: CFixedString) -> Self

Performs the conversion.

impl Write for CFixedString

fn write_str(&mut self, s: &str) -> Result<(), Error>

Writes a string slice into this writer, returning whether the write succeeded.

fn write_char(&mut self, c: char) -> Result<(), Error>

Writes a char into this writer, returning whether the write succeeded.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Glue for usage of the write! macro with implementors of this trait.