Struct jni::strings::JNIStr
[−]
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pub struct JNIStr { /* fields omitted */ }
Wrapper for std::ffi::CStr
that also takes care of encoding between
UTF-8 and Java's Modified UTF-8.
Methods
impl JNIStr
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unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a JNIStr
Construct a reference to a JNIStr
from a pointer. Equivalent to
CStr::from_ptr
.
Methods from Deref<Target=CStr>
fn as_ptr(&self) -> *const i8
1.0.0
Returns the inner pointer to this C string.
The returned pointer will be valid for as long as self
is and points
to a contiguous region of memory terminated with a 0 byte to represent
the end of the string.
WARNING
It is your responsibility to make sure that the underlying memory is not
freed too early. For example, the following code will cause undefined
behaviour when ptr
is used inside the unsafe
block:
use std::ffi::{CString}; let ptr = CString::new("Hello").unwrap().as_ptr(); unsafe { // `ptr` is dangling *ptr; }
This happens because the pointer returned by as_ptr
does not carry any
lifetime information and the string is deallocated immediately after
the CString::new("Hello").unwrap().as_ptr()
expression is evaluated.
To fix the problem, bind the string to a local variable:
use std::ffi::{CString}; let hello = CString::new("Hello").unwrap(); let ptr = hello.as_ptr(); unsafe { // `ptr` is valid because `hello` is in scope *ptr; }
fn to_bytes(&self) -> &[u8]
1.0.0
Converts this C string to a byte slice.
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 of u8
elements.
The returned slice will not contain the trailing nul that this C string has.
Note: This method is currently implemented as a 0-cost cast, but it is planned to alter its definition in the future to perform the length calculation whenever this method is called.
fn to_bytes_with_nul(&self) -> &[u8]
1.0.0
Converts this C string to a byte slice containing the trailing 0 byte.
This function is the equivalent of to_bytes
except that it will retain
the trailing nul instead of chopping it off.
Note: This method is currently implemented as a 0-cost cast, but it is planned to alter its definition in the future to perform the length calculation whenever this method is called.
fn to_str(&self) -> Result<&str, Utf8Error>
1.4.0
Yields a &str
slice if the CStr
contains valid UTF-8.
This function will calculate the length of this string and check for
UTF-8 validity, and then return the &str
if it's valid.
Note: This method is currently implemented to check for validity after a 0-cost cast, but it is planned to alter its definition in the future to perform the length calculation in addition to the UTF-8 check whenever this method is called.
fn to_string_lossy(&self) -> Cow<str>
1.4.0
Converts a CStr
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
.
Note: This method is currently implemented to check for validity after a 0-cost cast, but it is planned to alter its definition in the future to perform the length calculation in addition to the UTF-8 check whenever this method is called.
Trait Implementations
impl Deref for JNIStr
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type Target = CStr
The resulting type after dereferencing
fn deref(&self) -> &Self::Target
The method called to dereference a value
impl ToOwned for JNIStr
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type Owned = JNIString
fn to_owned(&self) -> JNIString
Creates owned data from borrowed data, usually by cloning. Read more