Struct widestring::WideCString
[−]
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pub struct WideCString { // some fields omitted }
An owned, mutable C-style "wide" string for windows FFI that is nul-aware and nul-terminated.
WideCString
is aware of nul values. Unless unchecked conversions are used, all WideCString
strings end with a nul-terminator in the underlying buffer, and contain no internal nul values.
The strings may still contain invalid or ill-formed UTF-16 data. These strings are intended to
be used with windows FFI functions that may require nul-terminated strings.
WideCString
can be converted to and from many other string types, including WideString
,
OsString
, and String
, making proper Unicode windows FFI safe and easy.
Examples
The following example constructs a WideCString
and shows how to convert a WideCString
to a
regular Rust String
.
use widestring::WideCString; let v = vec![84u16, 104u16, 101u16]; // 'T' 'h' 'e' // Create a wide string from the vector let wstr = WideCString::from_vec(v).unwrap(); // Convert to a rust string! let rust_str = wstr.to_string_lossy(); assert_eq!(rust_str, "The");
Methods
impl WideCString
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fn new() -> WideCString
Constructs a new empty WideCString
.
fn from_vec<T: Into<Vec<u16>>>(v: T) -> Result<WideCString, NulError>
Constructs a WideCString
from a container of UTF-16 data.
This method will consume the provided data and use the underlying elements to construct a new string. The data will be scanned for invalid nul values.
Failures
This function will return an error if the data contains a nul value.
The returned error will contain the Vec<u16>
as well as the position of the nul value.
Examples
use widestring::WideCString; let v = vec![84u16, 104u16, 101u16]; // 'T' 'h' 'e' // Create a wide string from the vector let wcstr = WideCString::from_vec(v).unwrap();
The following example demonstrates errors from nul values in a vector.
use widestring::WideCString; let v = vec![84u16, 0u16, 104u16, 101u16]; // 'T' NUL 'h' 'e' // Create a wide string from the vector let res = WideCString::from_vec(v); assert!(res.is_err()); assert_eq!(res.err().unwrap().nul_position(), 1);
fn from_vec_with_nul<T: Into<Vec<u16>>>(v: T) -> Result<WideCString, MissingNulError>
Constructs a WideCString
from a nul-terminated container of UTF-16 data.
This method will consume the provided data and use the underlying elements to construct a new string. The string will be truncated at the first nul value in the string.
Failures
This function will return an error if the data does not contain a nul to terminate the
string. The returned error will contain the consumed Vec<u16>
.
Examples
use widestring::WideCString; let v = vec![84u16, 104u16, 101u16, 0u16]; // 'T' 'h' 'e' NUL // Create a wide string from the vector let wcstr = WideCString::from_vec_with_nul(v).unwrap();
The following example demonstrates errors from missing nul values in a vector.
use widestring::WideCString; let v = vec![84u16, 104u16, 101u16]; // 'T' 'h' 'e' // Create a wide string from the vector let res = WideCString::from_vec_with_nul(v); assert!(res.is_err());
unsafe fn from_vec_unchecked<T: Into<Vec<u16>>>(v: T) -> WideCString
Creates a WideCString
from a vector without checking for interior nul values.
A terminating nul value will be appended if the vector does not already have a terminating nul.
Safety
This method is equivalent to from_vec
except that no runtime assertion is made that v
contains no nul values. Providing a vector with non-terminating nul values will result in an
invalid WideCString
.
unsafe fn from_vec_with_nul_unchecked<T: Into<Vec<u16>>>(v: T) -> WideCString
Creates a WideCString
from a vector that should have a nul terminator, without checking
for any nul values.
Safety
This method is equivalent to from_vec_with_nul
except that no runtime assertion is made
that v
contains no nul values. Providing a vector without interior nul values or without a
terminating nul value will result in an invalid WideCString
.
fn from_str<T: AsRef<OsStr>>(s: T) -> Result<WideCString, NulError>
Constructs a WideCString
from anything that can be converted to an OsStr
.
The string will be scanned for invalid nul values.
Failures
This function will return an error if the data contains a nul value.
The returned error will contain a Vec<u16>
as well as the position of the nul value.
Examples
use widestring::WideCString; let s = "MyString"; // Create a wide string from the string let wcstr = WideCString::from_str(s).unwrap();
The following example demonstrates errors from nul values in a vector.
use widestring::WideCString; let s = "My\u{0}String"; // Create a wide string from the string let res = WideCString::from_str(s); assert!(res.is_err()); assert_eq!(res.err().unwrap().nul_position(), 2);
fn from_str_with_nul<T: AsRef<OsStr>>(s: T) -> Result<WideCString, MissingNulError>
Constructs a WideCString
from anything that can be converted to an OsStr
with a nul
terminator.
The string will be truncated at the first nul value in the string.
Failures
This function will return an error if the data does not contain a nul to terminate the
string. The returned error will contain the consumed Vec<u16>
.
Examples
use widestring::WideCString; let s = "My\u{0}String"; // Create a wide string from the string let wcstr = WideCString::from_str_with_nul(s).unwrap(); assert_eq!(wcstr.to_string_lossy(), "My");
The following example demonstrates errors from missing nul values in a vector.
use widestring::WideCString; let s = "MyString"; // Create a wide string from the string let res = WideCString::from_str_with_nul(s); assert!(res.is_err());
fn from_wide_str<T: AsRef<WideStr>>(s: T) -> Result<WideCString, NulError>
Constructs a WideCString
from anything that can be converted to a WideStr
.
The string will be scanned for invalid nul values.
Failures
This function will return an error if the data contains a nul value.
The returned error will contain a Vec<u16>
as well as the position of the nul value.
fn from_wide_str_with_nul<T: AsRef<WideStr>>(s: T) -> Result<WideCString, MissingNulError>
Constructs a WideCString
from anything that can be converted to a WideStr
with a nul
terminator.
The string will be truncated at the first nul value in the string.
Failures
This function will return an error if the data does not contain a nul to terminate the
string. The returned error will contain the consumed Vec<u16>
.
unsafe fn from_ptr_str(p: *const u16) -> WideCString
Constructs a new WideCString
copied from a u16
nul-terminated string pointer.
This will scan for nul values beginning with p
. The first nul value will be used as the
nul terminator for the string, similar to how libc string functions such as strlen
work.
Safety
This function is unsafe as there is no guarantee that the given pointer is valid or has a nul terminator, and the function could scan past the underlying buffer.
p
must be non-null.
Panics
This function panics if p
is null.
Caveat
The lifetime for the returned string is inferred from its usage. To prevent accidental misuse, it's suggested to tie the lifetime to whichever source lifetime is safe in the context, such as by providing a helper function taking the lifetime of a host value for the string, or by explicit annotation.
unsafe fn from_ptr(p: *const u16, len: usize) -> Result<WideCString, NulError>
Constructs a new WideCString
copied from a u16
pointer and a length.
The len
argument is the number of u16
elements, not the number of bytes.
The string will be scanned for invalid nul values.
Failures
This function will return an error if the data contains a nul value.
The returned error will contain a Vec<u16>
as well as the position of the nul value.
Safety
This function is unsafe as there is no guarantee that the given pointer is valid for len
elements.
Panics
Panics if len
is greater than 0 but p
is a null pointer.
unsafe fn from_ptr_with_nul(p: *const u16, len: usize) -> Result<WideCString, MissingNulError>
Constructs a new WideString
copied from a u16
pointer and a length.
The len
argument is the number of u16
elements, not the number of bytes.
The string will be truncated at the first nul value in the string.
Failures
This function will return an error if the data does not contain a nul to terminate the
string. The returned error will contain the consumed Vec<u16>
.
Safety
This function is unsafe as there is no guarantee that the given pointer is valid for len
elements.
Panics
Panics if len
is greater than 0 but p
is a null pointer.
fn as_wide_c_str(&self) -> &WideCStr
Converts to a WideCStr
reference.
fn into_vec(self) -> Vec<u16>
Converts the wide string into a Vec<u16>
without a nul terminator, consuming the string in
the process.
The resulting vector will not contain a nul-terminator, and will contain no other nul values.
fn into_vec_with_nul(self) -> Vec<u16>
Converts the wide string into a Vec<u16>
, consuming the string in the process.
The resulting vector will contain a nul-terminator and no interior nul values.
fn into_raw(self) -> *mut u16
Transfers ownership of the wide string to a C caller.
Safety
The pointer must be returned to Rust and reconstituted using from_raw
to be properly
deallocated. Specifically, one should not use the standard C free
function to deallocate
this string.
Failure to call from_raw
will lead to a memory leak.
unsafe fn from_raw(p: *mut u16) -> WideCString
Retakes ownership of a CString that was transferred to C.
Safety
This should only ever be called with a pointer that was earlier obtained by calling
into_raw
on a WideCString
. Additionally, the length of the string will be recalculated
from the pointer.
Methods from Deref<Target=WideCStr>
fn to_wide_c_string(&self) -> WideCString
Copies the wide string to an new owned WideString
.
fn to_os_string(&self) -> OsString
Decodes a wide string to an owned OsString
.
This makes a string copy of the WideCStr
. Since WideCStr
makes no guaruntees that it is
valid UTF-16, there is no guaruntee that the resulting OsString
will be valid data. The
OsString
will not have a nul terminator.
Examples
use widestring::WideCString; use std::ffi::OsString; let s = "MyString"; // Create a wide string from the string let wstr = WideCString::from_str(s).unwrap(); // Create an OsString from the wide string let osstr = wstr.to_os_string(); assert_eq!(osstr, OsString::from(s));
fn to_wide_string(&self) -> WideString
Copies the wide string to a new owned WideString
.
The WideString
will not have a nul terminator.
fn to_string(&self) -> Result<String, FromUtf16Error>
Copies the wide string to a String
if it contains valid UTF-16 data.
Failures
Returns an error if the string contains any invalid UTF-16 data.
Examples
use widestring::WideCString; let s = "MyString"; // Create a wide string from the string let wstr = WideCString::from_str(s).unwrap(); // Create a regular string from the wide string let s2 = wstr.to_string().unwrap(); assert_eq!(s2, s);
fn to_string_lossy(&self) -> String
Copies the wide string to a String
.
Any non-Unicode sequences are replaced with U+FFFD REPLACEMENT CHARACTER.
Examples
use widestring::WideCString; let s = "MyString"; // Create a wide string from the string let wstr = WideCString::from_str(s).unwrap(); // Create a regular string from the wide string let s2 = wstr.to_string_lossy(); assert_eq!(s2, s);
fn as_slice(&self) -> &[u16]
Converts to a slice of the wide string.
The slice will not include the nul terminator.
fn as_slice_with_nul(&self) -> &[u16]
converts to a slice of the wide string, including the nul terminator.
fn as_ptr(&self) -> *const u16
Returns a raw pointer to the wide string.
The pointer is valid only as long as the lifetime of this reference.
fn len(&self) -> usize
Returns the length of the wide string as number of UTF-16 partial code units (not code points and not number of bytes) not including nul terminator.
fn is_empty(&self) -> bool
Returns whether this wide string contains no data (i.e. is only the nul terminator).
Trait Implementations
impl Debug for WideCString
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impl Clone for WideCString
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fn clone(&self) -> WideCString
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0
Performs copy-assignment from source
. Read more
impl PartialEq for WideCString
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fn eq(&self, __arg_0: &WideCString) -> bool
This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, __arg_0: &WideCString) -> bool
This method tests for !=
.
impl Eq for WideCString
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impl PartialOrd for WideCString
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fn partial_cmp(&self, __arg_0: &WideCString) -> Option<Ordering>
This method returns an ordering between self
and other
values if one exists. Read more
fn lt(&self, __arg_0: &WideCString) -> bool
This method tests less than (for self
and other
) and is used by the <
operator. Read more
fn le(&self, __arg_0: &WideCString) -> bool
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
fn gt(&self, __arg_0: &WideCString) -> bool
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
fn ge(&self, __arg_0: &WideCString) -> bool
This method tests greater than or equal to (for self
and other
) and is used by the >=
operator. Read more
impl Ord for WideCString
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fn cmp(&self, __arg_0: &WideCString) -> Ordering
This method returns an Ordering
between self
and other
. Read more
impl Hash for WideCString
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fn hash<__H: Hasher>(&self, __arg_0: &mut __H)
Feeds this value into the state given, updating the hasher as necessary.
fn hash_slice<H>(data: &[Self], state: &mut H) where H: Hasher
1.3.0
Feeds a slice of this type into the state provided.
impl Into<Vec<u16>> for WideCString
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impl<'a, T: ?Sized + AsRef<WideCStr>> From<&'a T> for WideCString
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fn from(s: &'a T) -> WideCString
Performs the conversion.
impl Index<RangeFull> for WideCString
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type Output = WideCStr
The returned type after indexing
fn index(&self, _index: RangeFull) -> &WideCStr
The method for the indexing (Foo[Bar]
) operation
impl Deref for WideCString
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type Target = WideCStr
The resulting type after dereferencing
fn deref(&self) -> &WideCStr
The method called to dereference a value
impl Default for WideCString
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fn default() -> WideCString
Returns the "default value" for a type. Read more