init modules cstr8 and cstr16 (plus dependencies)

Author: phip1611

Cargo.toml

@@ -16,3 +16,4 @@ bit_field = "0.10"
 [features]
 default = []
 alloc = []
+unstable = []

src/encoding/macros.rs

@@ -82,13 +82,13 @@ macro_rules! ucs2_cstr {
         // Use `const` values here to force errors to happen at compile
         // time.
 
-        const NUM_CHARS: usize = match $crate::str_num_ucs2_chars($s) {
+        const NUM_CHARS: usize = match $crate::encoding::str_num_ucs2_chars($s) {
             // Add one for the null char.
             Ok(num) => num + 1,
             Err(_) => panic!("input contains a character which cannot be represented in UCS-2"),
         };
 
-        const VAL: [u16; NUM_CHARS] = match $crate::str_to_ucs2($s) {
+        const VAL: [u16; NUM_CHARS] = match $crate::encoding::str_to_ucs2($s) {
             Ok(val) => val,
             // The string was already checked by `str_num_ucs2_chars`,
             // so this error is unreachable.

src/encoding/mod.rs

@@ -2,6 +2,7 @@
 
 mod macros;
 
+pub use crate::ucs2_cstr;
 /// These need to be public for the `ucs2_cstr!` macro, but are not
 /// intended to be called directly.
 #[doc(hidden)]

src/lib.rs

@@ -8,4 +8,5 @@
 extern crate alloc;
 
 pub mod encoding;
+pub mod polyfill;
 pub mod types;

src/polyfill.rs

@@ -0,0 +1,29 @@
+//! Polyfills for functions in the standard library that are currently gated
+//! behind unstable features.
+
+use core::mem::MaybeUninit;
+#[cfg(feature = "alloc")]
+use {alloc::vec::Vec, core::mem::ManuallyDrop};
+
+/// Polyfill for the unstable `MaybeUninit::slice_assume_init_ref` function.
+///
+/// See <https://github.com/rust-lang/rust/issues/63569>.
+pub const unsafe fn maybe_uninit_slice_assume_init_ref<T>(s: &[MaybeUninit<T>]) -> &[T] {
+    unsafe { &*(s as *const [MaybeUninit<T>] as *const [T]) }
+}
+
+/// Polyfill for the unstable `MaybeUninit::slice_as_mut_ptr` function.
+///
+/// See <https://github.com/rust-lang/rust/issues/63569>.
+pub fn maybe_uninit_slice_as_mut_ptr<T>(s: &mut [MaybeUninit<T>]) -> *mut T {
+    s.as_mut_ptr().cast::<T>()
+}
+
+/// Polyfill for the unstable `Vec::into_raw_parts` function.
+///
+/// See <https://github.com/rust-lang/rust/issues/65816>.
+#[cfg(feature = "alloc")]
+pub fn vec_into_raw_parts<T>(v: Vec<T>) -> (*mut T, usize, usize) {
+    let mut v = ManuallyDrop::new(v);
+    (v.as_mut_ptr(), v.len(), v.capacity())
+}