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-rw-r--r--vendor/memchr/src/ext.rs52
1 files changed, 52 insertions, 0 deletions
diff --git a/vendor/memchr/src/ext.rs b/vendor/memchr/src/ext.rs
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+/// A trait for adding some helper routines to pointers.
+pub(crate) trait Pointer {
+ /// Returns the distance, in units of `T`, between `self` and `origin`.
+ ///
+ /// # Safety
+ ///
+ /// Same as `ptr::offset_from` in addition to `self >= origin`.
+ unsafe fn distance(self, origin: Self) -> usize;
+
+ /// Casts this pointer to `usize`.
+ ///
+ /// Callers should not convert the `usize` back to a pointer if at all
+ /// possible. (And if you believe it's necessary, open an issue to discuss
+ /// why. Otherwise, it has the potential to violate pointer provenance.)
+ /// The purpose of this function is just to be able to do arithmetic, i.e.,
+ /// computing offsets or alignments.
+ fn as_usize(self) -> usize;
+}
+
+impl<T> Pointer for *const T {
+ unsafe fn distance(self, origin: *const T) -> usize {
+ // TODO: Replace with `ptr::sub_ptr` once stabilized.
+ usize::try_from(self.offset_from(origin)).unwrap_unchecked()
+ }
+
+ fn as_usize(self) -> usize {
+ self as usize
+ }
+}
+
+impl<T> Pointer for *mut T {
+ unsafe fn distance(self, origin: *mut T) -> usize {
+ (self as *const T).distance(origin as *const T)
+ }
+
+ fn as_usize(self) -> usize {
+ (self as *const T).as_usize()
+ }
+}
+
+/// A trait for adding some helper routines to raw bytes.
+pub(crate) trait Byte {
+ /// Converts this byte to a `char` if it's ASCII. Otherwise panics.
+ fn to_char(self) -> char;
+}
+
+impl Byte for u8 {
+ fn to_char(self) -> char {
+ assert!(self.is_ascii());
+ char::from(self)
+ }
+}