From 840c4e2873476a7d6101f71e4f63b3024245ccd1 Mon Sep 17 00:00:00 2001 From: C Date: Sat, 5 Dec 2020 00:52:48 +0000 Subject: refactor: moved IsZero into is_zero.rs --- library/alloc/src/vec/is_zero.rs | 71 ++++++++++++++++++++++++++++++++++++++ library/alloc/src/vec/mod.rs | 74 +++------------------------------------- 2 files changed, 75 insertions(+), 70 deletions(-) create mode 100644 library/alloc/src/vec/is_zero.rs (limited to 'library/alloc/src') diff --git a/library/alloc/src/vec/is_zero.rs b/library/alloc/src/vec/is_zero.rs new file mode 100644 index 00000000000..961f6ca171b --- /dev/null +++ b/library/alloc/src/vec/is_zero.rs @@ -0,0 +1,71 @@ +use crate::boxed::Box; + +#[rustc_specialization_trait] +pub(super) unsafe trait IsZero { + /// Whether this value is zero + fn is_zero(&self) -> bool; +} + +macro_rules! impl_is_zero { + ($t:ty, $is_zero:expr) => { + unsafe impl IsZero for $t { + #[inline] + fn is_zero(&self) -> bool { + $is_zero(*self) + } + } + }; +} + +impl_is_zero!(i16, |x| x == 0); +impl_is_zero!(i32, |x| x == 0); +impl_is_zero!(i64, |x| x == 0); +impl_is_zero!(i128, |x| x == 0); +impl_is_zero!(isize, |x| x == 0); + +impl_is_zero!(u16, |x| x == 0); +impl_is_zero!(u32, |x| x == 0); +impl_is_zero!(u64, |x| x == 0); +impl_is_zero!(u128, |x| x == 0); +impl_is_zero!(usize, |x| x == 0); + +impl_is_zero!(bool, |x| x == false); +impl_is_zero!(char, |x| x == '\0'); + +impl_is_zero!(f32, |x: f32| x.to_bits() == 0); +impl_is_zero!(f64, |x: f64| x.to_bits() == 0); + +unsafe impl IsZero for *const T { + #[inline] + fn is_zero(&self) -> bool { + (*self).is_null() + } +} + +unsafe impl IsZero for *mut T { + #[inline] + fn is_zero(&self) -> bool { + (*self).is_null() + } +} + +// `Option<&T>` and `Option>` are guaranteed to represent `None` as null. +// For fat pointers, the bytes that would be the pointer metadata in the `Some` +// variant are padding in the `None` variant, so ignoring them and +// zero-initializing instead is ok. +// `Option<&mut T>` never implements `Clone`, so there's no need for an impl of +// `SpecFromElem`. + +unsafe impl IsZero for Option<&T> { + #[inline] + fn is_zero(&self) -> bool { + self.is_none() + } +} + +unsafe impl IsZero for Option> { + #[inline] + fn is_zero(&self) -> bool { + self.is_none() + } +} \ No newline at end of file diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs index 1f410e3c028..69fcfaa6a7e 100644 --- a/library/alloc/src/vec/mod.rs +++ b/library/alloc/src/vec/mod.rs @@ -97,6 +97,10 @@ pub (crate) use self::into_iter::AsIntoIter; mod into_iter; +use self::is_zero::IsZero; + +mod is_zero; + /// A contiguous growable array type, written `Vec` but pronounced 'vector'. /// /// # Examples @@ -2042,76 +2046,6 @@ impl SpecFromElem for T { } } -#[rustc_specialization_trait] -unsafe trait IsZero { - /// Whether this value is zero - fn is_zero(&self) -> bool; -} - -macro_rules! impl_is_zero { - ($t:ty, $is_zero:expr) => { - unsafe impl IsZero for $t { - #[inline] - fn is_zero(&self) -> bool { - $is_zero(*self) - } - } - }; -} - -impl_is_zero!(i16, |x| x == 0); -impl_is_zero!(i32, |x| x == 0); -impl_is_zero!(i64, |x| x == 0); -impl_is_zero!(i128, |x| x == 0); -impl_is_zero!(isize, |x| x == 0); - -impl_is_zero!(u16, |x| x == 0); -impl_is_zero!(u32, |x| x == 0); -impl_is_zero!(u64, |x| x == 0); -impl_is_zero!(u128, |x| x == 0); -impl_is_zero!(usize, |x| x == 0); - -impl_is_zero!(bool, |x| x == false); -impl_is_zero!(char, |x| x == '\0'); - -impl_is_zero!(f32, |x: f32| x.to_bits() == 0); -impl_is_zero!(f64, |x: f64| x.to_bits() == 0); - -unsafe impl IsZero for *const T { - #[inline] - fn is_zero(&self) -> bool { - (*self).is_null() - } -} - -unsafe impl IsZero for *mut T { - #[inline] - fn is_zero(&self) -> bool { - (*self).is_null() - } -} - -// `Option<&T>` and `Option>` are guaranteed to represent `None` as null. -// For fat pointers, the bytes that would be the pointer metadata in the `Some` -// variant are padding in the `None` variant, so ignoring them and -// zero-initializing instead is ok. -// `Option<&mut T>` never implements `Clone`, so there's no need for an impl of -// `SpecFromElem`. - -unsafe impl IsZero for Option<&T> { - #[inline] - fn is_zero(&self) -> bool { - self.is_none() - } -} - -unsafe impl IsZero for Option> { - #[inline] - fn is_zero(&self) -> bool { - self.is_none() - } -} - //////////////////////////////////////////////////////////////////////////////// // Common trait implementations for Vec //////////////////////////////////////////////////////////////////////////////// -- cgit 1.4.1-3-g733a5