From e7298469c493cbe8fd60e81350593d86da84df40 Mon Sep 17 00:00:00 2001 From: Harald Hoyer Date: Fri, 22 Jan 2021 12:49:33 +0100 Subject: [PATCH] initial commit --- .github/dependabot.yml | 6 + .github/workflows/lint.yml | 48 +++++++ .github/workflows/test.yml | 26 ++++ .gitignore | 3 + Cargo.toml | 9 ++ LICENSE | 201 +++++++++++++++++++++++++++ README.md | 8 ++ rust-toolchain | 1 + src/lib.rs | 277 +++++++++++++++++++++++++++++++++++++ 9 files changed, 579 insertions(+) create mode 100644 .github/dependabot.yml create mode 100644 .github/workflows/lint.yml create mode 100644 .github/workflows/test.yml create mode 100644 .gitignore create mode 100644 Cargo.toml create mode 100644 LICENSE create mode 100644 README.md create mode 100644 rust-toolchain create mode 100644 src/lib.rs diff --git a/.github/dependabot.yml b/.github/dependabot.yml new file mode 100644 index 0000000..044bb97 --- /dev/null +++ b/.github/dependabot.yml @@ -0,0 +1,6 @@ +version: 2 +updates: +- package-ecosystem: "cargo" + directory: "/" + schedule: + interval: "daily" diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml new file mode 100644 index 0000000..adaf521 --- /dev/null +++ b/.github/workflows/lint.yml @@ -0,0 +1,48 @@ +on: [pull_request] + +name: lint + +jobs: + fmt: + name: cargo fmt + runs-on: ubuntu-latest + steps: + - uses: actions/checkout@v2 + - uses: actions-rs/toolchain@v1 + with: + components: rustfmt + toolchain: nightly + profile: minimal + override: true + - uses: actions-rs/cargo@v1 + with: + command: fmt + args: --all -- --check + + clippy: + name: cargo clippy + runs-on: ubuntu-latest + steps: + - uses: actions/checkout@v2 + - uses: actions-rs/toolchain@v1 + with: + components: clippy + toolchain: nightly + profile: minimal + override: true + - uses: actions-rs/cargo@v1 + with: + command: clippy + args: -- -D warnings + readme: + name: cargo readme + runs-on: ubuntu-latest + steps: + - uses: actions/checkout@v2 + - uses: actions-rs/toolchain@v1 + with: + toolchain: nightly + profile: minimal + override: true + - run: cargo install cargo-readme + - run: cargo readme > README.md && git diff --exit-code diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml new file mode 100644 index 0000000..fb9eb2b --- /dev/null +++ b/.github/workflows/test.yml @@ -0,0 +1,26 @@ + +on: [pull_request] +name: test +jobs: + test: + name: ${{ matrix.toolchain }} (${{ matrix.profile.name }}) + runs-on: ubuntu-latest + steps: + - uses: actions/checkout@v2 + - uses: actions-rs/toolchain@v1 + with: + toolchain: ${{ matrix.toolchain }} + override: true + - uses: actions-rs/cargo@v1 + with: + command: test + args: ${{ matrix.profile.flag }} + strategy: + fail-fast: false + matrix: + toolchain: + - nightly + profile: + - name: debug + - name: release + flag: --release diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..5ab7a50 --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +/.idea +/target +Cargo.lock diff --git a/Cargo.toml b/Cargo.toml new file mode 100644 index 0000000..4bf75ce --- /dev/null +++ b/Cargo.toml @@ -0,0 +1,9 @@ +[package] +name = "slabvec" +version = "0.1.0" +authors = ["Harald Hoyer "] +edition = "2018" + +# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html + +[dependencies] diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..261eeb9 --- /dev/null +++ b/LICENSE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. 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Array of `T` with dynamic allocations of `N` entries for slabs of size `M` +//! +//! The array will dynamically allocate slabs of size `M` to extend its internal +//! linked list, which will extend the capacity by `N`. +//! +//! Currently nightly until `#![feature(min_const_generics)]` hits stable with `1.51`. + +#![deny(missing_docs)] +#![deny(clippy::all)] +#![cfg_attr(not(test), no_std)] + +use core::alloc::GlobalAlloc; +use core::alloc::Layout; +use core::marker::PhantomData; +use core::mem::{align_of, size_of, MaybeUninit}; +use core::ptr::NonNull; + +#[inline] +const fn align_up(addr: usize) -> usize { + let align_mask = align_of::() - 1; + if addr & align_mask == 0 { + addr // already aligned + } else { + (addr | align_mask) + 1 + } +} + +/// Array of `T` with dynamic allocations of `N` entries for slabs of size `M` +pub struct SlabVec { + head: Option>>, + tail: Option>>, + len: usize, + alloc: &'static dyn GlobalAlloc, +} + +impl SlabVec { + /// Number of entries a [`SlabVec`] could hold + /// + /// Trick used because of const_generics being still unstable. + pub const NUM_ENTRIES: usize = + (M - size_of::>()) / align_up::(size_of::()); + + /// Get a new List using `alloc` as the allocator for its slabs + pub fn new(alloc: &'static dyn GlobalAlloc) -> Self { + let mut sl = Self { + alloc, + len: 0, + head: None, + tail: None, + }; + sl.add_page(); + sl + } + + /// Add one more page of size `M` with `N` entries + pub fn add_page(&mut self) { + let lp = NonNull::new({ + let ele = unsafe { + &mut *(self + .alloc + .alloc(Layout::from_size_align(M, align_of::>()).unwrap()) + as *mut MaybeUninit>) + }; + + unsafe { + ele.as_mut_ptr().write(ListPage:: { + header: ListPageHeader { next: None }, + entry: [T::default(); N], + }); + // As the yet unstable MaybeUninit::assume_init_mut() + &mut *ele.as_mut_ptr() + } + }); + + if self.head.is_none() { + self.head = lp; + } + + if let Some(mut tail) = self.tail { + unsafe { tail.as_mut() }.header.next = lp; + } + + self.tail = lp; + + self.len += N; + } + + /// Provides a forward iterator. + pub fn iter(&self) -> Iter<'_, T, N, M> { + Iter { + current: self.head, + index: 0, + len: self.len, + phantom: PhantomData, + } + } + + /// Provides a forward iterator with mutable references. + pub fn iter_mut(&mut self) -> IterMut<'_, T, N, M> { + IterMut { + current: self.head, + index: 0, + len: self.len, + phantom: PhantomData, + } + } +} + +impl Drop for SlabVec { + fn drop(&mut self) { + unsafe { + let mut this = self.head.take(); + while let Some(mut ele) = this { + this = ele.as_mut().header.next.take(); + self.alloc.dealloc( + ele.as_ptr() as *mut u8, + Layout::from_size_align(size_of::(), align_of::()).unwrap(), + ); + } + } + } +} + +#[repr(C)] +struct ListPageHeader { + next: Option>>, +} + +#[repr(C)] +struct ListPage { + header: ListPageHeader, + entry: [T; N], +} + +/// An iterator over the elements of a `SlabVec`. +/// +/// This `struct` is created by [`SlabVec::iter()`]. See its +/// documentation for more. +pub struct Iter<'a, T: Default + Copy + Sized, const N: usize, const M: usize> { + current: Option>>, + index: usize, + len: usize, + phantom: PhantomData<&'a SlabVec>, +} + +impl<'a, T: Default + Copy + Sized, const N: usize, const M: usize> Iterator for Iter<'a, T, N, M> { + type Item = &'a T; + + fn next(&mut self) -> Option { + let this: &ListPage = unsafe { &*(self.current?.as_ptr()) }; + + let ret = this.entry.get(self.index)?; + + self.len -= 1; + self.index += 1; + + if self.index == N { + self.current = this.header.next; + self.index = 0; + } + Some(ret) + } + + fn size_hint(&self) -> (usize, Option) { + (self.len, Some(self.len)) + } +} + +/// A mutable iterator over the elements of a `SlabVec`. +/// +/// This `struct` is created by [`SlabVec::iter_mut()`]. See its +/// documentation for more. +pub struct IterMut<'a, T: Default + Copy + Sized, const N: usize, const M: usize> { + current: Option>>, + index: usize, + len: usize, + phantom: PhantomData<&'a mut SlabVec>, +} + +impl<'a, T: Default + Copy + Sized, const N: usize, const M: usize> Iterator + for IterMut<'a, T, N, M> +{ + type Item = &'a mut T; + + fn next(&mut self) -> Option { + let this: &mut ListPage = unsafe { &mut *(self.current?.as_ptr()) }; + + let ret = this.entry.get_mut(self.index)?; + + self.len -= 1; + self.index += 1; + + if self.index == N { + self.current = this.header.next; + self.index = 0; + } + + Some(ret) + } + + fn size_hint(&self) -> (usize, Option) { + (self.len, Some(self.len)) + } +} + +#[cfg(test)] +mod tests { + use crate::SlabVec; + const PAGE_SIZE: usize = 4096; + + #[derive(Clone, Copy, Debug, Eq, PartialEq)] + #[repr(align(16))] + struct Data { + a: i32, + b: i32, + c: u64, + } + + impl Default for Data { + fn default() -> Self { + Self { a: -1, b: -1, c: 0 } + } + } + + type DataPageList = SlabVec::NUM_ENTRIES }, PAGE_SIZE>; + + #[test] + fn len() { + static mut SYSTEM: std::alloc::System = std::alloc::System; + let pl = DataPageList::new(unsafe { &mut SYSTEM }); + assert_eq!(pl.iter().count(), 255); + } + + #[test] + fn const_len() { + assert_eq!(DataPageList::NUM_ENTRIES, 255); + } + + #[test] + fn zero_len() { + assert_eq!( + SlabVec::::NUM_ENTRIES }, 16>::NUM_ENTRIES, + 0 + ); + } + + #[test] + fn iter() { + static mut SYSTEM: std::alloc::System = std::alloc::System; + let pl = DataPageList::new(unsafe { &mut SYSTEM }); + for entry in pl.iter() { + assert_eq!(*entry, Data::default()); + } + } + + #[test] + fn iter_mut() { + static mut SYSTEM: std::alloc::System = std::alloc::System; + let mut pl = DataPageList::new(unsafe { &mut SYSTEM }); + + for (i, entry) in pl.iter_mut().enumerate() { + *entry = Data { + a: i as _, + b: i as _, + c: i as _, + }; + } + + for (i, entry) in pl.iter().enumerate() { + assert_eq!(entry.a, i as _); + assert_eq!(entry.b, i as _); + assert_eq!(entry.c, i as _); + } + } +}