diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml new file mode 100644 index 0000000..157201d --- /dev/null +++ b/.github/workflows/test.yml @@ -0,0 +1,14 @@ +name: test + +on: [push, pull_request] + +jobs: + test: + runs-on: ubuntu-22.04 + steps: + - uses: actions/checkout@v3 + - run: rustup update 1.72 --no-self-update && rustup default 1.72 + - run: cargo build --all-targets + - run: cargo test --all-targets + - run: rustup component add rustfmt + - run: cargo fmt --check diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..96ef6c0 --- /dev/null +++ b/.gitignore @@ -0,0 +1,2 @@ +/target +Cargo.lock diff --git a/Cargo.toml b/Cargo.toml new file mode 100644 index 0000000..4ccc9ea --- /dev/null +++ b/Cargo.toml @@ -0,0 +1,11 @@ +[package] +name = "flatcontainer" +version = "0.1.0" +edition = "2021" +authors = ["Moritz Hoffmann "] +description = "A flat container representation for Rust" +license = "MIT OR Apache-2.0" +repository = "https://github.com/antiguru/flatcontainer" +rust-version = "1.70" + +[dependencies] diff --git a/LICENSE-APACHE b/LICENSE-APACHE new file mode 100644 index 0000000..1b5ec8b --- /dev/null +++ b/LICENSE-APACHE @@ -0,0 +1,176 @@ + 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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IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. diff --git a/README.md b/README.md new file mode 100644 index 0000000..4b870e8 --- /dev/null +++ b/README.md @@ -0,0 +1,40 @@ +flatcontainer +======= + +A flat container for Rust. + +```toml +[dependencies] +flatcontainer = "0.1" +``` + +## Example + +```rust +use flatcontainer::{ResultContainer, CopyOnto}; +fn main() { + let r: Result<_, u16> = Ok("abc"); + let mut c = ResultContainer::default(); + let idx = r.copy_onto(&mut c); + assert_eq!(r, c.index(idx)); +} +``` + +## Details + +TODO + +#### License + + +Licensed under either of Apache License, Version +2.0 or MIT license at your option. + + +
+ + +Unless you explicitly state otherwise, any contribution intentionally submitted +for inclusion in this crate by you, as defined in the Apache-2.0 license, shall +be dual licensed as above, without any additional terms or conditions. + diff --git a/src/lib.rs b/src/lib.rs new file mode 100644 index 0000000..9825005 --- /dev/null +++ b/src/lib.rs @@ -0,0 +1,503 @@ +use std::marker::PhantomData; + +/// A container for data. +pub trait Container: Default { + /// The type of the data that one gets out of the container. + type ReadItem<'a> + where + Self: 'a; + + /// The type to index into the container. Should be treated + /// as an opaque type, even if known. + type Index: Copy; + + /// Index into the container. The index must be obtained by + /// pushing data into the container. + fn index(&self, index: Self::Index) -> Self::ReadItem<'_>; + + /// The length of the container. 0 if unspecified. + fn len(&self) -> usize; + + /// Test whether the container is empty. True if length is not specified. + /// + /// Must return `true` if and only if [`Self::len`] returns 0. + fn is_empty(&self) -> bool; +} + +/// A trait to let types express a default container type. +pub trait Containerized { + /// The recommended container type. + type Container: Container; +} + +/// Push a type into a container. +pub trait CopyOnto { + /// Copy self into the target container, returning an index that allows to + /// look up the corresponding read item. + fn copy_onto(self, target: &mut C) -> C::Index; +} + +/// A container for [`Copy`] types. +#[derive(Debug)] +pub struct CopyContainer { + offsets: Vec, + slices: Vec, +} + +impl Container for CopyContainer { + type ReadItem<'a> = &'a [T] where Self: 'a; + type Index = usize; + + fn index(&self, index: Self::Index) -> Self::ReadItem<'_> { + &self.slices[self.offsets[index]..self.offsets[index + 1]] + } + + fn len(&self) -> usize { + self.offsets.len() + } + + fn is_empty(&self) -> bool { + self.offsets.is_empty() + } +} + +impl Default for CopyContainer { + fn default() -> Self { + Self { + offsets: vec![0], + slices: Vec::default(), + } + } +} + +impl<'a, T> CopyOnto> for &'a [T] +where + T: Copy, +{ + fn copy_onto(self, target: &mut CopyContainer) -> usize { + target.slices.extend(self); + target.offsets.push(target.slices.len()); + target.offsets.len() - 2 + } +} + +/// A container representing slices of data. +#[derive(Debug)] +pub struct SliceContainer { + offsets: Vec, + slices: Vec, + inner: C, +} + +impl Container for SliceContainer { + type ReadItem<'a> = (&'a C, &'a [C::Index]) where Self: 'a; + type Index = usize; + + fn index(&self, index: Self::Index) -> Self::ReadItem<'_> { + let slice = &self.slices[self.offsets[index]..self.offsets[index + 1]]; + (&self.inner, slice) + } + + fn len(&self) -> usize { + self.offsets.len() + } + + fn is_empty(&self) -> bool { + self.offsets.is_empty() + } +} + +impl Default for SliceContainer { + fn default() -> Self { + Self { + offsets: vec![0], + slices: Vec::default(), + inner: C::default(), + } + } +} + +impl<'a, C, T> CopyOnto> for &'a [T] +where + C: Container, + &'a T: CopyOnto, +{ + fn copy_onto(self, target: &mut SliceContainer) -> usize { + target + .slices + .extend(self.iter().map(|t| t.copy_onto(&mut target.inner))); + target.offsets.push(target.slices.len()); + target.offsets.len() - 2 + } +} + +impl<'a, C, T> CopyOnto> for &'a Vec +where + C: Container, + &'a [T]: CopyOnto>, +{ + fn copy_onto(self, target: &mut SliceContainer) -> usize { + self.as_slice().copy_onto(target) + } +} + +impl<'a, C: Container> CopyOnto> for &'a (&'a C, &'a [C::Index]) +where + C::ReadItem<'a>: CopyOnto, +{ + fn copy_onto(self, target: &mut SliceContainer) -> as Container>::Index { + let (container, indexes) = self; + target.slices.extend( + indexes + .iter() + .map(|&index| container.index(index).copy_onto(&mut target.inner)), + ); + target.offsets.push(target.slices.len()); + target.offsets.len() - 2 + } +} + +impl Containerized for Vec { + type Container = SliceContainer; +} + +impl Containerized for [T] { + type Container = SliceContainer; +} + +/// A container to store strings and read `&str`. +#[derive(Default, Debug)] +pub struct StringContainer { + inner: SliceContainer>, +} + +impl Container for StringContainer { + type ReadItem<'a>= &'a str where Self: 'a ; + type Index = usize; + + fn index(&self, index: Self::Index) -> Self::ReadItem<'_> { + unsafe { std::str::from_utf8_unchecked(self.inner.index(index).1) } + } + + fn len(&self) -> usize { + self.inner.len() + } + + fn is_empty(&self) -> bool { + self.inner.is_empty() + } +} + +impl Containerized for String { + type Container = StringContainer; +} + +impl<'a> CopyOnto for &'a String { + fn copy_onto(self, target: &mut StringContainer) -> usize { + self.as_str().copy_onto(target) + } +} + +impl<'a> CopyOnto for &'a str { + fn copy_onto(self, target: &mut StringContainer) -> usize { + self.as_bytes().copy_onto(&mut target.inner) + } +} + +/// A container for types where the read item type is equal to the index type. +#[derive(Debug)] +pub struct MirrorContainer(PhantomData<*const T>); + +impl Container for MirrorContainer { + type ReadItem<'a> = T where T: 'a; + type Index = T; + + fn index(&self, index: Self::Index) -> Self::ReadItem<'_> { + index + } + + fn len(&self) -> usize { + 0 + } + + fn is_empty(&self) -> bool { + true + } +} + +impl Default for MirrorContainer { + fn default() -> Self { + Self(PhantomData) + } +} + +mod implementations { + use super::*; + + macro_rules! implement_for { + ($index_type:ty) => { + impl Containerized for $index_type { + type Container = MirrorContainer; + } + + impl CopyOnto> for $index_type { + fn copy_onto(self, _target: &mut MirrorContainer) -> $index_type { + self + } + } + + impl<'a> CopyOnto> for &'a $index_type { + fn copy_onto(self, _target: &mut MirrorContainer<$index_type>) -> $index_type { + *self + } + } + }; + } + + implement_for!(()); + implement_for!(bool); + implement_for!(char); + + implement_for!(u8); + implement_for!(u16); + implement_for!(u32); + implement_for!(u64); + implement_for!(u128); + implement_for!(usize); + + implement_for!(i8); + implement_for!(i16); + implement_for!(i32); + implement_for!(i64); + implement_for!(i128); + implement_for!(isize); + + implement_for!(f32); + implement_for!(f64); + + implement_for!(std::num::Wrapping); + implement_for!(std::num::Wrapping); + implement_for!(std::num::Wrapping); + implement_for!(std::num::Wrapping); + implement_for!(std::num::Wrapping); + implement_for!(std::num::Wrapping); + + implement_for!(std::time::Duration); +} + +pub use result::ResultContainer; + +mod result { + use super::*; + + #[derive(Default)] + pub struct ResultContainer { + oks: T, + errs: E, + } + + impl Container for ResultContainer + where + T: Container, + E: Container, + { + type ReadItem<'a> = Result, E::ReadItem<'a>> where Self: 'a; + type Index = Result; + + fn index(&self, index: Self::Index) -> Self::ReadItem<'_> { + match index { + Ok(index) => Ok(self.oks.index(index)), + Err(index) => Err(self.errs.index(index)), + } + } + + fn len(&self) -> usize { + self.oks.len() + self.errs.len() + } + + fn is_empty(&self) -> bool { + self.oks.is_empty() && self.errs.is_empty() + } + } + + impl CopyOnto> for Result + where + TC: Container, + EC: Container, + T: CopyOnto, + E: CopyOnto, + { + fn copy_onto( + self, + target: &mut ResultContainer, + ) -> as Container>::Index { + match self { + Ok(t) => Ok(t.copy_onto(&mut target.oks)), + Err(e) => Err(e.copy_onto(&mut target.errs)), + } + } + } + + impl<'a, T, TC, E, EC> CopyOnto> for &'a Result + where + TC: Container, + EC: Container, + &'a T: CopyOnto, + &'a E: CopyOnto, + { + fn copy_onto( + self, + target: &mut ResultContainer, + ) -> as Container>::Index { + match self { + Ok(t) => Ok(t.copy_onto(&mut target.oks)), + Err(e) => Err(e.copy_onto(&mut target.errs)), + } + } + } + + impl Containerized for Result { + type Container = ResultContainer; + } +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn test_slice_string_onto() { + let mut c = StringContainer::default(); + let index = "abc".to_string().copy_onto(&mut c); + assert_eq!("abc", c.index(index)); + let index = "def".copy_onto(&mut c); + assert_eq!("def", c.index(index)); + } + + #[test] + fn test_vec() { + let mut c = SliceContainer::default(); + let slice = &[1u8, 2, 3]; + let idx = slice.copy_onto(&mut c); + assert_eq!(slice, c.index(idx).1) + } + + #[test] + fn test_vec_onto() { + let mut c: SliceContainer> = SliceContainer::default(); + let slice = &[1u8, 2, 3][..]; + let idx = slice.copy_onto(&mut c); + assert_eq!(slice, c.index(idx).1) + } + + struct Person { + name: String, + age: u16, + hobbies: Vec, + } + + impl Containerized for Person { + type Container = PersonContainer; + } + + #[derive(Default)] + struct PersonContainer { + index: Vec<( + <::Container as Container>::Index, + <::Container as Container>::Index, + < as Containerized>::Container as Container>::Index, + )>, + name_container: ::Container, + age_container: ::Container, + hobbies: as Containerized>::Container, + } + + #[derive(Debug)] + struct PersonRef<'a> { + name: <::Container as Container>::ReadItem<'a>, + age: <::Container as Container>::ReadItem<'a>, + hobbies: < as Containerized>::Container as Container>::ReadItem<'a>, + } + + impl Container for PersonContainer { + type ReadItem<'a> = PersonRef<'a> where Self: 'a; + type Index = usize; + + fn index(&self, index: Self::Index) -> Self::ReadItem<'_> { + let (name, age, hobbies) = self.index[index]; + PersonRef { + name: self.name_container.index(name), + age: self.age_container.index(age), + hobbies: self.hobbies.index(hobbies), + } + } + + fn len(&self) -> usize { + self.index.len() + } + + fn is_empty(&self) -> bool { + self.index.is_empty() + } + } + + impl CopyOnto for Person { + fn copy_onto(self, target: &mut PersonContainer) -> usize { + let name = self.name.copy_onto(&mut target.name_container); + let age = self.age.copy_onto(&mut target.age_container); + let hobbies = self.hobbies.copy_onto(&mut target.hobbies); + target.index.push((name, age, hobbies)); + target.index.len() - 1 + } + } + + impl<'a> CopyOnto for PersonRef<'a> { + fn copy_onto(self, target: &mut PersonContainer) -> usize { + let name = self.name.copy_onto(&mut target.name_container); + let age = self.age.copy_onto(&mut target.age_container); + let hobbies = self.hobbies.copy_onto(&mut target.hobbies); + target.index.push((name, age, hobbies)); + target.index.len() - 1 + } + } + + #[test] + fn test_person() { + let hobbies = ["Computers", "Guitar"]; + let p = Person { + name: "Moritz".to_string(), + age: 123, + hobbies: hobbies.iter().map(ToString::to_string).collect(), + }; + + let mut c = ::Container::default(); + let idx = p.copy_onto(&mut c); + let person_ref = c.index(idx); + assert_eq!("Moritz", person_ref.name); + assert_eq!(123, person_ref.age); + assert_eq!(2, person_ref.hobbies.1.len()); + for (idx, hobby) in person_ref.hobbies.1.iter().zip(hobbies) { + assert_eq!(hobby, person_ref.hobbies.0.index(*idx)); + } + + let mut cc = PersonContainer::default(); + + let idx = c.index(idx).copy_onto(&mut cc); + + let person_ref = cc.index(idx); + assert_eq!("Moritz", person_ref.name); + assert_eq!(123, person_ref.age); + assert_eq!(2, person_ref.hobbies.1.len()); + for (idx, hobby) in person_ref.hobbies.1.iter().zip(hobbies) { + assert_eq!(hobby, person_ref.hobbies.0.index(*idx)); + } + } + + #[test] + fn test_result() { + let r: Result<_, u16> = Ok("abc"); + let mut c = ResultContainer::default(); + let idx = r.copy_onto(&mut c); + assert_eq!(r, c.index(idx)); + } +}