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Diffstat (limited to 'vendor/simd-adler32/src/lib.rs')
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diff --git a/vendor/simd-adler32/src/lib.rs b/vendor/simd-adler32/src/lib.rs new file mode 100644 index 0000000..e61dddd --- /dev/null +++ b/vendor/simd-adler32/src/lib.rs @@ -0,0 +1,310 @@ +//! # simd-adler32 +//! +//! A SIMD-accelerated Adler-32 hash algorithm implementation. +//! +//! ## Features +//! +//! - No dependencies +//! - Support `no_std` (with `default-features = false`) +//! - Runtime CPU feature detection (when `std` enabled) +//! - Blazing fast performance on as many targets as possible (currently only x86 and x86_64) +//! - Default to scalar implementation when simd not available +//! +//! ## Quick start +//! +//! > Cargo.toml +//! +//! ```toml +//! [dependencies] +//! simd-adler32 = "*" +//! ``` +//! +//! > example.rs +//! +//! ```rust +//! use simd_adler32::Adler32; +//! +//! let mut adler = Adler32::new(); +//! adler.write(b"rust is pretty cool, man"); +//! let hash = adler.finish(); +//! +//! println!("{}", hash); +//! // 1921255656 +//! ``` +//! +//! ## Feature flags +//! +//! * `std` - Enabled by default +//! +//! Enables std support, see [CPU Feature Detection](#cpu-feature-detection) for runtime +//! detection support. +//! * `nightly` +//! +//! Enables nightly features required for avx512 support. +//! +//! * `const-generics` - Enabled by default +//! +//! Enables const-generics support allowing for user-defined array hashing by value. See +//! [`Adler32Hash`] for details. +//! +//! ## Support +//! +//! **CPU Features** +//! +//! | impl | arch | feature | +//! | ---- | ---------------- | ------- | +//! | ✅ | `x86`, `x86_64` | avx512 | +//! | ✅ | `x86`, `x86_64` | avx2 | +//! | ✅ | `x86`, `x86_64` | ssse3 | +//! | ✅ | `x86`, `x86_64` | sse2 | +//! | 🚧 | `arm`, `aarch64` | neon | +//! | | `wasm32` | simd128 | +//! +//! **MSRV** `1.36.0`\*\* +//! +//! Minimum supported rust version is tested before a new version is published. [**] Feature +//! `const-generics` needs to disabled to build on rustc versions `<1.51` which can be done +//! by updating your dependency definition to the following. +//! +//! ## CPU Feature Detection +//! simd-adler32 supports both runtime and compile time CPU feature detection using the +//! `std::is_x86_feature_detected` macro when the `Adler32` struct is instantiated with +//! the `new` fn. +//! +//! Without `std` feature enabled simd-adler32 falls back to compile time feature detection +//! using `target-feature` or `target-cpu` flags supplied to rustc. See [https://rust-lang.github.io/packed_simd/perf-guide/target-feature/rustflags.html](https://rust-lang.github.io/packed_simd/perf-guide/target-feature/rustflags.html) +//! for more information. +//! +//! Feature detection tries to use the fastest supported feature first. +#![cfg_attr(not(feature = "std"), no_std)] +#![cfg_attr(feature = "nightly", feature(stdsimd, avx512_target_feature))] + +#[doc(hidden)] +pub mod hash; +#[doc(hidden)] +pub mod imp; + +pub use hash::*; +use imp::{get_imp, Adler32Imp}; + +/// An adler32 hash generator type. +#[derive(Clone)] +pub struct Adler32 { + a: u16, + b: u16, + update: Adler32Imp, +} + +impl Adler32 { + /// Constructs a new `Adler32`. + /// + /// Potential overhead here due to runtime feature detection although in testing on 100k + /// and 10k random byte arrays it was not really noticeable. + /// + /// # Examples + /// ```rust + /// use simd_adler32::Adler32; + /// + /// let mut adler = Adler32::new(); + /// ``` + pub fn new() -> Self { + Default::default() + } + + /// Constructs a new `Adler32` using existing checksum. + /// + /// Potential overhead here due to runtime feature detection although in testing on 100k + /// and 10k random byte arrays it was not really noticeable. + /// + /// # Examples + /// ```rust + /// use simd_adler32::Adler32; + /// + /// let mut adler = Adler32::from_checksum(0xdeadbeaf); + /// ``` + pub fn from_checksum(checksum: u32) -> Self { + Self { + a: checksum as u16, + b: (checksum >> 16) as u16, + update: get_imp(), + } + } + + /// Computes hash for supplied data and stores results in internal state. + pub fn write(&mut self, data: &[u8]) { + let (a, b) = (self.update)(self.a, self.b, data); + + self.a = a; + self.b = b; + } + + /// Returns the hash value for the values written so far. + /// + /// Despite its name, the method does not reset the hasher’s internal state. Additional + /// writes will continue from the current value. If you need to start a fresh hash + /// value, you will have to use `reset`. + pub fn finish(&self) -> u32 { + (u32::from(self.b) << 16) | u32::from(self.a) + } + + /// Resets the internal state. + pub fn reset(&mut self) { + self.a = 1; + self.b = 0; + } +} + +/// Compute Adler-32 hash on `Adler32Hash` type. +/// +/// # Arguments +/// * `hash` - A Adler-32 hash-able type. +/// +/// # Examples +/// ```rust +/// use simd_adler32::adler32; +/// +/// let hash = adler32(b"Adler-32"); +/// println!("{}", hash); // 800813569 +/// ``` +pub fn adler32<H: Adler32Hash>(hash: &H) -> u32 { + hash.hash() +} + +/// A Adler-32 hash-able type. +pub trait Adler32Hash { + /// Feeds this value into `Adler32`. + fn hash(&self) -> u32; +} + +impl Default for Adler32 { + fn default() -> Self { + Self { + a: 1, + b: 0, + update: get_imp(), + } + } +} + +#[cfg(feature = "std")] +pub mod read { + //! Reader-based hashing. + //! + //! # Example + //! ```rust + //! use std::io::Cursor; + //! use simd_adler32::read::adler32; + //! + //! let mut reader = Cursor::new(b"Hello there"); + //! let hash = adler32(&mut reader).unwrap(); + //! + //! println!("{}", hash) // 800813569 + //! ``` + use crate::Adler32; + use std::io::{Read, Result}; + + /// Compute Adler-32 hash on reader until EOF. + /// + /// # Example + /// ```rust + /// use std::io::Cursor; + /// use simd_adler32::read::adler32; + /// + /// let mut reader = Cursor::new(b"Hello there"); + /// let hash = adler32(&mut reader).unwrap(); + /// + /// println!("{}", hash) // 800813569 + /// ``` + pub fn adler32<R: Read>(reader: &mut R) -> Result<u32> { + let mut hash = Adler32::new(); + let mut buf = [0; 4096]; + + loop { + match reader.read(&mut buf) { + Ok(0) => return Ok(hash.finish()), + Ok(n) => { + hash.write(&buf[..n]); + } + Err(err) => return Err(err), + } + } + } +} + +#[cfg(feature = "std")] +pub mod bufread { + //! BufRead-based hashing. + //! + //! Separate `BufRead` trait implemented to allow for custom buffer size optimization. + //! + //! # Example + //! ```rust + //! use std::io::{Cursor, BufReader}; + //! use simd_adler32::bufread::adler32; + //! + //! let mut reader = Cursor::new(b"Hello there"); + //! let mut reader = BufReader::new(reader); + //! let hash = adler32(&mut reader).unwrap(); + //! + //! println!("{}", hash) // 800813569 + //! ``` + use crate::Adler32; + use std::io::{BufRead, ErrorKind, Result}; + + /// Compute Adler-32 hash on buf reader until EOF. + /// + /// # Example + /// ```rust + /// use std::io::{Cursor, BufReader}; + /// use simd_adler32::bufread::adler32; + /// + /// let mut reader = Cursor::new(b"Hello there"); + /// let mut reader = BufReader::new(reader); + /// let hash = adler32(&mut reader).unwrap(); + /// + /// println!("{}", hash) // 800813569 + /// ``` + pub fn adler32<R: BufRead>(reader: &mut R) -> Result<u32> { + let mut hash = Adler32::new(); + + loop { + let consumed = match reader.fill_buf() { + Ok(buf) => { + if buf.is_empty() { + return Ok(hash.finish()); + } + + hash.write(buf); + buf.len() + } + Err(err) => match err.kind() { + ErrorKind::Interrupted => continue, + ErrorKind::UnexpectedEof => return Ok(hash.finish()), + _ => return Err(err), + }, + }; + + reader.consume(consumed); + } + } +} + +#[cfg(test)] +mod tests { + #[test] + fn test_from_checksum() { + let buf = b"rust is pretty cool man"; + let sum = 0xdeadbeaf; + + let mut simd = super::Adler32::from_checksum(sum); + let mut adler = adler::Adler32::from_checksum(sum); + + simd.write(buf); + adler.write_slice(buf); + + let simd = simd.finish(); + let scalar = adler.checksum(); + + assert_eq!(simd, scalar); + } +} |