diff options
Diffstat (limited to 'vendor/adler/src/lib.rs')
| -rw-r--r-- | vendor/adler/src/lib.rs | 287 |
1 files changed, 0 insertions, 287 deletions
diff --git a/vendor/adler/src/lib.rs b/vendor/adler/src/lib.rs deleted file mode 100644 index c7aa380..0000000 --- a/vendor/adler/src/lib.rs +++ /dev/null @@ -1,287 +0,0 @@ -//! Adler-32 checksum implementation. -//! -//! This implementation features: -//! -//! - Permissively licensed (0BSD) clean-room implementation. -//! - Zero dependencies. -//! - Zero `unsafe`. -//! - Decent performance (3-4 GB/s). -//! - `#![no_std]` support (with `default-features = false`). - -#![doc(html_root_url = "https://docs.rs/adler/1.0.2")] -// Deny a few warnings in doctests, since rustdoc `allow`s many warnings by default -#![doc(test(attr(deny(unused_imports, unused_must_use))))] -#![cfg_attr(docsrs, feature(doc_cfg))] -#![warn(missing_debug_implementations)] -#![forbid(unsafe_code)] -#![cfg_attr(not(feature = "std"), no_std)] - -#[cfg(not(feature = "std"))] -extern crate core as std; - -mod algo; - -use std::hash::Hasher; - -#[cfg(feature = "std")] -use std::io::{self, BufRead}; - -/// Adler-32 checksum calculator. -/// -/// An instance of this type is equivalent to an Adler-32 checksum: It can be created in the default -/// state via [`new`] (or the provided `Default` impl), or from a precalculated checksum via -/// [`from_checksum`], and the currently stored checksum can be fetched via [`checksum`]. -/// -/// This type also implements `Hasher`, which makes it easy to calculate Adler-32 checksums of any -/// type that implements or derives `Hash`. This also allows using Adler-32 in a `HashMap`, although -/// that is not recommended (while every checksum is a hash function, they are not necessarily a -/// good one). -/// -/// # Examples -/// -/// Basic, piecewise checksum calculation: -/// -/// ``` -/// use adler::Adler32; -/// -/// let mut adler = Adler32::new(); -/// -/// adler.write_slice(&[0, 1, 2]); -/// adler.write_slice(&[3, 4, 5]); -/// -/// assert_eq!(adler.checksum(), 0x00290010); -/// ``` -/// -/// Using `Hash` to process structures: -/// -/// ``` -/// use std::hash::Hash; -/// use adler::Adler32; -/// -/// #[derive(Hash)] -/// struct Data { -/// byte: u8, -/// word: u16, -/// big: u64, -/// } -/// -/// let mut adler = Adler32::new(); -/// -/// let data = Data { byte: 0x1F, word: 0xABCD, big: !0 }; -/// data.hash(&mut adler); -/// -/// // hash value depends on architecture endianness -/// if cfg!(target_endian = "little") { -/// assert_eq!(adler.checksum(), 0x33410990); -/// } -/// if cfg!(target_endian = "big") { -/// assert_eq!(adler.checksum(), 0x331F0990); -/// } -/// -/// ``` -/// -/// [`new`]: #method.new -/// [`from_checksum`]: #method.from_checksum -/// [`checksum`]: #method.checksum -#[derive(Debug, Copy, Clone)] -pub struct Adler32 { - a: u16, - b: u16, -} - -impl Adler32 { - /// Creates a new Adler-32 instance with default state. - #[inline] - pub fn new() -> Self { - Self::default() - } - - /// Creates an `Adler32` instance from a precomputed Adler-32 checksum. - /// - /// This allows resuming checksum calculation without having to keep the `Adler32` instance - /// around. - /// - /// # Example - /// - /// ``` - /// # use adler::Adler32; - /// let parts = [ - /// "rust", - /// "acean", - /// ]; - /// let whole = adler::adler32_slice(b"rustacean"); - /// - /// let mut sum = Adler32::new(); - /// sum.write_slice(parts[0].as_bytes()); - /// let partial = sum.checksum(); - /// - /// // ...later - /// - /// let mut sum = Adler32::from_checksum(partial); - /// sum.write_slice(parts[1].as_bytes()); - /// assert_eq!(sum.checksum(), whole); - /// ``` - #[inline] - pub fn from_checksum(sum: u32) -> Self { - Adler32 { - a: sum as u16, - b: (sum >> 16) as u16, - } - } - - /// Returns the calculated checksum at this point in time. - #[inline] - pub fn checksum(&self) -> u32 { - (u32::from(self.b) << 16) | u32::from(self.a) - } - - /// Adds `bytes` to the checksum calculation. - /// - /// If efficiency matters, this should be called with Byte slices that contain at least a few - /// thousand Bytes. - pub fn write_slice(&mut self, bytes: &[u8]) { - self.compute(bytes); - } -} - -impl Default for Adler32 { - #[inline] - fn default() -> Self { - Adler32 { a: 1, b: 0 } - } -} - -impl Hasher for Adler32 { - #[inline] - fn finish(&self) -> u64 { - u64::from(self.checksum()) - } - - fn write(&mut self, bytes: &[u8]) { - self.write_slice(bytes); - } -} - -/// Calculates the Adler-32 checksum of a byte slice. -/// -/// This is a convenience function around the [`Adler32`] type. -/// -/// [`Adler32`]: struct.Adler32.html -pub fn adler32_slice(data: &[u8]) -> u32 { - let mut h = Adler32::new(); - h.write_slice(data); - h.checksum() -} - -/// Calculates the Adler-32 checksum of a `BufRead`'s contents. -/// -/// The passed `BufRead` implementor will be read until it reaches EOF (or until it reports an -/// error). -/// -/// If you only have a `Read` implementor, you can wrap it in `std::io::BufReader` before calling -/// this function. -/// -/// # Errors -/// -/// Any error returned by the reader are bubbled up by this function. -/// -/// # Examples -/// -/// ```no_run -/// # fn run() -> Result<(), Box<dyn std::error::Error>> { -/// use adler::adler32; -/// -/// use std::fs::File; -/// use std::io::BufReader; -/// -/// let file = File::open("input.txt")?; -/// let mut file = BufReader::new(file); -/// -/// adler32(&mut file)?; -/// # Ok(()) } -/// # fn main() { run().unwrap() } -/// ``` -#[cfg(feature = "std")] -#[cfg_attr(docsrs, doc(cfg(feature = "std")))] -pub fn adler32<R: BufRead>(mut reader: R) -> io::Result<u32> { - let mut h = Adler32::new(); - loop { - let len = { - let buf = reader.fill_buf()?; - if buf.is_empty() { - return Ok(h.checksum()); - } - - h.write_slice(buf); - buf.len() - }; - reader.consume(len); - } -} - -#[cfg(test)] -mod tests { - use super::*; - - #[test] - fn zeroes() { - assert_eq!(adler32_slice(&[]), 1); - assert_eq!(adler32_slice(&[0]), 1 | 1 << 16); - assert_eq!(adler32_slice(&[0, 0]), 1 | 2 << 16); - assert_eq!(adler32_slice(&[0; 100]), 0x00640001); - assert_eq!(adler32_slice(&[0; 1024]), 0x04000001); - assert_eq!(adler32_slice(&[0; 1024 * 1024]), 0x00f00001); - } - - #[test] - fn ones() { - assert_eq!(adler32_slice(&[0xff; 1024]), 0x79a6fc2e); - assert_eq!(adler32_slice(&[0xff; 1024 * 1024]), 0x8e88ef11); - } - - #[test] - fn mixed() { - assert_eq!(adler32_slice(&[1]), 2 | 2 << 16); - assert_eq!(adler32_slice(&[40]), 41 | 41 << 16); - - assert_eq!(adler32_slice(&[0xA5; 1024 * 1024]), 0xd5009ab1); - } - - /// Example calculation from https://en.wikipedia.org/wiki/Adler-32. - #[test] - fn wiki() { - assert_eq!(adler32_slice(b"Wikipedia"), 0x11E60398); - } - - #[test] - fn resume() { - let mut adler = Adler32::new(); - adler.write_slice(&[0xff; 1024]); - let partial = adler.checksum(); - assert_eq!(partial, 0x79a6fc2e); // from above - adler.write_slice(&[0xff; 1024 * 1024 - 1024]); - assert_eq!(adler.checksum(), 0x8e88ef11); // from above - - // Make sure that we can resume computing from the partial checksum via `from_checksum`. - let mut adler = Adler32::from_checksum(partial); - adler.write_slice(&[0xff; 1024 * 1024 - 1024]); - assert_eq!(adler.checksum(), 0x8e88ef11); // from above - } - - #[cfg(feature = "std")] - #[test] - fn bufread() { - use std::io::BufReader; - fn test(data: &[u8], checksum: u32) { - // `BufReader` uses an 8 KB buffer, so this will test buffer refilling. - let mut buf = BufReader::new(data); - let real_sum = adler32(&mut buf).unwrap(); - assert_eq!(checksum, real_sum); - } - - test(&[], 1); - test(&[0; 1024], 0x04000001); - test(&[0; 1024 * 1024], 0x00f00001); - test(&[0xA5; 1024 * 1024], 0xd5009ab1); - } -} |