hashx/
lib.rs

1#![cfg_attr(docsrs, feature(doc_cfg))]
2#![doc = include_str!("../README.md")]
3// @@ begin lint list maintained by maint/add_warning @@
4#![allow(renamed_and_removed_lints)] // @@REMOVE_WHEN(ci_arti_stable)
5#![allow(unknown_lints)] // @@REMOVE_WHEN(ci_arti_nightly)
6#![warn(missing_docs)]
7#![warn(noop_method_call)]
8#![warn(unreachable_pub)]
9#![warn(clippy::all)]
10#![deny(clippy::await_holding_lock)]
11#![deny(clippy::cargo_common_metadata)]
12#![deny(clippy::cast_lossless)]
13#![deny(clippy::checked_conversions)]
14#![warn(clippy::cognitive_complexity)]
15#![deny(clippy::debug_assert_with_mut_call)]
16#![deny(clippy::exhaustive_enums)]
17#![deny(clippy::exhaustive_structs)]
18#![deny(clippy::expl_impl_clone_on_copy)]
19#![deny(clippy::fallible_impl_from)]
20#![deny(clippy::implicit_clone)]
21#![deny(clippy::large_stack_arrays)]
22#![warn(clippy::manual_ok_or)]
23#![deny(clippy::missing_docs_in_private_items)]
24#![warn(clippy::needless_borrow)]
25#![warn(clippy::needless_pass_by_value)]
26#![warn(clippy::option_option)]
27#![deny(clippy::print_stderr)]
28#![deny(clippy::print_stdout)]
29#![warn(clippy::rc_buffer)]
30#![deny(clippy::ref_option_ref)]
31#![warn(clippy::semicolon_if_nothing_returned)]
32#![warn(clippy::trait_duplication_in_bounds)]
33#![deny(clippy::unchecked_time_subtraction)]
34#![deny(clippy::unnecessary_wraps)]
35#![warn(clippy::unseparated_literal_suffix)]
36#![deny(clippy::unwrap_used)]
37#![deny(clippy::mod_module_files)]
38#![allow(clippy::let_unit_value)] // This can reasonably be done for explicitness
39#![allow(clippy::uninlined_format_args)]
40#![allow(clippy::significant_drop_in_scrutinee)] // arti/-/merge_requests/588/#note_2812945
41#![allow(clippy::result_large_err)] // temporary workaround for arti#587
42#![allow(clippy::needless_raw_string_hashes)] // complained-about code is fine, often best
43#![allow(clippy::needless_lifetimes)] // See arti#1765
44#![allow(mismatched_lifetime_syntaxes)] // temporary workaround for arti#2060
45#![allow(clippy::collapsible_if)] // See arti#2342
46#![deny(clippy::unused_async)]
47//! <!-- @@ end lint list maintained by maint/add_warning @@ -->
48
49mod compiler;
50mod constraints;
51mod err;
52mod generator;
53mod program;
54mod rand;
55mod register;
56mod scheduler;
57mod siphash;
58
59use crate::compiler::{Architecture, Executable};
60use crate::program::Program;
61use rand_core::RngCore;
62
63pub use crate::err::{CompilerError, Error};
64pub use crate::rand::SipRand;
65pub use crate::siphash::SipState;
66
67/// Option for selecting a HashX runtime
68#[derive(Default, Debug, Copy, Clone, Eq, PartialEq)]
69#[non_exhaustive]
70pub enum RuntimeOption {
71    /// Choose the interpreted runtime, without trying the compiler at all.
72    InterpretOnly,
73    /// Choose the compiled runtime only, and fail if it experiences any errors.
74    CompileOnly,
75    /// Always try the compiler first but fall back to the interpreter on error.
76    /// (This is the default)
77    #[default]
78    TryCompile,
79}
80
81/// Effective HashX runtime for a constructed program
82#[derive(Debug, Copy, Clone, Eq, PartialEq)]
83#[non_exhaustive]
84pub enum Runtime {
85    /// The interpreted runtime is active.
86    Interpret,
87    /// The compiled runtime is active.
88    Compiled,
89}
90
91/// Pre-built hash program that can be rapidly computed with different inputs
92///
93/// The program and initial state representation are not specified in this
94/// public interface, but [`std::fmt::Debug`] can describe program internals.
95#[derive(Debug)]
96pub struct HashX {
97    /// Keys used to generate an initial register state from the hash input
98    ///
99    /// Half of the key material generated from seed bytes go into the random
100    /// program generator, and the other half are saved here for use in each
101    /// hash invocation.
102    register_key: SipState,
103
104    /// A prepared randomly generated hash program
105    ///
106    /// In compiled runtimes this will be executable code, and in the
107    /// interpreter it's a list of instructions. There is no stable API for
108    /// program information, but the Debug trait will list programs in either
109    /// format.
110    program: RuntimeProgram,
111}
112
113/// Combination of [`Runtime`] and the actual program info used by that runtime
114///
115/// All variants of [`RuntimeProgram`] use some kind of inner heap allocation
116/// to store the program data.
117#[derive(Debug)]
118enum RuntimeProgram {
119    /// Select the interpreted runtime, and hold a Program for it to run.
120    Interpret(Program),
121    /// Select the compiled runtime, and hold an executable code page.
122    Compiled(Executable),
123}
124
125impl HashX {
126    /// The maximum available output size for [`Self::hash_to_bytes()`]
127    pub const FULL_SIZE: usize = 32;
128
129    /// Generate a new hash function with the supplied seed.
130    pub fn new(seed: &[u8]) -> Result<Self, Error> {
131        HashXBuilder::new().build(seed)
132    }
133
134    /// Check which actual program runtime is in effect.
135    ///
136    /// By default we try to generate code at runtime to accelerate the hash
137    /// function, but we fall back to an interpreter if this fails. The compiler
138    /// can be disabled entirely using [`RuntimeOption::InterpretOnly`] and
139    /// [`HashXBuilder`].
140    pub fn runtime(&self) -> Runtime {
141        match &self.program {
142            RuntimeProgram::Interpret(_) => Runtime::Interpret,
143            RuntimeProgram::Compiled(_) => Runtime::Compiled,
144        }
145    }
146
147    /// Calculate the first 64-bit word of the hash, without converting to bytes.
148    pub fn hash_to_u64(&self, input: u64) -> u64 {
149        self.hash_to_regs(input).digest(self.register_key)[0]
150    }
151
152    /// Calculate the hash function at its full output width, returning a fixed
153    /// size byte array.
154    pub fn hash_to_bytes(&self, input: u64) -> [u8; Self::FULL_SIZE] {
155        let words = self.hash_to_regs(input).digest(self.register_key);
156        let mut bytes = [0_u8; Self::FULL_SIZE];
157        for word in 0..words.len() {
158            bytes[word * 8..(word + 1) * 8].copy_from_slice(&words[word].to_le_bytes());
159        }
160        bytes
161    }
162
163    /// Common setup for hashes with any output format
164    #[inline(always)]
165    fn hash_to_regs(&self, input: u64) -> register::RegisterFile {
166        let mut regs = register::RegisterFile::new(self.register_key, input);
167        match &self.program {
168            RuntimeProgram::Interpret(program) => program.interpret(&mut regs),
169            RuntimeProgram::Compiled(executable) => executable.invoke(&mut regs),
170        }
171        regs
172    }
173}
174
175/// Builder for creating [`HashX`] instances with custom settings
176#[derive(Default, Debug, Clone, Eq, PartialEq)]
177pub struct HashXBuilder {
178    /// Current runtime() setting for this builder
179    runtime: RuntimeOption,
180}
181
182impl HashXBuilder {
183    /// Create a new [`HashXBuilder`] with default settings.
184    ///
185    /// Immediately calling [`Self::build()`] would be equivalent to using
186    /// [`HashX::new()`].
187    pub fn new() -> Self {
188        Default::default()
189    }
190
191    /// Select a new [`RuntimeOption`].
192    pub fn runtime(&mut self, runtime: RuntimeOption) -> &mut Self {
193        self.runtime = runtime;
194        self
195    }
196
197    /// Build a [`HashX`] instance with a seed and the selected options.
198    pub fn build(&self, seed: &[u8]) -> Result<HashX, Error> {
199        let (key0, key1) = SipState::pair_from_seed(seed);
200        let mut rng = SipRand::new(key0);
201        self.build_from_rng(&mut rng, key1)
202    }
203
204    /// Build a [`HashX`] instance from an arbitrary [`RngCore`] and
205    /// a [`SipState`] key used for initializing the register file.
206    pub fn build_from_rng<R: RngCore>(
207        &self,
208        rng: &mut R,
209        register_key: SipState,
210    ) -> Result<HashX, Error> {
211        let program = Program::generate(rng)?;
212        self.build_from_program(program, register_key)
213    }
214
215    /// Build a [`HashX`] instance from an already-generated [`Program`] and
216    /// [`SipState`] key.
217    ///
218    /// The program is either stored as-is or compiled, depending on the current
219    /// [`RuntimeOption`]. Requires a program as well as a [`SipState`] to be
220    /// used for initializing the register file.
221    fn build_from_program(&self, program: Program, register_key: SipState) -> Result<HashX, Error> {
222        Ok(HashX {
223            register_key,
224            program: match self.runtime {
225                RuntimeOption::InterpretOnly => RuntimeProgram::Interpret(program),
226                RuntimeOption::CompileOnly => {
227                    RuntimeProgram::Compiled(Architecture::compile((&program).into())?)
228                }
229                RuntimeOption::TryCompile => match Architecture::compile((&program).into()) {
230                    Ok(exec) => RuntimeProgram::Compiled(exec),
231                    Err(_) => RuntimeProgram::Interpret(program),
232                },
233            },
234        })
235    }
236}
hashx/lib.rs

hashx/
lib.rs
