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#![cfg_attr(docsrs, feature(doc_auto_cfg, doc_cfg))]
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#![doc = include_str!("../README.md")]
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// @@ begin lint list maintained by maint/add_warning @@
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#![allow(renamed_and_removed_lints)] // @@REMOVE_WHEN(ci_arti_stable)
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#![allow(unknown_lints)] // @@REMOVE_WHEN(ci_arti_nightly)
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#![warn(missing_docs)]
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#![warn(noop_method_call)]
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#![warn(unreachable_pub)]
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#![warn(clippy::all)]
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#![deny(clippy::await_holding_lock)]
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#![deny(clippy::cargo_common_metadata)]
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#![deny(clippy::cast_lossless)]
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#![deny(clippy::checked_conversions)]
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#![warn(clippy::cognitive_complexity)]
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#![deny(clippy::debug_assert_with_mut_call)]
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#![deny(clippy::exhaustive_enums)]
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#![deny(clippy::exhaustive_structs)]
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#![deny(clippy::expl_impl_clone_on_copy)]
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#![deny(clippy::fallible_impl_from)]
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#![deny(clippy::implicit_clone)]
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#![deny(clippy::large_stack_arrays)]
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#![warn(clippy::manual_ok_or)]
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#![deny(clippy::missing_docs_in_private_items)]
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#![warn(clippy::needless_borrow)]
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#![warn(clippy::needless_pass_by_value)]
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#![warn(clippy::option_option)]
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#![deny(clippy::print_stderr)]
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#![deny(clippy::print_stdout)]
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#![warn(clippy::rc_buffer)]
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#![deny(clippy::ref_option_ref)]
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#![warn(clippy::semicolon_if_nothing_returned)]
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#![warn(clippy::trait_duplication_in_bounds)]
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#![deny(clippy::unchecked_duration_subtraction)]
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#![deny(clippy::unnecessary_wraps)]
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#![warn(clippy::unseparated_literal_suffix)]
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#![deny(clippy::unwrap_used)]
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#![deny(clippy::mod_module_files)]
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#![allow(clippy::let_unit_value)] // This can reasonably be done for explicitness
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#![allow(clippy::uninlined_format_args)]
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#![allow(clippy::significant_drop_in_scrutinee)] // arti/-/merge_requests/588/#note_2812945
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#![allow(clippy::result_large_err)] // temporary workaround for arti#587
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#![allow(clippy::needless_raw_string_hashes)] // complained-about code is fine, often best
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#![allow(clippy::needless_lifetimes)] // See arti#1765
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//! <!-- @@ end lint list maintained by maint/add_warning @@ -->
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mod bucket_array;
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mod collision;
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mod err;
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mod solution;
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mod solver;
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// Export bucket_array::mem API only to the fuzzer.
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// (This is not stable; you should not use it except for testing.)
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#[cfg(feature = "bucket-array")]
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pub use bucket_array::mem::{BucketArray, BucketArrayMemory, BucketArrayPair, Count, Uninit};
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use hashx::{HashX, HashXBuilder};
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pub use hashx::{Runtime, RuntimeOption};
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pub use err::{Error, HashError};
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pub use solution::{Solution, SolutionArray, SolutionByteArray, SolutionItem, SolutionItemArray};
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pub use solver::SolverMemory;
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/// One Equi-X instance, customized for a challenge string
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///
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/// This includes pre-computed state that depends on the
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/// puzzle's challenge as well as any options set via [`EquiXBuilder`].
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#[derive(Debug)]
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pub struct EquiX {
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    /// HashX instance generated for this puzzle's challenge string
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    hash: HashX,
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}
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impl EquiX {
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    /// Make a new [`EquiX`] instance with a challenge string and
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    /// default options.
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    ///
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    /// It's normal for this to fail with a [`HashError::ProgramConstraints`]
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    /// for a small fraction of challenge values. Those challenges must be
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    /// skipped by solvers and rejected by verifiers.
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    pub fn new(challenge: &[u8]) -> Result<Self, Error> {
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        EquiXBuilder::new().build(challenge)
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    }
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    /// Check which actual program runtime is in effect.
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    ///
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    /// By default we try to generate machine code at runtime to accelerate the
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    /// hash function, but we fall back to an interpreter if this fails. The
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    /// compiler can be disabled entirely using [`RuntimeOption::InterpretOnly`]
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    /// and [`EquiXBuilder`].
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    pub fn runtime(&self) -> Runtime {
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        self.hash.runtime()
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    }
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    /// Check a [`Solution`] against this particular challenge.
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    ///
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    /// Having a [`Solution`] instance guarantees that the order of items
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    /// has already been checked. This only needs to check hash tree sums.
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    /// Returns either `Ok` or [`Error::HashSum`].
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    pub fn verify(&self, solution: &Solution) -> Result<(), Error> {
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        solution::check_all_tree_sums(&self.hash, solution)
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    }
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    /// Search for solutions using this particular challenge.
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    ///
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    /// Returns a buffer with a variable number of solutions.
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    /// Memory for the solver is allocated dynamically and not reused.
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    pub fn solve(&self) -> SolutionArray {
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        let mut mem = SolverMemory::new();
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        self.solve_with_memory(&mut mem)
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    }
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    /// Search for solutions, using the provided [`SolverMemory`].
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    ///
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    /// Returns a buffer with a variable number of solutions.
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    ///
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    /// Allows reuse of solver memory. Preferred for callers which may perform
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    /// several solve operations in rapid succession, such as in the common case
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    /// of layering an effort adjustment protocol above Equi-X.
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    pub fn solve_with_memory(&self, mem: &mut SolverMemory) -> SolutionArray {
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        let mut result = Default::default();
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        solver::find_solutions(&self.hash, mem, &mut result);
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        result
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    }
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}
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/// Builder for creating [`EquiX`] instances with custom settings
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#[derive(Debug, Clone, Eq, PartialEq)]
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pub struct EquiXBuilder {
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    /// Inner [`HashXBuilder`] for options related to our hash function
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    hash: HashXBuilder,
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}
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impl EquiXBuilder {
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    /// Create a new [`EquiXBuilder`] with default settings.
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    ///
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    /// Immediately calling [`Self::build()`] would be equivalent to using
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    /// [`EquiX::new()`].
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    pub fn new() -> Self {
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        Self {
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            hash: HashXBuilder::new(),
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        }
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    }
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    /// Select a new [`RuntimeOption`].
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    pub fn runtime(&mut self, runtime: RuntimeOption) -> &mut Self {
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        self.hash.runtime(runtime);
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        self
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    }
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    /// Build an [`EquiX`] instance with a challenge string and the
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    /// selected options.
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    ///
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    /// It's normal for this to fail with a [`HashError::ProgramConstraints`]
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    /// for a small fraction of challenge values. Those challenges must be
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    /// skipped by solvers and rejected by verifiers.
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    pub fn build(&self, challenge: &[u8]) -> Result<EquiX, Error> {
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        match self.hash.build(challenge) {
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            Err(e) => Err(Error::Hash(e)),
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            Ok(hash) => Ok(EquiX { hash }),
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        }
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    }
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    /// Search for solutions to a particular challenge.
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    ///
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    /// Each solve invocation returns zero or more solutions.
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    /// Memory for the solver is allocated dynamically and not reused.
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    ///
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    /// It's normal for this to fail with a [`HashError::ProgramConstraints`]
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    /// for a small fraction of challenge values. Those challenges must be
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    /// skipped by solvers and rejected by verifiers.
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    pub fn solve(&self, challenge: &[u8]) -> Result<SolutionArray, Error> {
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        Ok(self.build(challenge)?.solve())
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    }
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    /// Check a [`Solution`] against a particular challenge string.
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    ///
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    /// Having a [`Solution`] instance guarantees that the order of items
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    /// has already been checked. This only needs to check hash tree sums.
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    /// Returns either `Ok` or [`Error::HashSum`].
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    pub fn verify(&self, challenge: &[u8], solution: &Solution) -> Result<(), Error> {
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        self.build(challenge)?.verify(solution)
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    }
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    /// Check a [`SolutionItemArray`].
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    ///
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    /// Returns an error if the array is not a well formed [`Solution`] or it's
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    /// not suitable for the given challenge.
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    pub fn verify_array(&self, challenge: &[u8], array: &SolutionItemArray) -> Result<(), Error> {
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        // Check Solution validity before we even construct the instance
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        self.verify(challenge, &Solution::try_from_array(array)?)
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    }
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    /// Check a [`SolutionByteArray`].
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    ///
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    /// Returns an error if the array is not a well formed [`Solution`] or it's
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    /// not suitable for the given challenge.
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    pub fn verify_bytes(&self, challenge: &[u8], array: &SolutionByteArray) -> Result<(), Error> {
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        self.verify(challenge, &Solution::try_from_bytes(array)?)
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    }
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}
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impl Default for EquiXBuilder {
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    fn default() -> Self {
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        Self::new()
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    }
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}
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/// Search for solutions, using default [`EquiXBuilder`] options.
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///
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/// Each solve invocation returns zero or more solutions.
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/// Memory for the solver is allocated dynamically and not reused.
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///
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/// It's normal for this to fail with a [`HashError::ProgramConstraints`] for
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/// a small fraction of challenge values. Those challenges must be skipped
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/// by solvers and rejected by verifiers.
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pub fn solve(challenge: &[u8]) -> Result<SolutionArray, Error> {
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    Ok(EquiX::new(challenge)?.solve())
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}
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/// Check a [`Solution`] against a particular challenge.
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///
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/// Having a [`Solution`] instance guarantees that the order of items
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/// has already been checked. This only needs to check hash tree sums.
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/// Returns either `Ok` or [`Error::HashSum`].
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///
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/// Uses default [`EquiXBuilder`] options.
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pub fn verify(challenge: &[u8], solution: &Solution) -> Result<(), Error> {
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    EquiX::new(challenge)?.verify(solution)
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}
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/// Check a [`SolutionItemArray`].
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///
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/// Returns an error if the array is not a well formed [`Solution`] or it's
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/// not suitable for the given challenge.
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///
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/// Uses default [`EquiXBuilder`] options.
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pub fn verify_array(challenge: &[u8], array: &SolutionItemArray) -> Result<(), Error> {
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    // Check Solution validity before we even construct the instance
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    verify(challenge, &Solution::try_from_array(array)?)
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}
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/// Check a [`SolutionByteArray`].
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///
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/// Returns an error if the array is not a well formed [`Solution`] or it's
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/// not suitable for the given challenge.
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///
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/// Uses default [`EquiXBuilder`] options.
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pub fn verify_bytes(challenge: &[u8], array: &SolutionByteArray) -> Result<(), Error> {
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    // Check Solution validity before we even construct the instance
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    verify(challenge, &Solution::try_from_bytes(array)?)
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}