Struct WorkBudget 

pub struct WorkBudget { /* private fields */ }

A local work counter for one bounded search or iteration.

Exhaustion is sticky: once a charge is refused, every later charge is refused. A caller that runs out skips the step it bounds and reports the skip; exhaustion never refuses the decode session.

Implementations

impl WorkBudget

pub const RECURSION_DEPTH: usize = 256

The recursion ceiling of WorkBudget::recursion_guard.

pub fn new(limit: usize) -> Self

Creates a work counter with limit units.

pub fn charge(&self) -> bool

Charges one work unit, returning false after exhaustion.

pub fn charge_by(&self, work: usize) -> bool

Charges several work units, with sticky exhaustion on refusal.

A charging slice also charges every counter it was drawn from. A charge that one of them cannot pay exhausts this counter only.

pub fn exhausted(&self) -> bool

Returns whether this counter has refused a charge.

pub fn exhaust(&self)

Marks this counter exhausted. The counters it was drawn from are not.

pub fn remaining(&self) -> usize

Returns the work units a charge can still use: the smallest remainder of this counter and every counter it was drawn from.

pub fn consumed(&self) -> usize

Returns work charged to this counter and the remainder forfeited by exhaustion.

pub fn recursion_guard( &self, ) -> Result<WorkBudgetRecursionGuard<'_>, BudgetExhausted>

Enters one recursive frame, refusing past WorkBudget::RECURSION_DEPTH. The refusal exhausts the counter; it does not touch a decode session.

pub fn child_slice(&self, limit: usize) -> WorkBudget

Creates a child counter capped by this counter’s remainder.

The child’s charges do not reach this counter until WorkBudget::consume_child transfers them.

pub fn charging_slice(&self, limit: usize) -> WorkBudget

Creates a child counter of at most limit units whose every charge is also charged to this counter, so the work below a counter never exceeds its limit.

Exhausting the child, by its own limit or by an ancestor that cannot pay, leaves this counter usable.

pub fn consume_child(&self, child: &WorkBudget) -> Result<(), BudgetExhausted>

Charges this counter for work consumed by a child counter.

Errors

BudgetExhausted when the child’s work is above this counter’s remainder. The counter marks itself exhausted in that case.

Trait Implementations

impl Debug for WorkBudget

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.