102 lines
2.2 KiB
Rust
102 lines
2.2 KiB
Rust
#[allow(unused_imports)]
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use alloc::prelude::*;
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use core::fmt;
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#[cfg(feature = "std")]
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use std::error;
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#[derive(Debug)]
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pub struct Error(String);
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impl fmt::Display for Error {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "{}", self.0)
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}
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}
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#[cfg(feature = "std")]
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impl error::Error for Error {
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fn description(&self) -> &str {
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&self.0
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}
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}
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/// Stack with limit.
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#[derive(Debug)]
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pub struct StackWithLimit<T>
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where
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T: Clone,
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{
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/// Stack values.
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values: Vec<T>,
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/// Stack limit (maximal stack len).
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limit: usize,
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}
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impl<T> StackWithLimit<T>
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where
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T: Clone,
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{
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pub fn with_limit(limit: usize) -> Self {
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StackWithLimit {
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values: Vec::new(),
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limit: limit,
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}
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}
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pub fn is_empty(&self) -> bool {
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self.values.is_empty()
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}
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pub fn len(&self) -> usize {
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self.values.len()
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}
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pub fn top(&self) -> Result<&T, Error> {
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self.values
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.last()
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.ok_or_else(|| Error("non-empty stack expected".into()))
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}
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pub fn top_mut(&mut self) -> Result<&mut T, Error> {
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self.values
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.last_mut()
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.ok_or_else(|| Error("non-empty stack expected".into()))
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}
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pub fn get(&self, index: usize) -> Result<&T, Error> {
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if index >= self.values.len() {
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return Err(Error(format!(
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"trying to get value at position {} on stack of size {}",
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index,
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self.values.len()
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)));
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}
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Ok(self
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.values
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.get(self.values.len() - 1 - index)
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.expect("checked couple of lines above"))
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}
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pub fn push(&mut self, value: T) -> Result<(), Error> {
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if self.values.len() >= self.limit {
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return Err(Error(format!("exceeded stack limit {}", self.limit)));
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}
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self.values.push(value);
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Ok(())
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}
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pub fn pop(&mut self) -> Result<T, Error> {
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self.values
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.pop()
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.ok_or_else(|| Error("non-empty stack expected".into()))
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}
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pub fn resize(&mut self, new_size: usize, dummy: T) {
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debug_assert!(new_size <= self.values.len());
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self.values.resize(new_size, dummy);
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}
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}
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