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//! This module implements a growable array in stable memory.
use crate::base_vec::BaseVec;
pub use crate::base_vec::InitError;
use crate::storable::BoundedStorable;
use crate::{GrowFailed, Memory};
use std::fmt;
#[cfg(test)]
mod tests;
const MAGIC: [u8; 3] = *b"SVC"; // Short for "stable vector".
/// An implementation of growable arrays in stable memory.
pub struct Vec<T: BoundedStorable, M: Memory>(BaseVec<T, M>);
impl<T: BoundedStorable, M: Memory> Vec<T, M> {
/// Creates a new empty vector in the specified memory,
/// overwriting any data structures the memory might have
/// contained previously.
///
/// Complexity: O(1)
pub fn new(memory: M) -> Result<Self, GrowFailed> {
BaseVec::<T, M>::new(memory, MAGIC).map(Self)
}
/// Initializes a vector in the specified memory.
///
/// Complexity: O(1)
///
/// PRECONDITION: the memory is either empty or contains a valid
/// stable vector.
pub fn init(memory: M) -> Result<Self, InitError> {
BaseVec::<T, M>::init(memory, MAGIC).map(Self)
}
/// Returns the underlying memory instance.
pub fn into_memory(self) -> M {
self.0.into_memory()
}
/// Returns true if the vector is empty.
///
/// Complexity: O(1)
pub fn is_empty(&self) -> bool {
self.0.is_empty()
}
/// Returns the number of items in the vector.
///
/// Complexity: O(1)
pub fn len(&self) -> u64 {
self.0.len()
}
/// Sets the item at the specified index to the specified value.
///
/// Complexity: O(T::MAX_SIZE)
///
/// PRECONDITION: index < self.len()
pub fn set(&self, index: u64, item: &T) {
self.0.set(index, item)
}
/// Returns the item at the specified index.
///
/// Complexity: O(T::MAX_SIZE)
pub fn get(&self, index: u64) -> Option<T> {
self.0.get(index)
}
/// Adds a new item at the end of the vector.
///
/// Complexity: O(T::MAX_SIZE)
pub fn push(&self, item: &T) -> Result<(), GrowFailed> {
self.0.push(item)
}
/// Removes the item at the end of the vector.
///
/// Complexity: O(T::MAX_SIZE)
pub fn pop(&self) -> Option<T> {
self.0.pop()
}
pub fn iter(&self) -> impl Iterator<Item = T> + '_ {
self.0.iter()
}
#[cfg(test)]
fn to_vec(&self) -> std::vec::Vec<T> {
self.0.to_vec()
}
}
impl<T: BoundedStorable + fmt::Debug, M: Memory> fmt::Debug for Vec<T, M> {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
self.0.fmt(fmt)
}
}