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//
// imag - the personal information management suite for the commandline
// Copyright (C) 2015-2020 Matthias Beyer <mail@beyermatthias.de> and contributors
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; version
// 2.1 of the License.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//
use std::iter::FromIterator;
use failure::Fallible as Result;
pub struct Tree<T: Sized> {
elements: Vec<TreeElement<T>>
}
impl<T: Sized> Tree<T> {
pub fn new() -> Self {
Tree { elements: Vec::new() }
}
pub fn with_capacity(cap: usize) -> Self {
Tree { elements: Vec::with_capacity(cap) }
}
pub fn add_node(&mut self, t: T) {
self.elements.push(TreeElement {
parent_idx: None,
childs_indexes: Vec::new(),
element: t
});
}
pub fn build_tree<ID, IG>(&mut self, ig: IG) -> TreeBuilder<T, ID, IG>
where ID: PartialEq + Sized,
IG: IdGetter<T, ID = ID>
{
TreeBuilder(self, ig)
}
}
impl<A> FromIterator<A> for Tree<A>
where A: Sized
{
fn from_iter<T>(iter: T) -> Self
where
T: IntoIterator<Item = A>
{
Tree { elements: Vec::from_iter(iter.into_iter().map(|e| TreeElement::new(e))) }
}
}
struct TreeElement<T> {
pub parent_idx: Option<usize>,
pub childs_indexes: Vec<usize>,
pub element: T
}
impl<T> PartialEq<TreeElement<T>> for TreeElement<T>
where T: PartialEq
{
fn eq(&self, other: &TreeElement<T>) -> bool {
self.element == other.element
}
}
impl<T> TreeElement<T> {
fn new(t: T) -> Self {
TreeElement {
parent_idx: None,
childs_indexes: Vec::new(),
element: t
}
}
}
pub trait IdGetter<T>
where T: Sized,
{
type ID: PartialEq + Sized;
fn get_id_for_node(&self, node: &T) -> Result<Self::ID>;
fn get_id_for_parent_of(&self, node: &T) -> Result<Option<Self::ID>>;
}
pub struct TreeBuilder<'a, T, ID, IG>(&'a mut Tree<T>, IG)
where T: Sized,
ID: PartialEq + Sized,
IG: IdGetter<T, ID = ID>;
impl<'a, T, ID, IG> TreeBuilder<'a, T, ID, IG>
where T: Sized,
ID: PartialEq + Sized,
IG: IdGetter<T, ID = ID>
{
pub fn build(&mut self) -> Result<()> {
let mut i = 0;
while let Some(node) = self.0.elements.get(i) {
if let Some(parent_id) = self.1.get_id_for_parent_of(&node.element)? {
if let Some(parent_idx) = self.find_node_idx(&parent_id)? {
if let Some(parent) = self.0.elements.get_mut(parent_idx) {
parent.childs_indexes.push(i);
}
if let Some(child) = self.0.elements.get_mut(i) {
child.parent_idx = Some(parent_idx);
}
}
}
i += 1
}
Ok(())
}
fn find_node_idx<'t>(&'t self, search_id: &IG::ID) -> Result<Option<usize>> {
let mut i = 0;
while let Some(node) = self.0.elements.get(i) {
let id = self.1.get_id_for_node(&node.element)?;
if id == *search_id {
return Ok(Some(i))
}
i += 1
}
return Ok(None)
}
}
pub struct Traverse<'a, T: Sized>(&'a Tree<T>);
#[cfg(test)]
mod tests {
use super::*;
struct IdGetterImpl;
impl IdGetter<usize> for IdGetterImpl {
type ID = usize;
fn get_id_for_node(&self, node: &usize) -> Result<Self::ID> {
Ok(*node)
}
fn get_id_for_parent_of(&self, node: &usize) -> Result<Option<Self::ID>> {
if *node > 1 {
Ok(Some(*node - 1))
} else {
Ok(None)
}
}
}
#[test]
fn test_insertion() {
let mut tree = Tree::new();
(1..100).for_each(|i| {
tree.add_node(i);
});
assert!((1..100).all(|i| tree.elements.iter().any(|e| e.element == i)));
}
#[test]
fn test_insertion_and_linking() {
let mut tree = Tree::new();
(1..100).for_each(|i| tree.add_node(i));
let r = tree.build_tree::<usize, IdGetterImpl>(IdGetterImpl).build();
assert!(r.is_ok());
}
#[test]
fn test_linking_leaves_none_unlinked() {
let mut tree = Tree::new();
(1..100).for_each(|i| tree.add_node(i));
let r = tree.build_tree::<usize, IdGetterImpl>(IdGetterImpl) .build();
assert!(r.is_ok());
let c = tree.elements.iter()
.filter(|element| element.parent_idx.is_none())
.count();
assert_eq!(c, 1);
let c = tree.elements.iter()
.filter(|element| element.childs_indexes.is_empty())
.count();
assert_eq!(c, 1);
}
}
|
