1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164

use crate::envelope::Envelope;
use crate::object::RTreeObject;
use crate::params::RTreeParams;

#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};

#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(
    feature = "serde",
    serde(bound(
        serialize = "T: Serialize, T::Envelope: Serialize",
        deserialize = "T: Deserialize<'de>, T::Envelope: Deserialize<'de>"
    ))
)]

/// An internal tree node.
///
/// For most applications, using this type should not be required.
pub enum RTreeNode<T>
where
    T: RTreeObject,
{
    /// A leaf node, only containing the r-tree object
    Leaf(T),
    /// A parent node containing several child nodes
    Parent(ParentNode<T>),
}

/// Represents an internal parent node.
///
/// For most applications, using this type should not be required. Allows read access to this
/// node's envelope and its children.
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct ParentNode<T>
where
    T: RTreeObject,
{
    pub(crate) children: Vec<RTreeNode<T>>,
    pub(crate) envelope: T::Envelope,
}

impl<T> RTreeObject for RTreeNode<T>
where
    T: RTreeObject,
{
    type Envelope = T::Envelope;

    fn envelope(&self) -> Self::Envelope {
        match self {
            RTreeNode::Leaf(ref t) => t.envelope(),
            RTreeNode::Parent(ref data) => data.envelope,
        }
    }
}

#[doc(hidden)]
impl<T> RTreeNode<T>
where
    T: RTreeObject,
{
    pub fn is_leaf(&self) -> bool {
        match self {
            RTreeNode::Leaf(..) => true,
            RTreeNode::Parent(..) => false,
        }
    }
}

impl<T> ParentNode<T>
where
    T: RTreeObject,
{
    /// Returns this node's children
    pub fn children(&self) -> &[RTreeNode<T>] {
        &self.children
    }

    /// Returns the smallest envelope that encompasses all children.
    pub fn envelope(&self) -> T::Envelope {
        self.envelope
    }

    pub(crate) fn new_root<Params>() -> Self
    where
        Params: RTreeParams,
    {
        ParentNode {
            envelope: Envelope::new_empty(),
            children: Vec::with_capacity(Params::MAX_SIZE + 1),
        }
    }

    pub(crate) fn new_parent(children: Vec<RTreeNode<T>>) -> Self {
        let envelope = envelope_for_children(&children);

        ParentNode { envelope, children }
    }

    #[cfg(test)]
    pub fn sanity_check<Params>(&self, check_max_size: bool) -> Option<usize>
    where
        Params: RTreeParams,
    {
        if self.children.is_empty() {
            Some(0)
        } else {
            let mut result = None;
            self.sanity_check_inner::<Params>(check_max_size, 1, &mut result);
            result
        }
    }

    #[cfg(test)]
    fn sanity_check_inner<Params>(
        &self,
        check_max_size: bool,
        height: usize,
        leaf_height: &mut Option<usize>,
    ) where
        Params: RTreeParams,
    {
        if height > 1 {
            let min_size = Params::MIN_SIZE;
            assert!(self.children.len() >= min_size);
        }
        let mut envelope = T::Envelope::new_empty();
        if check_max_size {
            let max_size = Params::MAX_SIZE;
            assert!(self.children.len() <= max_size);
        }

        for child in &self.children {
            match child {
                RTreeNode::Leaf(ref t) => {
                    envelope.merge(&t.envelope());
                    if let Some(ref leaf_height) = leaf_height {
                        assert_eq!(height, *leaf_height);
                    } else {
                        *leaf_height = Some(height);
                    }
                }
                RTreeNode::Parent(ref data) => {
                    envelope.merge(&data.envelope);
                    data.sanity_check_inner::<Params>(check_max_size, height + 1, leaf_height);
                }
            }
        }
        assert_eq!(self.envelope, envelope);
    }
}

pub fn envelope_for_children<T>(children: &[RTreeNode<T>]) -> T::Envelope
where
    T: RTreeObject,
{
    let mut result = T::Envelope::new_empty();
    for child in children {
        result.merge(&child.envelope());
    }
    result
}