✨ Adds range tree data structure

frontend/src/uxbox/util/range_tree.js

@@ -0,0 +1,192 @@
+/* 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This Source Code Form is "Incompatible With Secondary Licenses", as
+ * defined by the Mozilla Public License, v. 2.0.
+ *
+ * Copyright (c) 2020 UXBOX Labs SL
+ */
+
+"use strict";
+
+goog.provide("uxbox.util.range_tree");
+goog.require("cljs.core")
+
+goog.scope(function() {
+    const eq = cljs.core._EQ_;
+    const vec = cljs.core.vec;
+    const nil = cljs.core.nil;
+     
+    class Node {
+        constructor(value, data) {
+            this.value = value;
+            this.data = [ data ];
+            this.left = null;
+            this.right = null;
+        }
+    }
+    
+    // Will store a map from key to list of data
+    //   value => [ data ]
+    // The values can be queried in range and the data stored will be retrived whole
+    // but can be removed/updated individually using clojurescript equality
+    class RangeTree {
+        constructor() {
+            this.root = null;
+        }
+     
+        insert(value, data) {
+            this.root = recInsert(this.root, value, data);
+            return this;
+        }
+     
+        remove(value, data) {
+            this.root = recRemove(this.root, value, data);
+            return this;
+        }
+    
+        update (value, oldData, newData) {
+            this.root = recUpdate(this.root, value, oldData, newData);
+            return this;
+        }
+    
+        get(value) {
+            return recGet(this.root, value);
+        }
+    
+        rangeQuery (fromValue, toValue) {
+            return recRangeQuery(this.root, fromValue, toValue, []);
+        }
+    }
+
+    // Tree implementation functions
+
+    // Insert recursively in the tree
+    function recInsert (branch, value, data) {
+        if (branch === null) {
+            return new Node(value, data);
+        } else if (branch.value === value) {
+            // Find node we'll add to the end of the list
+            branch.data.push(data);
+        } else if (branch.value > value) {
+            // Target value is less than the current value we go left
+            branch.left = recInsert(branch.left, value, data);
+        } else if (branch.value < value) {
+            branch.right = recInsert(branch.right, value, data);
+        }
+        return branch;
+    }
+
+    // Search for the min node
+    function searchMin(branch) {
+        if (branch.left === null) {
+            return branch;
+        } else {
+            return searchMin(branch.left);
+        }
+    }
+
+    // Remove the lefmost node of the current branch
+    function recRemoveMin(branch) {
+        if (branch.left === null) {
+            return branch.right;
+        } else {
+            branch.left = recRemoveMin(branch.left);
+            return branch;
+        }
+    }
+
+    // Remove the data element for the value given
+    function recRemove(branch, value, data) {
+        if (branch === null) {
+            // Not found
+            return branch;
+        } else if (branch.value === value) {
+            // Node found, we remove the data
+            branch.data = branch.data.filter ((it) => !eq(it, data));
+
+            if (branch.data.length > 0) {
+                return branch;
+            }
+
+            // If the data is empty we need to remove the branch
+            if (branch.right === null) {
+                return branch.left;
+            } else if (branch.left === null) {
+                return branch.right;
+            } else {
+                const oldBranch = branch;
+                const newBranch = searchMin(branch.right);
+                newBranch.right = recRemoveMin(oldBranch.right);
+                newBranch.left = oldBranch.left;
+                return newBranch;
+            }
+        } else if (branch.value > value) {
+            // Target value is less than the current value we go left
+            branch.left = recRemove (branch.left, value, data);
+            return branch;
+        } else if (branch.value < value) {
+            branch.right = recRemove (branch.right, value, data);
+            return branch;
+        }
+    }
+
+    // Retrieve all the data related to value
+    function recGet(branch, value) {
+        if (branch === null) {
+            return null;
+        } else if (branch.value === value) {
+            return branch.data;
+        } else if (branch.value > value) {
+            return recGet(branch.left, value);
+        } else if (branch.value < value) {
+            return recGet(branch.right, value);
+        }
+    }
+    
+    function recUpdate(branch, value, oldData, newData) {
+        if (branch === null) {
+            return branch;
+        } else if (branch.value === value) {
+            branch.data = branch.data.map((it) => (eq(it, oldData)) ? newData : it);
+            return branch;
+        } else if (branch.value > value) {
+            return recUpdate(branch.left, value, oldData, newData);
+        } else if (branch.value < value) {
+            return recUpdate(branch.right, value, oldData, newData);
+        }
+    }
+
+    function recRangeQuery(branch, fromValue, toValue, result) {
+        if (branch === null) {
+            return result;
+        }
+        if (fromValue < branch.value) {
+            recRangeQuery(branch.left, fromValue, toValue, result);
+        }
+        if (fromValue <= branch.value && toValue >= branch.value) {
+            Array.prototype.push.apply(result, branch.data);
+        }
+        if (toValue > branch.value) {
+            recRangeQuery(branch.right, fromValue, toValue, result);
+        }
+        return result;
+    }
+
+    // External API to CLJS
+    const self = uxbox.util.range_tree;
+    self.make_tree = () => new RangeTree();
+    self.insert = (tree, value, data) => tree.insert(value, data);
+    self.remove = (tree, value, data) => tree.remove(value, data);
+    self.update = (tree, value, oldData, newData) => tree.update(value, oldData, newData);
+    self.get = (tree, value) => {
+        const result = tree.get(value);
+        if (!result) {
+            return nil;
+        }
+        return vec(result);
+    };
+    self.range_query = (tree, from_value, to_value) => vec(tree.rangeQuery(from_value, to_value));
+});