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skiplist: Use `Map.size` to get number of nodes

pull/5003/head
Richard Hansen 2021-04-12 03:42:16 -04:00
parent 1cdfe9193b
commit c00031a8d8
1 changed files with 15 additions and 18 deletions
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33
src/static/js/skiplist.js
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@ -121,7 +121,7 @@ class Point {
this._skipList._end.levels++;
this._skipList._start.downPtrs[lvl] = this._skipList._end;
this._skipList._end.upPtrs[lvl] = this._skipList._start;
this._skipList._start.downSkips[lvl] = this._skipList._numNodes + 1;
this._skipList._start.downSkips[lvl] = this._skipList._keyToNodeMap.size + 1;
this._skipList._start.downSkipWidths[lvl] = this._skipList._totalWidth;
this.widthSkips[lvl] = 0;
}
@ -147,7 +147,6 @@ class Point {
up.downSkipWidths[lvl] += newWidth;
}
this._skipList._keyToNodeMap.set(newNode.key, newNode);
this._skipList._numNodes++;
this._skipList._totalWidth += newWidth;
}
@ -171,7 +170,6 @@ class Point {
}
}
this._skipList._keyToNodeMap.delete(elem.key);
this._skipList._numNodes--;
this._skipList._totalWidth -= elemWidth;
}
@ -189,7 +187,6 @@ class SkipList {
// if there are N elements in the skiplist, "start" is element -1 and "end" is element N
this._start = new Node(null, 1);
this._end = new Node(null, 1, null, null);
this._numNodes = 0;
this._totalWidth = 0;
this._keyToNodeMap = new Map();
this._start.downPtrs[0] = this._end;
@ -252,20 +249,20 @@ class SkipList {
return lowIndex + 1;
}
length() { return this._numNodes; }
length() { return this._keyToNodeMap.size; }
atIndex(i) {
if (i < 0) console.warn(`atIndex(${i})`);
if (i >= this._numNodes) console.warn(`atIndex(${i}>=${this._numNodes})`);
if (i >= this._keyToNodeMap.size) console.warn(`atIndex(${i}>=${this._keyToNodeMap.size})`);
return (new Point(this, i)).getNode().entry;
}
// differs from Array.splice() in that new elements are in an array, not varargs
splice(start, deleteCount, newEntryArray) {
if (start < 0) console.warn(`splice(${start}, ...)`);
if (start + deleteCount > this._numNodes) {
console.warn(`splice(${start}, ${deleteCount}, ...), N=${this._numNodes}`);
console.warn('%s %s %s', typeof start, typeof deleteCount, typeof this._numNodes);
if (start + deleteCount > this._keyToNodeMap.size) {
console.warn(`splice(${start}, ${deleteCount}, ...), N=${this._keyToNodeMap.size}`);
console.warn('%s %s %s', typeof start, typeof deleteCount, typeof this._keyToNodeMap.size);
console.trace();
}
@ -280,21 +277,21 @@ class SkipList {
next(entry) { return this._keyToNodeMap.get(entry.key).downPtrs[0].entry || null; }
prev(entry) { return this._keyToNodeMap.get(entry.key).upPtrs[0].entry || null; }
push(entry) { this.splice(this._numNodes, 0, [entry]); }
push(entry) { this.splice(this._keyToNodeMap.size, 0, [entry]); }
slice(start, end) {
// act like Array.slice()
if (start === undefined) start = 0;
else if (start < 0) start += this._numNodes;
if (end === undefined) end = this._numNodes;
else if (end < 0) end += this._numNodes;
else if (start < 0) start += this._keyToNodeMap.size;
if (end === undefined) end = this._keyToNodeMap.size;
else if (end < 0) end += this._keyToNodeMap.size;
if (start < 0) start = 0;
if (start > this._numNodes) start = this._numNodes;
if (start > this._keyToNodeMap.size) start = this._keyToNodeMap.size;
if (end < 0) end = 0;
if (end > this._numNodes) end = this._numNodes;
if (end > this._keyToNodeMap.size) end = this._keyToNodeMap.size;
window.dmesg(String([start, end, this._numNodes]));
window.dmesg(String([start, end, this._keyToNodeMap.size]));
if (end <= start) return [];
let n = this.atIndex(start);
const array = [n];
@ -321,12 +318,12 @@ class SkipList {
totalWidth() { return this._totalWidth; }
offsetOfIndex(i) {
if (i < 0) return 0;
if (i >= this._numNodes) return this._totalWidth;
if (i >= this._keyToNodeMap.size) return this._totalWidth;
return this.offsetOfEntry(this.atIndex(i));
}
indexOfOffset(offset) {
if (offset <= 0) return 0;
if (offset >= this._totalWidth) return this._numNodes;
if (offset >= this._totalWidth) return this._keyToNodeMap.size;
return this.indexOfEntry(this.atOffset(offset));
}
}