https://github.com/mikolalysenko/morton-page

Morton order page index for multidimensional arrays
https://github.com/mikolalysenko/morton-page

Last synced: about 2 months ago
JSON representation

Morton order page index for multidimensional arrays

• Host: GitHub
• URL: https://github.com/mikolalysenko/morton-page
• Owner: mikolalysenko
• License: mit
• Created: 2013-07-17T16:08:10.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2013-07-18T14:21:09.000Z (over 11 years ago)
• Last Synced: 2024-10-20T14:28:18.395Z (2 months ago)
• Language: JavaScript
• Size: 54.7 KB
• Stars: 12
• Watchers: 5
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
morton-page

===========

A data structure for maintaining a list of pages keyed by [Morton order](http://en.wikipedia.org/wiki/Z-order_curve) (also known as z-order or interleaving).

## Example

```javascript

//Create a 2D page store having a capacity of (1<<4) == 16

var pageStore = require("morton-page")(2, 4)

//Add a page

pageStore.add({key: [10, 10], value: "foo"})

//Retrieve a page

var x = pageStore.get(10, 10)

console.log(x)

//Remove the page

pageStore.remove(10, 10)

//Try pulling the page out (returns null now)

console.log(pageStore.get(10, 10))

```

## Install

    npm install morton-page

## API

```javascript

var createPageStore = require("morton-page")

```

### Constructor

#### `var store = createPageStore(dimension, log_size[, shift, key])`

Creates a z-order page store.

* `dimension` is the dimension of the pages

* `log_size` is the log base 2 of the number of buckets in the store

* `shift` is the number of bits to shift each page by before indexing (default: `0`)

* `key` is the property of each page to use for the index (default: `"key"`)

**Returns** An instance of a `MortonPageStore` class specialized for the given input parameters.

### Methods

#### `store.add(page)`

Adds a page to the store

* `page` is an object with a field called `key` which is an array of coordinates representing the identifier of the page in the store.

#### `store.get(i0, i1, ...)`

Retrieves the page with the given key from the page store

* `i0, i1, ...` is the name of the page

**Returns** The page with the key `i0, i1, ...` if it is in the store, or `null` otherwise.

#### `store.remove(i0, i1, ...)`

Removes the page with the given key from the store.

* `i0, i1, ...` is the key of the page

## FAQ

### Why use this instead of an object?

Basically it is faster and does not require creating any string objects.  All of the methods in this class require 0 allocations and thus will not trigger garbage collection events.

## Credits

(c) 2013 Mikola Lysenko. MIT License