https://github.com/mafintosh/multi-random-access

An abstract-random-access compliant instance that combines multiple other abstract-random-access instances into a single one.
https://github.com/mafintosh/multi-random-access

Last synced: about 1 month ago
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An abstract-random-access compliant instance that combines multiple other abstract-random-access instances into a single one.

• Host: GitHub
• URL: https://github.com/mafintosh/multi-random-access
• Owner: mafintosh
• License: mit
• Created: 2016-08-01T16:44:25.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2020-01-25T01:10:14.000Z (about 5 years ago)
• Last Synced: 2024-12-17T15:47:24.492Z (about 1 month ago)
• Language: JavaScript
• Size: 16.6 KB
• Stars: 15
• Watchers: 3
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-dat - multi-random-access - combine multiple `abstract-random-access` stores into a single one (Dat Core Modules / Storage)

README

        
# multi-random-access

An [abstract-random-access](https://github.com/juliangruber/abstract-random-access) compliant instance (API similar to [random-access-file](https://github.com/mafintosh/random-access-file)) that combines multiple other abstract-random-access instances into a single one.

```

npm install multi-random-access

```

[![build status](http://img.shields.io/travis/mafintosh/multi-random-access.svg?style=flat)](http://travis-ci.org/mafintosh/multi-random-access)

## Usage

In the below example we'll create a multi-random-access instance that writes to different instances of [random-access-memory](https://github.com/mafintosh/random-access-memory), each containing 10 bytes of data.

``` js

var multi = require('multi-random-access')

var ram = require('random-access-memory')

var storage = multi(function (offset, cb) {

  var index = Math.floor(offset / 10)

  console.log('Creating new underlying storage')

  cb(null, {

    start: index * 10,

    end: index * 10 + 10,

    storage: ram()

  })

})

storage.write(0, Buffer('hello world'), function (err) {

  if (err) throw err

  storage.read(0, 11, function (err, buf) {

    if (err) throw err

    console.log(buf.toString())

  })

})

```

## API

#### `var storage = multi([options], open)`

Create a new instance. `open` is a function that is called when a new storage instance is needed. A new instance is needed when a read or write happens in a byte range that has not been opened yet.

The signature for open is `(offset, cb)`. You should call the callback with an object containing the following properties:

``` js

function open (offset, cb) {

  cb(null, {

    start: startByteOffset,

    end: endByteOffset,

    storage: abstractRandomAccessInstance

  })

}

```

Options include:

``` js

{

  limit: 16 // start closes old stores after this many was opened

}

```

## License

MIT