https://github.com/xujif/node_mmap_mio

A cross-platform memory-mapping library for nodejs(& TypeScript)
https://github.com/xujif/node_mmap_mio

Last synced: about 1 month ago
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A cross-platform memory-mapping library for nodejs(& TypeScript)

• Host: GitHub
• URL: https://github.com/xujif/node_mmap_mio
• Owner: xujif
• License: mit
• Created: 2019-01-07T09:31:26.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2019-02-27T05:15:49.000Z (almost 6 years ago)
• Last Synced: 2024-11-28T20:50:27.210Z (about 1 month ago)
• Language: C++
• Homepage:
• Size: 33.2 KB
• Stars: 5
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • License: LICENSE

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README

        
## mmap-mio

A cross-platform memory-mapped library for nodejs(& TypeScript).  

powered by [mio (C++11 cross-platform memory mapping library)](https://github.com/mandreyel/mio)

and [node-addon-api](https://github.com/nodejs/node-addon-api)  

* TypeScript support.

* only support node 8.0+.

* gc friendly.

### Usage

```javascript

const { mmap ,mmap_ro } = require('mmap-mio') 

const m = mmap('./file.hex')

const ro = mmap_ro('./file.hex') // for read-only mode 

const buffer = m.buffer() // get file Buffer

// buffer.toString()

// buffer[0] = 65

// const byte = buffer[123]

m.sync() // force flush changes to disk.

m.unmap() // unmap the file. Note: do not access the buffer after unmapped;

```

### Api

```TypeScript

/**

 * Creates an instance of MappedFile.

 *

 * @export

 * @param {(string | number)} path_or_fd

 * @param {number} [offset]

 * @param {number} [size_to_map]

 * @returns {MappedFile}

 */

function mmap(path_or_fd: string | number, offset?: number, size_to_map ?: number): MappedFile

/**

 * Creates an instance of ReadOnlyMappedFile.

 *

 * @export

 * @param {(string | number)} path_or_fd

 * @param {number} [offset]

 * @param {number} [size_to_map]

 * @returns {ReadOnlyMappedFile}

 */

function mmap_ro(path_or_fd: string | number, offset ?: number, size_to_map ?: number): ReadOnlyMappedFile

// same as ReadOnlyMappedFile

class MappedFile {

  constructor(path_or_fd: string | number, offset ?: number, size_to_map ?: number);

  readonly writable: boolean

  readonly length: number // mapped length

  readonly offset: number

  buffer(offset?:number,length?:number): Buffer // get the buffer of mapped data

  size(): number  // mapped length same with .length

  isMapped(): boolean  

  unmap(): void  // unmap the file

  sync(): void  // flush changes to disk

}

```