node-mmap

KO | EN

gitlite — search

#javascript #python #hacktoberfest #react #ai #typescript #llm #go #golang #android #machine-learning #rust #deep-learning #linux

(★ 54)

mmap(2) bindings for node.js

node-mmap Latest Version Download

Download Latest Version (.zip)

// repository documentation

Was this content helpful?

★ 0 (0 ratings)

# node-mmap

mmap(2) bindings for node.js - stop slurping, start mapping.

** This module is no longer maintained. **

## Installing

Through [npm](http://npmjs.org/):

npm install mmap

Or compile it from source with this one-liner:

node-waf configure build install

## Usage

buffer = mmap.map(n_bytes, protection, flags, fd, offset);

<table>
 <tr>
 <td>n_bytes</td>
 <td>The number of bytes to map into memory.</td>
 </tr>
 <tr>
 <td>protection</td>
 <td>Memory protection: either PROT_NONE or a bitwise OR of PROT_READ, PROT_WRITE and PROT_EXEC.</td>
 </tr>
 <tr>
 <td>flags</td>
 <td>Flags: either MAP_SHARED or MAP_PRIVATE.</td>
 </tr>
 <tr>
 <td>fd</td>
 <td>File descriptor.</td>
 </tr>
 <tr>
 <td>offset</td>
 <td>File offset. Must be either zero or a multiple of mmap.PAGESIZE.</td>
 </tr>
</table>

See [the man page](http://www.opengroup.org/onlinepubs/000095399/functions/mmap.html) for more details.

## Examples

Map a file into memory:

fs = require('fs'), mmap = require('mmap');
 fd = fs.openSync('/path/to/file', 'r');
 size = fs.fstatSync(fd).size;
 buffer = mmap.map(size, mmap.PROT_READ, mmap.MAP_SHARED, fd, 0);
 // calculate faux checksum
 var checksum = 0;
 for (var i = 0; i < buffer.length; i++) {
 checksum ^= buffer[i];
 }

The file is automatically unmapped when the buffer object is garbage collected.

## Bugs and limitations

* Specifying the memory address is not implemented. I couldn't think of a reason
  why you would want to do that from JavaScript. Convince me otherwise. :-)

* Reading from and writing to memory-mapped files is a potentially blocking
  operation. *Do not* use this module in performance critical code. Better yet,
  don't use this module at all.

node-mmap

node-mmap Latest Version Download

Today's picks

Was this content helpful?

Recent Feedback

node-mmap

node-mmap Latest Version Download

Today's picks

Was this content helpful?

Recent Feedback

Download README