binary
|
======
|
|
Unpack multibyte binary values from buffers and streams.
|
You can specify the endianness and signedness of the fields to be unpacked too.
|
|
This module is a cleaner and more complete version of
|
[bufferlist](https://github.com/substack/node-bufferlist)'s binary module that
|
runs on pre-allocated buffers instead of a linked list.
|
|
[](http://travis-ci.org/substack/node-binary)
|
|
examples
|
========
|
|
stream.js
|
---------
|
|
``` js
|
var binary = require('binary');
|
|
var ws = binary()
|
.word32lu('x')
|
.word16bs('y')
|
.word16bu('z')
|
.tap(function (vars) {
|
console.dir(vars);
|
})
|
;
|
process.stdin.pipe(ws);
|
process.stdin.resume();
|
```
|
|
output:
|
|
```
|
$ node examples/stream.js
|
abcdefgh
|
{ x: 1684234849, y: 25958, z: 26472 }
|
^D
|
```
|
|
parse.js
|
--------
|
|
``` js
|
var buf = new Buffer([ 97, 98, 99, 100, 101, 102, 0 ]);
|
|
var binary = require('binary');
|
var vars = binary.parse(buf)
|
.word16ls('ab')
|
.word32bu('cf')
|
.word8('x')
|
.vars
|
;
|
console.dir(vars);
|
```
|
|
output:
|
|
```
|
{ ab: 25185, cf: 1667523942, x: 0 }
|
```
|
|
methods
|
=======
|
|
`var binary = require('binary')`
|
|
var b = binary()
|
----------------
|
|
Return a new writable stream `b` that has the chainable methods documented below
|
for buffering binary input.
|
|
binary.parse(buf)
|
-----------------
|
|
Parse a static buffer in one pass. Returns a chainable interface with the
|
methods below plus a `vars` field to get at the variable stash as the last item
|
in a chain.
|
|
In parse mode, methods will set their keys to `null` if the buffer isn't big
|
enough except `buffer()` and `scan()` which read up up to the end of the buffer
|
and stop.
|
|
b.word{8,16,32,64}{l,b}{e,u,s}(key)
|
-----------------------------------
|
|
Parse bytes in the buffer or stream given:
|
|
* number of bits
|
* endianness ( l : little, b : big ),
|
* signedness ( u and e : unsigned, s : signed )
|
|
These functions won't start parsing until all previous parser functions have run
|
and the data is available.
|
|
The result of the parse goes into the variable stash at `key`.
|
If `key` has dots (`.`s), it refers to a nested address. If parent container
|
values don't exist they will be created automatically, so for instance you can
|
assign into `dst.addr` and `dst.port` and the `dst` key in the variable stash
|
will be `{ addr : x, port : y }` afterwards.
|
|
b.buffer(key, size)
|
-------------------
|
|
Take `size` bytes directly off the buffer stream, putting the resulting buffer
|
slice in the variable stash at `key`. If `size` is a string, use the value at
|
`vars[size]`. The key follows the same dotted address rules as the word
|
functions.
|
|
b.scan(key, buffer)
|
-------------------
|
|
Search for `buffer` in the stream and store all the intervening data in the
|
stash at at `key`, excluding the search buffer. If `buffer` passed as a string,
|
it will be converted into a Buffer internally.
|
|
For example, to read in a line you can just do:
|
|
``` js
|
var b = binary()
|
.scan('line', new Buffer('\r\n'))
|
.tap(function (vars) {
|
console.log(vars.line)
|
})
|
;
|
stream.pipe(b);
|
```
|
|
b.tap(cb)
|
---------
|
|
The callback `cb` is provided with the variable stash from all the previous
|
actions once they've all finished.
|
|
You can nest additional actions onto `this` inside the callback.
|
|
b.into(key, cb)
|
---------------
|
|
Like `.tap()`, except all nested actions will assign into a `key` in the `vars`
|
stash.
|
|
b.loop(cb)
|
----------
|
|
Loop, each time calling `cb(end, vars)` for function `end` and the variable
|
stash with `this` set to a new chain for nested parsing. The loop terminates
|
once `end` is called.
|
|
b.flush()
|
---------
|
|
Clear the variable stash entirely.
|
|
installation
|
============
|
|
To install with [npm](http://github.com/isaacs/npm):
|
|
```
|
npm install binary
|
```
|
|
notes
|
=====
|
|
The word64 functions will only return approximations since javascript uses ieee
|
floating point for all number types. Mind the loss of precision.
|
|
license
|
=======
|
|
MIT
|
