mirror of
https://github.com/musix-org/musix-oss
synced 2024-11-14 03:30:18 +00:00
112 lines
3.2 KiB
Markdown
112 lines
3.2 KiB
Markdown
ref-struct
|
|
==========
|
|
### Create ABI-compliant "[struct][]" instances on top of Buffers
|
|
[](https://travis-ci.org/TooTallNate/ref-struct)
|
|
[](https://ci.appveyor.com/project/TooTallNate/ref-struct)
|
|
|
|
|
|
This module offers a "struct" implementation on top of Node.js Buffers
|
|
using the ref "type" interface.
|
|
|
|
Installation
|
|
------------
|
|
|
|
Install with `npm`:
|
|
|
|
``` bash
|
|
$ npm install ref-struct
|
|
```
|
|
|
|
|
|
Examples
|
|
--------
|
|
|
|
Say you wanted to emulate the `timeval` struct from the stdlib:
|
|
|
|
``` c
|
|
struct timeval {
|
|
time_t tv_sec; /* seconds since Jan. 1, 1970 */
|
|
suseconds_t tv_usec; /* and microseconds */
|
|
};
|
|
```
|
|
|
|
``` js
|
|
var ref = require('ref')
|
|
var StructType = require('ref-struct')
|
|
|
|
// define the time types
|
|
var time_t = ref.types.long
|
|
var suseconds_t = ref.types.long
|
|
|
|
// define the "timeval" struct type
|
|
var timeval = StructType({
|
|
tv_sec: time_t,
|
|
tv_usec: suseconds_t
|
|
})
|
|
|
|
// now we can create instances of it
|
|
var tv = new timeval
|
|
```
|
|
|
|
#### With `node-ffi`
|
|
|
|
This gets very powerful when combined with `node-ffi` to invoke C functions:
|
|
|
|
``` js
|
|
var ffi = require('ffi')
|
|
|
|
var tv = new timeval
|
|
gettimeofday(tv.ref(), null)
|
|
```
|
|
|
|
#### Progressive API
|
|
|
|
You can build up a Struct "type" incrementally (useful when interacting with a
|
|
parser) using the `defineProperty()` function. But as soon as you _create_ an
|
|
instance of the struct type, then the struct type is finalized, and no more
|
|
properties may be added to it.
|
|
|
|
``` js
|
|
var ref = require('ref')
|
|
var StructType = require('ref-struct')
|
|
|
|
var MyStruct = StructType()
|
|
MyStruct.defineProperty('width', ref.types.int)
|
|
MyStruct.defineProperty('height', ref.types.int)
|
|
|
|
var i = new MyStruct({ width: 5, height: 10 })
|
|
|
|
MyStruct.defineProperty('weight', ref.types.int)
|
|
// AssertionError: an instance of this Struct type has already been created, cannot add new "fields" anymore
|
|
// at Function.defineProperty (/Users/nrajlich/ref-struct/lib/struct.js:180:3)
|
|
```
|
|
|
|
|
|
License
|
|
-------
|
|
|
|
(The MIT License)
|
|
|
|
Copyright (c) 2012 Nathan Rajlich <nathan@tootallnate.net>
|
|
|
|
Permission is hereby granted, free of charge, to any person obtaining
|
|
a copy of this software and associated documentation files (the
|
|
'Software'), to deal in the Software without restriction, including
|
|
without limitation the rights to use, copy, modify, merge, publish,
|
|
distribute, sublicense, and/or sell copies of the Software, and to
|
|
permit persons to whom the Software is furnished to do so, subject to
|
|
the following conditions:
|
|
|
|
The above copyright notice and this permission notice shall be
|
|
included in all copies or substantial portions of the Software.
|
|
|
|
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
|
|
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
|
|
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
|
|
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
|
|
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
|
|
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
|
|
[struct]: http://wikipedia.org/wiki/Struct_(C_programming_language)
|