xdenser / node-struct Goto Github PK

Hi,
currently I'm using your package in a Typescript project that I have inherited from a collegue. I really enjoy working with it, so far. What do you think about generating some Typescript declaration files?

I've never done it by hand so far, but Microsoft provides a generator that might be helpful dts-gen (https://github.com/Microsoft/dts-gen).

Calling dts-gen -m struct is not very helpful:

/** Declaration file generated by dts-gen */

export = struct;

declare function struct(...args: any[]): any;

declare namespace struct {
    // Circular reference from struct
    const Struct: any;

    const prototype: {
    };

}

The following code:

var Person = Struct()
    .chars('firstName',10)
    .chars('lastName',10)
    .array('items',3,'chars',10)
    .word16Sle('balance'),
People = Struct()
    .word8('presentCount')
    .array('list',2,Person);


Person.allocate();
People.allocate();

console.log(People.buffer());
console.log(Person.buffer());

should log two (pretty large) Buffers, however today it will log:
Buffer < 36 00 ....lots of data ...>
Buffer <>

With the second buffer always being empty.

This change: 9c46c8a#diff-168726dbe96b3ce427e7fedce31bb0bcL190 is a breaking change, and only the patch version was upped.

This should have been a major version change.

I am in a Chinese Company，in my project,I want exchange data from node.js to C++ Application.Can I Use this library to help me?

Below is code which is leading error ,

var Struct = require('struct');
/*************************/
var Person = Struct()
.chars('username',60)
.chars('id',100);

Person.allocate();
Person.set('username',"sravani");
Person.set('id',"123456889994");

console.log("username: "+ Person.get('username') +"id:" +Person.get('sid'));

/**************/
[root@sravani nodejs]# node struct.js
home/wsadmin/src/sravani/nodejs/node_modules/struct/index.js:398
throw new Error('Can not find field ' + key);
^

Error: Can not find field sid
at Struct.get (/home/wsadmin/src/sravani/nodejs/node_modules/struct/index.js:398:19)
at Object. (/home/wsadmin/src/sravani/nodejs/struct.js:11:65)
at Module._compile (module.js:571:32)
at Object.Module._extensions..js (module.js:580:10)
at Module.load (module.js:488:32)
at tryModuleLoad (module.js:447:12)
at Function.Module._load (module.js:439:3)
at Module.runMain (module.js:605:10)
at run (bootstrap_node.js:423:7)
at startup (bootstrap_node.js:147:9)

Hey. What about if the structure is an array and its length is not defined? I see an option to use an array with a larger advance. Is it going to be?

I am using struct to write the header of binary files. If the struct template is Header, is it ok to do:

Header.allocate();
var data1=Header.buffer();

fill data1 with my settings, and then do again

Header.allocate();
var data2=Header.buffer();

to create file number 2?

Hello,

So I wanted to get an object (fields) from a buffer. I was wondering how do you pass already read field as the length of an array?

This is what I've tried but It doesn't work...

  var PacketRecordsBodyOneBSegment = Struct()
      .word8('number_of_io'); // length of the following array ...
  var length = PacketRecordsBodyOneBSegment.fields.number_of_io;
  console.log('OneB length:', length); // undefined
  PacketRecordsBodyOneBSegment = PacketRecordsBodyOneBSegment
      .array('events', length, PacketRecordsBodyOneBio);

Ideally, something like this would be awesome, but I don't know how to implement it:

  var PacketRecordsBodyOneBSegment = Struct()
      .word8('number_of_io'); // length of the following array ...
      .array('events', 'number_of_io', PacketRecordsBodyOneBio);

Thanks.

There is an issue with node-struct in how the clone function is implemented, the closures array is copied using the assignment operator rather than the slice, so modifying the fields for the cloned struct results in modifying the original struct as well.

Original Code

this.clone = function () { var c = new Struct; var p = c._getPriv(); p.closures = priv.closures; return c; }

Modified With Fix

this.clone = function () { var c = new Struct; var p = c._getPriv(); p.closures = priv.closures.slice(0); return c; }

No Null-terminating string support?

Hi. I'm a little unsure if I'm using this correctly. My code:

var struct = require('struct').Struct().word64Ube('connection_id').word32Ube('action').word32Ube('transaction_id');

struct.allocate();

struct.set("connection_id", 0x41727101980);
struct.set("action", 0);
struct.set("transaction_id", 84548454);

var buf = struct.buffer();

and then passing the buffer on to a dgram client. Is this correct usage?

By looking at the API i dont see the reason why setting a buffer is prefixed with '_',i think that there should be a "public" method for this. Which is the reason for that decision?

Yesterday, #16 was merged and broke lots of modules using tilde or caret versions. Can you do a minor or major version bump rather than a patch version bump? The exported API has changed, so I would expect at least a minor version, if not a major. Should probably be 1.0.0.

Using this hex value: 0x100000000000002 should print this integer to the console: 72057594037927938

What I am seeing is this: 72057594037927940

I have a few test cases, but this is the easiest to paste:
var idStruct = Struct().word64Ule('id');
idStruct.allocate();
idStruct.fields.id = 72057594037927938;

console.log( "id: " + idStruct.get('id') );

I'm trying to use this library with a C struct that contains a few time_t variables. Looking on my system they're 8 byte variables. However, when I read with time_t variable any sort of word64 variable in your library the data after this read gets corrupted (I'm assuming this means I'm reading too much or too little data from the buffer). I've also tried word32 and word16 variables with no luck (really just shooting in the dark at that point).

Do you have any suggestions for reading time_t variables? (I know it's a unique request)

Hi Denys

Instead of hardcoding 'ascii' as the encoding of chars(name,length), if you can make it as an optional param that will be great.
something like
chars(name, length, encoding)

-sanjeev

Usually array in buffer are defined with array size contained in a field stored above, that can be done to read non defined array length ?

There's no way to retrieve the offset where each field is located. The offset is just used implicitly when constructing the structure, but I think it would be nice if each field get an 'offset' entry to expose this information.

Probably, a 'length' and storing this in an array, to make it possible to retrieve the list in a static order would be nice to have.

I'm using a 64-bit Linux. My problem is that long has 64 bits on my system while it has 32 bits on 32 bit machines. Is there a way to automatically detect on which system this lib is running and to automagically adjust the length of longs?

PS: I want it to run cross platform. Therefore, just using word64Sle is not sufficient.

Hello, I use struct 0.0.6, but found Struct.chars('hex') has a problem:

var Struct = require('struct').Struct;
var Test = Struct()
    .chars("flag", 2, 'hex');

var buf = new Buffer(2);

var s = Test.clone();

buf[0] = 97;
buf[1] = 98;
console.log(buf.toString('hex', 0, 2));
// outputs "6162", it's right

s._setBuff(buf);
console.log(s.fields.flag);
// outputs "ab", but hex value "6162" expected

And Struct parse to buffer also have this problem:

var expected = new Buffer('aa', 'hex');
console.log(expected);
// outputs: <Buffer aa>

var Struct = require('struct').Struct;
var buf = new Buffer(1);
var ThisPacket = Struct()
    .chars("cmd", 1, 'hex');
var s = ThisPacket.clone();
s._setBuff(buf);
var fields = s.fields;
fields.cmd = 'aa';
console.log(buf);
// outputs: <Buffer 61>

It seems Struct.chars() only support Node's default encoding utf8.

Some buffer streams are returned in an internal byte order and are thus reversed. Could offer an option to support this or new functions.