Binary data structure transformation for JavaScript

Installation

Using npm:

$ npm install cppmsg

To run the tests:

$ node test.js

Description

You can use this module, parse binary data from the c + +, can also be generate binary data(from json object) that c/c++ can phrase. This module provides follow function:

• Encode json data to binary data
• Decode binary data to json
• support more data type: int8/16/32/64, uint8/16/32, float,double,bool,string
• support msg nested;

You can phrase C++ binary data sturct from network to json. Note: c/c++ data struct must one bit algin.

cppMsg.msg constructor overloads

• new cppMsg.msg() create empty cppMsg;
• new cppMsg.msg( ds ) ds is data struct define Array
• new cppMsg.msg( ds, data) ds is data struct define Array. data(optional) is init json data.
• new cppMsg.msg( ds, null, opts) ds is data struct define Array. data(optional) is init json data.
  • opts, {useIconv: true } ,useIconv boolean, maybe use iconv-lite convert code

cppMsg.msg methods

• encodeMsg( data ) : json data object;
• encodeMsg2( data ) : json data object( use msg internal buffer, return internal buffer );
• encodeMsgToBuff (data, buff, offset?) : encode to buffer
  • data, object;
  • buff, target buffer;
    • offset, data offset, default 0;
• decodeMsg( buf, offset? ) : decode Buffer to json data object;
  • offset, data offset, default 0;

next methods using stream mode:

• push_uint8
• push_int8
• push_uint16
• push_int16
• push_uint32
• push_int32
• push_string
• push_char
• encode( data ) : data is json data stream.

Examples

Normal Mode

Assume this for all examples below

C++ Code:

//C++ struct define Must one byte algin
struct head{
	int mainType;
    int subType;
};

struct msg{
	int reg;
    int chkCode;
    int iType;
    bool bMonitor;
    char workPath[10];
    unsigned int processID;
    struct head testObj;
    long long testin64;
	float floatArray3[3];
};

Nodejs code:

	var cppMsg = require('./cppMsg.js');

	var msg_def = {
		msgHead:[
					['mainType','int32'],
					['subType', 'int32']
				]
	};


	var msg = new cppMsg.msg(
		[
			['reg','int32'],
			['chkCode','int32'],
			['iType','int32'],
			['bMonitor', 'bool'],
			['workPath','string',10],
			['processID','uint32'],
			['testObj','object', msg_def.msgHead], // nested other
			['testint64','int64'],
			['floatArray3', 'float', , , 3]
		],null, {useIconv: false}
		);

	var buff = msg.encodeMsg2( {
			reg     : 2,
			chkCode : 0,
			iType   : 2,
			bMonitor : false,
			workPath : 'no 你 work',
			processID : 1234,
			testObj  :{
				mainType : 0x01020304,
				subType  : 0x0A0B0C0D
			},
			testint64 : 0xCDEF,
			floatArray3: [1.1, 2.2, 9.7]
		}  );

	console.log( buff );

	var data = msg.decodeMsg( buff );
	console.log( data );

stream mode

	msg.push_int32(2);  // reg
	msg.push_int32(0);  // chkCode
	msg.push_int32(2);  // iType

	msg.push_uint8(0);  // bMonitor
	msg.push_string('no worker path',10);
	msg.push_string('no worker path',20);
	msg.push_string('brnn-20',20);
	msg.push_uint32( 1234 ); // processID

	console.log( msg.encode());

Changelog

1.2.1

1. Fixed encodeMsg2 using internal cache causing string dirty;
2. optimize performance encodeMsg;
3. add decodeMsgFromBuff

1.2.0

1. add method encodeMsg2, Improve performance 1x
2. optimize performance encodeMsg
3. optimize performance decodeMsg, Improve performance 1x
4. change msg construct add params opts
   • opts, {useIconv: true }
     • useIconv, boolean, true(default): use iconv-lite convert code.( false, Improve performance)
5. Default string code,change to utf8

1.1.0

1. Using ES6 syntax
2. optimize performance encodeMsg

1.0.3

1. fix int64 decode/encode error( Works only for numbers <= Number.MAX_SAFE_INTEGER ).
2. fix object decode error.

1.0.2

1. merge darnold79 change,add array support.

1.0.1

1. string type add encode support(using iconv-lite).

1.0.0

1. init.

LICENSE

The MIT License (MIT)

Copyright (c) 2017 Shudingbo Copyright (c) 2017 darnold79 (node-cppMsg-dynamic)