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Generator: Javascript: use forEach and Uint8Array
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@IamPete1
IamPete1 committed Nov 11, 2024
1 parent 7f3234f commit d7c5920
Showing 1 changed file with 45 additions and 70 deletions.
115 changes: 45 additions & 70 deletions generator/mavgen_javascript.py
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Original file line number Diff line number Diff line change
Expand Up @@ -35,17 +35,9 @@ def generate_preamble(outf, msgs, args, xml):
*/
jspack = require("jspack").jspack,
_ = require("underscore"),
events = require("events"), // for .emit(..), MAVLink20Processor inherits from events.EventEmitter
util = require("util");
var Buffer = require('buffer').Buffer; // required in react - no impact in node
var Long = require('long');
// Add a convenience method to Buffer
Buffer.prototype.toByteArray = function () {
return Array.prototype.slice.call(this, 0)
}
${MAVHEAD} = function(){};
Expand All @@ -54,7 +46,7 @@ def generate_preamble(outf, msgs, args, xml):
var bytes = buffer;
var crcOUT = crcIN === undefined ? 0xffff : crcIN;
_.each(bytes, function(e) {
bytes.forEach(function(e) {
var tmp = e ^ (crcOUT & 0xff);
tmp = (tmp ^ (tmp << 4)) & 0xff;
crcOUT = (crcOUT >> 8) ^ (tmp << 8) ^ (tmp << 3) ^ (tmp >> 4);
Expand Down Expand Up @@ -132,16 +124,15 @@ def generate_preamble(outf, msgs, args, xml):
// Convenience setter to facilitate turning the unpacked array of data into member properties
${MAVHEAD}.message.prototype.set = function(args,verbose) {
// inspect
_.each(this.fieldnames, function(e, i) {
this.fieldnames.forEach(function(e, i) {
var num = parseInt(i,10);
if (this.hasOwnProperty(e) && isNaN(num) ){ // asking for an attribute that's non-numeric is ok unless its already an attribute we have
if ( verbose >= 1) { console.log("WARNING, overwriting an existing property is DANGEROUS:"+e+" ==>"+i+"==>"+args[i]+" -> "+JSON.stringify(this)); }
}
}, this);
//console.log(this.fieldnames);
// then modify
_.each(this.fieldnames, function(e, i) {
// then modify
this.fieldnames.forEach(function(e, i) {
this[e] = args[i];
}, this);
};
Expand All @@ -167,11 +158,11 @@ def generate_preamble(outf, msgs, args, xml):
// first add the linkid(1 byte) and timestamp(6 bytes) that start the signature
this._msgbuf = this._msgbuf.concat(jspack.Pack('<BIH', [mav.signing.link_id, tlow, thigh ] ) );
h.update(mav.signing.secret_key); // secret is already a Buffer
h.update(new Buffer.from(this._msgbuf));
h.update(mav.signing.secret_key);
h.update(new Uint8Array.from(this._msgbuf));
var hashDigest = h.digest();
sig = hashDigest.slice(0,6)
this._msgbuf = this._msgbuf.concat( ... sig );
this._msgbuf = this._msgbuf.concat( ... sig );
mav.signing.timestamp += 1
}
Expand Down Expand Up @@ -392,7 +383,7 @@ def generate_mavlink_class(outf, msgs, xml):
// MAVLink signing state class
MAVLinkSigning = function MAVLinkSigning(object){
this.secret_key = new Buffer.from([]); //new Buffer.from([ 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42 ]) // secret key must be a Buffer obj of 32 length
this.secret_key = new Uint8Array();
this.timestamp = 1
this.link_id = 0
this.sign_outgoing = false // todo false this
Expand All @@ -411,8 +402,8 @@ def generate_mavlink_class(outf, msgs, xml):
this.logger = logger;
this.seq = 0;
this.buf = new Buffer.from([]);
this.bufInError = new Buffer.from([]);
this.buf = new Uint8Array();
this.bufInError = new Uint8Array();
this.srcSystem = (typeof srcSystem === 'undefined') ? 0 : srcSystem;
this.srcComponent = (typeof srcComponent === 'undefined') ? 0 : srcComponent;
Expand Down Expand Up @@ -468,12 +459,18 @@ def generate_mavlink_class(outf, msgs, xml):
return ( ret <= 0 ) ? 1 : ret;
}
// Combine two buffers into one
${MAVPROCESSOR}.prototype.concat_buffer = function(A, B) {
const out = new Uint8Array(A.length + B.length)
out.set(A, 0)
out.set(B, A.length)
return out
}
// add data to the local buffer
${MAVPROCESSOR}.prototype.pushBuffer = function(data) {
if(data) {
this.buf = Buffer.concat([this.buf, data]); // python calls this self.buf.extend(c)
this.total_bytes_received += data.length;
}
this.buf = this.concat_buffer(this.buf, new Uint8Array([data]));
this.total_bytes_received += 1;
}
// Decode prefix. Elides the prefix.
Expand Down Expand Up @@ -514,6 +511,10 @@ def generate_mavlink_class(outf, msgs, xml):
// input some data bytes, possibly returning a new message - python equiv function is called parse_char / __parse_char_legacy
${MAVPROCESSOR}.prototype.parseChar = function(c) {
if (c == null) {
return
}
var m = null;
try {
Expand All @@ -526,7 +527,7 @@ def generate_mavlink_class(outf, msgs, xml):
this.log('error', e.message);
this.total_receive_errors += 1;
m = new ${MAVHEAD}.messages.bad_data(this.bufInError, e.message);
this.bufInError = new Buffer.from([]);
this.bufInError = new Uint8Array();
}
Expand Down Expand Up @@ -578,15 +579,15 @@ def generate_mavlink_class(outf, msgs, xml):
// input some data bytes, possibly returning an array of new messages
${MAVPROCESSOR}.prototype.parseBuffer = function(s) {
// Get a message, if one is available in the stream.
var m = this.parseChar(s);
// No messages available, bail.
if ( null === m ) {
return null;
}
// While more valid messages can be read from the existing buffer, add
// them to the array of new messages and return them.
var ret = [m];
Expand All @@ -601,47 +602,21 @@ def generate_mavlink_class(outf, msgs, xml):
}
// from Buffer to ArrayBuffer
function toArrayBuffer(buf) {
var ab = new ArrayBuffer(buf.length);
var view = new Uint8Array(ab);
for (var i = 0; i < buf.length; ++i) {
view[i] = buf[i];
}
return ab;
}
// and back
function toBuffer(ab) {
var buf = Buffer.alloc(ab.byteLength);
var view = new Uint8Array(ab);
for (var i = 0; i < buf.length; ++i) {
buf[i] = view[i];
}
return buf;
}
//check signature on incoming message , many of the comments in this file come from the python impl
${MAVPROCESSOR}.prototype.check_signature = function(msgbuf, srcSystem, srcComponent) {
//if (isinstance(msgbuf, array.array)){
// msgbuf = msgbuf.tostring()
//}
if ( Buffer.isBuffer(msgbuf) ) {
msgbuf = toArrayBuffer(msgbuf);
}
${MAVPROCESSOR}.prototype.check_signature = function(msgbuf, srcSystem, srcComponent) {
//timestamp_buf = msgbuf[-12:-6]
var timestamp_buf= msgbuf.slice(-12,-6);
//link_id = msgbuf[-13]
var link_id= new Buffer.from(msgbuf.slice(-13,-12)); // just a single byte really, but returned as a buffer
var link_id = new Uint8Array.from(msgbuf.slice(-13,-12)); // just a single byte really, but returned as a buffer
link_id = link_id[0]; // get the first byte.
//self.mav_sign_unpacker = jspack.Unpack('<IH')
// (tlow, thigh) = self.mav_sign_unpacker.unpack(timestamp_buf)
// I means unsigned 4bytes, H means unsigned 2 byte
var t = jspack.Unpack('<IH',new Buffer.from(timestamp_buf))
// I means unsigned 4bytes, H means unsigned 2 bytes
var t = jspack.Unpack('<IH',new Uint8Array.from(timestamp_buf))
const [tlow, thigh] = t;
// due to js not being able to shift numbers more than 32, we'll use this instead..
Expand Down Expand Up @@ -682,24 +657,24 @@ def generate_mavlink_class(outf, msgs, xml):
// just the last 6 of 13 available are the actual sig . ie excluding the linkid(1) and timestamp(6)
var sigpart = msgbuf.slice(-6);
sigpart = new Buffer.from(sigpart);
sigpart = new Uint8Array.from(sigpart);
// not sig part 0- end-minus-6
var notsigpart = msgbuf.slice(0,-6);
notsigpart = new Buffer.from(notsigpart);
notsigpart = new Uint8Array.from(notsigpart);
h.update(this.signing.secret_key); // secret is already a Buffer
//var tmp = h.copy().digest();
h.update(notsigpart);
//var tmp2 = h.copy().digest()
var hashDigest = h.digest();
sig1 = hashDigest.slice(0,6)
//sig1 = str(h.digest())[:6]
//sig2 = str(msgbuf)[-6:]
// can't just compare sigs, need a full buffer compare like this...
//if (sig1 != sigpart){
if (Buffer.compare(sig1,sigpart)){
if (Uint8Array.compare(sig1,sigpart)){
//console.log('sig mismatch',sig1,sigpart)
return false
}
Expand All @@ -722,7 +697,7 @@ def generate_mavlink_class(outf, msgs, xml):
# Mavlink2 only
if (xml.protocol_marker == 253):
t.write(outf, """
unpacked = jspack.Unpack('cBBBBBBHB', msgbuf.slice(0, 10)); // the H in here causes msgIDlow to takeup 2 bytes, the rest 1
unpacked = jspack.Unpack('BBBBBBBHB', msgbuf.slice(0, 10)); // the H in here causes msgIDlow to takeup 2 bytes, the rest 1
magic = unpacked[0];
mlen = unpacked[1];
incompat_flags = unpacked[2];
Expand Down Expand Up @@ -778,8 +753,8 @@ def generate_mavlink_class(outf, msgs, xml):
return;
}
if (magic.charCodeAt(0) != this.protocol_marker) {
throw new Error("Invalid MAVLink prefix ("+magic.charCodeAt(0)+")");
if (magic != this.protocol_marker) {
throw new Error("Invalid MAVLink prefix ("+magic+")");
}
// is packet supposed to be signed?
Expand Down Expand Up @@ -807,13 +782,13 @@ def generate_mavlink_class(outf, msgs, xml):
}
if( false === _.has(${MAVHEAD}.map, msgId) ) {
if (!(msgId in ${MAVHEAD}.map)) {
throw new Error("Unknown MAVLink message ID (" + msgId + ")");
}
// here's the common chunks of packet we want to work with below..
var headerBuf= msgbuf.slice(${MAVHEAD}.HEADER_LEN); // first10
var sigBuf = msgbuf.slice(-signature_len); // last 13 or nothing
//var headerBuf= msgbuf.slice(${MAVHEAD}.HEADER_LEN); // first10
//var sigBuf = msgbuf.slice(-signature_len); // last 13 or nothing
var crcBuf1 = msgbuf.slice(-2); // either last-2 or last-2-prior-to-signature
var crcBuf2 = msgbuf.slice(-15,-13); // either last-2 or last-2-prior-to-signature
var payloadBuf = msgbuf.slice(${MAVHEAD}.HEADER_LEN, -(signature_len+2)); // the remaining bit between the header and the crc
Expand Down Expand Up @@ -893,9 +868,9 @@ def generate_mavlink_class(outf, msgs, xml):
# Mavlink2 only
if (xml.protocol_marker == 253):
t.write(outf, """
//put any truncated 0's back in (ie zero-pad )
//put any truncated 0's back in (ie zero-pad )
if (paylen > payloadBuf.length) {
payloadBuf = Buffer.concat([payloadBuf, Buffer.alloc(paylen - payloadBuf.length)]);
payloadBuf = this.concat_buffer(payloadBuf, new Uint8Array(paylen - payloadBuf.length).fill(0));
}
""")

Expand All @@ -915,7 +890,7 @@ def generate_mavlink_class(outf, msgs, xml):
if (elementsInMsg == actualElementsInMsg) {
// Reorder the fields to match the order map
_.each(t, function(e, i, l) {
t.forEach(function(e, i, l) {
args[i] = t[decoder.order_map[i]]
});
} else {
Expand Down Expand Up @@ -959,7 +934,7 @@ def generate_mavlink_class(outf, msgs, xml):
}
// Finally reorder the fields to match the order map
_.each(t, function(e, i, l) {
t.forEach(function(e, i, l) {
args[i] = tempArgs[decoder.order_map[i]]
});
}
Expand Down

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