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Generator: Javascript: use forEach and Uint8Array
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generator/mavgen_javascript.py

Lines changed: 45 additions & 70 deletions
Original file line numberDiff line numberDiff line change
@@ -35,17 +35,9 @@ def generate_preamble(outf, msgs, args, xml):
3535
*/
3636
3737
jspack = require("jspack").jspack,
38-
_ = require("underscore"),
3938
events = require("events"), // for .emit(..), MAVLink20Processor inherits from events.EventEmitter
4039
util = require("util");
4140
42-
var Buffer = require('buffer').Buffer; // required in react - no impact in node
43-
var Long = require('long');
44-
45-
// Add a convenience method to Buffer
46-
Buffer.prototype.toByteArray = function () {
47-
return Array.prototype.slice.call(this, 0)
48-
}
4941
5042
${MAVHEAD} = function(){};
5143
@@ -54,7 +46,7 @@ def generate_preamble(outf, msgs, args, xml):
5446
5547
var bytes = buffer;
5648
var crcOUT = crcIN === undefined ? 0xffff : crcIN;
57-
_.each(bytes, function(e) {
49+
bytes.forEach(function(e) {
5850
var tmp = e ^ (crcOUT & 0xff);
5951
tmp = (tmp ^ (tmp << 4)) & 0xff;
6052
crcOUT = (crcOUT >> 8) ^ (tmp << 8) ^ (tmp << 3) ^ (tmp >> 4);
@@ -132,16 +124,15 @@ def generate_preamble(outf, msgs, args, xml):
132124
// Convenience setter to facilitate turning the unpacked array of data into member properties
133125
${MAVHEAD}.message.prototype.set = function(args,verbose) {
134126
// inspect
135-
_.each(this.fieldnames, function(e, i) {
127+
this.fieldnames.forEach(function(e, i) {
136128
var num = parseInt(i,10);
137129
if (this.hasOwnProperty(e) && isNaN(num) ){ // asking for an attribute that's non-numeric is ok unless its already an attribute we have
138130
if ( verbose >= 1) { console.log("WARNING, overwriting an existing property is DANGEROUS:"+e+" ==>"+i+"==>"+args[i]+" -> "+JSON.stringify(this)); }
139131
}
140132
}, this);
141-
//console.log(this.fieldnames);
142133
143-
// then modify
144-
_.each(this.fieldnames, function(e, i) {
134+
// then modify
135+
this.fieldnames.forEach(function(e, i) {
145136
this[e] = args[i];
146137
}, this);
147138
};
@@ -167,11 +158,11 @@ def generate_preamble(outf, msgs, args, xml):
167158
// first add the linkid(1 byte) and timestamp(6 bytes) that start the signature
168159
this._msgbuf = this._msgbuf.concat(jspack.Pack('<BIH', [mav.signing.link_id, tlow, thigh ] ) );
169160
170-
h.update(mav.signing.secret_key); // secret is already a Buffer
171-
h.update(new Buffer.from(this._msgbuf));
161+
h.update(mav.signing.secret_key);
162+
h.update(new Uint8Array.from(this._msgbuf));
172163
var hashDigest = h.digest();
173164
sig = hashDigest.slice(0,6)
174-
this._msgbuf = this._msgbuf.concat( ... sig );
165+
this._msgbuf = this._msgbuf.concat( ... sig );
175166
176167
mav.signing.timestamp += 1
177168
}
@@ -392,7 +383,7 @@ def generate_mavlink_class(outf, msgs, xml):
392383
393384
// MAVLink signing state class
394385
MAVLinkSigning = function MAVLinkSigning(object){
395-
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
386+
this.secret_key = new Uint8Array();
396387
this.timestamp = 1
397388
this.link_id = 0
398389
this.sign_outgoing = false // todo false this
@@ -411,8 +402,8 @@ def generate_mavlink_class(outf, msgs, xml):
411402
this.logger = logger;
412403
413404
this.seq = 0;
414-
this.buf = new Buffer.from([]);
415-
this.bufInError = new Buffer.from([]);
405+
this.buf = new Uint8Array();
406+
this.bufInError = new Uint8Array();
416407
417408
this.srcSystem = (typeof srcSystem === 'undefined') ? 0 : srcSystem;
418409
this.srcComponent = (typeof srcComponent === 'undefined') ? 0 : srcComponent;
@@ -468,12 +459,18 @@ def generate_mavlink_class(outf, msgs, xml):
468459
return ( ret <= 0 ) ? 1 : ret;
469460
}
470461
462+
// Combine two buffers into one
463+
${MAVPROCESSOR}.prototype.concat_buffer = function(A, B) {
464+
const out = new Uint8Array(A.length + B.length)
465+
out.set(A, 0)
466+
out.set(B, A.length)
467+
return out
468+
}
469+
471470
// add data to the local buffer
472471
${MAVPROCESSOR}.prototype.pushBuffer = function(data) {
473-
if(data) {
474-
this.buf = Buffer.concat([this.buf, data]); // python calls this self.buf.extend(c)
475-
this.total_bytes_received += data.length;
476-
}
472+
this.buf = this.concat_buffer(this.buf, new Uint8Array([data]));
473+
this.total_bytes_received += 1;
477474
}
478475
479476
// Decode prefix. Elides the prefix.
@@ -514,6 +511,10 @@ def generate_mavlink_class(outf, msgs, xml):
514511
// input some data bytes, possibly returning a new message - python equiv function is called parse_char / __parse_char_legacy
515512
${MAVPROCESSOR}.prototype.parseChar = function(c) {
516513
514+
if (c == null) {
515+
return
516+
}
517+
517518
var m = null;
518519
519520
try {
@@ -526,7 +527,7 @@ def generate_mavlink_class(outf, msgs, xml):
526527
this.log('error', e.message);
527528
this.total_receive_errors += 1;
528529
m = new ${MAVHEAD}.messages.bad_data(this.bufInError, e.message);
529-
this.bufInError = new Buffer.from([]);
530+
this.bufInError = new Uint8Array();
530531
531532
}
532533
@@ -578,15 +579,15 @@ def generate_mavlink_class(outf, msgs, xml):
578579
579580
// input some data bytes, possibly returning an array of new messages
580581
${MAVPROCESSOR}.prototype.parseBuffer = function(s) {
581-
582+
582583
// Get a message, if one is available in the stream.
583584
var m = this.parseChar(s);
584585
585586
// No messages available, bail.
586587
if ( null === m ) {
587588
return null;
588589
}
589-
590+
590591
// While more valid messages can be read from the existing buffer, add
591592
// them to the array of new messages and return them.
592593
var ret = [m];
@@ -601,47 +602,21 @@ def generate_mavlink_class(outf, msgs, xml):
601602
602603
}
603604
604-
// from Buffer to ArrayBuffer
605-
function toArrayBuffer(buf) {
606-
var ab = new ArrayBuffer(buf.length);
607-
var view = new Uint8Array(ab);
608-
for (var i = 0; i < buf.length; ++i) {
609-
view[i] = buf[i];
610-
}
611-
return ab;
612-
}
613-
// and back
614-
function toBuffer(ab) {
615-
var buf = Buffer.alloc(ab.byteLength);
616-
var view = new Uint8Array(ab);
617-
for (var i = 0; i < buf.length; ++i) {
618-
buf[i] = view[i];
619-
}
620-
return buf;
621-
}
622-
623605
//check signature on incoming message , many of the comments in this file come from the python impl
624-
${MAVPROCESSOR}.prototype.check_signature = function(msgbuf, srcSystem, srcComponent) {
625-
626-
//if (isinstance(msgbuf, array.array)){
627-
// msgbuf = msgbuf.tostring()
628-
//}
629-
if ( Buffer.isBuffer(msgbuf) ) {
630-
msgbuf = toArrayBuffer(msgbuf);
631-
}
606+
${MAVPROCESSOR}.prototype.check_signature = function(msgbuf, srcSystem, srcComponent) {
632607
633608
//timestamp_buf = msgbuf[-12:-6]
634609
var timestamp_buf= msgbuf.slice(-12,-6);
635610
636611
//link_id = msgbuf[-13]
637-
var link_id= new Buffer.from(msgbuf.slice(-13,-12)); // just a single byte really, but returned as a buffer
612+
var link_id = new Uint8Array.from(msgbuf.slice(-13,-12)); // just a single byte really, but returned as a buffer
638613
link_id = link_id[0]; // get the first byte.
639614
640615
//self.mav_sign_unpacker = jspack.Unpack('<IH')
641616
// (tlow, thigh) = self.mav_sign_unpacker.unpack(timestamp_buf)
642617
643-
// I means unsigned 4bytes, H means unsigned 2 byte
644-
var t = jspack.Unpack('<IH',new Buffer.from(timestamp_buf))
618+
// I means unsigned 4bytes, H means unsigned 2 bytes
619+
var t = jspack.Unpack('<IH',new Uint8Array.from(timestamp_buf))
645620
const [tlow, thigh] = t;
646621
647622
// due to js not being able to shift numbers more than 32, we'll use this instead..
@@ -682,24 +657,24 @@ def generate_mavlink_class(outf, msgs, xml):
682657
683658
// just the last 6 of 13 available are the actual sig . ie excluding the linkid(1) and timestamp(6)
684659
var sigpart = msgbuf.slice(-6);
685-
sigpart = new Buffer.from(sigpart);
660+
sigpart = new Uint8Array.from(sigpart);
686661
// not sig part 0- end-minus-6
687662
var notsigpart = msgbuf.slice(0,-6);
688-
notsigpart = new Buffer.from(notsigpart);
663+
notsigpart = new Uint8Array.from(notsigpart);
689664
690665
h.update(this.signing.secret_key); // secret is already a Buffer
691666
//var tmp = h.copy().digest();
692667
h.update(notsigpart);
693668
//var tmp2 = h.copy().digest()
694669
var hashDigest = h.digest();
695670
sig1 = hashDigest.slice(0,6)
696-
671+
697672
//sig1 = str(h.digest())[:6]
698673
//sig2 = str(msgbuf)[-6:]
699674
700675
// can't just compare sigs, need a full buffer compare like this...
701676
//if (sig1 != sigpart){
702-
if (Buffer.compare(sig1,sigpart)){
677+
if (Uint8Array.compare(sig1,sigpart)){
703678
//console.log('sig mismatch',sig1,sigpart)
704679
return false
705680
}
@@ -722,7 +697,7 @@ def generate_mavlink_class(outf, msgs, xml):
722697
# Mavlink2 only
723698
if (xml.protocol_marker == 253):
724699
t.write(outf, """
725-
unpacked = jspack.Unpack('cBBBBBBHB', msgbuf.slice(0, 10)); // the H in here causes msgIDlow to takeup 2 bytes, the rest 1
700+
unpacked = jspack.Unpack('BBBBBBBHB', msgbuf.slice(0, 10)); // the H in here causes msgIDlow to takeup 2 bytes, the rest 1
726701
magic = unpacked[0];
727702
mlen = unpacked[1];
728703
incompat_flags = unpacked[2];
@@ -778,8 +753,8 @@ def generate_mavlink_class(outf, msgs, xml):
778753
return;
779754
}
780755
781-
if (magic.charCodeAt(0) != this.protocol_marker) {
782-
throw new Error("Invalid MAVLink prefix ("+magic.charCodeAt(0)+")");
756+
if (magic != this.protocol_marker) {
757+
throw new Error("Invalid MAVLink prefix ("+magic+")");
783758
}
784759
785760
// is packet supposed to be signed?
@@ -807,13 +782,13 @@ def generate_mavlink_class(outf, msgs, xml):
807782
808783
}
809784
810-
if( false === _.has(${MAVHEAD}.map, msgId) ) {
785+
if (!(msgId in ${MAVHEAD}.map)) {
811786
throw new Error("Unknown MAVLink message ID (" + msgId + ")");
812787
}
813788
814789
// here's the common chunks of packet we want to work with below..
815-
var headerBuf= msgbuf.slice(${MAVHEAD}.HEADER_LEN); // first10
816-
var sigBuf = msgbuf.slice(-signature_len); // last 13 or nothing
790+
//var headerBuf= msgbuf.slice(${MAVHEAD}.HEADER_LEN); // first10
791+
//var sigBuf = msgbuf.slice(-signature_len); // last 13 or nothing
817792
var crcBuf1 = msgbuf.slice(-2); // either last-2 or last-2-prior-to-signature
818793
var crcBuf2 = msgbuf.slice(-15,-13); // either last-2 or last-2-prior-to-signature
819794
var payloadBuf = msgbuf.slice(${MAVHEAD}.HEADER_LEN, -(signature_len+2)); // the remaining bit between the header and the crc
@@ -893,9 +868,9 @@ def generate_mavlink_class(outf, msgs, xml):
893868
# Mavlink2 only
894869
if (xml.protocol_marker == 253):
895870
t.write(outf, """
896-
//put any truncated 0's back in (ie zero-pad )
871+
//put any truncated 0's back in (ie zero-pad )
897872
if (paylen > payloadBuf.length) {
898-
payloadBuf = Buffer.concat([payloadBuf, Buffer.alloc(paylen - payloadBuf.length)]);
873+
payloadBuf = this.concat_buffer(payloadBuf, new Uint8Array(paylen - payloadBuf.length).fill(0));
899874
}
900875
""")
901876

@@ -915,7 +890,7 @@ def generate_mavlink_class(outf, msgs, xml):
915890
916891
if (elementsInMsg == actualElementsInMsg) {
917892
// Reorder the fields to match the order map
918-
_.each(t, function(e, i, l) {
893+
t.forEach(function(e, i, l) {
919894
args[i] = t[decoder.order_map[i]]
920895
});
921896
} else {
@@ -959,7 +934,7 @@ def generate_mavlink_class(outf, msgs, xml):
959934
}
960935
961936
// Finally reorder the fields to match the order map
962-
_.each(t, function(e, i, l) {
937+
t.forEach(function(e, i, l) {
963938
args[i] = tempArgs[decoder.order_map[i]]
964939
});
965940
}

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