Setup Decimal/Hex to binary for buffer-parser

General
1

I'm having trouble converting a single decimal to binary and then parsing it with buffer-parser.
Let say I have decimal number 256. I'm converting that to a binary string and then into a buffer.

var payload = msg.payload.toString(2);
msg.payload = Buffer.from(payload, "utf-8");
return msg;

My buffer = 100000000

The issue i'm having is Buffer-parser sets bit 0 as true instead of bit 8.

[true,false,false,false,false,false,false,false,false,false,false,false,false,false,false,false,false]

I'm expecting a result with bit 8 as true.
Is there a proper way to get this binary data into buffer-parser?

2

So this is what I've come up with so far but it seems kind of convoluted.
Also I'm having trouble getting a number out of bits 3-7.

[
    {
        "id": "f49454a0393f7fa0",
        "type": "inject",
        "z": "d03c03b6d2f91f47",
        "name": "",
        "props": [
            {
                "p": "payload"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "256",
        "payloadType": "num",
        "x": 190,
        "y": 1580,
        "wires": [
            [
                "24264fdf5894afce"
            ]
        ]
    },
    {
        "id": "57da651af048c75b",
        "type": "debug",
        "z": "d03c03b6d2f91f47",
        "name": "",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 790,
        "y": 1580,
        "wires": []
    },
    {
        "id": "24264fdf5894afce",
        "type": "function",
        "z": "d03c03b6d2f91f47",
        "name": "function 11",
        "func": "var payload = (msg.payload.toString(2));\npayload = ([...payload].reverse().join(\"\")).split(\"\")\nvar delay = 250; //I shortened your delay\nvar ticker = \"0\";\nvar array = payload\ndo {\n\n    if (payload.length < 21) {\n        array.push(ticker);\n\n    }\n}\nwhile (payload.length < 21)\n\nmsg.buffer = array\n\nmsg.payload = (Buffer.from(payload, \"binary\"));\n\n\n\nreturn msg;\n",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 370,
        "y": 1580,
        "wires": [
            [
                "f8f80d3e98422312"
            ]
        ]
    },
    {
        "id": "f8f80d3e98422312",
        "type": "buffer-parser",
        "z": "d03c03b6d2f91f47",
        "name": "",
        "data": "payload",
        "dataType": "msg",
        "specification": "spec",
        "specificationType": "ui",
        "items": [
            {
                "type": "bool",
                "name": "first_message_after_reset",
                "offset": 0,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "user_button_triggered",
                "offset": 1,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "user_BLE_triggered",
                "offset": 2,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "buffer",
                "name": "retries",
                "offset": 3,
                "length": 5,
                "offsetbit": 0,
                "scale": "1",
                "mask": ""
            },
            {
                "type": "bool",
                "name": "Rule1",
                "offset": 8,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule2",
                "offset": 9,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule3",
                "offset": 10,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule4",
                "offset": 11,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule5",
                "offset": 12,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule6",
                "offset": 13,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule7",
                "offset": 14,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule8",
                "offset": 15,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule9",
                "offset": 16,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule10",
                "offset": 17,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule11",
                "offset": 18,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "Rule12",
                "offset": 19,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            },
            {
                "type": "bool",
                "name": "end_of_transfer_limit",
                "offset": 20,
                "length": 1,
                "offsetbit": 0,
                "scale": "1",
                "mask": "1"
            }
        ],
        "swap1": "",
        "swap2": "",
        "swap3": "",
        "swap1Type": "swap",
        "swap2Type": "swap",
        "swap3Type": "swap",
        "msgProperty": "payload",
        "msgPropertyType": "str",
        "resultType": "keyvalue",
        "resultTypeType": "return",
        "multipleResult": false,
        "fanOutMultipleResult": false,
        "setTopic": true,
        "outputs": 1,
        "x": 610,
        "y": 1580,
        "wires": [
            [
                "57da651af048c75b"
            ]
        ]
    }
]

2023-12-21_15-28-39
2023-12-21_15-28-39823×116 4.96 KB

3

The issue is to do with byte swap / system architecture etc.

Here is how you can handle it in 3 different ways:

chrome_ODhvuI4Bar

Demo flow (use CTRL+I to import)

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4

Hi Steve, thanks very much for the example. I should have included in my first post that my source is a uint32 integer.
So for example 1048832.
I'm struggling getting this into a format that will work with 32 byte swap.

5

This seems to work.

msg.payload = msg.payload.toString(2).padStart(32, "0");
msg.payload = (Buffer.from(msg.payload, "utf8"));

return msg;

*I take that back. I just got lucky with number 1048832.

6

We should go back to the beginning.

Do you actually need to be converting bit strings?

What is the source data - a 32 bit UINT?

7

The source is from a CoAP payload. Processed through a proto buff with this information provided.

  /* Reason of transmission - unsigned integer where each bit indicates different possible communication reason.                */
  /* Can be more than one:                                                                                                      */
  /*  - bit 0: first message after sensor reset                                                                                 */
  /*  - bit 1: user button triggered                                                                                            */
  /*  - bit 2: user BLE triggered                                                                                               */
  /*  - bit 3-7: number of retries -> incremented after each unsuccessful transmission. Max value 31.                            */
  /*                                  Set to 0 after a successful transmission.                                                 */
  /*  - bit 8...19: rule 1...12 was met                                                                                         */
  /*  - bit 20: triggered after the end of the limit                                                                            */
  uint32 transfer_reason = 6;
8

Send it through a buffer maker (1 row, uint32) to generate a buffer , pass that to buffer parser (use the example I posted earlier)

9

Ah it's always so simple in the end. Thanks again.

10

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