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Adding support for shift modified keycodes. Adding comments referenci… #4

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7b10a53
Adding support for shift modified keycodes. Adding comments referenci…
macyabbey Dec 9, 2018
556e4ae
Giving the right bit address for the different types of modifiers.
macyabbey Dec 14, 2018
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259 changes: 216 additions & 43 deletions src/usb-barcode-scanner-utils.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -13,50 +13,223 @@ export function getDeviceByPath(path: string): Device|undefined {
return _.find(getDevices(), { 'path': path });
}


/**
* Keyboard keycodes defined in USB HID Usage Tables specification
* https://www.usb.org/sites/default/files/documents/hut1_12v2.pdf
* Page 53
*
* Map is
*
* Usage Id (Decimal) : {
* unmodified: "<unmodified US english character>",
* shift: "<shift modified US english character>"
* }
*/
export function defaultHidMap(): Object {
return {
4: "A",
5: "B",
6: "C",
7: "D",
8: "E",
9: "F",
10: "G",
11: "H",
12: "I",
13: "J",
14: "K",
15: "L",
16: "M",
17: "N",
18: "O",
19: "P",
20: "Q",
21: "R",
22: "S",
23: "T",
24: "U",
25: "V",
26: "W",
27: "X",
28: "Y",
29: "Z",
30: "1",
31: "2",
32: "3",
33: "4",
34: "5",
35: "6",
36: "7",
37: "8",
38: "9",
39: "0",
40: "enter",
44: " ",
45: "-",
55: ".",
56: "/",
85: "*",
87: "+"
4: {
unmodified: "a",
shift: "A"
},
5: {
unmodified: "b",
shift: "B"
},
6: {
unmodified: "c",
shift: "C"
},
7: {
unmodified: "d",
shift: "D"
},
8: {
unmodified: "e",
shift: "E"
},
9: {
unmodified: "f",
shift: "F"
},
10: {
unmodified: "g",
shift: "G"
},
11: {
unmodified: "h",
shift: "H"
},
12: {
unmodified: "i",
shift: "I"
},
13: {
unmodified: "j",
shift: "J"
},
14: {
unmodified: "k",
shift: "K"
},
15: {
unmodified: "l",
shift: "L"
},
16: {
unmodified: "m",
shift: "M"
},
17: {
unmodified: "n",
shift: "N"
},
18: {
unmodified: "o",
shift: "O"
},
19: {
unmodified: "p",
shift: "P"
},
20: {
unmodified: "q",
shift: "Q"
},
21: {
unmodified: "r",
shift: "R"
},
22: {
unmodified: "s",
shift: "S"
},
23: {
unmodified: "t",
shift: "T"
},
24: {
unmodified: "u",
shift: "U"
},
25: {
unmodified: "v",
shift: "V"
},
26: {
unmodified: "w",
shift: "W"
},
27: {
unmodified: "x",
shift: "X"
},
28: {
unmodified: "y",
shift: "Y"
},
29: {
unmodified: "z",
shift: "Z"
},
30: {
unmodified: "1",
shift: "!"
},
31: {
unmodified: "2",
shift: "@"
},
32: {
unmodified: "3",
shift: "#"
},
33: {
unmodified: "4",
shift: "$"
},
34: {
unmodified: "5",
shift: "%"
},
35: {
unmodified: "6",
shift: "^"
},
36: {
unmodified: "7",
shift: "&"
},
37: {
unmodified: "8",
shift: "*"
},
38: {
unmodified: "9",
shift: "("
},
39: {
unmodified: "0",
shift: ")"
},
40: {
unmodified: "enter"
},
43: {
unmodified: "\t",
},
44: {
unmodified: " "
},
45: {
unmodified: "-",
shift: "_"
},
46: {
unmodified: "=",
shift: "+"
},
47: {
unmodified: "[",
shift: "{"
},
48: {
unmodified: "]",
shift: "}"
},
49: {
unmodified: "\\",
shift: "|"
},
51: {
unmodified: ";",
shift: ":"
},
52: {
unmodified: "'",
shift: "\""
},
53: {
unmodified: "`",
shift: "~"
},
54: {
unmodified: ",",
shift: "<"
},
55: {
unmodified: ".",
shift: ">"
},
56: {
unmodified: "/",
shift: "?"
},
85: {
unmodified: "*",
},
87: {
unmodified: "+"
}
}
}
54 changes: 51 additions & 3 deletions src/usb-barcode-scanner.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -41,14 +41,62 @@ export class UsbScanner extends EventEmitter implements onDataScanned {
}

startScanning(): void {
/**
* USB HID Report Specification: https://www.usb.org/sites/default/files/documents/hid1_11.pdf
* Starting Page 55
*
* Note USB barcode scanners always send a "input" type report which is a "long item" of 8 bytes.
*/

/**
* Page 60 in the specification
*/
const HID_REPORT_BYTE_SIGNIFICANCE = {
MODIFIER: 0,
RESERVED: 1,
KEY_CODE_1: 2,
KEY_CODE_2: 3,
KEY_CODE_3: 4,
KEY_CODE_4: 5,
KEY_CODE_5: 6,
KEY_CODE_6: 7
};

const MODIFIER_BITS = {
LEFT_CTRL: 0x1,
LEFT_SHIFT: 0x2,
LEFT_ALT: 0x3,
LEFT_GUI: 0x4,
RIGHT_CTRL: 0x5,
RIGHT_SHIFT: 0x6,
RIGHT_ALT: 0x7,
RIGHT_GUI: 0x8

@jie-meng jie-meng Aug 8, 2019 •
edited
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Should be

const MODIFIER_BITS = {
    LEFT_CTRL: 0x1,
    LEFT_SHIFT: 0x2,
    LEFT_ALT: 0x4,
    LEFT_GUI: 0x8,
    RIGHT_CTRL: 0x10,
    RIGHT_SHIFT: 0x20,
    RIGHT_ALT: 0x40,
    RIGHT_GUI: 0x80,
};

};

const REPORT_ENDING_KEY_CODE = 40;

let bcodeBuffer: string[] = [];
let barcode: string = '';

if (this.hid) {
this.hid.on('data', (chunk) => {
if (this.hidMap[chunk[2]]) {
if (chunk[2] !== 40) {
bcodeBuffer.push(this.hidMap[chunk[2]]);
let keyCode1 = chunk[HID_REPORT_BYTE_SIGNIFICANCE.KEY_CODE_1];
let modifierByte = chunk[HID_REPORT_BYTE_SIGNIFICANCE.MODIFIER];
let isShiftModified = modifierByte & MODIFIER_BITS.LEFT_SHIFT || modifierByte & MODIFIER_BITS.RIGHT_SHIFT;
if (keyCode1) {
if (keyCode1 !== REPORT_ENDING_KEY_CODE) {
let hidMapEntry = this.hidMap[keyCode1];
if (hidMapEntry) {
if (typeof hidMapEntry === 'object') {
if (isShiftModified && hidMapEntry.shift) {
bcodeBuffer.push(hidMapEntry.shift);
} else {
bcodeBuffer.push(hidMapEntry.unmodified);
}
} else {
bcodeBuffer.push(hidMapEntry);
}
}
} else {
barcode = bcodeBuffer.join("");
bcodeBuffer = [];
Expand Down