mirror of https://github.com/espruino/BangleApps
131 lines
3.4 KiB
JavaScript
131 lines
3.4 KiB
JavaScript
// Encoding documentation:
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// https://en.wikipedia.org/wiki/Code_39#Encoding
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/*
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* JS source adapted from https://github.com/lindell/JsBarcode
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2016 Johan Lindell (johan@lindell.me)
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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const Barcode = require("cards.Barcode.js");
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class CODE39 extends Barcode {
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constructor(data, options){
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data = data.toUpperCase();
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// Calculate mod43 checksum if enabled
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if(options.mod43){
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data += getCharacter(mod43checksum(data));
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}
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super(data, options);
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}
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encode(){
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// First character is always a *
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var result = getEncoding("*");
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// Take every character and add the binary representation to the result
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for(let i = 0; i < this.data.length; i++){
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result += getEncoding(this.data[i]) + "0";
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}
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// Last character is always a *
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result += getEncoding("*");
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return {
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data: result,
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text: this.text
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};
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}
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valid(){
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return /^[0-9A-Z\-\.\ \$\/\+\%]+$/.test(this.data);
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}
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}
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// All characters. The position in the array is the (checksum) value
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var characters = [
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"0", "1", "2", "3",
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"4", "5", "6", "7",
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"8", "9", "A", "B",
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"C", "D", "E", "F",
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"G", "H", "I", "J",
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"K", "L", "M", "N",
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"O", "P", "Q", "R",
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"S", "T", "U", "V",
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"W", "X", "Y", "Z",
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"-", ".", " ", "$",
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"/", "+", "%", "*"
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];
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// The decimal representation of the characters, is converted to the
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// corresponding binary with the getEncoding function
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var encodings = [
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20957, 29783, 23639, 30485,
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20951, 29813, 23669, 20855,
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29789, 23645, 29975, 23831,
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30533, 22295, 30149, 24005,
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21623, 29981, 23837, 22301,
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30023, 23879, 30545, 22343,
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30161, 24017, 21959, 30065,
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23921, 22385, 29015, 18263,
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29141, 17879, 29045, 18293,
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17783, 29021, 18269, 17477,
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17489, 17681, 20753, 35770
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];
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// Get the binary representation of a character by converting the encodings
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// from decimal to binary
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function getEncoding(character){
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return getBinary(characterValue(character));
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}
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function getBinary(characterValue){
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return encodings[characterValue].toString(2);
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}
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function getCharacter(characterValue){
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return characters[characterValue];
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}
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function characterValue(character){
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return characters.indexOf(character);
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}
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function mod43checksum(data){
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var checksum = 0;
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for(let i = 0; i < data.length; i++){
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checksum += characterValue(data[i]);
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}
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checksum = checksum % 43;
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return checksum;
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}
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module.exports = CODE39;
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