Initial commit

node_modules/@serialport/parser-slip-encoder/dist/encoder.js

@@ -0,0 +1,63 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.SlipEncoder = void 0;
+const stream_1 = require("stream");
+/**
+ * A transform stream that emits SLIP-encoded data for each incoming packet.
+ *
+ * Runs in O(n) time, adding a 0xC0 character at the end of each
+ * received packet and escaping characters, according to RFC 1055.
+ */
+class SlipEncoder extends stream_1.Transform {
+    opts;
+    constructor(options = {}) {
+        super(options);
+        const { START, ESC = 0xdb, END = 0xc0, ESC_START, ESC_END = 0xdc, ESC_ESC = 0xdd, bluetoothQuirk = false } = options;
+        this.opts = {
+            START,
+            ESC,
+            END,
+            ESC_START,
+            ESC_END,
+            ESC_ESC,
+            bluetoothQuirk,
+        };
+    }
+    _transform(chunk, encoding, cb) {
+        const chunkLength = chunk.length;
+        if (this.opts.bluetoothQuirk && chunkLength === 0) {
+            // Edge case: push no data. Bluetooth-quirky SLIP parsers don't like
+            // lots of 0xC0s together.
+            return cb();
+        }
+        // Allocate memory for the worst-case scenario: all bytes are escaped,
+        // plus start and end separators.
+        const encoded = Buffer.alloc(chunkLength * 2 + 2);
+        let j = 0;
+        if (this.opts.bluetoothQuirk == true) {
+            encoded[j++] = this.opts.END;
+        }
+        if (this.opts.START !== undefined) {
+            encoded[j++] = this.opts.START;
+        }
+        for (let i = 0; i < chunkLength; i++) {
+            let byte = chunk[i];
+            if (byte === this.opts.START && this.opts.ESC_START) {
+                encoded[j++] = this.opts.ESC;
+                byte = this.opts.ESC_START;
+            }
+            else if (byte === this.opts.END) {
+                encoded[j++] = this.opts.ESC;
+                byte = this.opts.ESC_END;
+            }
+            else if (byte === this.opts.ESC) {
+                encoded[j++] = this.opts.ESC;
+                byte = this.opts.ESC_ESC;
+            }
+            encoded[j++] = byte;
+        }
+        encoded[j++] = this.opts.END;
+        cb(null, encoded.slice(0, j));
+    }
+}
+exports.SlipEncoder = SlipEncoder;