Initial

test/imaps/node_modules/base64-stream/lib/decode.js

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+const { Transform } = require('stream');
+
+/**
+ * Decodes a Base64 data stream, coming in as a string or Buffer of UTF-8 text, into binary Buffers.
+ * @extends Transform
+ */
+module.exports = class Base64Decode extends Transform {
+    /**
+     * Create a Base64Decode
+     */
+    constructor() {
+        super({ decodeStrings: false });
+        // Any extra chars from the last chunk
+        this.extra = '';
+    }
+
+    /**
+     * Decodes a Base64 data stream, coming in as a string or Buffer of UTF-8 text, into binary Buffers.
+     * @param {Buffer|string} chunk
+     * @param encoding
+     * @param cb
+     * @private
+     */
+    _transform(chunk, encoding, cb) {
+        // Convert chunk to a string
+        chunk = '' + chunk;
+
+        // Add previous extra and remove any newline characters
+        chunk = this.extra + chunk.replace(/(\r\n|\n|\r)/gm, '');
+
+        // 4 characters represent 3 bytes, so we can only decode in groups of 4 chars
+        const remaining = chunk.length % 4;
+
+        // Store the extra chars for later
+        this.extra = chunk.slice(chunk.length - remaining);
+        chunk = chunk.slice(0, chunk.length - remaining);
+
+        // Create the new buffer and push
+        const buf = Buffer.from(chunk, 'base64');
+        this.push(buf);
+        cb();
+    }
+
+    /**
+     * Emits 1, 2, or 3 extra characters of base64 data.
+     * @param cb
+     * @private
+     */
+    _flush(cb) {
+        if (this.extra.length) {
+            this.push(Buffer.from(this.extra, 'base64'));
+        }
+
+        cb();
+    }
+};