Add 'buffer.manager.ts'

buffer.manager.ts

@@ -0,0 +1,33 @@
+export class BufferManager {
+
+  private buffer: Buffer;
+
+  constructor(
+    private readonly maxBufferSize: number,
+  ) {
+    this.buffer = Buffer.alloc(0);
+  }
+
+  hasRoom(chunk: Buffer): boolean {
+    return chunk.length + this.buffer.length <= this.maxBufferSize;
+  }
+
+  append(chunk: Buffer) {
+
+    if (!this.hasRoom(chunk)) {
+      throw new Error('Buffer overflow - data will be lost. Check hasRoom before calling');
+    }
+
+    this.buffer = Buffer.concat([this.buffer, chunk]);
+  }
+
+  appendAndGetCompletedBuffer(chunk: Buffer): Buffer {
+
+    const fillSize = this.maxBufferSize - this.buffer.length;
+    const completedBuffer = Buffer.concat([this.buffer, chunk.slice(0, fillSize)]);
+
+    this.buffer = Buffer.from(chunk.slice(fillSize, chunk.length)); // ??? could be an issue
+
+    return completedBuffer;
+  }
+}