content: /*
   * Copyright 2020  Google LLC
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.taobao.arthas.grpcweb.proxy;
  
  /**
   * Creates frames from the input bytes.
   */
  public class MessageFramer {
    public enum Type {
      DATA ((byte) 0x00),
      TRAILER ((byte) 0x80);
  
      public final byte value;
      Type(byte b) {
        value = b;
      }
    }
  
    // TODO: handle more than single frame; i.e., input byte array size > (2GB - 1)
    public byte[] getPrefix(byte[] in, Type type) {
      int len = in.length;
      return new byte[] {
          type.value,
          (byte) ((len >> 24) & 0xff),
          (byte) ((len >> 16) & 0xff),
          (byte) ((len >> 8) & 0xff),
          (byte) ((len >> 0) & 0xff),
      };
    }
  }
  