/*
 *
 * Copyright 2016, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 *
 */
#if SWIFT_PACKAGE
  import CgRPC
#endif
import Foundation // for String.Encoding

/// Representation of raw data that may be sent and received using gRPC
public class ByteBuffer {

  /// Pointer to underlying C representation
  internal var underlyingByteBuffer: UnsafeMutableRawPointer!

  /// Creates a ByteBuffer from an underlying C representation.
  /// The ByteBuffer takes ownership of the passed-in representation.
  ///
  /// - Parameter underlyingByteBuffer: the underlying C representation
  internal init(underlyingByteBuffer: UnsafeMutableRawPointer) {
    self.underlyingByteBuffer = underlyingByteBuffer
  }

  /// Creates a byte buffer that contains a copy of the contents of `data`
  ///
  /// - Parameter data: the data to store in the buffer
  public init(data: Data) {
    data.withUnsafeBytes { (bytes) in
      underlyingByteBuffer = cgrpc_byte_buffer_create_by_copying_data(bytes, data.count)
    }
  }

  deinit {
    cgrpc_byte_buffer_destroy(underlyingByteBuffer);
  }

  /// Gets data from the contents of the ByteBuffer
  ///
  /// - Returns: data formed from the ByteBuffer contents
  public func data() -> Data? {
    var length : Int = 0
    guard let bytes = cgrpc_byte_buffer_copy_data(underlyingByteBuffer, &length) else {
      return nil
    }
    return Data(bytesNoCopy: UnsafeMutableRawPointer(mutating: bytes),
                count: length,
                deallocator: .free)
  }
}