1// Copyright (c) 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef LIBRARIES_NACL_IO_FIFO_CHAR_H_
6#define LIBRARIES_NACL_IO_FIFO_CHAR_H_
7
8#include <vector>
9
10#include "nacl_io/fifo_interface.h"
11
12#include "sdk_util/macros.h"
13
14namespace nacl_io {
15
16// FIFOChar
17//
18// A FIFOChar is a circular buffer, signalling FULL and EMPTY as appropriate.
19class FIFOChar : public FIFOInterface {
20 public:
21  explicit FIFOChar(size_t size);
22  virtual ~FIFOChar();
23
24  virtual bool IsEmpty();
25  virtual bool IsFull();
26  virtual bool Resize(size_t len);
27
28  virtual size_t ReadAvailable();
29  virtual size_t WriteAvailable();
30
31  // Reads out no more than the requested len without updating the tail.
32  // Returns actual amount read.
33  size_t Peek(void* buf, size_t len);
34
35  // Reads out the data making room in the FIFO.  Returns actual amount
36  // read.
37  size_t Read(void* buf, size_t len);
38
39  // Writes into the FIFO no more than len bytes, returns actual amount
40  // written.
41  size_t Write(const void* buf, size_t len);
42
43 private:
44  char* buffer_;
45  size_t size_;   // Size of the FIFO
46  size_t avail_;  // How much data is currently available
47  size_t tail_;   // Next read location
48
49  DISALLOW_COPY_AND_ASSIGN(FIFOChar);
50};
51
52}  // namespace nacl_io
53
54#endif  // LIBRARIES_NACL_IO_FIFO_CHAR_H_
55