native_client_sdk/src/libraries/nacl_io/fifo_char.h

   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
  14 namespace nacl_io {
  15
  16 // FIFOChar
  17 //
  18 // A FIFOChar is a circular buffer, signalling FULL and EMPTY as appropriate.
  19 class 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_