xbmc/filesystem/CircularCache.h

   1 /*
   2  *  Copyright (C) 2005-2018 Team Kodi
   3  *  This file is part of Kodi - https://kodi.tv
   4  *
   5  *  SPDX-License-Identifier: GPL-2.0-or-later
   6  *  See LICENSES/README.md for more information.
   7  */
   8
   9 #pragma once
  10
  11 #include "CacheStrategy.h"
  12 #include "threads/CriticalSection.h"
  13 #include "threads/Event.h"
  14
  15 namespace XFILE {
  16
  17 class CCircularCache : public CCacheStrategy
  18 {
  19 public:
  20     CCircularCache(size_t front, size_t back);
  21     ~CCircularCache() override;
  22
  23     int Open() override;
  24     void Close() override;
  25
  26     size_t GetMaxWriteSize(const size_t& iRequestSize) override;
  27     int WriteToCache(const char *buf, size_t len) override;
  28     int ReadFromCache(char *buf, size_t len) override;
  29     int64_t WaitForData(uint32_t minimum, std::chrono::milliseconds timeout) override;
  30
  31     int64_t Seek(int64_t pos) override;
  32     bool Reset(int64_t pos) override;
  33
  34     int64_t CachedDataEndPosIfSeekTo(int64_t iFilePosition) override;
  35     int64_t CachedDataStartPos() override;
  36     int64_t CachedDataEndPos() override;
  37     bool IsCachedPosition(int64_t iFilePosition) override;
  38
  39     CCacheStrategy *CreateNew() override;
  40 protected:
  41     int64_t           m_beg;       /**< index in file (not buffer) of beginning of valid data */
  42     int64_t           m_end;       /**< index in file (not buffer) of end of valid data */
  43     int64_t           m_cur;       /**< current reading index in file */
  44     uint8_t          *m_buf;       /**< buffer holding data */
  45     size_t            m_size;      /**< size of data buffer used (m_buf) */
  46     size_t            m_size_back; /**< guaranteed size of back buffer (actual size can be smaller, or larger if front buffer doesn't need it) */
  47     CCriticalSection  m_sync;
  48     CEvent            m_written;
  49 #ifdef TARGET_WINDOWS
  50     HANDLE            m_handle;
  51 #endif
  52 };
  53
  54 } // namespace XFILE
  55