00001 #ifndef XRD_CLI_READAHEAD 00002 #define XRD_CLI_READAHEAD 00003 /******************************************************************************/ 00004 /* */ 00005 /* X r d C l i e n t R e a d A h e a d . h h */ 00006 /* */ 00007 /* Author: Fabrizio Furano (CERN IT-DM, 2009) */ 00008 /* */ 00009 /* This file is part of the XRootD software suite. */ 00010 /* */ 00011 /* XRootD is free software: you can redistribute it and/or modify it under */ 00012 /* the terms of the GNU Lesser General Public License as published by the */ 00013 /* Free Software Foundation, either version 3 of the License, or (at your */ 00014 /* option) any later version. */ 00015 /* */ 00016 /* XRootD is distributed in the hope that it will be useful, but WITHOUT */ 00017 /* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or */ 00018 /* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public */ 00019 /* License for more details. */ 00020 /* */ 00021 /* You should have received a copy of the GNU Lesser General Public License */ 00022 /* along with XRootD in a file called COPYING.LESSER (LGPL license) and file */ 00023 /* COPYING (GPL license). If not, see <http://www.gnu.org/licenses/>. */ 00024 /* */ 00025 /* The copyright holder's institutional names and contributor's names may not */ 00026 /* be used to endorse or promote products derived from this software without */ 00027 /* specific prior written permission of the institution or contributor. */ 00028 /******************************************************************************/ 00029 00031 // // 00032 // Classes to implement a selectable read ahead decision maker // 00033 // // 00035 00036 class XrdClientReadAheadMgr { 00037 public: 00038 enum XrdClient_RAStrategy { 00039 RAStr_none, 00040 RAStr_pureseq, 00041 RAStr_SlidingAvg 00042 }; 00043 00044 protected: 00045 long RASize; 00046 XrdClient_RAStrategy currstrategy; 00047 00048 public: 00049 00050 static XrdClientReadAheadMgr *CreateReadAheadMgr(XrdClient_RAStrategy strategy); 00051 00052 00053 XrdClientReadAheadMgr() { RASize = 0; }; 00054 virtual ~XrdClientReadAheadMgr() {}; 00055 00056 virtual int GetReadAheadHint(long long offset, long len, long long &raoffset, long &ralen, long blksize) = 0; 00057 virtual int Reset() = 0; 00058 virtual void SetRASize(long bytes) { RASize = bytes; }; 00059 00060 static bool TrimReadRequest(long long &offs, long &len, long rasize, long blksize); 00061 00062 XrdClient_RAStrategy GetCurrentStrategy() { return currstrategy; } 00063 }; 00064 #endif