src/FileArea.cpp

   1 //
   2 // This file is part of the aMule Project.
   3 //
   4 // Copyright (c) 2003-2008 aMule Team ( admin@amule.org / http://www.amule.org )
   5 // Copyright (c) 1998 Vadim Zeitlin ( zeitlin@dptmaths.ens-cachan.fr )
   6 //
   7 // Any parts of this program derived from the xMule, lMule or eMule project,
   8 // or contributed by third-party developers are copyrighted by their
   9 // respective authors.
  10 //
  11 // This program is free software; you can redistribute it and/or modify
  12 // it under the terms of the GNU General Public License as published by
  13 // the Free Software Foundation; either version 2 of the License, or
  14 // (at your option) any later version.
  15 //
  16 // This program is distributed in the hope that it will be useful,
  17 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 // GNU General Public License for more details.
  20 //
  21 // You should have received a copy of the GNU General Public License
  22 // along with this program; if not, write to the Free Software
  23 // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA
  24 //
  25
  26
  27 #include "FileArea.h"           // Interface declarations.
  28 #include "Logger.h"             // Needed for AddDebugLogLineM
  29
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include "config.h"
  33 #endif
  34
  35 #ifdef HAVE_SYS_MMAN_H
  36 #include <sys/mman.h>
  37 #endif
  38
  39
  40 CFileArea::CFileArea()
  41         : m_buffer(NULL), m_mmap_buffer(NULL), m_length(0),
  42           m_fd(CFile::fd_invalid)
  43 {
  44 }
  45
  46
  47 CFileArea::~CFileArea()
  48 {
  49         Close();
  50 }
  51
  52 bool CFileArea::Close()
  53 {
  54         if (m_fd != CFile::fd_invalid)
  55         {
  56                 close(m_fd);
  57                 m_fd = CFile::fd_invalid;
  58         }
  59         if (m_buffer != NULL && m_mmap_buffer == NULL)
  60         {
  61                 delete[] m_buffer;
  62                 m_buffer = NULL;
  63         }
  64 #ifdef HAVE_MMAP
  65         #warning using experimental MMAP file reading
  66         if (m_mmap_buffer)
  67         {
  68                 munmap(m_mmap_buffer, m_length);
  69                 m_mmap_buffer = NULL;
  70         }
  71 #endif
  72         return true;
  73 }
  74
  75
  76 void CFileArea::Read(const CFile& file, size_t count)
  77 {
  78         Close();
  79
  80 #ifdef HAVE_MMAP
  81         const uint64 pageSize = 8192u;
  82         uint64 offset = file.GetPosition();
  83         uint64 offStart = offset & (~(pageSize-1));
  84         uint64 offEnd = (offset + count + pageSize - 1) & (~(pageSize-1));
  85         m_length = offEnd - offStart;
  86         void *p = mmap(NULL, m_length, PROT_READ, MAP_SHARED, file.fd(), offStart);
  87         if (p != MAP_FAILED)
  88         {
  89                 m_mmap_buffer = (byte*) p;
  90                 m_buffer = m_mmap_buffer + (offset - offStart);
  91                 file.Seek(offset + count);
  92                 return;
  93         }
  94 #endif
  95         m_buffer = new byte[count];
  96         file.Read(m_buffer, count);
  97 }
  98
  99 bool CFileArea::Flush()
 100 {
 101         /* currently we don't support write */
 102         return true;
 103 }
 104