nova-tt/semaphore_win32.hpp

   1 //  semaphore class, win32 wrapper
   2 //  based on API proposed in N2043
   3 //
   4 //  Copyright (C) 2008, 2009 Tim Blechmann
   5 //
   6 //  This program is free software; you can redistribute it and/or modify
   7 //  it under the terms of the GNU General Public License as published by
   8 //  the Free Software Foundation; either version 2 of the License, or
   9 //  (at your option) any later version.
  10 //
  11 //  This program is distributed in the hope that it will be useful,
  12 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 //  GNU General Public License for more details.
  15 //
  16 //  You should have received a copy of the GNU General Public License
  17 //  along with this program; see the file COPYING.  If not, write to
  18 //  the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 //  Boston, MA 02111-1307, USA.
  20
  21 #ifndef NOVA_TT_SEMAPHORE_WIN32_HPP
  22 #define NOVA_TT_SEMAPHORE_WIN32_HPP
  23
  24 #include <cassert>
  25 #include <limits>
  26
  27 #include <boost/noncopyable.hpp>
  28 #include <boost/static_assert.hpp>
  29
  30 #include <windows.h>
  31
  32 namespace nova {
  33 namespace nova_tt {
  34
  35 /** semaphore class */
  36 template <bool has_timed_wait = false>
  37 class semaphore:
  38     boost::noncopyable
  39 {
  40 public:
  41     semaphore(unsigned int i=0)
  42     {
  43         ghSemaphore = CreateSemaphore(
  44             NULL,           // default security attributes
  45             i,  // initial count
  46             (std::numeric_limits<LONG>::numeric_limits::max)(),  // maximum count
  47             NULL);          // unnamed semaphore
  48         assert(ghSemaphore != NULL);
  49         //TODO: take care of NULL return -> exception
  50         //printf("CreateSemaphore error: %d\n", GetLastError());
  51     }
  52
  53     ~semaphore(void)
  54     {
  55         CloseHandle(ghSemaphore);
  56     }
  57
  58     /** signal semaphore */
  59     void post(void)
  60     {
  61         int status = ReleaseSemaphore(
  62                         ghSemaphore,  // handle to semaphore
  63                         1,            // increase count by one
  64                         NULL);      // not interested in previous count
  65         assert(status != 0);
  66         //TODO report:
  67         //printf("ReleaseSemaphore error: %d\n", GetLastError());
  68     }
  69
  70     /** wait until this semaphore is signaled */
  71     void wait(void)
  72     {
  73         int status = WaitForSingleObject(
  74             ghSemaphore,
  75             INFINITE);           // wait forever
  76         assert(status == 0);
  77         //TODO: report error status
  78     }
  79
  80     /** try to wait for the semaphore
  81      *
  82      * \return true, if the value can be decremented
  83      *         false, otherweise
  84      */
  85     bool try_wait(void)
  86     {
  87         int status = WaitForSingleObject(
  88             ghSemaphore,
  89             0L);           // zero-second time-out interval
  90         return status == 0;
  91     }
  92
  93     /** try to wait for the semaphore until timeout
  94      *
  95      * \return true, if the value can be decremented
  96      *         false, otherweise
  97      */
  98     bool timed_wait(struct timespec const & absolute_timeout)
  99     {
 100         long milisecons = 0 ;//TODO absolute_timeout - now
 101         BOOST_STATIC_ASSERT(has_timed_wait);
 102         int status = WaitForSingleObject(
 103             ghSemaphore,
 104             milisecons);   // zero-second time-out interval
 105         return status == 0;
 106     }
 107
 108     int value(void)
 109     {
 110         int ret;
 111         bool status = ReleaseSemaphore( ghSemaphore, 0, (long*)&ret );
 112         assert(status == 0);
 113         if (ret < 0)
 114             return 0;
 115         else
 116             return ret;
 117     }
 118
 119 private:
 120     HANDLE ghSemaphore;
 121 };
 122
 123 } // namespace nova_tt
 124 } // namespace nova
 125
 126 #endif /* NOVA_TT_SEMAPHORE_WIN32_HPP */