GNU Radio 3.5.1 C++ API
gr_vmcircbuf.h
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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2003 Free Software Foundation, Inc.
00004  * 
00005  * This file is part of GNU Radio
00006  * 
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 3, or (at your option)
00010  * any later version.
00011  * 
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  * 
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 51 Franklin Street,
00020  * Boston, MA 02110-1301, USA.
00021  */
00022 
00023 #ifndef _GR_VMCIRCBUF_H_
00024 #define _GR_VMCIRCBUF_H_
00025 
00026 #include <gr_core_api.h>
00027 #include <vector>
00028 
00029 /*!
00030  * \brief abstract class to implement doubly mapped virtual memory circular buffers
00031  * \ingroup internal
00032  */
00033 class GR_CORE_API gr_vmcircbuf {
00034  protected:
00035   int    d_size;
00036   char  *d_base;
00037 
00038   // CREATORS
00039   gr_vmcircbuf (int size) : d_size (size), d_base (0) {};
00040 
00041  public:
00042   virtual ~gr_vmcircbuf ();
00043 
00044   // ACCESSORS
00045   void *pointer_to_first_copy ()  const { return d_base; }
00046   void *pointer_to_second_copy () const { return d_base + d_size; }
00047 };
00048 
00049 /*!
00050  * \brief abstract factory for creating circular buffers
00051  */
00052 class GR_CORE_API gr_vmcircbuf_factory {
00053  protected:
00054   gr_vmcircbuf_factory () {};
00055   virtual ~gr_vmcircbuf_factory ();
00056 
00057  public:
00058 
00059   /*!
00060    * \brief return name of this factory
00061    */
00062   virtual const char *name () const = 0;
00063 
00064   /*!
00065    * \brief return granularity of mapping, typically equal to page size
00066    */
00067   virtual int granularity () = 0;
00068 
00069   /*!
00070    * \brief return a gr_vmcircbuf, or 0 if unable.
00071    *
00072    * Call this to create a doubly mapped circular buffer.
00073    */
00074   virtual gr_vmcircbuf *make (int size) = 0;
00075 };
00076 
00077 /*
00078  * \brief pulls together all implementations of gr_vmcircbuf
00079  */
00080 class GR_CORE_API gr_vmcircbuf_sysconfig {
00081  public:
00082 
00083   /*
00084    * \brief return the single instance of the default factory.
00085    *
00086    * returns the default factory to use if it's already defined,
00087    * else find the first working factory and use it.
00088    */
00089   static gr_vmcircbuf_factory *get_default_factory ();
00090 
00091     
00092   static int granularity ()            { return get_default_factory()->granularity(); }
00093   static gr_vmcircbuf *make (int size) { return get_default_factory()->make(size);    }
00094   
00095 
00096   // N.B. not all factories are guaranteed to work.
00097   // It's too hard to check everything at config time, so we check at runtime
00098   static std::vector<gr_vmcircbuf_factory *> all_factories ();
00099 
00100   // make this factory the default
00101   static void set_default_factory (gr_vmcircbuf_factory *f);
00102 
00103   /*!
00104    * \brief  Does this factory really work?
00105    *
00106    * verbose = 0: silent
00107    * verbose = 1: names of factories tested and results
00108    * verbose = 2: all intermediate results
00109    */
00110   static bool test_factory (gr_vmcircbuf_factory *f, int verbose);
00111 
00112   /*!
00113    * \brief Test all factories, return true if at least one of them works
00114    * verbose = 0: silent
00115    * verbose = 1: names of factories tested and results
00116    * verbose = 2: all intermediate results
00117    */
00118   static bool test_all_factories (int verbose);
00119 };
00120 
00121 
00122 #endif /* _GR_VMCIRCBUF_H_ */