base/fifo_buffer.hh

   1 /*
   2  * Copyright (c) 2002-2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef __FIFO_BUFFER_HH__
  30 #define __FIFO_BUFFER_HH__
  31
  32 #include "base/res_list.hh"
  33
  34
  35 //
  36 //  The FifoBuffer requires only that the objects to be used have a default
  37 //  constructor and a dump() method
  38 //
  39 template<class T>
  40 class FifoBuffer
  41 {
  42   public:
  43     typedef typename res_list<T>::iterator iterator;
  44
  45   private:
  46     res_list<T> *buffer;
  47
  48     unsigned size;
  49
  50   public:
  51     FifoBuffer(unsigned sz)
  52     {
  53         buffer = new res_list<T>(sz, true, 0);
  54         size = sz;
  55     }
  56
  57     void add(T &item)
  58     {
  59         assert(buffer->num_free() > 0);
  60         buffer->add_head(item);
  61     }
  62
  63     iterator head() { return buffer->head(); }
  64     iterator tail() { return buffer->tail(); }
  65
  66     unsigned count() {return buffer->count();}
  67     unsigned free_slots() {return buffer->num_free();}
  68
  69     T *peek() { return (count() > 0) ? tail().data_ptr() : 0; }
  70
  71     T remove()
  72     {
  73         assert(buffer->count() > 0);
  74         T rval = *buffer->tail();
  75         buffer->remove_tail();
  76         return rval;
  77     }
  78
  79     void dump();
  80
  81     ~FifoBuffer() { delete buffer; }
  82 };
  83
  84
  85 #endif
  86