libs/evoral/evoral/EventRingBuffer.hpp

   1 /* This file is part of Evoral.
   2  * Copyright (C) 2008 Dave Robillard <http://drobilla.net>
   3  *
   4  * Evoral is free software; you can redistribute it and/or modify it under the
   5  * terms of the GNU General Public License as published by the Free Software
   6  * Foundation; either version 2 of the License, or (at your option) any later
   7  * version.
   8  *
   9  * Evoral is distributed in the hope that it will be useful, but WITHOUT ANY
  10  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  11  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  16  */
  17
  18 #ifndef EVORAL_EVENT_RING_BUFFER_HPP
  19 #define EVORAL_EVENT_RING_BUFFER_HPP
  20
  21 #include <glib.h>
  22 #include <evoral/RingBuffer.hpp>
  23 #include <evoral/EventSink.hpp>
  24 #include <evoral/types.hpp>
  25
  26 #include <iostream>
  27 using namespace std;
  28
  29 namespace Evoral {
  30
  31
  32 /** A RingBuffer of events (generic time-stamped binary "blobs").
  33  *
  34  * This packs a timestamp, size, and size bytes of data flat into the buffer.
  35  * Useful for MIDI events, OSC messages, etc.
  36  */
  37 class EventRingBuffer : public Evoral::RingBuffer<uint8_t>, public Evoral::EventSink {
  38 public:
  39
  40         /** @param capacity Ringbuffer capacity in bytes.
  41          */
  42         EventRingBuffer(size_t capacity) : RingBuffer<uint8_t>(capacity)
  43         {}
  44
  45         size_t capacity() const { return _size; }
  46
  47         bool peek_time(EventTime* time);
  48
  49         uint32_t write(EventTime  time, EventType  type, uint32_t  size, const uint8_t* buf);
  50         bool     read (EventTime* time, EventType* type, uint32_t* size,       uint8_t* buf);
  51 };
  52
  53
  54 inline bool
  55 EventRingBuffer::peek_time(EventTime* time)
  56 {
  57         bool success = RingBuffer<uint8_t>::full_peek(sizeof(EventTime), (uint8_t*)time);
  58         return success;
  59 }
  60
  61
  62 inline bool
  63 EventRingBuffer::read(EventTime* time, EventType* type, uint32_t* size, uint8_t* buf)
  64 {
  65         bool success = RingBuffer<uint8_t>::full_read(sizeof(EventTime), (uint8_t*)time);
  66         if (success)
  67                 success = RingBuffer<uint8_t>::full_read(sizeof(EventType), (uint8_t*)type);
  68         if (success)
  69                 success = RingBuffer<uint8_t>::full_read(sizeof(uint32_t), (uint8_t*)size);
  70         if (success)
  71                 success = RingBuffer<uint8_t>::full_read(*size, buf);
  72
  73         return success;
  74 }
  75
  76
  77 inline uint32_t
  78 EventRingBuffer::write(EventTime time, EventType type, uint32_t size, const uint8_t* buf)
  79 {
  80         if (write_space() < (sizeof(EventTime) + sizeof(EventType) + sizeof(uint32_t) + size)) {
  81                 return 0;
  82         } else {
  83                 RingBuffer<uint8_t>::write(sizeof(EventTime), (uint8_t*)&time);
  84                 RingBuffer<uint8_t>::write(sizeof(EventType), (uint8_t*)&type);
  85                 RingBuffer<uint8_t>::write(sizeof(uint32_t), (uint8_t*)&size);
  86                 RingBuffer<uint8_t>::write(size, buf);
  87                 return size;
  88         }
  89 }
  90
  91
  92 } // namespace Evoral
  93
  94 #endif // EVORAL_EVENT_RING_BUFFER_HPP
  95