RAUL 0.8.0

- Main Page
- Modules
- Namespaces
- Classes
- Files

- File List

RingBuffer.hpp

    00001 /* This file is part of Raul.
    00002  * Copyright (C) 2007-2009 David Robillard <http://drobilla.net>
    00003  *
    00004  * Raul is free software; you can redistribute it and/or modify it under the
    00005  * terms of the GNU General Public License as published by the Free Software
    00006  * Foundation; either version 2 of the License, or (at your option) any later
    00007  * version.
    00008  *
    00009  * Raul is distributed in the hope that it will be useful, but WITHOUT ANY
    00010  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    00011  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for details.
    00012  *
    00013  * You should have received a copy of the GNU General Public License along
    00014  * with this program; if not, write to the Free Software Foundation, Inc.,
    00015  * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
    00016  */
    00017
    00018 #ifndef RAUL_RING_BUFFER_HPP
    00019 #define RAUL_RING_BUFFER_HPP
    00020
    00021 #include <stdint.h>
    00022
    00023 #include <cassert>
    00024 #include <cstdlib>
    00025 #include <cstring>
    00026 #include <iostream>
    00027
    00028 #include <glib.h>
    00029
    00030 #include "raul/log.hpp"
    00031
    00032 namespace Raul {
    00033
    00034
    00040 class RingBuffer {
    00041 public:
    00044     explicit RingBuffer(uint32_t size)
    00045         : _buf(static_cast<char*>(malloc(size)))
    00046         , _size(size)
    00047     {
    00048         reset();
    00049         assert(read_space() == 0);
    00050         assert(write_space() == size - 1);
    00051     }
    00052
    00053     virtual ~RingBuffer() {
    00054         free(_buf);
    00055     }
    00056
    00060     void reset() {
    00061         g_atomic_int_set(&_write_ptr, 0);
    00062         g_atomic_int_set(&_read_ptr, 0);
    00063     }
    00064
    00065     uint32_t write_space() const {
    00066         const uint32_t w = g_atomic_int_get(&_write_ptr);
    00067         const uint32_t r = g_atomic_int_get(&_read_ptr);
    00068
    00069         if (w > r) {
    00070             return ((r - w + _size) % _size) - 1;
    00071         } else if (w < r) {
    00072             return (r - w) - 1;
    00073         } else {
    00074             return _size - 1;
    00075         }
    00076     }
    00077
    00078     uint32_t read_space() const {
    00079         const uint32_t w = g_atomic_int_get(&_write_ptr);
    00080         const uint32_t r = g_atomic_int_get(&_read_ptr);
    00081
    00082         if (w > r) {
    00083             return w - r;
    00084         } else {
    00085             return (w - r + _size) % _size;
    00086         }
    00087     }
    00088
    00089     uint32_t capacity() const { return _size; }
    00090
    00091     uint32_t peek(uint32_t size, void* dst);
    00092     bool     full_peek(uint32_t size, void* dst);
    00093
    00094     uint32_t read(uint32_t size, void* dst);
    00095     bool     full_read(uint32_t size, void* dst);
    00096
    00097     bool     skip(uint32_t size);
    00098
    00099     void     write(uint32_t size, const void* src);
    00100
    00101 protected:
    00102     mutable uint32_t _write_ptr;
    00103     mutable uint32_t _read_ptr;
    00104
    00105     char* const    _buf;
    00106     const uint32_t _size;
    00107 };
    00108
    00109
    00116 inline uint32_t
    00117 RingBuffer::peek(uint32_t size, void* dst)
    00118 {
    00119     const uint32_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
    00120
    00121     const uint32_t read_size = (priv_read_ptr + size < _size)
    00122             ? size
    00123             : _size - priv_read_ptr;
    00124
    00125     memcpy(dst, &_buf[priv_read_ptr], read_size);
    00126
    00127     return read_size;
    00128 }
    00129
    00130
    00131 inline bool
    00132 RingBuffer::full_peek(uint32_t size, void* dst)
    00133 {
    00134     if (read_space() < size) {
    00135         return false;
    00136     }
    00137
    00138     const uint32_t read_size = peek(size, dst);
    00139
    00140     if (read_size < size) {
    00141         peek(size - read_size, (char*)dst + read_size);
    00142     }
    00143
    00144     return true;
    00145 }
    00146
    00147
    00154 inline uint32_t
    00155 RingBuffer::read(uint32_t size, void* dst)
    00156 {
    00157     const uint32_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
    00158
    00159     const uint32_t read_size = (priv_read_ptr + size < _size)
    00160             ? size
    00161             : _size - priv_read_ptr;
    00162
    00163     memcpy(dst, &_buf[priv_read_ptr], read_size);
    00164
    00165     g_atomic_int_set(&_read_ptr, (priv_read_ptr + read_size) % _size);
    00166
    00167     return read_size;
    00168 }
    00169
    00170
    00171 inline bool
    00172 RingBuffer::full_read(uint32_t size, void* dst)
    00173 {
    00174     if (read_space() < size) {
    00175         return false;
    00176     }
    00177
    00178     const uint32_t read_size = read(size, dst);
    00179
    00180     if (read_size < size) {
    00181         read(size - read_size, (char*)dst + read_size);
    00182     }
    00183
    00184     return true;
    00185 }
    00186
    00187
    00188 inline bool
    00189 RingBuffer::skip(uint32_t size)
    00190 {
    00191     if (read_space() < size) {
    00192         warn << "Attempt to skip past end of RingBuffer" << std::endl;
    00193         return false;
    00194     }
    00195
    00196     const uint32_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
    00197     g_atomic_int_set(&_read_ptr, (priv_read_ptr + size) % _size);
    00198
    00199     return true;
    00200 }
    00201
    00202
    00203 inline void
    00204 RingBuffer::write(uint32_t size, const void* src)
    00205 {
    00206     const uint32_t priv_write_ptr = g_atomic_int_get(&_write_ptr);
    00207
    00208     if (priv_write_ptr + size <= _size) {
    00209         memcpy(&_buf[priv_write_ptr], src, size);
    00210         g_atomic_int_set(&_write_ptr, (priv_write_ptr + size) % _size);
    00211     } else {
    00212         const uint32_t this_size = _size - priv_write_ptr;
    00213         assert(this_size < size);
    00214         assert(priv_write_ptr + this_size <= _size);
    00215         memcpy(&_buf[priv_write_ptr], src, this_size);
    00216         memcpy(&_buf[0], (char*)src + this_size, size - this_size);
    00217         g_atomic_int_set(&_write_ptr, size - this_size);
    00218     }
    00219 }
    00220
    00221
    00222 } // namespace Raul
    00223
    00224 #endif // RAUL_RING_BUFFER_HPP
    00225