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authorDavid Robillard <d@drobilla.net>2007-07-24 19:26:47 +0000
committerDavid Robillard <d@drobilla.net>2007-07-24 19:26:47 +0000
commit3b4a308ff647def75e647ac8f97e1e48b57672c3 (patch)
treea33e3a5c78f2ee7f23e151f39fe17ab39b0b81c8 /raul/RingBuffer.hpp
parentfcb302e6248527b2f1fb655f4d0a64af18f5f059 (diff)
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Consistently rename all C++ files .cpp/.hpp.
Fix (some) inclusion guard names to not clash with other libs. git-svn-id: http://svn.drobilla.net/lad/raul@613 a436a847-0d15-0410-975c-d299462d15a1
Diffstat (limited to 'raul/RingBuffer.hpp')
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diff --git a/raul/RingBuffer.hpp b/raul/RingBuffer.hpp
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+/* This file is part of Raul.
+ * Copyright (C) 2007 Dave Robillard <http://drobilla.net>
+ *
+ * Raul is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 2 of the License, or (at your option) any later
+ * version.
+ *
+ * Raul is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef RAUL_RING_BUFFER_HPP
+#define RAUL_RING_BUFFER_HPP
+
+#include <cassert>
+#include <glib.h>
+
+namespace Raul {
+
+
+/** A lock-free RingBuffer.
+ * Read/Write realtime safe.
+ * Single-reader Single-writer thread safe.
+ */
+template <typename T>
+class RingBuffer {
+public:
+
+ /** @param size Size in bytes.
+ */
+ RingBuffer(size_t size)
+ : _size(size)
+ , _buf(new T[size])
+ {
+ reset();
+ assert(read_space() == 0);
+ assert(write_space() == size - 1);
+ }
+
+ virtual ~RingBuffer() {
+ delete[] _buf;
+ }
+
+ /** Reset(empty) the ringbuffer.
+ * NOT thread safe.
+ */
+ void reset() {
+ g_atomic_int_set(&_write_ptr, 0);
+ g_atomic_int_set(&_read_ptr, 0);
+ }
+
+ size_t write_space() const {
+
+ const size_t w = g_atomic_int_get(&_write_ptr);
+ const size_t r = g_atomic_int_get(&_read_ptr);
+
+ if (w > r) {
+ return ((r - w + _size) % _size) - 1;
+ } else if(w < r) {
+ return (r - w) - 1;
+ } else {
+ return _size - 1;
+ }
+ }
+
+ size_t read_space() const {
+
+ const size_t w = g_atomic_int_get(&_write_ptr);
+ const size_t r = g_atomic_int_get(&_read_ptr);
+
+ if (w > r) {
+ return w - r;
+ } else {
+ return (w - r + _size) % _size;
+ }
+ }
+
+ size_t capacity() const { return _size; }
+
+ size_t read(size_t size, T* dst);
+ void write(size_t size, const T* src);
+
+ bool full_read(size_t size, T* dst);
+
+protected:
+ mutable gint _write_ptr;
+ mutable gint _read_ptr;
+
+ size_t _size; ///< Size (capacity) in bytes
+ T* _buf; ///< size, event, size, event...
+};
+
+
+/** Read from the ringbuffer.
+ *
+ * Note that a full read may not be done if the data wraps around.
+ * Caller must check return value and call again if necessary, or use the
+ * full_read method which does this automatically.
+ */
+template<typename T>
+size_t
+RingBuffer<T>::read(size_t size, T* dst)
+{
+ const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
+
+ const size_t read_size = (priv_read_ptr + size < _size)
+ ? size
+ : _size - priv_read_ptr;
+
+ memcpy(dst, &_buf[priv_read_ptr], read_size);
+
+ g_atomic_int_set(&_read_ptr, (priv_read_ptr + read_size) % _size);
+
+ return read_size;
+}
+
+
+template<typename T>
+inline void
+RingBuffer<T>::write(size_t size, const T* src)
+{
+ const size_t priv_write_ptr = g_atomic_int_get(&_write_ptr);
+
+ if (priv_write_ptr + size <= _size) {
+ memcpy(&_buf[priv_write_ptr], src, size);
+ g_atomic_int_set(&_write_ptr, (priv_write_ptr + size) % _size);
+ } else {
+ const size_t this_size = _size - priv_write_ptr;
+ assert(this_size < size);
+ assert(priv_write_ptr + this_size <= _size);
+ memcpy(&_buf[priv_write_ptr], src, this_size);
+ memcpy(&_buf[0], src+this_size, size - this_size);
+ g_atomic_int_set(&_write_ptr, size - this_size);
+ }
+}
+
+
+template<typename T>
+bool
+RingBuffer<T>::full_read(size_t size, T* dst)
+{
+ if (read_space() < size)
+ return false;
+
+ const size_t read_size = read(size, dst);
+
+ if (read_size < size)
+ read(size - read_size, dst + read_size);
+
+ return true;
+}
+
+
+} // namespace Raul
+
+#endif // RAUL_RING_BUFFER_HPP
+