RingBuffer.hpp
/* This file is part of Raul.
* Copyright (C) 2007-2009 David 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 <stdint.h>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <glib.h>
#include "raul/log.hpp"
namespace Raul {
class RingBuffer {
public:
explicit RingBuffer(uint32_t size)
: _buf(static_cast<char*>(malloc(size)))
, _size(size)
{
reset();
assert(read_space() == 0);
assert(write_space() == size - 1);
}
virtual ~RingBuffer() {
free(_buf);
}
void reset() {
g_atomic_int_set(&_write_ptr, 0);
g_atomic_int_set(&_read_ptr, 0);
}
uint32_t write_space() const {
const uint32_t w = g_atomic_int_get(&_write_ptr);
const uint32_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;
}
}
uint32_t read_space() const {
const uint32_t w = g_atomic_int_get(&_write_ptr);
const uint32_t r = g_atomic_int_get(&_read_ptr);
if (w > r) {
return w - r;
} else {
return (w - r + _size) % _size;
}
}
uint32_t capacity() const { return _size; }
uint32_t peek(uint32_t size, void* dst);
bool full_peek(uint32_t size, void* dst);
uint32_t read(uint32_t size, void* dst);
bool full_read(uint32_t size, void* dst);
bool skip(uint32_t size);
void write(uint32_t size, const void* src);
protected:
mutable uint32_t _write_ptr;
mutable uint32_t _read_ptr;
char* const _buf;
const uint32_t _size;
};
inline uint32_t
RingBuffer::peek(uint32_t size, void* dst)
{
const uint32_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
const uint32_t read_size = (priv_read_ptr + size < _size)
? size
: _size - priv_read_ptr;
memcpy(dst, &_buf[priv_read_ptr], read_size);
return read_size;
}
inline bool
RingBuffer::full_peek(uint32_t size, void* dst)
{
if (read_space() < size) {
return false;
}
const uint32_t read_size = peek(size, dst);
if (read_size < size) {
peek(size - read_size, (char*)dst + read_size);
}
return true;
}
inline uint32_t
RingBuffer::read(uint32_t size, void* dst)
{
const uint32_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
const uint32_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;
}
inline bool
RingBuffer::full_read(uint32_t size, void* dst)
{
if (read_space() < size) {
return false;
}
const uint32_t read_size = read(size, dst);
if (read_size < size) {
read(size - read_size, (char*)dst + read_size);
}
return true;
}
inline bool
RingBuffer::skip(uint32_t size)
{
if (read_space() < size) {
warn << "Attempt to skip past end of RingBuffer" << std::endl;
return false;
}
const uint32_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
g_atomic_int_set(&_read_ptr, (priv_read_ptr + size) % _size);
return true;
}
inline void
RingBuffer::write(uint32_t size, const void* src)
{
const uint32_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 uint32_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], (char*)src + this_size, size - this_size);
g_atomic_int_set(&_write_ptr, size - this_size);
}
}
} // namespace Raul
#endif // RAUL_RING_BUFFER_HPP
Raul::RingBuffer::reset
void reset()
Reset(empty) the ringbuffer.
Definition: RingBuffer.hpp:60
Raul::RingBuffer::peek
uint32_t peek(uint32_t size, void *dst)
Peek at the ringbuffer (read w/o advancing read pointer).
Definition: RingBuffer.hpp:117
Raul::RingBuffer
A lock-free RingBuffer.
Definition: RingBuffer.hpp:40
Raul::RingBuffer::_buf
char *const _buf
Contents.
Definition: RingBuffer.hpp:105
Raul
Definition: Array.hpp:26
Raul::RingBuffer::RingBuffer
RingBuffer(uint32_t size)
Definition: RingBuffer.hpp:44
Raul::RingBuffer::read
uint32_t read(uint32_t size, void *dst)
Read from the ringbuffer.
Definition: RingBuffer.hpp:155
Raul::RingBuffer::_size
const uint32_t _size
Size (capacity) in bytes.
Definition: RingBuffer.hpp:106