276 lines
6.0 KiB
C++
276 lines
6.0 KiB
C++
/*
|
|
Copyright (C) 2000 Paul Davis & Benno Senoner
|
|
|
|
This program 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.
|
|
|
|
This program 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 more 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., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
|
|
$Id$
|
|
*/
|
|
|
|
#ifndef ringbuffer_npt_h
|
|
#define ringbuffer_npt_h
|
|
|
|
//#include <sys/mman.h>
|
|
|
|
#include <glib.h>
|
|
|
|
/* ringbuffer class where the element size is not required to be a power of two */
|
|
|
|
template<class T>
|
|
class RingBufferNPT
|
|
{
|
|
public:
|
|
RingBufferNPT (size_t sz) {
|
|
size = sz;
|
|
buf = new T[size];
|
|
reset ();
|
|
|
|
};
|
|
|
|
virtual ~RingBufferNPT() {
|
|
delete [] buf;
|
|
}
|
|
|
|
void reset () {
|
|
/* !!! NOT THREAD SAFE !!! */
|
|
g_atomic_int_set (&write_ptr, 0);
|
|
g_atomic_int_set (&read_ptr, 0);
|
|
}
|
|
|
|
void set (size_t r, size_t w) {
|
|
/* !!! NOT THREAD SAFE !!! */
|
|
g_atomic_int_set (&write_ptr, w);
|
|
g_atomic_int_set (&read_ptr, r);
|
|
}
|
|
|
|
size_t read (T *dest, size_t cnt);
|
|
size_t write (T *src, size_t cnt);
|
|
|
|
struct rw_vector {
|
|
T *buf[2];
|
|
size_t len[2];
|
|
};
|
|
|
|
void get_read_vector (rw_vector *);
|
|
void get_write_vector (rw_vector *);
|
|
|
|
void decrement_read_ptr (size_t cnt) {
|
|
g_atomic_int_set (&read_ptr, (g_atomic_int_get(&read_ptr) - cnt) % size);
|
|
}
|
|
|
|
void increment_read_ptr (size_t cnt) {
|
|
g_atomic_int_set (&read_ptr, (g_atomic_int_get(&read_ptr) + cnt) % size);
|
|
}
|
|
|
|
void increment_write_ptr (size_t cnt) {
|
|
g_atomic_int_set (&write_ptr, (g_atomic_int_get(&write_ptr) + cnt) % size);
|
|
}
|
|
|
|
size_t write_space () {
|
|
size_t w, r;
|
|
|
|
w = g_atomic_int_get (&write_ptr);
|
|
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 () {
|
|
size_t w, r;
|
|
|
|
w = g_atomic_int_get (&write_ptr);
|
|
r = g_atomic_int_get (&read_ptr);
|
|
|
|
if (w > r) {
|
|
return w - r;
|
|
} else {
|
|
return (w - r + size) % size;
|
|
}
|
|
}
|
|
|
|
T *buffer () { return buf; }
|
|
size_t get_write_ptr () const { return g_atomic_int_get (&write_ptr); }
|
|
size_t get_read_ptr () const { return g_atomic_int_get (&read_ptr); }
|
|
size_t bufsize () const { return size; }
|
|
|
|
protected:
|
|
T *buf;
|
|
size_t size;
|
|
mutable gint write_ptr;
|
|
mutable gint read_ptr;
|
|
};
|
|
|
|
template<class T> size_t
|
|
RingBufferNPT<T>::read (T *dest, size_t cnt)
|
|
{
|
|
size_t free_cnt;
|
|
size_t cnt2;
|
|
size_t to_read;
|
|
size_t n1, n2;
|
|
size_t priv_read_ptr;
|
|
|
|
priv_read_ptr=g_atomic_int_get(&read_ptr);
|
|
|
|
if ((free_cnt = read_space ()) == 0) {
|
|
return 0;
|
|
}
|
|
|
|
to_read = cnt > free_cnt ? free_cnt : cnt;
|
|
|
|
cnt2 = priv_read_ptr + to_read;
|
|
|
|
if (cnt2 > size) {
|
|
n1 = size - priv_read_ptr;
|
|
n2 = cnt2 % size;
|
|
} else {
|
|
n1 = to_read;
|
|
n2 = 0;
|
|
}
|
|
|
|
memcpy (dest, &buf[priv_read_ptr], n1 * sizeof (T));
|
|
priv_read_ptr = (priv_read_ptr + n1) % size;
|
|
|
|
if (n2) {
|
|
memcpy (dest+n1, buf, n2 * sizeof (T));
|
|
priv_read_ptr = n2;
|
|
}
|
|
|
|
g_atomic_int_set(&read_ptr, priv_read_ptr);
|
|
return to_read;
|
|
}
|
|
|
|
template<class T> size_t
|
|
RingBufferNPT<T>::write (T *src, size_t cnt)
|
|
{
|
|
size_t free_cnt;
|
|
size_t cnt2;
|
|
size_t to_write;
|
|
size_t n1, n2;
|
|
size_t priv_write_ptr;
|
|
|
|
priv_write_ptr=g_atomic_int_get(&write_ptr);
|
|
|
|
if ((free_cnt = write_space ()) == 0) {
|
|
return 0;
|
|
}
|
|
|
|
to_write = cnt > free_cnt ? free_cnt : cnt;
|
|
|
|
cnt2 = priv_write_ptr + to_write;
|
|
|
|
if (cnt2 > size) {
|
|
n1 = size - priv_write_ptr;
|
|
n2 = cnt2 % size;
|
|
} else {
|
|
n1 = to_write;
|
|
n2 = 0;
|
|
}
|
|
|
|
memcpy (&buf[priv_write_ptr], src, n1 * sizeof (T));
|
|
priv_write_ptr = (priv_write_ptr + n1) % size;
|
|
|
|
if (n2) {
|
|
memcpy (buf, src+n1, n2 * sizeof (T));
|
|
priv_write_ptr = n2;
|
|
}
|
|
|
|
g_atomic_int_set(&write_ptr, priv_write_ptr);
|
|
return to_write;
|
|
}
|
|
|
|
template<class T> void
|
|
RingBufferNPT<T>::get_read_vector (RingBufferNPT<T>::rw_vector *vec)
|
|
{
|
|
size_t free_cnt;
|
|
size_t cnt2;
|
|
size_t w, r;
|
|
|
|
w = g_atomic_int_get (&write_ptr);
|
|
r = g_atomic_int_get (&read_ptr);
|
|
|
|
if (w > r) {
|
|
free_cnt = w - r;
|
|
} else {
|
|
free_cnt = (w - r + size) % size;
|
|
}
|
|
|
|
cnt2 = r + free_cnt;
|
|
|
|
if (cnt2 > size) {
|
|
/* Two part vector: the rest of the buffer after the
|
|
current write ptr, plus some from the start of
|
|
the buffer.
|
|
*/
|
|
|
|
vec->buf[0] = &buf[r];
|
|
vec->len[0] = size - r;
|
|
vec->buf[1] = buf;
|
|
vec->len[1] = cnt2 % size;
|
|
|
|
} else {
|
|
|
|
/* Single part vector: just the rest of the buffer */
|
|
|
|
vec->buf[0] = &buf[r];
|
|
vec->len[0] = free_cnt;
|
|
vec->len[1] = 0;
|
|
}
|
|
}
|
|
|
|
template<class T> void
|
|
RingBufferNPT<T>::get_write_vector (RingBufferNPT<T>::rw_vector *vec)
|
|
{
|
|
size_t free_cnt;
|
|
size_t cnt2;
|
|
size_t w, r;
|
|
|
|
w = g_atomic_int_get (&write_ptr);
|
|
r = g_atomic_int_get (&read_ptr);
|
|
|
|
if (w > r) {
|
|
free_cnt = ((r - w + size) % size) - 1;
|
|
} else if (w < r) {
|
|
free_cnt = (r - w) - 1;
|
|
} else {
|
|
free_cnt = size - 1;
|
|
}
|
|
|
|
cnt2 = w + free_cnt;
|
|
|
|
if (cnt2 > size) {
|
|
|
|
/* Two part vector: the rest of the buffer after the
|
|
current write ptr, plus some from the start of
|
|
the buffer.
|
|
*/
|
|
|
|
vec->buf[0] = &buf[w];
|
|
vec->len[0] = size - w;
|
|
vec->buf[1] = buf;
|
|
vec->len[1] = cnt2 % size;
|
|
} else {
|
|
vec->buf[0] = &buf[w];
|
|
vec->len[0] = free_cnt;
|
|
vec->len[1] = 0;
|
|
}
|
|
}
|
|
|
|
#endif /* __ringbuffer_npt_h__ */
|