/*
* Copyright (C) 2005-2008 by Pieter Palmers
*
* This file is part of FFADO
* FFADO = Free Firewire (pro-)audio drivers for linux
*
* FFADO is based upon FreeBoB
*
* 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) version 3 of the License.
*
* 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, see .
*
*/
/*
* Copied from the jackd sources
* function names changed in order to avoid naming problems when using this in
* a jackd backend.
*/
/* Original license:
* note that LGPL2.1 allows relicensing the code to GPLv3 or higher
*
* Copyright (C) 2000 Paul Davis
* Copyright (C) 2003 Rohan Drape
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) version 3 of the License.
*
* 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
//#include
#include
#include
#ifdef USE_MLOCK
#include
#endif /* USE_MLOCK */
#include "ringbuffer.h"
/* Create a new ringbuffer to hold at least `sz' bytes of data. The
actual buffer size is rounded up to the next power of two. */
ffado_ringbuffer_t *
ffado_ringbuffer_create (size_t sz)
{
int power_of_two;
ffado_ringbuffer_t *rb;
rb = malloc (sizeof (ffado_ringbuffer_t));
for (power_of_two = 1; 1 << power_of_two < sz; power_of_two++);
rb->size = 1 << power_of_two;
rb->size_mask = rb->size;
rb->size_mask -= 1;
rb->write_ptr = 0;
rb->read_ptr = 0;
rb->buf = malloc (rb->size);
rb->mlocked = 0;
return rb;
}
/* Free all data associated with the ringbuffer `rb'. */
void
ffado_ringbuffer_free (ffado_ringbuffer_t * rb)
{
#ifdef USE_MLOCK
if (rb->mlocked) {
munlock (rb->buf, rb->size);
}
#endif /* USE_MLOCK */
free (rb->buf);
}
/* Lock the data block of `rb' using the system call 'mlock'. */
int
ffado_ringbuffer_mlock (ffado_ringbuffer_t * rb)
{
#ifdef USE_MLOCK
if (mlock (rb->buf, rb->size)) {
return -1;
}
#endif /* USE_MLOCK */
rb->mlocked = 1;
return 0;
}
/* Reset the read and write pointers to zero. This is not thread
safe. */
void
ffado_ringbuffer_reset (ffado_ringbuffer_t * rb)
{
rb->read_ptr = 0;
rb->write_ptr = 0;
}
/* Return the number of bytes available for reading. This is the
number of bytes in front of the read pointer and behind the write
pointer. */
size_t
ffado_ringbuffer_read_space (const ffado_ringbuffer_t * rb)
{
size_t w, r;
w = rb->write_ptr;
r = rb->read_ptr;
if (w > r) {
return w - r;
} else {
return (w - r + rb->size) & rb->size_mask;
}
}
/* Return the number of bytes available for writing. This is the
number of bytes in front of the write pointer and behind the read
pointer. */
size_t
ffado_ringbuffer_write_space (const ffado_ringbuffer_t * rb)
{
size_t w, r;
w = rb->write_ptr;
r = rb->read_ptr;
if (w > r) {
return ((r - w + rb->size) & rb->size_mask) - 1;
} else if (w < r) {
return (r - w) - 1;
} else {
return rb->size - 1;
}
}
/* The copying data reader. Copy at most `cnt' bytes from `rb' to
`dest'. Returns the actual number of bytes copied. */
size_t
ffado_ringbuffer_read (ffado_ringbuffer_t * rb, char *dest, size_t cnt)
{
size_t free_cnt;
size_t cnt2;
size_t to_read;
size_t n1, n2;
if ((free_cnt = ffado_ringbuffer_read_space (rb)) == 0) {
return 0;
}
to_read = cnt > free_cnt ? free_cnt : cnt;
cnt2 = rb->read_ptr + to_read;
if (cnt2 > rb->size) {
n1 = rb->size - rb->read_ptr;
n2 = cnt2 & rb->size_mask;
} else {
n1 = to_read;
n2 = 0;
}
memcpy (dest, &(rb->buf[rb->read_ptr]), n1);
rb->read_ptr += n1;
rb->read_ptr &= rb->size_mask;
if (n2) {
memcpy (dest + n1, &(rb->buf[rb->read_ptr]), n2);
rb->read_ptr += n2;
rb->read_ptr &= rb->size_mask;
}
return to_read;
}
/* The copying data reader w/o read pointer advance. Copy at most
`cnt' bytes from `rb' to `dest'. Returns the actual number of bytes
copied. */
size_t
ffado_ringbuffer_peek (ffado_ringbuffer_t * rb, char *dest, size_t cnt)
{
size_t free_cnt;
size_t cnt2;
size_t to_read;
size_t n1, n2;
size_t tmp_read_ptr;
tmp_read_ptr = rb->read_ptr;
if ((free_cnt = ffado_ringbuffer_read_space (rb)) == 0) {
return 0;
}
to_read = cnt > free_cnt ? free_cnt : cnt;
cnt2 = tmp_read_ptr + to_read;
if (cnt2 > rb->size) {
n1 = rb->size - tmp_read_ptr;
n2 = cnt2 & rb->size_mask;
} else {
n1 = to_read;
n2 = 0;
}
memcpy (dest, &(rb->buf[tmp_read_ptr]), n1);
tmp_read_ptr += n1;
tmp_read_ptr &= rb->size_mask;
if (n2) {
memcpy (dest + n1, &(rb->buf[tmp_read_ptr]), n2);
tmp_read_ptr += n2;
tmp_read_ptr &= rb->size_mask;
}
return to_read;
}
/* The copying data writer. Copy at most `cnt' bytes to `rb' from
`src'. Returns the actual number of bytes copied. */
size_t
ffado_ringbuffer_write (ffado_ringbuffer_t * rb, const char *src, size_t cnt)
{
size_t free_cnt;
size_t cnt2;
size_t to_write;
size_t n1, n2;
if ((free_cnt = ffado_ringbuffer_write_space (rb)) == 0) {
return 0;
}
to_write = cnt > free_cnt ? free_cnt : cnt;
cnt2 = rb->write_ptr + to_write;
if (cnt2 > rb->size) {
n1 = rb->size - rb->write_ptr;
n2 = cnt2 & rb->size_mask;
} else {
n1 = to_write;
n2 = 0;
}
memcpy (&(rb->buf[rb->write_ptr]), src, n1);
rb->write_ptr += n1;
rb->write_ptr &= rb->size_mask;
if (n2) {
memcpy (&(rb->buf[rb->write_ptr]), src + n1, n2);
rb->write_ptr += n2;
rb->write_ptr &= rb->size_mask;
}
return to_write;
}
/* Advance the read pointer `cnt' places. */
void
ffado_ringbuffer_read_advance (ffado_ringbuffer_t * rb, size_t cnt)
{
rb->read_ptr += cnt;
rb->read_ptr &= rb->size_mask;
}
/* Advance the write pointer `cnt' places. */
void
ffado_ringbuffer_write_advance (ffado_ringbuffer_t * rb, size_t cnt)
{
rb->write_ptr += cnt;
rb->write_ptr &= rb->size_mask;
}
/* The non-copying data reader. `vec' is an array of two places. Set
the values at `vec' to hold the current readable data at `rb'. If
the readable data is in one segment the second segment has zero
length. */
void
ffado_ringbuffer_get_read_vector (const ffado_ringbuffer_t * rb,
ffado_ringbuffer_data_t * vec)
{
size_t free_cnt;
size_t cnt2;
size_t w, r;
w = rb->write_ptr;
r = rb->read_ptr;
if (w > r) {
free_cnt = w - r;
} else {
free_cnt = (w - r + rb->size) & rb->size_mask;
}
cnt2 = r + free_cnt;
if (cnt2 > rb->size) {
/* Two part vector: the rest of the buffer after the current write
ptr, plus some from the start of the buffer. */
vec[0].buf = &(rb->buf[r]);
vec[0].len = rb->size - r;
vec[1].buf = rb->buf;
vec[1].len = cnt2 & rb->size_mask;
} else {
/* Single part vector: just the rest of the buffer */
vec[0].buf = &(rb->buf[r]);
vec[0].len = free_cnt;
vec[1].len = 0;
}
}
/* The non-copying data writer. `vec' is an array of two places. Set
the values at `vec' to hold the current writeable data at `rb'. If
the writeable data is in one segment the second segment has zero
length. */
void
ffado_ringbuffer_get_write_vector (const ffado_ringbuffer_t * rb,
ffado_ringbuffer_data_t * vec)
{
size_t free_cnt;
size_t cnt2;
size_t w, r;
w = rb->write_ptr;
r = rb->read_ptr;
if (w > r) {
free_cnt = ((r - w + rb->size) & rb->size_mask) - 1;
} else if (w < r) {
free_cnt = (r - w) - 1;
} else {
free_cnt = rb->size - 1;
}
cnt2 = w + free_cnt;
if (cnt2 > rb->size) {
/* Two part vector: the rest of the buffer after the current write
ptr, plus some from the start of the buffer. */
vec[0].buf = &(rb->buf[w]);
vec[0].len = rb->size - w;
vec[1].buf = rb->buf;
vec[1].len = cnt2 & rb->size_mask;
} else {
vec[0].buf = &(rb->buf[w]);
vec[0].len = free_cnt;
vec[1].len = 0;
}
}