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/*
* melisma - extensible and scriptable audio engine
* Copyright (C) 2026 Ludvig Gunne Lindström
*
* 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 3 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, see <https://www.gnu.org/licenses/>.
*/
#include "mem.h"
#include "melisma/ring.h"
struct ml_ring
{
_Atomic size_t head;
_Atomic size_t tail;
size_t len;
uint8_t data[];
};
ml_ring *ml_ring_init(size_t len)
{
size_t size = sizeof(ml_ring) + len;
ml_ring *r = scalloc(1,size);
r->len = len;
return r;
}
void ml_ring_free(ml_ring *r)
{
free(r);
}
int ml_ring_empty(ml_ring *r)
{
size_t head = atomic_load_explicit(&r->head,memory_order_relaxed);
size_t tail = atomic_load_explicit(&r->tail,memory_order_acquire);
return tail == head;
}
int ml_ring_has_space(ml_ring *r, size_t len)
{
size_t head = atomic_load_explicit(&r->head,memory_order_acquire);
size_t tail = atomic_load_explicit(&r->tail,memory_order_relaxed);
size_t used = tail >= head ? tail - head : r->len - head + tail;
size_t free = r->len - 1 - used;
return free >= len;
}
int ml_ring_put(ml_ring *r, uint8_t c)
{
size_t tail = atomic_load_explicit(&r->tail,memory_order_relaxed);
size_t head = atomic_load_explicit(&r->head,memory_order_acquire);
size_t new_tail = (tail + 1) % r->len;
if (new_tail == head)
{
return -1;
}
r->data[tail] = c;
atomic_store_explicit(&r->tail,new_tail,memory_order_release);
return 0;
}
int ml_ring_get(ml_ring *r, uint8_t *c)
{
size_t tail = atomic_load_explicit(&r->tail,memory_order_acquire);
size_t head = atomic_load_explicit(&r->head,memory_order_relaxed);
size_t new_head = (head + 1) % r->len;
if (head == tail)
{
return -1;
}
*c = r->data[head];
atomic_store_explicit(&r->head,new_head,memory_order_release);
return 0;
}
size_t ml_ring_write(ml_ring *r, const void *ptr, size_t len)
{
size_t l = 0;
const uint8_t *uptr = ptr;
for (; l < len; l++)
{
if (ml_ring_put(r,uptr[l]) < 0)
{
break;
}
}
return l;
}
size_t ml_ring_read(ml_ring *r, void *ptr, size_t len)
{
size_t l = 0;
uint8_t *uptr = ptr;
for (; l < len; l++)
{
if (ml_ring_get(r,&uptr[l]) < 0)
{
break;
}
}
return l;
}
void ml_ring_put_blocking(ml_ring *r, uint8_t c)
{
while (ml_ring_put(r,c) < 0)
;
}
uint8_t ml_ring_get_blocking(ml_ring *r)
{
uint8_t c;
while (ml_ring_get(r,&c) < 0)
;
return c;
}
void ml_ring_write_blocking(ml_ring *r, const void *ptr, size_t len)
{
const uint8_t *uptr = ptr;
while (len--)
{
ml_ring_put_blocking(r,*(uptr++));
}
}
void ml_ring_read_blocking(ml_ring *r, void *ptr, size_t len)
{
uint8_t *uptr = ptr;
while (len--)
{
*(uptr++) = ml_ring_get_blocking(r);
}
}
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