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/*
* Copyright © 2019, VideoLAN and dav1d authors
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <SDL.h>
#include <assert.h>
#include "dp_fifo.h"
// FIFO structure
struct dp_fifo
{
SDL_mutex *lock;
SDL_cond *cond_change;
size_t capacity;
size_t count;
void **entries;
int push_wait;
int flush;
};
Dav1dPlayPtrFifo *dp_fifo_create(size_t capacity)
{
Dav1dPlayPtrFifo *fifo;
assert(capacity > 0);
if (capacity <= 0)
return NULL;
fifo = malloc(sizeof(*fifo));
if (fifo == NULL)
return NULL;
fifo->capacity = capacity;
fifo->count = 0;
fifo->push_wait = 0;
fifo->flush = 0;
fifo->lock = SDL_CreateMutex();
if (fifo->lock == NULL) {
free(fifo);
return NULL;
}
fifo->cond_change = SDL_CreateCond();
if (fifo->cond_change == NULL) {
SDL_DestroyMutex(fifo->lock);
free(fifo);
return NULL;
}
fifo->entries = calloc(capacity, sizeof(void*));
if (fifo->entries == NULL) {
dp_fifo_destroy(fifo);
return NULL;
}
return fifo;
}
// Destroy FIFO
void dp_fifo_destroy(Dav1dPlayPtrFifo *fifo)
{
assert(fifo->count == 0);
SDL_DestroyMutex(fifo->lock);
SDL_DestroyCond(fifo->cond_change);
free(fifo->entries);
free(fifo);
}
// Push to FIFO
void dp_fifo_push(Dav1dPlayPtrFifo *fifo, void *element)
{
SDL_LockMutex(fifo->lock);
while (fifo->count == fifo->capacity) {
fifo->push_wait = 1;
SDL_CondWait(fifo->cond_change, fifo->lock);
fifo->push_wait = 0;
if (fifo->flush) {
SDL_CondSignal(fifo->cond_change);
SDL_UnlockMutex(fifo->lock);
return;
}
}
fifo->entries[fifo->count++] = element;
if (fifo->count == 1)
SDL_CondSignal(fifo->cond_change);
SDL_UnlockMutex(fifo->lock);
}
// Helper that shifts the FIFO array
static void *dp_fifo_array_shift(void **arr, size_t len)
{
void *shifted_element = arr[0];
for (size_t i = 1; i < len; ++i)
arr[i-1] = arr[i];
return shifted_element;
}
// Get item from FIFO
void *dp_fifo_shift(Dav1dPlayPtrFifo *fifo)
{
SDL_LockMutex(fifo->lock);
while (fifo->count == 0)
SDL_CondWait(fifo->cond_change, fifo->lock);
void *res = dp_fifo_array_shift(fifo->entries, fifo->count--);
if (fifo->count == fifo->capacity - 1)
SDL_CondSignal(fifo->cond_change);
SDL_UnlockMutex(fifo->lock);
return res;
}
void dp_fifo_flush(Dav1dPlayPtrFifo *fifo, void (*destroy_elem)(void *))
{
SDL_LockMutex(fifo->lock);
fifo->flush = 1;
if (fifo->push_wait) {
SDL_CondSignal(fifo->cond_change);
SDL_CondWait(fifo->cond_change, fifo->lock);
}
while (fifo->count)
destroy_elem(fifo->entries[--fifo->count]);
fifo->flush = 0;
SDL_UnlockMutex(fifo->lock);
}
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