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/***
This file is part of PulseAudio.
Copyright 2013 Matthias Wabersich
Copyright 2013 Hajime Fujita
PulseAudio 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) any later version.
PulseAudio 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 Lesser General Public License
along with PulseAudio; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <stdint.h>
#include <limits.h>
#include <pulse/xmalloc.h>
#include <pulsecore/core-error.h>
#include <pulsecore/macro.h>
#include "raop-packet-buffer.h"
struct pa_raop_packet_buffer {
pa_memchunk *packets;
pa_mempool *mempool;
size_t size;
size_t count;
uint16_t seq;
size_t pos;
};
pa_raop_packet_buffer *pa_raop_packet_buffer_new(pa_mempool *mempool, const size_t size) {
pa_raop_packet_buffer *pb = pa_xnew0(pa_raop_packet_buffer, 1);
pa_assert(mempool);
pa_assert(size > 0);
pb->count = 0;
pb->size = size;
pb->mempool = mempool;
pb->packets = pa_xnew0(pa_memchunk, size);
pb->seq = pb->pos = 0;
return pb;
}
void pa_raop_packet_buffer_free(pa_raop_packet_buffer *pb) {
size_t i;
pa_assert(pb);
for (i = 0; pb->packets && i < pb->size; i++) {
if (pb->packets[i].memblock)
pa_memblock_unref(pb->packets[i].memblock);
pa_memchunk_reset(&pb->packets[i]);
}
pa_xfree(pb->packets);
pb->packets = NULL;
pa_xfree(pb);
}
void pa_raop_packet_buffer_reset(pa_raop_packet_buffer *pb, uint16_t seq) {
size_t i;
pa_assert(pb);
pa_assert(pb->packets);
pb->pos = 0;
pb->count = 0;
pb->seq = (!seq) ? UINT16_MAX : seq - 1;
for (i = 0; i < pb->size; i++) {
if (pb->packets[i].memblock)
pa_memblock_unref(pb->packets[i].memblock);
pa_memchunk_reset(&pb->packets[i]);
}
}
pa_memchunk *pa_raop_packet_buffer_prepare(pa_raop_packet_buffer *pb, uint16_t seq, const size_t size) {
pa_memchunk *packet = NULL;
size_t i;
pa_assert(pb);
pa_assert(pb->packets);
if (seq == 0) {
/* 0 means seq reached UINT16_MAX and has been wrapped... */
pa_assert(pb->seq == UINT16_MAX);
pb->seq = 0;
} else {
/* ...otherwise, seq MUST have be increased! */
pa_assert(seq == pb->seq + 1);
pb->seq++;
}
i = (pb->pos + 1) % pb->size;
if (pb->packets[i].memblock)
pa_memblock_unref(pb->packets[i].memblock);
pa_memchunk_reset(&pb->packets[i]);
pb->packets[i].memblock = pa_memblock_new(pb->mempool, size);
pb->packets[i].length = size;
pb->packets[i].index = 0;
packet = &pb->packets[i];
if (pb->count < pb->size)
pb->count++;
pb->pos = i;
return packet;
}
pa_memchunk *pa_raop_packet_buffer_retrieve(pa_raop_packet_buffer *pb, uint16_t seq) {
pa_memchunk *packet = NULL;
size_t delta, i;
pa_assert(pb);
pa_assert(pb->packets);
if (seq == pb->seq)
packet = &pb->packets[pb->pos];
else {
if (seq < pb->seq) {
/* Regular case: pb->seq did not wrapped since seq. */
delta = pb->seq - seq;
} else {
/* Tricky case: pb->seq wrapped since seq! */
delta = pb->seq + (UINT16_MAX - seq);
}
/* If the requested packet is too old, do nothing and return */
if (delta > pb->count)
return NULL;
i = (pb->size + pb->pos - delta) % pb->size;
if (delta < pb->size && pb->packets[i].memblock)
packet = &pb->packets[i];
}
return packet;
}
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