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/*C
(c) 2005 bl0rg.net
**/
#include "conf.h"
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "fec-group.h"
/*M
\emph{Maximal number of elements in the ring buffer.}
**/
unsigned int fec_rb_size = 0;
/*M
\emph{Index of first valid element in ring buffer.}
**/
static unsigned int fec_rb_start = 0;
/*M
\emph{Index of first invalid element in ring buffer.}
**/
static unsigned int fec_rb_end = 0;
/*M
\emph{Number of elements in the ring buffer.}
**/
unsigned int fec_rb_cnt = 0;
/*M
\emph{Ring buffer array.}
**/
fec_group_t *fec_rb = NULL;
void fec_rb_clear(void) {
fec_rb_start = 0;
fec_rb_end = 0;
fec_rb_cnt = 0;
int i;
for (i = 0; i < fec_rb_size; i++)
fec_group_clear(fec_rb + i);
}
void fec_rb_pop(void) {
assert(fec_rb != NULL);
assert(fec_rb_end != fec_rb_start);
fec_group_destroy(fec_rb + fec_rb_start);
fec_rb_start = (fec_rb_start + 1) % fec_rb_size;
fec_rb_cnt--;
}
void fec_rb_destroy(void) {
if (fec_rb != NULL) {
while (fec_rb_cnt)
fec_rb_pop();
free(fec_rb);
fec_rb = NULL;
}
fec_rb_size = 0;
fec_rb_clear();
}
void fec_rb_init(unsigned int size) {
fec_rb_destroy();
fec_rb = malloc(sizeof(fec_group_t) * size);
assert(fec_rb != NULL);
int i;
for (i = 0; i < fec_rb_size; i++)
fec_group_clear(fec_rb + i);
fec_rb_size = size;
fec_rb_clear();
}
unsigned int fec_rb_length(void) {
assert(fec_rb != NULL);
if (fec_rb_end >= fec_rb_start)
return fec_rb_end - fec_rb_start;
else
return fec_rb_end + (fec_rb_size - fec_rb_start);
}
int fec_rb_insert_pkt(fec_pkt_t *pkt, int idx) {
assert(pkt != NULL);
assert(fec_rb != NULL);
#ifdef DEBUG
fprintf(stderr, "insert packet at idx %d, gseq %d, pseq %d\n",
idx, pkt->hdr.group_seq, pkt->hdr.packet_seq);
#endif
if (idx < 0) {
/* try to grow the buffer downwards */
if ((fec_rb_length() - idx) <= fec_rb_size) {
fec_rb_start = (fec_rb_start + idx) % fec_rb_size;
idx = 0;
} else
/* drop the packet silently */
return 0;
} else if (idx >= fec_rb_size - 1) {
/* not enough place left in ring buffer */
return 0;
}
fec_group_t *dst_group = fec_rb + ((idx + fec_rb_start) % fec_rb_size);
if (dst_group->buf != NULL) {
assert(dst_group->seq == pkt->hdr.group_seq);
fec_group_insert_pkt(dst_group, pkt);
} else {
assert(dst_group->pkts == NULL);
fec_group_init(dst_group,
pkt->hdr.fec_k,
pkt->hdr.fec_n,
pkt->hdr.group_seq,
pkt->hdr.group_tstamp,
pkt->hdr.fec_len);
fec_group_insert_pkt(dst_group, pkt);
fec_rb_cnt++;
}
#ifdef DEBUG
fprintf(stderr, "packet inserted at %d, end: %d\n",
(idx + fec_rb_start) % fec_rb_size,
fec_rb_end);
#endif
/* adjust the end pointer */
if (idx >= fec_rb_length())
fec_rb_end = ((idx + fec_rb_start + 1) % fec_rb_size);
assert(fec_rb_start != fec_rb_end);
/* XXX kann anscheinend auch passieren wenn wraparound. Generell
muessen hier alle asserts abgefangen werden und mit einer error
struktur sauber verarbeitet werden. */
assert(fec_rb[fec_rb_end].buf == NULL);
return 1;
}
void fec_rb_print(void) {
assert(fec_rb != NULL);
fprintf(stderr, "start: %.3u, end: %.3u, len: %.3u\n",
fec_rb_start, fec_rb_end, fec_rb_length());
}
void fec_rb_print_rb(void) {
unsigned int i;
for (i = fec_rb_start; i != fec_rb_end; i = (i + 1) % fec_rb_size) {
if (fec_rb[i].buf != NULL)
fprintf(stderr, "%.3u: seq %.3u\n", i, fec_rb[i].seq);
}
}
fec_group_t *fec_rb_first(void) {
assert(fec_rb != NULL);
if (fec_rb_start == fec_rb_end)
return NULL;
/* first should always be the first in buffer */
return fec_rb + fec_rb_start;
}
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