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#include <shared/container/ring.h>
#include <shared/mem.h>
#include <stdbool.h>
static bool at_end(ring_t *r) {
return r->_head + 1 == r->_tail
|| (r->_head + 1 == r->capacity && r->_tail == 0);
}
size_t ring_used(ring_t *r) {
if (r->_head >= r->_tail)
return r->_head - r->_tail;
else
return r->_head + r->capacity - r->_tail;
}
size_t ring_avail(ring_t *r) {
return r->capacity - ring_used(r);
}
void ring_put(ring_t *r, const void *buf, size_t len) {
// TODO do something similar to ring_get
for (size_t i = 0; i < len; i++)
ring_put1b(r, ((uint8_t*)buf)[i]);
}
void ring_put1b(ring_t *r, uint8_t byte) {
if (at_end(r)) return;
r->buf[r->_head++] = byte;
if (r->_head >= r->capacity) r->_head = 0;
}
size_t ring_get(ring_t *r, void *buf, size_t len) {
size_t read = 0;
size_t plen;
void *pbuf;
for (size_t i = 0; i < 2; i++) {
plen = len - read;
pbuf = ring_contig(r, &plen);
if (buf) memcpy(buf + read, pbuf, plen);
read += plen;
}
return read;
}
void *ring_contig(ring_t *r, size_t *len) {
void *ret = &r->buf[r->_tail];
size_t avail;
if (r->_head >= r->_tail)
avail = r->_head - r->_tail;
else
avail = r->capacity - r->_tail;
if (*len > avail)
*len = avail;
r->_tail += *len;
if (r->_tail >= r->capacity) r->_tail = 0;
return ret;
}
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