/*
* Copy and nul-terminate a ringbuffer to a string.
*/
ssize_t
ringbuf_to_string(char *buf, size_t len, struct ringbuf *rb)
{
size_t copy_len, n;
if (buf == NULL || rb == NULL || len == 0)
return (-1);
copy_len = MINIMUM(len - 1, ringbuf_used(rb));
if (copy_len == 0)
return (copy_len);
if (rb->start < rb->end)
memcpy(buf, rb->buf + rb->start, copy_len);
else {
/* If the buffer is wrapped, copy each hunk separately */
n = rb->len - rb->start;
memcpy(buf, rb->buf + rb->start, MINIMUM(n, copy_len));
if (copy_len > n)
memcpy(buf + n, rb->buf,
MINIMUM(rb->end, copy_len - n));
}
buf[copy_len] = '\0';
return (ringbuf_used(rb));
}
/*
* Append a line to a ring buffer, will delete lines from start
* of buffer as necessary
*/
int
ringbuf_append_line(struct ringbuf *rb, char *line)
{
size_t llen, used, copy_len;
int overflow = 0;
if (rb == NULL || line == NULL)
return (-1);
llen = strlen(line);
if (llen == 0)
return (-1);
if (line[llen - 1] != '\n')
llen++; /* one extra for appended '\n' */
if (llen >= rb->len)
return (-1);
/*
* If necessary, advance start pointer to make room for appended
* string. Ensure that start pointer is at the beginning of a line
* once we are done (i.e move to after '\n').
*/
used = ringbuf_used(rb);
if (used + llen >= rb->len) {
rb->start = (rb->start + used + llen - rb->len) % rb->len;
/* Find next '\n' */
while (rb->buf[rb->start] != '\n')
rb->start = (rb->start + 1) % rb->len;
/* Skip it */
rb->start = (rb->start + 1) % rb->len;
overflow = 1;
}
/*
* Now append string, starting from last pointer and wrapping if
* necessary
*/
if (rb->end + llen > rb->len) {
copy_len = rb->len - rb->end;
memcpy(rb->buf + rb->end, line, copy_len);
memcpy(rb->buf, line + copy_len, llen - copy_len - 1);
rb->buf[llen - copy_len - 1] = '\n';
} else {
memcpy(rb->buf + rb->end, line, llen - 1);
rb->buf[rb->end + llen - 1] = '\n';
}
rb->end = (rb->end + llen) % rb->len;
return (overflow);
}
ssize_t ringbuf_read(ringbuf_t *rb, char *target, size_t len)
{
size_t used, tail_len;
if (!rb || !target) {
return -1;
}
used = ringbuf_used(rb);
len = MIN(len, used);
tail_len = rb->len - rb->start + 1;
tail_len = MIN(len, tail_len);
memcpy(target, rb->buf + rb->start, tail_len);
if (len - tail_len > 0) {
memcpy(target + tail_len, rb->buf, len - tail_len);
}
rb->start = (rb->start + len) % rb->len;
return len;
}
