diff options
Diffstat (limited to 'common/queue.c')
| -rw-r--r-- | common/queue.c | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/common/queue.c b/common/queue.c index 780bd41d3b..c8436344c1 100644 --- a/common/queue.c +++ b/common/queue.c @@ -67,17 +67,23 @@ int queue_is_full(struct queue const *q) * |****************| */ -struct queue_chunk queue_get_write_chunk(struct queue const *q) +struct queue_chunk queue_get_write_chunk(struct queue const *q, size_t offset) { size_t head = q->state->head & q->buffer_units_mask; - size_t tail = q->state->tail & q->buffer_units_mask; - size_t last = (queue_is_full(q) ? tail : /* Full */ - ((tail < head) ? head : /* Wrapped */ - q->buffer_units)); /* Normal | Empty */ + size_t tail = (q->state->tail + offset) & q->buffer_units_mask; + size_t last = (tail < head) ? head : /* Wrapped */ + q->buffer_units; /* Normal | Empty */ + + /* Make sure that the offset doesn't exceed free space. */ + if (queue_space(q) <= offset) + return ((struct queue_chunk) { + .count = 0, + .buffer = NULL, + }); return ((struct queue_chunk) { - .length = (last - tail) * q->unit_bytes, - .buffer = q->buffer + tail * q->unit_bytes, + .count = last - tail, + .buffer = q->buffer + (tail * q->unit_bytes), }); } @@ -90,8 +96,8 @@ struct queue_chunk queue_get_read_chunk(struct queue const *q) q->buffer_units)); /* Wrapped | Full */ return ((struct queue_chunk) { - .length = (last - head) * q->unit_bytes, - .buffer = q->buffer + head * q->unit_bytes, + .count = (last - head), + .buffer = q->buffer + (head * q->unit_bytes), }); } |