-/* Copyright (c) 2008, 2009, 2012 Nicira, Inc.
+/* Copyright (c) 2008, 2009, 2012, 2013 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <unistd.h>
#include "util.h"
-/* The queue size must be a power of 2. */
-BUILD_ASSERT_DECL(!(BYTEQ_SIZE & (BYTEQ_SIZE - 1)));
-
-/* Initializes 'q' as empty. */
+/* Initializes 'q' as an empty byteq that uses the 'size' bytes of 'buffer' to
+ * store data. 'size' must be a power of 2.
+ *
+ * The caller must ensure that 'buffer' remains available to the byteq as long
+ * as 'q' is in use. */
void
-byteq_init(struct byteq *q)
+byteq_init(struct byteq *q, uint8_t *buffer, size_t size)
{
+ ovs_assert(is_pow2(size));
+ q->buffer = buffer;
+ q->size = size;
q->head = q->tail = 0;
}
int
byteq_avail(const struct byteq *q)
{
- return BYTEQ_SIZE - byteq_used(q);
+ return q->size - byteq_used(q);
}
/* Returns true if no bytes are queued in 'q',
byteq_tailroom(const struct byteq *q)
{
int used = byteq_used(q);
- int tail_to_end = BYTEQ_SIZE - (q->tail & (BYTEQ_SIZE - 1));
+ int tail_to_end = q->size - (q->tail & (q->size - 1));
return MIN(used, tail_to_end);
}
const uint8_t *
byteq_tail(const struct byteq *q)
{
- return &q->buffer[q->tail & (BYTEQ_SIZE - 1)];
+ return &q->buffer[q->tail & (q->size - 1)];
}
/* Removes 'n' bytes from the tail of 'q', which must have at least 'n' bytes
uint8_t *
byteq_head(struct byteq *q)
{
- return &q->buffer[q->head & (BYTEQ_SIZE - 1)];
+ return &q->buffer[q->head & (q->size - 1)];
}
/* Returns the number of contiguous bytes of free space starting at the head
byteq_headroom(const struct byteq *q)
{
int avail = byteq_avail(q);
- int head_to_end = BYTEQ_SIZE - (q->head & (BYTEQ_SIZE - 1));
+ int head_to_end = q->size - (q->head & (q->size - 1));
return MIN(avail, head_to_end);
}