/* Ensures that 'b' has room for at least 'size' bytes at its head,
* reallocating and copying its data if necessary. Its tailroom, if any, is
* preserved. */
void
ofpbuf_prealloc_headroom(struct ofpbuf *b, size_t size)
{
if (size > ofpbuf_headroom(b)) {
ofpbuf_resize__(b, MAX(size, 64), ofpbuf_tailroom(b));
}
}
/* Trims the size of 'b' to fit its actual content, reducing its tailroom to
* 0. Its headroom, if any, is preserved. */
void
ofpbuf_trim(struct ofpbuf *b)
{
if (ofpbuf_tailroom(b) > 0) {
ofpbuf_resize_tailroom__(b, 0);
}
}
/* Trims the size of 'b' to fit its actual content, reducing its headroom and
* tailroom to 0, if any.
*
* Buffers not obtained from malloc() are not resized, since that wouldn't save
* any memory.
*
* Caller needs to updates 'b->header' and 'b->msg' so that they point to the
* same locations in the data. (If they pointed into the tailroom or headroom
* then they become invalid.)
*
*/
void
ofpbuf_trim(struct ofpbuf *b)
{
if (b->source == OFPBUF_MALLOC
&& (ofpbuf_headroom(b) || ofpbuf_tailroom(b))) {
ofpbuf_resize__(b, 0, 0);
}
}
/* Returns a string that describes some of 'b''s metadata plus a hex dump of up
* to 'maxbytes' from the start of the buffer. */
char *
ofpbuf_to_string(const struct ofpbuf *b, size_t maxbytes)
{
struct ds s;
ds_init(&s);
ds_put_format(&s, "size=%"PRIu32", allocated=%"PRIu32", head=%"PRIuSIZE", tail=%"PRIuSIZE"\n",
b->size, b->allocated,
ofpbuf_headroom(b), ofpbuf_tailroom(b));
ds_put_hex_dump(&s, b->data, MIN(b->size, maxbytes), 0, false);
return ds_cstr(&s);
}
/* Shifts all of the data within the allocated space in 'b' by 'delta' bytes.
* For example, a 'delta' of 1 would cause each byte of data to move one byte
* forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each
* byte to move one byte backward (from 'p' to 'p-1').
*
* If used, user must make sure the 'header' and 'msg' pointers are updated
* after shifting.
*/
void
ofpbuf_shift(struct ofpbuf *b, int delta)
{
ovs_assert(delta > 0 ? delta <= ofpbuf_tailroom(b)
: delta < 0 ? -delta <= ofpbuf_headroom(b)
: true);
if (delta != 0) {
char *dst = (char *) b->data + delta;
memmove(dst, b->data, b->size);
b->data = dst;
}
}
/* Shifts all of the data within the allocated space in 'b' by 'delta' bytes.
* For example, a 'delta' of 1 would cause each byte of data to move one byte
* forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each
* byte to move one byte backward (from 'p' to 'p-1'). */
void
ofpbuf_shift(struct ofpbuf *b, int delta)
{
ovs_assert(delta > 0 ? delta <= ofpbuf_tailroom(b)
: delta < 0 ? -delta <= ofpbuf_headroom(b)
: true);
if (delta != 0) {
char *dst = (char *) ofpbuf_data(b) + delta;
memmove(dst, ofpbuf_data(b), ofpbuf_size(b));
ofpbuf_set_data(b, dst);
}
}
static void
ofpbuf_copy__(struct ofpbuf *b, uint8_t *new_base,
size_t new_headroom, size_t new_tailroom)
{
const uint8_t *old_base = b->base;
size_t old_headroom = ofpbuf_headroom(b);
size_t old_tailroom = ofpbuf_tailroom(b);
size_t copy_headroom = MIN(old_headroom, new_headroom);
size_t copy_tailroom = MIN(old_tailroom, new_tailroom);
memcpy(&new_base[new_headroom - copy_headroom],
&old_base[old_headroom - copy_headroom],
copy_headroom + b->size + copy_tailroom);
}
