This changes implementations of all iov_*
functions, completing the previous step.
All iov_* functions now ensure that this offset
argument is within the iovec (using assertion),
but lets to specify `bytes' value larger than
actual length of the iovec - in this case they
stops at the actual end of iovec. It is also
suggested to use convinient `-1' value as `bytes'
to mean just this -- "up to the end".
There's one very minor semantic change here: new
requiriment is that `offset' points to inside of
iovec. This is checked just at the end of functions
(assert()), it does not actually need to be enforced,
but using any of these functions with offset pointing
past the end of iovec is wrong anyway.
Note: the new code in iov.c uses arithmetic with
void pointers. I thought this is not supported
everywhere and is a GCC extension (indeed, the C
standard does not define void arithmetic). However,
the original code already use void arith in
iov_from_buf() function:
(memcpy(..., buf + buf_off,...)
which apparently works well so far (it is this
way in qemu 1.0). So I left it this way and used
it in other places.
Signed-off-by: Michael Tokarev<address@hidden>
---
iov.c | 91 ++++++++++++++++++++++++++++-------------------------------------
iov.h | 12 +++++++-
2 files changed, 49 insertions(+), 54 deletions(-)
diff --git a/iov.c b/iov.c
index bc58cab..fd518dd 100644
--- a/iov.c
+++ b/iov.c
@@ -7,6 +7,7 @@
* Author(s):
* Anthony Liguori<address@hidden>
* Amit Shah<address@hidden>
+ * Michael Tokarev<address@hidden>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
@@ -17,75 +18,61 @@
#include "iov.h"
-size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt, size_t iov_off,
- const void *buf, size_t size)
+size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt,
+ size_t offset, const void *buf, size_t bytes)
{
- size_t iovec_off, buf_off;
+ size_t done;
unsigned int i;
-
- iovec_off = 0;
- buf_off = 0;
- for (i = 0; i< iov_cnt&& size; i++) {
- if (iov_off< (iovec_off + iov[i].iov_len)) {
- size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off, size);
-
- memcpy(iov[i].iov_base + (iov_off - iovec_off), buf + buf_off,
len);
-
- buf_off += len;
- iov_off += len;
- size -= len;
+ for (i = 0, done = 0; done< bytes&& i< iov_cnt; i++) {
+ if (offset< iov[i].iov_len) {
+ size_t len = MIN(iov[i].iov_len - offset, bytes - done);
+ memcpy(iov[i].iov_base + offset, buf + done, len);
+ done += len;
+ offset = 0;
+ } else {
+ offset -= iov[i].iov_len;
}
- iovec_off += iov[i].iov_len;
}
- return buf_off;
+ assert(offset == 0);
+ return done;
}