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samba-mirror/lib/util/iov_buf.h
Stefan Metzmacher a9c53b9eff lib/util: inline iov_{buflen,buf,advance}()
The main reason for this change was the use of
iov_advance() in the next commits in
source3/smbd/smb2_server.c

And the function calls to iov_advance() showed up
in profiling with callgrind.

While there iov_buf() and iov_buflen() are moved as
well, as they are also used there.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
2023-09-06 19:30:35 +00:00

103 lines
2.2 KiB
C

/*
* Unix SMB/CIFS implementation.
* Samba system utilities
* Copyright (C) Volker Lendecke 2014
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __LIB_IOV_BUF_H__
#define __LIB_IOV_BUF_H__
#include "replace.h"
#include <talloc.h>
#include "system/filesys.h"
static inline
ssize_t iov_buf(const struct iovec *iov, int iovcnt,
uint8_t *buf, size_t buflen)
{
size_t needed = 0;
uint8_t *p = buf;
int i;
for (i=0; i<iovcnt; i++) {
size_t thislen = iov[i].iov_len;
size_t tmp;
tmp = needed + thislen;
if (tmp < needed) {
/* wrap */
return -1;
}
needed = tmp;
if ((p != NULL) && needed <= buflen && thislen > 0) {
memcpy(p, iov[i].iov_base, thislen);
p += thislen;
}
}
return needed;
}
static inline
ssize_t iov_buflen(const struct iovec *iov, int iovcnt)
{
return iov_buf(iov, iovcnt, NULL, 0);
}
static inline
bool iov_advance(struct iovec **iov, int *iovcnt, size_t n)
{
struct iovec *v = *iov;
int cnt = *iovcnt;
while (n > 0) {
if (cnt == 0) {
return false;
}
if (n < v->iov_len) {
v->iov_base = (char *)v->iov_base + n;
v->iov_len -= n;
break;
}
n -= v->iov_len;
v += 1;
cnt -= 1;
}
/*
* Skip 0-length iovec's
*
* There might be empty buffers at the end of iov. Next time we do a
* readv/writev based on this iov would give 0 transferred bytes, also
* known as EPIPE. So we need to be careful discarding them.
*/
while ((cnt > 0) && (v->iov_len == 0)) {
v += 1;
cnt -= 1;
}
*iov = v;
*iovcnt = cnt;
return true;
}
uint8_t *iov_concat(TALLOC_CTX *mem_ctx, const struct iovec *iov, int count);
#endif