qemu/iov.c

133 lines
3.3 KiB
C
Raw Normal View History

/*
* Helpers for getting linearized buffers from iov / filling buffers into iovs
*
* Copyright IBM, Corp. 2007, 2008
* Copyright (C) 2010 Red Hat, Inc.
*
* Author(s):
* Anthony Liguori <aliguori@us.ibm.com>
* Amit Shah <amit.shah@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "iov.h"
size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt,
const void *buf, size_t iov_off, size_t size)
{
size_t iovec_off, buf_off;
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;
}
iovec_off += iov[i].iov_len;
}
return buf_off;
}
size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
void *buf, size_t iov_off, size_t size)
{
uint8_t *ptr;
size_t iovec_off, buf_off;
unsigned int i;
ptr = buf;
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(ptr + buf_off, iov[i].iov_base + (iov_off - iovec_off), len);
buf_off += len;
iov_off += len;
size -= len;
}
iovec_off += iov[i].iov_len;
}
return buf_off;
}
size_t iov_clear(const struct iovec *iov, const unsigned int iov_cnt,
size_t iov_off, size_t size)
{
size_t iovec_off, buf_off;
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);
memset(iov[i].iov_base + (iov_off - iovec_off), 0, len);
buf_off += len;
iov_off += len;
size -= len;
}
iovec_off += iov[i].iov_len;
}
return buf_off;
}
size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt)
{
size_t len;
unsigned int i;
len = 0;
for (i = 0; i < iov_cnt; i++) {
len += iov[i].iov_len;
}
return len;
}
void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
FILE *fp, const char *prefix, size_t limit)
{
unsigned int i, v, b;
uint8_t *c;
c = iov[0].iov_base;
for (i = 0, v = 0, b = 0; b < limit; i++, b++) {
if (i == iov[v].iov_len) {
i = 0; v++;
if (v == iov_cnt) {
break;
}
c = iov[v].iov_base;
}
if ((b % 16) == 0) {
fprintf(fp, "%s: %04x:", prefix, b);
}
if ((b % 4) == 0) {
fprintf(fp, " ");
}
fprintf(fp, " %02x", c[i]);
if ((b % 16) == 15) {
fprintf(fp, "\n");
}
}
if ((b % 16) != 0) {
fprintf(fp, "\n");
}
}