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1 | /* | |
2 | * Helpers for getting linearized buffers from iov / filling buffers into iovs | |
3 | * | |
4 | * Copyright IBM, Corp. 2007, 2008 | |
5 | * Copyright (C) 2010 Red Hat, Inc. | |
6 | * | |
7 | * Author(s): | |
8 | * Anthony Liguori <aliguori@us.ibm.com> | |
9 | * Amit Shah <amit.shah@redhat.com> | |
10 | * | |
11 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
12 | * the COPYING file in the top-level directory. | |
13 | */ | |
14 | ||
15 | #include "iov.h" | |
16 | ||
17 | size_t iov_from_buf(struct iovec *iov, unsigned int iov_cnt, | |
18 | const void *buf, size_t iov_off, size_t size) | |
19 | { | |
20 | size_t iovec_off, buf_off; | |
21 | unsigned int i; | |
22 | ||
23 | iovec_off = 0; | |
24 | buf_off = 0; | |
25 | for (i = 0; i < iov_cnt && size; i++) { | |
26 | if (iov_off < (iovec_off + iov[i].iov_len)) { | |
27 | size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off, size); | |
28 | ||
29 | memcpy(iov[i].iov_base + (iov_off - iovec_off), buf + buf_off, len); | |
30 | ||
31 | buf_off += len; | |
32 | iov_off += len; | |
33 | size -= len; | |
34 | } | |
35 | iovec_off += iov[i].iov_len; | |
36 | } | |
37 | return buf_off; | |
38 | } | |
39 | ||
40 | size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt, | |
41 | void *buf, size_t iov_off, size_t size) | |
42 | { | |
43 | uint8_t *ptr; | |
44 | size_t iovec_off, buf_off; | |
45 | unsigned int i; | |
46 | ||
47 | ptr = buf; | |
48 | iovec_off = 0; | |
49 | buf_off = 0; | |
50 | for (i = 0; i < iov_cnt && size; i++) { | |
51 | if (iov_off < (iovec_off + iov[i].iov_len)) { | |
52 | size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off , size); | |
53 | ||
54 | memcpy(ptr + buf_off, iov[i].iov_base + (iov_off - iovec_off), len); | |
55 | ||
56 | buf_off += len; | |
57 | iov_off += len; | |
58 | size -= len; | |
59 | } | |
60 | iovec_off += iov[i].iov_len; | |
61 | } | |
62 | return buf_off; | |
63 | } | |
64 | ||
65 | size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt) | |
66 | { | |
67 | size_t len; | |
68 | unsigned int i; | |
69 | ||
70 | len = 0; | |
71 | for (i = 0; i < iov_cnt; i++) { | |
72 | len += iov[i].iov_len; | |
73 | } | |
74 | return len; | |
75 | } |