1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2016 Jakub Klama <jceel@FreeBSD.org>.
5 * Copyright (c) 2018 Alexander Motin <mav@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer
13 *    in this position and unchanged.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/param.h>
32#include <sys/types.h>
33#include <sys/uio.h>
34
35#include <stdlib.h>
36#include <string.h>
37#include "iov.h"
38
39void
40seek_iov(const struct iovec *iov1, int niov1, struct iovec *iov2, int *niov2,
41    size_t seek)
42{
43	size_t remainder = 0;
44	size_t left = seek;
45	int i, j;
46
47	for (i = 0; i < niov1; i++) {
48		size_t toseek = MIN(left, iov1[i].iov_len);
49		left -= toseek;
50
51		if (toseek == iov1[i].iov_len)
52			continue;
53
54		if (left == 0) {
55			remainder = toseek;
56			break;
57		}
58	}
59
60	for (j = i; j < niov1; j++) {
61		iov2[j - i].iov_base = (char *)iov1[j].iov_base + remainder;
62		iov2[j - i].iov_len = iov1[j].iov_len - remainder;
63		remainder = 0;
64	}
65
66	*niov2 = j - i;
67}
68
69size_t
70count_iov(const struct iovec *iov, int niov)
71{
72	size_t total = 0;
73	int i;
74
75	for (i = 0; i < niov; i++)
76		total += iov[i].iov_len;
77
78	return (total);
79}
80
81void
82truncate_iov(struct iovec *iov, int *niov, size_t length)
83{
84	size_t done = 0;
85	int i;
86
87	for (i = 0; i < *niov; i++) {
88		size_t toseek = MIN(length - done, iov[i].iov_len);
89		done += toseek;
90
91		if (toseek <= iov[i].iov_len) {
92			iov[i].iov_len = toseek;
93			*niov = i + 1;
94			return;
95		}
96	}
97}
98
99ssize_t
100iov_to_buf(const struct iovec *iov, int niov, void **buf)
101{
102	size_t ptr, total;
103	int i;
104
105	total = count_iov(iov, niov);
106	*buf = realloc(*buf, total);
107	if (*buf == NULL)
108		return (-1);
109
110	for (i = 0, ptr = 0; i < niov; i++) {
111		memcpy((uint8_t *)*buf + ptr, iov[i].iov_base, iov[i].iov_len);
112		ptr += iov[i].iov_len;
113	}
114
115	return (total);
116}
117
118ssize_t
119buf_to_iov(const void *buf, size_t buflen, const struct iovec *iov, int niov,
120    size_t seek)
121{
122	struct iovec *diov;
123	size_t off = 0, len;
124	int  i;
125
126	if (seek > 0) {
127		int ndiov;
128
129		diov = malloc(sizeof(struct iovec) * niov);
130		seek_iov(iov, niov, diov, &ndiov, seek);
131		iov = diov;
132		niov = ndiov;
133	}
134
135	for (i = 0; i < niov && off < buflen; i++) {
136		len = MIN(iov[i].iov_len, buflen - off);
137		memcpy(iov[i].iov_base, (const uint8_t *)buf + off, len);
138		off += len;
139	}
140
141	if (seek > 0)
142		free(diov);
143
144	return ((ssize_t)off);
145}
146
147