1/*
2 * Copyright (c) 2015, Intel Corporation
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation and/or
13 * other materials provided with the distribution.
14 *
15 * 3. Neither the name of the copyright holder nor the names of its contributors
16 * may be used to endorse or promote products derived from this software without
17 * specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
21 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
23 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
26 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "FullIo.hpp"
32
33#include <cerrno>
34#include <unistd.h>
35
36namespace utility
37{
38
39/** Workaround c++ `void *` arithmetic interdiction. */
40template <class Ptr>
41Ptr *add(Ptr *ptr, size_t count) {
42    return (char *)ptr + count;
43}
44
45template <class Buff>
46static bool fullAccess(ssize_t (&accessor)(int, Buff, size_t),
47                       bool (&accessFailed)(ssize_t),
48                       int fd, Buff buf, size_t count) {
49    size_t done = 0; // Bytes already access in previous iterations
50    while (done < count) {
51        ssize_t accessed = accessor(fd, add(buf, done), count - done);
52        if (accessFailed(accessed)) {
53            return false;
54        }
55        done += accessed;
56    }
57    return true;
58}
59
60static bool accessFailed(ssize_t accessRes) {
61    return accessRes == -1 and errno != EAGAIN and errno != EINTR;
62}
63
64bool fullWrite(int fd, const void *buf, size_t count) {
65    return fullAccess(::write, accessFailed, fd, buf, count);
66}
67
68static bool readFailed(ssize_t readRes) {
69    if (readRes == 0) { // read should not return 0 (EOF)
70        errno = 0;
71        return true;
72    }
73    return accessFailed(readRes);
74}
75bool fullRead(int fd, void *buf, size_t count) {
76    return fullAccess(::read, readFailed, fd, buf, count);
77}
78
79} // namespace utility
80
81