1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, sin-ack <sin-ack@protonmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/ByteBuffer.h>
#include <AK/Format.h>
#include <AK/Stream.h>
namespace AK {
ErrorOr<void> Stream::read_entire_buffer(Bytes buffer)
{
size_t nread = 0;
while (nread < buffer.size()) {
if (is_eof())
return Error::from_string_literal("Reached end-of-file before filling the entire buffer");
auto result = read(buffer.slice(nread));
if (result.is_error()) {
if (result.error().is_errno() && result.error().code() == EINTR) {
continue;
}
return result.release_error();
}
nread += result.value().size();
}
return {};
}
ErrorOr<ByteBuffer> Stream::read_until_eof(size_t block_size)
{
return read_until_eof_impl(block_size);
}
ErrorOr<ByteBuffer> Stream::read_until_eof_impl(size_t block_size, size_t expected_file_size)
{
ByteBuffer data;
data.ensure_capacity(expected_file_size);
size_t total_read = 0;
Bytes buffer;
while (!is_eof()) {
if (buffer.is_empty()) {
buffer = TRY(data.get_bytes_for_writing(block_size));
}
auto nread = TRY(read(buffer)).size();
total_read += nread;
buffer = buffer.slice(nread);
}
data.resize(total_read);
return data;
}
ErrorOr<void> Stream::discard(size_t discarded_bytes)
{
// Note: This was chosen arbitrarily.
// Note: This can't be PAGE_SIZE because it is defined to sysconf() on Lagom.
constexpr size_t continuous_read_size = 4096;
Array<u8, continuous_read_size> buffer;
while (discarded_bytes > 0) {
if (is_eof())
return Error::from_string_literal("Reached end-of-file before reading all discarded bytes");
auto slice = TRY(read(buffer.span().slice(0, min(discarded_bytes, continuous_read_size))));
discarded_bytes -= slice.size();
}
return {};
}
ErrorOr<void> Stream::write_entire_buffer(ReadonlyBytes buffer)
{
size_t nwritten = 0;
while (nwritten < buffer.size()) {
auto result = write(buffer.slice(nwritten));
if (result.is_error()) {
if (result.error().is_errno() && result.error().code() == EINTR) {
continue;
}
return result.release_error();
}
nwritten += result.value();
}
return {};
}
ErrorOr<size_t> SeekableStream::tell() const
{
// Seek with 0 and SEEK_CUR does not modify anything despite the const_cast,
// so it's safe to do this.
return const_cast<SeekableStream*>(this)->seek(0, SeekMode::FromCurrentPosition);
}
ErrorOr<size_t> SeekableStream::size()
{
auto original_position = TRY(tell());
auto seek_result = seek(0, SeekMode::FromEndPosition);
if (seek_result.is_error()) {
// Let's try to restore the original position, just in case.
auto restore_result = seek(original_position, SeekMode::SetPosition);
if (restore_result.is_error()) {
dbgln("SeekableStream::size: Couldn't restore initial position, stream might have incorrect position now!");
}
return seek_result.release_error();
}
TRY(seek(original_position, SeekMode::SetPosition));
return seek_result.value();
}
ErrorOr<void> SeekableStream::discard(size_t discarded_bytes)
{
TRY(seek(discarded_bytes, SeekMode::FromCurrentPosition));
return {};
}
}
|
