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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
|
// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#include <algorithm>
#include <utility>
#include "common/assert.h"
#include "core/file_sys/vfs_concat.h"
#include "core/file_sys/vfs_static.h"
namespace FileSys {
ConcatenatedVfsFile::ConcatenatedVfsFile(ConcatenationMap&& concatenation_map_, std::string&& name_)
: concatenation_map(std::move(concatenation_map_)), name(std::move(name_)) {
DEBUG_ASSERT(this->VerifyContinuity());
}
bool ConcatenatedVfsFile::VerifyContinuity() const {
u64 last_offset = 0;
for (auto& entry : concatenation_map) {
if (entry.offset != last_offset) {
return false;
}
last_offset = entry.offset + entry.file->GetSize();
}
return true;
}
ConcatenatedVfsFile::~ConcatenatedVfsFile() = default;
VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(const std::vector<VirtualFile>& files,
std::string&& name) {
// Fold trivial cases.
if (files.empty()) {
return nullptr;
}
if (files.size() == 1) {
return files.front();
}
// Make the concatenation map from the input.
std::vector<ConcatenationEntry> concatenation_map;
concatenation_map.reserve(files.size());
u64 last_offset = 0;
for (auto& file : files) {
concatenation_map.emplace_back(ConcatenationEntry{
.offset = last_offset,
.file = file,
});
last_offset += file->GetSize();
}
return VirtualFile(new ConcatenatedVfsFile(std::move(concatenation_map), std::move(name)));
}
VirtualFile ConcatenatedVfsFile::MakeConcatenatedFile(u8 filler_byte,
const std::multimap<u64, VirtualFile>& files,
std::string&& name) {
// Fold trivial cases.
if (files.empty()) {
return nullptr;
}
if (files.size() == 1) {
return files.begin()->second;
}
// Make the concatenation map from the input.
std::vector<ConcatenationEntry> concatenation_map;
concatenation_map.reserve(files.size());
u64 last_offset = 0;
// Iteration of a multimap is ordered, so offset will be strictly non-decreasing.
for (auto& [offset, file] : files) {
if (offset > last_offset) {
concatenation_map.emplace_back(ConcatenationEntry{
.offset = last_offset,
.file = std::make_shared<StaticVfsFile>(filler_byte, offset - last_offset),
});
}
concatenation_map.emplace_back(ConcatenationEntry{
.offset = offset,
.file = file,
});
last_offset = offset + file->GetSize();
}
return VirtualFile(new ConcatenatedVfsFile(std::move(concatenation_map), std::move(name)));
}
std::string ConcatenatedVfsFile::GetName() const {
if (concatenation_map.empty()) {
return "";
}
if (!name.empty()) {
return name;
}
return concatenation_map.front().file->GetName();
}
std::size_t ConcatenatedVfsFile::GetSize() const {
if (concatenation_map.empty()) {
return 0;
}
return concatenation_map.back().offset + concatenation_map.back().file->GetSize();
}
bool ConcatenatedVfsFile::Resize(std::size_t new_size) {
return false;
}
VirtualDir ConcatenatedVfsFile::GetContainingDirectory() const {
if (concatenation_map.empty()) {
return nullptr;
}
return concatenation_map.front().file->GetContainingDirectory();
}
bool ConcatenatedVfsFile::IsWritable() const {
return false;
}
bool ConcatenatedVfsFile::IsReadable() const {
return true;
}
std::size_t ConcatenatedVfsFile::Read(u8* data, std::size_t length, std::size_t offset) const {
const ConcatenationEntry key{
.offset = offset,
.file = nullptr,
};
// Read nothing if the map is empty.
if (concatenation_map.empty()) {
return 0;
}
// Binary search to find the iterator to the first position we can check.
// It must exist, since we are not empty and are comparing unsigned integers.
auto it = std::prev(std::upper_bound(concatenation_map.begin(), concatenation_map.end(), key));
u64 cur_length = length;
u64 cur_offset = offset;
while (cur_length > 0 && it != concatenation_map.end()) {
// Check if we can read the file at this position.
const auto& file = it->file;
const u64 map_offset = it->offset;
const u64 file_size = file->GetSize();
if (cur_offset > map_offset + file_size) {
// Entirely out of bounds read.
break;
}
// Read the file at this position.
const u64 file_seek = cur_offset - map_offset;
const u64 intended_read_size = std::min<u64>(cur_length, file_size - file_seek);
const u64 actual_read_size =
file->Read(data + (cur_offset - offset), intended_read_size, file_seek);
// Update tracking.
cur_offset += actual_read_size;
cur_length -= actual_read_size;
it++;
// If we encountered a short read, we're done.
if (actual_read_size < intended_read_size) {
break;
}
}
return cur_offset - offset;
}
std::size_t ConcatenatedVfsFile::Write(const u8* data, std::size_t length, std::size_t offset) {
return 0;
}
bool ConcatenatedVfsFile::Rename(std::string_view new_name) {
return false;
}
} // namespace FileSys
|
