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
190
191
192
193
194
195
196
197
198
|
// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
#include <algorithm>
#include <cstddef>
#include <limits>
#include <memory>
#include <string>
#include "Common/CDUtils.h"
#include "Common/CommonTypes.h"
#include "Common/FileUtil.h"
#include "DiscIO/Blob.h"
#include "DiscIO/CISOBlob.h"
#include "DiscIO/CompressedBlob.h"
#include "DiscIO/DriveBlob.h"
#include "DiscIO/FileBlob.h"
#include "DiscIO/WbfsBlob.h"
namespace DiscIO
{
void SectorReader::SetSectorSize(int blocksize)
{
m_block_size = std::max(blocksize, 0);
for (auto& cache_entry : m_cache)
{
cache_entry.Reset();
cache_entry.data.resize(m_chunk_blocks * m_block_size);
}
}
void SectorReader::SetChunkSize(int block_cnt)
{
m_chunk_blocks = std::max(block_cnt, 1);
// Clear cache and resize the data arrays
SetSectorSize(m_block_size);
}
SectorReader::~SectorReader()
{
}
const SectorReader::Cache* SectorReader::FindCacheLine(u64 block_num)
{
auto itr = std::find_if(m_cache.begin(), m_cache.end(), [&](const Cache& entry)
{
return entry.Contains(block_num);
});
if (itr == m_cache.end())
return nullptr;
itr->MarkUsed();
return &*itr;
}
SectorReader::Cache* SectorReader::GetEmptyCacheLine()
{
Cache* oldest = &m_cache[0];
// Find the Least Recently Used cache line to replace.
for (auto& cache_entry : m_cache)
{
if (cache_entry.IsLessRecentlyUsedThan(*oldest))
oldest = &cache_entry;
cache_entry.ShiftLRU();
}
oldest->Reset();
return oldest;
}
const SectorReader::Cache* SectorReader::GetCacheLine(u64 block_num)
{
if (auto entry = FindCacheLine(block_num))
return entry;
// Cache miss. Fault in the missing entry.
Cache* cache = GetEmptyCacheLine();
// We only read aligned chunks, this avoids duplicate overlapping entries.
u64 chunk_idx = block_num / m_chunk_blocks;
u32 blocks_read = ReadChunk(cache->data.data(), chunk_idx);
if (!blocks_read)
return nullptr;
cache->Fill(chunk_idx * m_chunk_blocks, blocks_read);
// Secondary check for out-of-bounds read.
// If we got less than m_chunk_blocks, we may still have missed.
// We do this after the cache fill since the cache line itself is
// fine, the problem is being asked to read past the end of the disk.
return cache->Contains(block_num) ? cache : nullptr;
}
bool SectorReader::Read(u64 offset, u64 size, u8* out_ptr)
{
u64 remain = size;
u64 block = 0;
u32 position_in_block = static_cast<u32>(offset % m_block_size);
while (remain > 0)
{
block = offset / m_block_size;
const Cache* cache = GetCacheLine(block);
if (!cache)
return false;
// Cache entries are aligned chunks, we may not want to read from the start
u32 read_offset = static_cast<u32>(block - cache->block_idx) * m_block_size + position_in_block;
u32 can_read = m_block_size * cache->num_blocks - read_offset;
u32 was_read = static_cast<u32>(std::min<u64>(can_read, remain));
std::copy(cache->data.begin() + read_offset,
cache->data.begin() + read_offset + was_read,
out_ptr);
offset += was_read;
out_ptr += was_read;
remain -= was_read;
position_in_block = 0;
}
return true;
}
// Crap default implementation if not overridden.
bool SectorReader::ReadMultipleAlignedBlocks(u64 block_num, u64 cnt_blocks, u8* out_ptr)
{
for (u64 i = 0; i < cnt_blocks; ++i)
{
if (!GetBlock(block_num + i, out_ptr))
return false;
out_ptr += m_block_size;
}
return true;
}
u32 SectorReader::ReadChunk(u8* buffer, u64 chunk_num)
{
u64 block_num = chunk_num * m_chunk_blocks;
u32 cnt_blocks = m_chunk_blocks;
// If we are reading the end of a disk, there may not be enough blocks to
// read a whole chunk. We need to clamp down in that case.
u64 end_block = (GetDataSize() + m_block_size - 1) / m_block_size;
if (end_block)
cnt_blocks = static_cast<u32>(std::min<u64>(m_chunk_blocks, end_block - block_num));
if (ReadMultipleAlignedBlocks(block_num, cnt_blocks, buffer))
{
if (cnt_blocks < m_chunk_blocks)
{
std::fill(buffer + cnt_blocks * m_block_size,
buffer + m_chunk_blocks * m_block_size,
0u);
}
return cnt_blocks;
}
// end_block may be zero on real disks if we fail to get the media size.
// We have to fallback to probing the disk instead.
if (!end_block)
{
for (u32 i = 0; i < cnt_blocks; ++i)
{
if (!GetBlock(block_num + i, buffer))
{
std::fill(buffer, buffer + (cnt_blocks - i) * m_block_size, 0u);
return i;
}
buffer += m_block_size;
}
return cnt_blocks;
}
return 0;
}
std::unique_ptr<IBlobReader> CreateBlobReader(const std::string& filename)
{
if (cdio_is_cdrom(filename))
return DriveReader::Create(filename);
if (!File::Exists(filename))
return nullptr;
if (IsWbfsBlob(filename))
return WbfsFileReader::Create(filename);
if (IsGCZBlob(filename))
return CompressedBlobReader::Create(filename);
if (IsCISOBlob(filename))
return CISOFileReader::Create(filename);
// Still here? Assume plain file - since we know it exists due to the File::Exists check above.
return PlainFileReader::Create(filename);
}
} // namespace
|
