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
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "search.h"
#include "md5.h"
#include <algorithm>
#include <cassert>
Hasher::Hash Hasher::createHash(const byte *data, uint32 size) {
md5_context ctx;
md5_starts(&ctx);
md5_update(&ctx, data, size);
Hash hash;
md5_finish(&ctx, hash.digest);
return hash;
}
SearchData SearchCreator::create(const char *filename) {
FILE *f = fopen(filename, "rb");
assert(f);
SearchData data;
data.size = fileSize(f);
byte *buffer = new byte[data.size];
fread(buffer, 1, data.size, f);
fclose(f);
data = create(buffer, data.size);
delete[] buffer;
return data;
}
SearchData SearchCreator::create(const byte *buffer, uint32 size) {
SearchData data;
data.size = size;
data.hash = Hasher::createHash(buffer, data.size);
data.byteSum = 0;
for (uint32 i = 0; i < data.size; ++i)
data.byteSum += buffer[i];
return data;
}
SumCreator::SumCreator(InputList list, const DataInput &input) : _curOffset(0), _input(input), _sums() {
// Sort in ascending order
list.sort(std::less<uint32>());
uint32 byteSum = 0;
uint32 oldSize = 0;
for (InputList::const_iterator i = list.begin(); i != list.end(); ++i) {
// Strip out entries, which exceed the buffer size
if (*i > _input.size())
continue;
// Strip out duplicates
if (_sums.find(*i) != _sums.end())
continue;
// Only add the bytes exceeding the old sum's size
// to the sum. This saves a few accesses.
for (uint32 j = oldSize; j < *i; ++j)
byteSum += _input[j];
_sums[*i] = byteSum;
// Save this sum's size
oldSize = *i;
}
}
bool SumCreator::nextByte() {
// Calculate the bytes available for summing. We need to add
// 1 here, since we will only update the offset AFTER everything
// is done.
const uint32 sizeLeft = _input.size() - (_curOffset + 1);
if (!sizeLeft) {
_sums.clear();
return false;
}
// Grab the old first byte.
const byte firstByte = _input[_curOffset];
typedef std::list<uint32> DeletionList;
DeletionList toRemove;
for (SumMap::iterator i = _sums.begin(); i != _sums.end(); ++i) {
// If this entry needs to sum up a larger buffer than the buffer
// size left, we will remove the entry and continue to the next
// one.
if (i->first > sizeLeft) {
// Add the current entry to the removal list.
toRemove.push_back(i->first);
continue;
}
// Update the byte sum. First we remove the old first byte
// from the sum, next we add the next available byte.
i->second -= firstByte;
i->second += _input[_curOffset + i->first];
}
// Remove all entries flagged for removal
for (DeletionList::const_iterator i = toRemove.begin(); i != toRemove.end(); ++i)
_sums.erase(*i);
// Update out offset.
++_curOffset;
// We return whether there are still some sums left available.
return !_sums.empty();
}
bool SumCreator::hasSum(uint32 size) const {
return _sums.find(size) != _sums.end();
}
uint32 SumCreator::getSum(uint32 size) const {
SumMap::const_iterator s = _sums.find(size);
if (s == _sums.end())
return 0;
return s->second;
}
Search::Search(const char *filename) : _data(), _search() {
FILE *src = fopen(filename, "rb");
assert(src);
uint32 size = fileSize(src);
byte *data = new byte[size];
fread(data, 1, size, src);
fclose(src);
_data.resize(size);
std::copy(data, data + size, _data.begin());
delete[] data;
}
Search::Search(const byte *data, uint32 size) : _data(), _search() {
_data.resize(size);
std::copy(data, data + size, _data.begin());
}
void Search::addData(SearchData data) {
// Do not add any duplicates
if (std::find(_search.begin(), _search.end(), data) != _search.end())
return;
_search.push_back(data);
}
bool Search::search(ResultList &res) {
SumCreator::InputList list;
for (SearchList::const_iterator i = _search.begin(); i != _search.end(); ++i)
list.push_back(i->size);
SumCreator sum(list, _data);
list.clear();
do {
const uint32 offset = sum.getOffset();
for (SearchList::iterator i = _search.begin(); i != _search.end(); ) {
if (!sum.hasSum(i->size)) {
i = _search.erase(i);
continue;
}
const uint32 byteSum = sum.getSum(i->size);
if (byteSum == i->byteSum) {
if (Hasher::createHash(&_data[offset], i->size) == i->hash) {
res.push_back(ResultData(*i, offset));
i = _search.erase(i);
continue;
}
}
++i;
}
} while (sum.nextByte());
return !res.empty();
}
|
