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
|
/* -*- c-basic-offset: 2 -*- */
/* Copyright(C) 2011 Brazil
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License version 2.1 as published by the Free Software Foundation.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
*/
#include "id-cursor.hpp"
#include <algorithm>
#include "trie.hpp"
namespace grn {
namespace dat {
IdCursor::IdCursor()
: trie_(NULL),
offset_(0),
limit_(MAX_UINT32),
flags_(ID_RANGE_CURSOR),
cur_(INVALID_KEY_ID),
end_(INVALID_KEY_ID),
count_(0) {}
IdCursor::~IdCursor() = default;
void IdCursor::open(const Trie &trie,
const String &min_str,
const String &max_str,
UInt32 offset,
UInt32 limit,
UInt32 flags) {
UInt32 min_id = INVALID_KEY_ID;
if (min_str.ptr() != NULL) {
UInt32 key_pos;
GRN_DAT_THROW_IF(PARAM_ERROR,
!trie.search(min_str.ptr(), min_str.length(), &key_pos));
min_id = trie.get_key(key_pos).id();
}
UInt32 max_id = INVALID_KEY_ID;
if (max_str.ptr() != NULL) {
UInt32 key_pos;
GRN_DAT_THROW_IF(PARAM_ERROR,
!trie.search(max_str.ptr(), max_str.length(), &key_pos));
max_id = trie.get_key(key_pos).id();
}
open(trie, min_id, max_id, offset, limit, flags);
}
void IdCursor::open(const Trie &trie,
UInt32 min_id,
UInt32 max_id,
UInt32 offset,
UInt32 limit,
UInt32 flags) {
flags = fix_flags(flags);
IdCursor new_cursor(trie, offset, limit, flags);
new_cursor.init(min_id, max_id);
new_cursor.swap(this);
}
void IdCursor::close() {
IdCursor new_cursor;
new_cursor.swap(this);
}
const Key &IdCursor::next() {
if (count_ >= limit_) {
return Key::invalid_key();
}
while (cur_ != end_) {
const Key &key = trie_->ith_key(cur_);
if ((flags_ & ASCENDING_CURSOR) == ASCENDING_CURSOR) {
++cur_;
} else {
--cur_;
}
if (key.is_valid()) {
++count_;
return key;
}
}
return Key::invalid_key();
}
IdCursor::IdCursor(const Trie &trie,
UInt32 offset,
UInt32 limit,
UInt32 flags)
: trie_(&trie),
offset_(offset),
limit_(limit),
flags_(flags),
cur_(INVALID_KEY_ID),
end_(INVALID_KEY_ID),
count_(0) {}
UInt32 IdCursor::fix_flags(UInt32 flags) const {
const UInt32 cursor_type = flags & CURSOR_TYPE_MASK;
GRN_DAT_THROW_IF(PARAM_ERROR, (cursor_type != 0) &&
(cursor_type != ID_RANGE_CURSOR));
flags |= ID_RANGE_CURSOR;
const UInt32 cursor_order = flags & CURSOR_ORDER_MASK;
GRN_DAT_THROW_IF(PARAM_ERROR, (cursor_order != 0) &&
(cursor_order != ASCENDING_CURSOR) &&
(cursor_order != DESCENDING_CURSOR));
if (cursor_order == 0) {
flags |= ASCENDING_CURSOR;
}
const UInt32 cursor_options = flags & CURSOR_OPTIONS_MASK;
GRN_DAT_THROW_IF(PARAM_ERROR,
cursor_options & ~(EXCEPT_LOWER_BOUND | EXCEPT_UPPER_BOUND));
return flags;
}
void IdCursor::init(UInt32 min_id, UInt32 max_id) {
if (min_id == INVALID_KEY_ID) {
min_id = trie_->min_key_id();
} else if ((flags_ & EXCEPT_LOWER_BOUND) == EXCEPT_LOWER_BOUND) {
++min_id;
}
if (max_id == INVALID_KEY_ID) {
max_id = trie_->max_key_id();
} else if ((flags_ & EXCEPT_UPPER_BOUND) == EXCEPT_UPPER_BOUND) {
--max_id;
}
if ((max_id < min_id) || ((max_id - min_id) < offset_)) {
return;
}
if ((flags_ & ASCENDING_CURSOR) == ASCENDING_CURSOR) {
cur_ = min_id;
end_ = max_id + 1;
for (UInt32 i = 0; (i < offset_) && (cur_ != end_); ++i) {
while (cur_ != end_) {
if (trie_->ith_key(cur_++).is_valid()) {
break;
}
}
}
} else {
cur_ = max_id;
end_ = min_id - 1;
for (UInt32 i = 0; (i < offset_) && (cur_ != end_); ++i) {
while (cur_ != end_) {
if (trie_->ith_key(cur_--).is_valid()) {
break;
}
}
}
}
}
void IdCursor::swap(IdCursor *cursor) {
std::swap(trie_, cursor->trie_);
std::swap(offset_, cursor->offset_);
std::swap(limit_, cursor->limit_);
std::swap(flags_, cursor->flags_);
std::swap(cur_, cursor->cur_);
std::swap(end_, cursor->end_);
std::swap(count_, cursor->count_);
}
} // namespace dat
} // namespace grn
|
