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
|
/* Copyright (C) 2010 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. 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.
*
* 0 A.D. 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 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_PRIORITYQUEUE
#define INCLUDED_PRIORITYQUEUE
/*
* Priority queues for pathfinder.
* (These probably aren't suitable for more general uses.)
*/
#ifdef NDEBUG
#define PRIORITYQUEUE_DEBUG 0
#else
#define PRIORITYQUEUE_DEBUG 1
#endif
template <typename Item, typename CMP>
struct QueueItemPriority
{
bool operator()(const Item& a, const Item& b)
{
if (CMP()(b.rank, a.rank)) // higher costs are lower priority
return true;
if (CMP()(a.rank, b.rank))
return false;
// Need to tie-break to get a consistent ordering
// TODO: Should probably tie-break on g or h or something, but don't bother for now
if (a.id < b.id)
return true;
if (b.id < a.id)
return false;
#if PRIORITYQUEUE_DEBUG
debug_warn(L"duplicate tiles in queue");
#endif
return false;
}
};
/**
* Priority queue implemented as a binary heap.
* This is quite dreadfully slow in MSVC's debug STL implementation,
* so we shouldn't use it unless we reimplement the heap functions more efficiently.
*/
template <typename ID, typename R, typename CMP = std::less<R> >
class PriorityQueueHeap
{
public:
struct Item
{
ID id;
R rank; // f = g+h (estimated total cost of path through here)
};
void push(const Item& item)
{
m_Heap.push_back(item);
push_heap(m_Heap.begin(), m_Heap.end(), QueueItemPriority<Item, CMP>());
}
Item* find(ID id)
{
for (size_t n = 0; n < m_Heap.size(); ++n)
{
if (m_Heap[n].id == id)
return &m_Heap[n];
}
return NULL;
}
void promote(ID id, R newrank)
{
for (size_t n = 0; n < m_Heap.size(); ++n)
{
if (m_Heap[n].id == id)
{
#if PRIORITYQUEUE_DEBUG
ENSURE(m_Heap[n].rank > newrank);
#endif
m_Heap[n].rank = newrank;
push_heap(m_Heap.begin(), m_Heap.begin()+n+1, QueueItemPriority<Item, CMP>());
return;
}
}
}
Item pop()
{
#if PRIORITYQUEUE_DEBUG
ENSURE(m_Heap.size());
#endif
Item r = m_Heap.front();
pop_heap(m_Heap.begin(), m_Heap.end(), QueueItemPriority<Item, CMP>());
m_Heap.pop_back();
return r;
}
bool empty()
{
return m_Heap.empty();
}
size_t size()
{
return m_Heap.size();
}
std::vector<Item> m_Heap;
};
/**
* Priority queue implemented as an unsorted array.
* This means pop() is O(n), but push and promote are O(1), and n is typically small
* (average around 50-100 in some rough tests).
* It seems fractionally slower than a binary heap in optimised builds, but is
* much simpler and less susceptible to MSVC's painfully slow debug STL.
*/
template <typename ID, typename R, typename CMP = std::less<R> >
class PriorityQueueList
{
public:
struct Item
{
ID id;
R rank; // f = g+h (estimated total cost of path through here)
};
void push(const Item& item)
{
m_List.push_back(item);
}
Item* find(ID id)
{
for (size_t n = 0; n < m_List.size(); ++n)
{
if (m_List[n].id == id)
return &m_List[n];
}
return NULL;
}
void promote(ID id, R newrank)
{
find(id)->rank = newrank;
}
Item pop()
{
#if PRIORITYQUEUE_DEBUG
ENSURE(m_List.size());
#endif
// Loop backwards looking for the best (it's most likely to be one
// we've recently pushed, so going backwards saves a bit of copying)
Item best = m_List.back();
size_t bestidx = m_List.size()-1;
for (ssize_t i = (ssize_t)bestidx-1; i >= 0; --i)
{
if (QueueItemPriority<Item, CMP>()(best, m_List[i]))
{
bestidx = i;
best = m_List[i];
}
}
// Swap the matched element with the last in the list, then pop the new last
m_List[bestidx] = m_List[m_List.size()-1];
m_List.pop_back();
return best;
}
bool empty()
{
return m_List.empty();
}
size_t size()
{
return m_List.size();
}
std::vector<Item> m_List;
};
#endif // INCLUDED_PRIORITYQUEUE
|
