OpenTTD Source  20241120-master-g6d3adc6169
pool_func.hpp
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1 /*
2  * This file is part of OpenTTD.
3  * OpenTTD 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, version 2.
4  * OpenTTD 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.
5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
6  */
7 
10 #ifndef POOL_FUNC_HPP
11 #define POOL_FUNC_HPP
12 
13 #include "alloc_func.hpp"
14 #include "bitmath_func.hpp"
15 #include "mem_func.hpp"
16 #include "pool_type.hpp"
17 #include "../error_func.h"
18 
19 #include "../saveload/saveload_error.hpp" // SlErrorCorruptFmt
20 
25 #define DEFINE_POOL_METHOD(type) \
26  template <class Titem, typename Tindex, size_t Tgrowth_step, size_t Tmax_size, PoolType Tpool_type, bool Tcache, bool Tzero> \
27  type Pool<Titem, Tindex, Tgrowth_step, Tmax_size, Tpool_type, Tcache, Tzero>
28 
33 DEFINE_POOL_METHOD(inline)::Pool(const char *name) :
34  PoolBase(Tpool_type),
35  name(name),
36  size(0),
37  first_free(0),
38  first_unused(0),
39  items(0),
40 #ifdef WITH_ASSERT
41  checked(0),
42 #endif /* WITH_ASSERT */
43  cleaning(false),
44  data(nullptr),
45  alloc_cache(nullptr)
46 { }
47 
54 DEFINE_POOL_METHOD(inline void)::ResizeFor(size_t index)
55 {
56  assert(index >= this->size);
57  assert(index < Tmax_size);
58 
59  size_t new_size = std::min(Tmax_size, Align(index + 1, Tgrowth_step));
60 
61  this->data = ReallocT(this->data, new_size);
62  MemSetT(this->data + this->size, 0, new_size - this->size);
63 
64  this->used_bitmap.resize(Align(new_size, BITMAP_SIZE) / BITMAP_SIZE);
65  if (this->size % BITMAP_SIZE != 0) {
66  /* Already-allocated bits above old size are now unused. */
67  this->used_bitmap[this->size / BITMAP_SIZE] &= ~((~static_cast<BitmapStorage>(0)) << (this->size % BITMAP_SIZE));
68  }
69  if (new_size % BITMAP_SIZE != 0) {
70  /* Bits above new size are considered used. */
71  this->used_bitmap[new_size / BITMAP_SIZE] |= (~static_cast<BitmapStorage>(0)) << (new_size % BITMAP_SIZE);
72  }
73 
74  this->size = new_size;
75 }
76 
81 DEFINE_POOL_METHOD(inline size_t)::FindFirstFree()
82 {
83  for (auto it = std::next(std::begin(this->used_bitmap), this->first_free / BITMAP_SIZE); it != std::end(this->used_bitmap); ++it) {
84  BitmapStorage available = ~(*it);
85  if (available == 0) continue;
86  return std::distance(std::begin(this->used_bitmap), it) * BITMAP_SIZE + FindFirstBit(available);
87  }
88 
89  assert(this->first_unused == this->size);
90 
91  if (this->first_unused < Tmax_size) {
92  this->ResizeFor(this->first_unused);
93  return this->first_unused;
94  }
95 
96  assert(this->first_unused == Tmax_size);
97 
98  return NO_FREE_ITEM;
99 }
100 
108 DEFINE_POOL_METHOD(inline void *)::AllocateItem(size_t size, size_t index)
109 {
110  assert(this->data[index] == nullptr);
111 
112  this->first_unused = std::max(this->first_unused, index + 1);
113  this->items++;
114 
115  Titem *item;
116  if (Tcache && this->alloc_cache != nullptr) {
117  assert(sizeof(Titem) == size);
118  item = reinterpret_cast<Titem *>(this->alloc_cache);
119  this->alloc_cache = this->alloc_cache->next;
120  if (Tzero) {
121  /* Explicitly casting to (void *) prevents a clang warning -
122  * we are actually memsetting a (not-yet-constructed) object */
123  memset(static_cast<void *>(item), 0, sizeof(Titem));
124  }
125  } else if (Tzero) {
126  item = reinterpret_cast<Titem *>(CallocT<uint8_t>(size));
127  } else {
128  item = reinterpret_cast<Titem *>(MallocT<uint8_t>(size));
129  }
130  this->data[index] = item;
131  SetBit(this->used_bitmap[index / BITMAP_SIZE], index % BITMAP_SIZE);
132  item->index = (Tindex)(uint)index;
133  return item;
134 }
135 
142 DEFINE_POOL_METHOD(void *)::GetNew(size_t size)
143 {
144  size_t index = this->FindFirstFree();
145 
146 #ifdef WITH_ASSERT
147  assert(this->checked != 0);
148  this->checked--;
149 #endif /* WITH_ASSERT */
150  if (index == NO_FREE_ITEM) {
151  FatalError("{}: no more free items", this->name);
152  }
153 
154  this->first_free = index + 1;
155  return this->AllocateItem(size, index);
156 }
157 
165 DEFINE_POOL_METHOD(void *)::GetNew(size_t size, size_t index)
166 {
167  if (index >= Tmax_size) {
168  SlErrorCorruptFmt("{} index {} out of range ({})", this->name, index, Tmax_size);
169  }
170 
171  if (index >= this->size) this->ResizeFor(index);
172 
173  if (this->data[index] != nullptr) {
174  SlErrorCorruptFmt("{} index {} already in use", this->name, index);
175  }
176 
177  return this->AllocateItem(size, index);
178 }
179 
186 DEFINE_POOL_METHOD(void)::FreeItem(size_t index)
187 {
188  assert(index < this->size);
189  assert(this->data[index] != nullptr);
190  if (Tcache) {
191  AllocCache *ac = reinterpret_cast<AllocCache *>(this->data[index]);
192  ac->next = this->alloc_cache;
193  this->alloc_cache = ac;
194  } else {
195  free(this->data[index]);
196  }
197  this->data[index] = nullptr;
198  this->first_free = std::min(this->first_free, index);
199  this->items--;
200  if (!this->cleaning) {
201  ClrBit(this->used_bitmap[index / BITMAP_SIZE], index % BITMAP_SIZE);
202  Titem::PostDestructor(index);
203  }
204 }
205 
207 DEFINE_POOL_METHOD(void)::CleanPool()
208 {
209  this->cleaning = true;
210  for (size_t i = 0; i < this->first_unused; i++) {
211  delete this->Get(i); // 'delete nullptr;' is very valid
212  }
213  assert(this->items == 0);
214  free(this->data);
215  this->used_bitmap.clear();
216  this->used_bitmap.shrink_to_fit();
217  this->first_unused = this->first_free = this->size = 0;
218  this->data = nullptr;
219  this->cleaning = false;
220 
221  if (Tcache) {
222  while (this->alloc_cache != nullptr) {
223  AllocCache *ac = this->alloc_cache;
224  this->alloc_cache = ac->next;
225  free(ac);
226  }
227  }
228 }
229 
230 #undef DEFINE_POOL_METHOD
231 
237 #define INSTANTIATE_POOL_METHODS(name) \
238  template void * name ## Pool::GetNew(size_t size); \
239  template void * name ## Pool::GetNew(size_t size, size_t index); \
240  template void name ## Pool::FreeItem(size_t index); \
241  template void name ## Pool::CleanPool();
242 
243 #endif /* POOL_FUNC_HPP */
Functions related to the allocation of memory.
T * ReallocT(T *t_ptr, size_t num_elements)
Simplified reallocation function that allocates the specified number of elements of the given type.
Definition: alloc_func.hpp:111
Functions related to bit mathematics.
constexpr T SetBit(T &x, const uint8_t y)
Set a bit in a variable.
constexpr uint8_t FindFirstBit(T x)
Search the first set bit in a value.
constexpr T ClrBit(T &x, const uint8_t y)
Clears a bit in a variable.
constexpr T Align(const T x, uint n)
Return the smallest multiple of n equal or greater than x.
Definition: math_func.hpp:37
Functions related to memory operations.
void MemSetT(T *ptr, uint8_t value, size_t num=1)
Type-safe version of memset().
Definition: mem_func.hpp:49
#define DEFINE_POOL_METHOD(type)
Helper for defining the method's signature.
Definition: pool_func.hpp:25
Definition of Pool, structure used to access PoolItems, and PoolItem, base structure for Vehicle,...
void free(const void *ptr)
Version of the standard free that accepts const pointers.
Definition: stdafx.h:334
Base class for base of all pools.
Definition: pool_type.hpp:29
Base class for all pools.
Definition: pool_type.hpp:80