/usr/include/fst/memory.h is in libfst-dev 1.5.3+r3-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 | // See www.openfst.org for extensive documentation on this weighted
// finite-state transducer library.
//
// FST memory utilities.
#ifndef FST_LIB_MEMORY_H_
#define FST_LIB_MEMORY_H_
#include <list>
#include <memory>
#include <utility>
#include <fst/types.h>
#include <fstream>
namespace fst {
//
// MEMORY ALLOCATION UTILITIES
//
// Default block allocation size
const int kAllocSize = 64;
// Minimum number of allocations per block
const int kAllocFit = 4;
// Base class for MemoryArena that allows e.g. MemoryArenaCollection to
// easily manipulate collections of variously sized arenas.
class MemoryArenaBase {
public:
virtual ~MemoryArenaBase() {}
virtual size_t Size() const = 0;
};
// Allocates 'size' unintialized memory chunks of size sizeof(T) from
// underlying blocks of (at least) size 'block_size * sizeof(T)'. All
// blocks are freed when this class is deleted. Result of allocate()
// will be aligned to sizeof(T).
template <typename T>
class MemoryArena : public MemoryArenaBase {
public:
explicit MemoryArena(size_t block_size = kAllocSize)
: block_size_(block_size * sizeof(T)), block_pos_(0) {
blocks_.push_front(new char[block_size_]);
}
~MemoryArena() override {
for (auto it = blocks_.begin(); it != blocks_.end(); ++it) {
delete[] * it;
}
}
void *Allocate(size_t size) {
size_t byte_size = size * sizeof(T);
if (byte_size * kAllocFit > block_size_) {
// large block; add new large block
char *ptr = new char[byte_size];
blocks_.push_back(ptr);
return ptr;
}
if (block_pos_ + byte_size > block_size_) {
// Doesn't fit; add new standard block
char *ptr = new char[block_size_];
block_pos_ = 0;
blocks_.push_front(ptr);
}
// Fits; use current block
char *ptr = blocks_.front() + block_pos_;
block_pos_ += byte_size;
return ptr;
}
size_t Size() const override { return sizeof(T); }
private:
size_t block_size_; // default block size in bytes
size_t block_pos_; // current position in block in bytes
std::list<char *> blocks_; // list of allocated blocks
DISALLOW_COPY_AND_ASSIGN(MemoryArena);
};
// Base class for MemoryPool that allows e.g. MemoryPoolCollection to
// easily manipulate collections of variously sized pools.
class MemoryPoolBase {
public:
virtual ~MemoryPoolBase() {}
virtual size_t Size() const = 0;
};
// Allocates and frees initially uninitialized memory chunks of size
// sizeof(T). Keeps an internal list of freed chunks that are reused
// (as is) on the next allocation if available. Chunks are constructed
// in blocks of size 'pool_size'. All memory is freed when the class is
// deleted. The result of Allocate() will be suitably memory-aligned.
//
// Combined with placement operator new and destroy fucntions for the
// T class, this can be used to improve allocation efficiency. See
// nlp/fst/lib/visit.h (global new) and
// nlp/fst/lib/dfs-visit.h (class new) for examples of this usage.
template <typename T>
class MemoryPool : public MemoryPoolBase {
public:
struct Link {
char buf[sizeof(T)];
Link *next;
};
// 'pool_size' specifies the size of the initial pool and how it is extended
explicit MemoryPool(size_t pool_size = kAllocSize)
: mem_arena_(pool_size), free_list_(0) {}
~MemoryPool() override {}
void *Allocate() {
if (free_list_ == 0) {
Link *link = static_cast<Link *>(mem_arena_.Allocate(1));
link->next = 0;
return link;
} else {
Link *link = free_list_;
free_list_ = link->next;
return link;
}
}
void Free(void *ptr) {
if (ptr) {
Link *link = static_cast<Link *>(ptr);
link->next = free_list_;
free_list_ = link;
}
}
size_t Size() const override { return sizeof(T); }
private:
MemoryArena<Link> mem_arena_;
Link *free_list_;
DISALLOW_COPY_AND_ASSIGN(MemoryPool);
};
//
// MEMORY ALLOCATION COLLECTION UTILITIES
//
// Stores a collection of memory arenas
class MemoryArenaCollection {
public:
// 'block_size' specifies the block size of the arenas
explicit MemoryArenaCollection(size_t block_size = kAllocSize)
: block_size_(block_size), ref_count_(1) {}
~MemoryArenaCollection() {
for (size_t i = 0; i < arenas_.size(); ++i) delete arenas_[i];
}
template <typename T>
MemoryArena<T> *Arena() {
if (sizeof(T) >= arenas_.size()) arenas_.resize(sizeof(T) + 1, 0);
MemoryArenaBase *arena = arenas_[sizeof(T)];
if (arena == 0) {
arena = new MemoryArena<T>(block_size_);
arenas_[sizeof(T)] = arena;
}
return static_cast<MemoryArena<T> *>(arena);
}
size_t BlockSize() const { return block_size_; }
size_t RefCount() const { return ref_count_; }
size_t IncrRefCount() { return ++ref_count_; }
size_t DecrRefCount() { return --ref_count_; }
private:
size_t block_size_;
size_t ref_count_;
std::vector<MemoryArenaBase *> arenas_;
DISALLOW_COPY_AND_ASSIGN(MemoryArenaCollection);
};
// Stores a collection of memory pools
class MemoryPoolCollection {
public:
// 'pool_size' specifies the size of initial pool and how it is extended
explicit MemoryPoolCollection(size_t pool_size = kAllocSize)
: pool_size_(pool_size), ref_count_(1) {}
~MemoryPoolCollection() {
for (size_t i = 0; i < pools_.size(); ++i) delete pools_[i];
}
template <typename T>
MemoryPool<T> *Pool() {
if (sizeof(T) >= pools_.size()) pools_.resize(sizeof(T) + 1, 0);
MemoryPoolBase *pool = pools_[sizeof(T)];
if (pool == 0) {
pool = new MemoryPool<T>(pool_size_);
pools_[sizeof(T)] = pool;
}
return static_cast<MemoryPool<T> *>(pool);
}
size_t PoolSize() const { return pool_size_; }
size_t RefCount() const { return ref_count_; }
size_t IncrRefCount() { return ++ref_count_; }
size_t DecrRefCount() { return --ref_count_; }
private:
size_t pool_size_;
size_t ref_count_;
std::vector<MemoryPoolBase *> pools_;
DISALLOW_COPY_AND_ASSIGN(MemoryPoolCollection);
};
//
// STL MEMORY ALLOCATORS
//
// STL allocator using memory arenas. Memory is allocated from
// underlying blocks of size 'block_size * sizeof(T)'. Memory is freed
// only when all objects using this allocator are destroyed and there
// is otherwise no reuse (unlike PoolAllocator).
//
// This allocator has object-local state so it should not be used with
// splicing or swapping operations between objects created with
// different allocators nor should it be used if copies must be
// thread-safe. The result of allocate() will be suitably
// memory-aligned.
template <typename T>
class BlockAllocator {
public:
typedef std::allocator<T> A;
typedef typename A::size_type size_type;
typedef typename A::difference_type difference_type;
typedef typename A::pointer pointer;
typedef typename A::const_pointer const_pointer;
typedef typename A::reference reference;
typedef typename A::const_reference const_reference;
typedef typename A::value_type value_type;
template <typename U>
struct rebind {
typedef BlockAllocator<U> other;
};
explicit BlockAllocator(size_t block_size = kAllocSize)
: arenas_(new MemoryArenaCollection(block_size)) {}
BlockAllocator(const BlockAllocator<T> &arena_alloc)
: arenas_(arena_alloc.Arenas()) {
Arenas()->IncrRefCount();
}
template <typename U>
BlockAllocator(const BlockAllocator<U> &arena_alloc)
: arenas_(arena_alloc.Arenas()) {
Arenas()->IncrRefCount();
}
~BlockAllocator() {
if (Arenas()->DecrRefCount() == 0) delete Arenas();
}
pointer address(reference ref) const { return A().address(ref); }
const_pointer address(const_reference ref) const { return A().address(ref); }
size_type max_size() const { return A().max_size(); }
template <class U, class... Args>
void construct(U *p, Args &&... args) {
A().construct(p, std::forward<Args>(args)...);
}
void destroy(pointer p) { A().destroy(p); }
pointer allocate(size_type n, const void *hint = 0) {
if (n * kAllocFit <= kAllocSize) {
return static_cast<pointer>(Arena()->Allocate(n));
} else {
return A().allocate(n, hint);
}
}
void deallocate(pointer p, size_type n) {
if (n * kAllocFit > kAllocSize) {
A().deallocate(p, n);
}
}
MemoryArenaCollection *Arenas() const { return arenas_; }
private:
MemoryArena<T> *Arena() { return arenas_->Arena<T>(); }
MemoryArenaCollection *arenas_;
BlockAllocator<T> operator=(const BlockAllocator<T> &);
};
template <typename T, typename U>
bool operator==(const BlockAllocator<T> &alloc1,
const BlockAllocator<U> &alloc2) {
return false;
}
template <typename T, typename U>
bool operator!=(const BlockAllocator<T> &alloc1,
const BlockAllocator<U> &alloc2) {
return true;
}
// STL allocator using memory pools. Memory is allocated from underlying
// blocks of size 'block_size * sizeof(T)'. Keeps an internal list of freed
// chunks thare are reused on the next allocation.
//
// This allocator has object-local state so it should not be used with
// splicing or swapping operations between objects created with
// different allocators nor should it be used if copies must be
// thread-safe. The result of allocate() will be suitably
// memory-aligned.
template <typename T>
class PoolAllocator {
public:
typedef std::allocator<T> A;
typedef typename A::size_type size_type;
typedef typename A::difference_type difference_type;
typedef typename A::pointer pointer;
typedef typename A::const_pointer const_pointer;
typedef typename A::reference reference;
typedef typename A::const_reference const_reference;
typedef typename A::value_type value_type;
template <typename U>
struct rebind {
typedef PoolAllocator<U> other;
};
explicit PoolAllocator(size_t pool_size = kAllocSize)
: pools_(new MemoryPoolCollection(pool_size)) {}
PoolAllocator(const PoolAllocator<T> &pool_alloc)
: pools_(pool_alloc.Pools()) {
Pools()->IncrRefCount();
}
template <typename U>
PoolAllocator(const PoolAllocator<U> &pool_alloc)
: pools_(pool_alloc.Pools()) {
Pools()->IncrRefCount();
}
~PoolAllocator() {
if (Pools()->DecrRefCount() == 0) delete Pools();
}
pointer address(reference ref) const { return A().address(ref); }
const_pointer address(const_reference ref) const { return A().address(ref); }
size_type max_size() const { return A().max_size(); }
template <class U, class... Args>
void construct(U *p, Args &&... args) {
A().construct(p, std::forward<Args>(args)...);
}
void destroy(pointer p) { A().destroy(p); }
pointer allocate(size_type n, const void *hint = 0) {
if (n == 1) {
return static_cast<pointer>(Pool<1>()->Allocate());
} else if (n == 2) {
return static_cast<pointer>(Pool<2>()->Allocate());
} else if (n <= 4) {
return static_cast<pointer>(Pool<4>()->Allocate());
} else if (n <= 8) {
return static_cast<pointer>(Pool<8>()->Allocate());
} else if (n <= 16) {
return static_cast<pointer>(Pool<16>()->Allocate());
} else if (n <= 32) {
return static_cast<pointer>(Pool<32>()->Allocate());
} else if (n <= 64) {
return static_cast<pointer>(Pool<64>()->Allocate());
} else {
return A().allocate(n, hint);
}
}
void deallocate(pointer p, size_type n) {
if (n == 1) {
Pool<1>()->Free(p);
} else if (n == 2) {
Pool<2>()->Free(p);
} else if (n <= 4) {
Pool<4>()->Free(p);
} else if (n <= 8) {
Pool<8>()->Free(p);
} else if (n <= 16) {
Pool<16>()->Free(p);
} else if (n <= 32) {
Pool<32>()->Free(p);
} else if (n <= 64) {
Pool<64>()->Free(p);
} else {
A().deallocate(p, n);
}
}
MemoryPoolCollection *Pools() const { return pools_; }
private:
template <int n>
struct TN {
T buf[n];
};
template <int n>
MemoryPool<TN<n>> *Pool() {
return pools_->Pool<TN<n>>();
}
MemoryPoolCollection *pools_;
PoolAllocator<T> operator=(const PoolAllocator<T> &);
};
template <typename T, typename U>
bool operator==(const PoolAllocator<T> &alloc1,
const PoolAllocator<U> &alloc2) {
return false;
}
template <typename T, typename U>
bool operator!=(const PoolAllocator<T> &alloc1,
const PoolAllocator<U> &alloc2) {
return true;
}
} // namespace fst
#endif // FST_LIB_MEMORY_H_
|