Gecko [ 0.0.0.0 ]

Name	Size	Permission
backward	[ DIR ]	drwxr-xr-x
bits	[ DIR ]	drwxr-xr-x
debug	[ DIR ]	drwxr-xr-x
decimal	[ DIR ]	drwxr-xr-x
experimental	[ DIR ]	drwxr-xr-x
ext	[ DIR ]	drwxr-xr-x
parallel	[ DIR ]	drwxr-xr-x
pstl	[ DIR ]	drwxr-xr-x
tr1	[ DIR ]	drwxr-xr-x
tr2	[ DIR ]	drwxr-xr-x
algorithm	3.31 KB	-rw-r--r--
any	18.71 KB	-rw-r--r--
array	15.4 KB	-rw-r--r--
atomic	51.16 KB	-rw-r--r--
barrier	7.87 KB	-rw-r--r--
bit	14 KB	-rw-r--r--
bitset	49.19 KB	-rw-r--r--
cassert	1.61 KB	-rw-r--r--
ccomplex	1.3 KB	-rw-r--r--
cctype	2.34 KB	-rw-r--r--
cerrno	1.73 KB	-rw-r--r--
cfenv	2 KB	-rw-r--r--
cfloat	1.84 KB	-rw-r--r--
charconv	29.13 KB	-rw-r--r--
chrono	94.45 KB	-rw-r--r--
cinttypes	2.09 KB	-rw-r--r--
ciso646	1.43 KB	-rw-r--r--
climits	1.87 KB	-rw-r--r--
clocale	1.86 KB	-rw-r--r--
cmath	94.84 KB	-rw-r--r--
codecvt	5.15 KB	-rw-r--r--
compare	37.25 KB	-rw-r--r--
complex	74.84 KB	-rw-r--r--
complex.h	1.56 KB	-rw-r--r--
concepts	12.72 KB	-rw-r--r--
condition_variable	12.59 KB	-rw-r--r--
coroutine	9.39 KB	-rw-r--r--
csetjmp	1.9 KB	-rw-r--r--
csignal	1.81 KB	-rw-r--r--
cstdalign	1.37 KB	-rw-r--r--
cstdarg	1.82 KB	-rw-r--r--
cstdbool	1.37 KB	-rw-r--r--
cstddef	6.54 KB	-rw-r--r--
cstdint	3.75 KB	-rw-r--r--
cstdio	4.33 KB	-rw-r--r--
cstdlib	6.76 KB	-rw-r--r--
cstring	3.17 KB	-rw-r--r--
ctgmath	1.33 KB	-rw-r--r--
ctime	2.24 KB	-rw-r--r--
cuchar	2.84 KB	-rw-r--r--
cwchar	6.39 KB	-rw-r--r--
cwctype	2.73 KB	-rw-r--r--
cxxabi.h	21.77 KB	-rw-r--r--
deque	4.56 KB	-rw-r--r--
exception	5.31 KB	-rw-r--r--
execution	1.87 KB	-rw-r--r--
expected	49.81 KB	-rw-r--r--
fenv.h	1.96 KB	-rw-r--r--
filesystem	1.72 KB	-rw-r--r--
format	128.31 KB	-rw-r--r--
forward_list	2.91 KB	-rw-r--r--
fstream	41.58 KB	-rw-r--r--
functional	47.31 KB	-rw-r--r--
future	52.04 KB	-rw-r--r--
generator	22.16 KB	-rw-r--r--
initializer_list	2.93 KB	-rw-r--r--
iomanip	16.4 KB	-rw-r--r--
ios	1.67 KB	-rw-r--r--
iosfwd	8.21 KB	-rw-r--r--
iostream	3.02 KB	-rw-r--r--
istream	35.62 KB	-rw-r--r--
iterator	3.02 KB	-rw-r--r--
latch	2.7 KB	-rw-r--r--
limits	82.01 KB	-rw-r--r--
list	3.86 KB	-rw-r--r--
locale	1.5 KB	-rw-r--r--
map	4.37 KB	-rw-r--r--
math.h	4.47 KB	-rw-r--r--
memory	5.26 KB	-rw-r--r--
memory_resource	14.15 KB	-rw-r--r--
mutex	26.99 KB	-rw-r--r--
new	8.48 KB	-rw-r--r--
numbers	6.93 KB	-rw-r--r--
numeric	25.5 KB	-rw-r--r--
optional	44.03 KB	-rw-r--r--
ostream	30.54 KB	-rw-r--r--
print	4.73 KB	-rw-r--r--
queue	2.54 KB	-rw-r--r--
random	1.63 KB	-rw-r--r--
ranges	271.85 KB	-rw-r--r--
ratio	22.26 KB	-rw-r--r--
regex	3.16 KB	-rw-r--r--
scoped_allocator	17.41 KB	-rw-r--r--
semaphore	3.04 KB	-rw-r--r--
set	4.16 KB	-rw-r--r--
shared_mutex	24.6 KB	-rw-r--r--
source_location	2.7 KB	-rw-r--r--
span	14.12 KB	-rw-r--r--
spanstream	12.2 KB	-rw-r--r--
sstream	38.83 KB	-rw-r--r--
stack	2.46 KB	-rw-r--r--
stacktrace	21.21 KB	-rw-r--r--
stdatomic.h	4.02 KB	-rw-r--r--
stdexcept	9.65 KB	-rw-r--r--
stdfloat	1.72 KB	-rw-r--r--
stdlib.h	2.25 KB	-rw-r--r--
stop_token	15.72 KB	-rw-r--r--
streambuf	29.24 KB	-rw-r--r--
string	4.23 KB	-rw-r--r--
string_view	27.52 KB	-rw-r--r--
syncstream	8.18 KB	-rw-r--r--
system_error	17.96 KB	-rw-r--r--
text_encoding	16.26 KB	-rw-r--r--
tgmath.h	1.33 KB	-rw-r--r--
thread	9.77 KB	-rw-r--r--
tuple	99.71 KB	-rw-r--r--
type_traits	118.17 KB	-rw-r--r--
typeindex	3.43 KB	-rw-r--r--
typeinfo	8.1 KB	-rw-r--r--
unordered_map	3.69 KB	-rw-r--r--
unordered_set	3.48 KB	-rw-r--r--
utility	7.38 KB	-rw-r--r--
valarray	40.2 KB	-rw-r--r--
variant	64.81 KB	-rw-r--r--
vector	4.98 KB	-rw-r--r--
version	1.42 KB	-rw-r--r--

Code Editor : memory_resource

// <memory_resource> -*- C++ -*-

// Copyright (C) 2018-2024 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library 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 3, or (at your option)
// any later version.

// 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 General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file include/memory_resource
 *  This is a Standard C++ Library header.
 *
 *  This header declares the @ref pmr (std::pmr) memory resources.
 *  @ingroup pmr
 */

#ifndef _GLIBCXX_MEMORY_RESOURCE
#define _GLIBCXX_MEMORY_RESOURCE 1

#pragma GCC system_header

#include <bits/requires_hosted.h> // polymorphic allocation

#define __glibcxx_want_polymorphic_allocator
#define __glibcxx_want_memory_resource
#include <bits/version.h>

#if __cplusplus >= 201703L

/**
 * @defgroup pmr Polymorphic memory resources
 *
 * @anchor pmr
 * @ingroup memory
 * @since C++17
 *
 * Memory resources are classes that implement the `std::pmr::memory_resource`
 * interface for allocating and deallocating memory. Unlike traditional C++
 * allocators, memory resources are not value types and are used via pointers
 * to the abstract base class. They are only responsible for allocating and
 * deallocating, not for construction and destruction of objects. As a result,
 * memory resources just allocate raw memory as type `void*` and are not
 * templates that allocate/deallocate and construct/destroy a specific type.
 *
 * The class template `std::pmr::polymorphic_allocator` is an allocator that
 * uses a memory resource for its allocations.
 */

#include <bits/memory_resource.h>
#include <vector>			// vector
#include <shared_mutex>			// shared_mutex
#include <bits/align.h>			// align
#include <debug/assertions.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace pmr
{

#ifdef __cpp_lib_polymorphic_allocator // C++ >= 20 && HOSTED
  template<typename _Tp = std::byte>
    class polymorphic_allocator;
#endif

// Global memory resources

/// A pmr::memory_resource that uses `new` to allocate memory
  /**
   * @ingroup pmr
   * @headerfile memory_resource
   * @since C++17
   */
  [[nodiscard, __gnu__::__returns_nonnull__, __gnu__::__const__]]
  memory_resource*
  new_delete_resource() noexcept;

/// A pmr::memory_resource that always throws `bad_alloc`
  [[nodiscard, __gnu__::__returns_nonnull__, __gnu__::__const__]]
  memory_resource*
  null_memory_resource() noexcept;

/// Replace the default memory resource pointer
  [[__gnu__::__returns_nonnull__]]
  memory_resource*
  set_default_resource(memory_resource* __r) noexcept;

/// Get the current default memory resource pointer
  [[__gnu__::__returns_nonnull__]]
  memory_resource*
  get_default_resource() noexcept;

// Pool resource classes
  struct pool_options;
#if __cpp_lib_memory_resource >= 201603L // C++ >= 17 && hosted && gthread
  class synchronized_pool_resource;
#endif
  class unsynchronized_pool_resource;
  class monotonic_buffer_resource;

/// Parameters for tuning a pool resource's behaviour.
  /**
   * @ingroup pmr
   * @headerfile memory_resource
   * @since C++17
   */
  struct pool_options
  {
    /** @brief Upper limit on number of blocks in a chunk.
     *
     * A lower value prevents allocating huge chunks that could remain mostly
     * unused, but means pools will need to replenished more frequently.
     */
    size_t max_blocks_per_chunk = 0;

/* @brief Largest block size (in bytes) that should be served from pools.
     *
     * Larger allocations will be served directly by the upstream resource,
     * not from one of the pools managed by the pool resource.
     */
    size_t largest_required_pool_block = 0;
  };

// Common implementation details for un-/synchronized pool resources.
  class __pool_resource
  {
    friend class synchronized_pool_resource;
    friend class unsynchronized_pool_resource;

__pool_resource(const pool_options& __opts, memory_resource* __upstream);

~__pool_resource();

__pool_resource(const __pool_resource&) = delete;
    __pool_resource& operator=(const __pool_resource&) = delete;

// Allocate a large unpooled block.
    void*
    allocate(size_t __bytes, size_t __alignment);

// Deallocate a large unpooled block.
    void
    deallocate(void* __p, size_t __bytes, size_t __alignment);

// Deallocate unpooled memory.
    void release() noexcept;

memory_resource* resource() const noexcept
    { return _M_unpooled.get_allocator().resource(); }

struct _Pool;

_Pool* _M_alloc_pools();

const pool_options _M_opts;

struct _BigBlock;
    // Collection of blocks too big for any pool, sorted by address.
    // This also stores the only copy of the upstream memory resource pointer.
    _GLIBCXX_STD_C::pmr::vector<_BigBlock> _M_unpooled;

const int _M_npools;
  };

#if __cpp_lib_memory_resource >= 201603L // C++ >= 17 && hosted && gthread
  /// A thread-safe memory resource that manages pools of fixed-size blocks.
  /**
   * @ingroup pmr
   * @headerfile memory_resource
   * @since C++17
   */
  class synchronized_pool_resource : public memory_resource
  {
  public:
    synchronized_pool_resource(const pool_options& __opts,
				 memory_resource* __upstream)
    __attribute__((__nonnull__));

synchronized_pool_resource()
    : synchronized_pool_resource(pool_options(), get_default_resource())
    { }

explicit
    synchronized_pool_resource(memory_resource* __upstream)
    __attribute__((__nonnull__))
    : synchronized_pool_resource(pool_options(), __upstream)
    { }

explicit
    synchronized_pool_resource(const pool_options& __opts)
    : synchronized_pool_resource(__opts, get_default_resource()) { }

synchronized_pool_resource(const synchronized_pool_resource&) = delete;

virtual ~synchronized_pool_resource();

synchronized_pool_resource&
    operator=(const synchronized_pool_resource&) = delete;

void release();

memory_resource*
    upstream_resource() const noexcept
    __attribute__((__returns_nonnull__))
    { return _M_impl.resource(); }

pool_options options() const noexcept { return _M_impl._M_opts; }

protected:
    void*
    do_allocate(size_t __bytes, size_t __alignment) override;

void
    do_deallocate(void* __p, size_t __bytes, size_t __alignment) override;

bool
    do_is_equal(const memory_resource& __other) const noexcept override
    { return this == &__other; }

public:
    // Thread-specific pools (only public for access by implementation details)
    struct _TPools;

private:
    _TPools* _M_alloc_tpools(lock_guard<shared_mutex>&);
    _TPools* _M_alloc_shared_tpools(lock_guard<shared_mutex>&);
    auto _M_thread_specific_pools() noexcept;

__pool_resource _M_impl;
    __gthread_key_t _M_key;
    // Linked list of thread-specific pools. All threads share _M_tpools[0].
    _TPools* _M_tpools = nullptr;
    mutable shared_mutex _M_mx;
  };
#endif // __cpp_lib_memory_resource >= 201603L

/// A non-thread-safe memory resource that manages pools of fixed-size blocks.
  /**
   * @ingroup pmr
   * @headerfile memory_resource
   * @since C++17
   */
  class unsynchronized_pool_resource : public memory_resource
  {
  public:
    [[__gnu__::__nonnull__]]
    unsynchronized_pool_resource(const pool_options& __opts,
				 memory_resource* __upstream);

unsynchronized_pool_resource()
    : unsynchronized_pool_resource(pool_options(), get_default_resource())
    { }

[[__gnu__::__nonnull__]]
    explicit
    unsynchronized_pool_resource(memory_resource* __upstream)
    : unsynchronized_pool_resource(pool_options(), __upstream)
    { }

explicit
    unsynchronized_pool_resource(const pool_options& __opts)
    : unsynchronized_pool_resource(__opts, get_default_resource()) { }

unsynchronized_pool_resource(const unsynchronized_pool_resource&) = delete;

virtual ~unsynchronized_pool_resource();

unsynchronized_pool_resource&
    operator=(const unsynchronized_pool_resource&) = delete;

void release();

[[__gnu__::__returns_nonnull__]]
    memory_resource*
    upstream_resource() const noexcept
    { return _M_impl.resource(); }

pool_options options() const noexcept { return _M_impl._M_opts; }

protected:
    void*
    do_allocate(size_t __bytes, size_t __alignment) override;

void
    do_deallocate(void* __p, size_t __bytes, size_t __alignment) override;

bool
    do_is_equal(const memory_resource& __other) const noexcept override
    { return this == &__other; }

private:
    using _Pool = __pool_resource::_Pool;

auto _M_find_pool(size_t) noexcept;

__pool_resource _M_impl;
    _Pool* _M_pools = nullptr;
  };

/// A memory resource that allocates from a fixed-size buffer.
  /**
   * The main feature of a `pmr::monotonic_buffer_resource` is that its
   * `do_deallocate` does nothing. This makes it very fast because there is no
   * need to manage a free list, and every allocation simply returns a new
   * block of memory, rather than searching for a suitably-sized free block.
   * Because deallocating is a no-op, the amount of memory used by the resource
   * only grows until `release()` (or the destructor) is called to return all
   * memory to upstream.
   *
   * A `monotonic_buffer_resource` can be initialized with a buffer that
   * will be used to satisfy all allocation requests, until the buffer is full.
   * After that a new buffer will be allocated from the upstream resource.
   * By using a stack buffer and `pmr::null_memory_resource()` as the upstream
   * you can get a memory resource that only uses the stack and never
   * dynamically allocates.
   *
   * @ingroup pmr
   * @headerfile memory_resource
   * @since C++17
   */
  class monotonic_buffer_resource : public memory_resource
  {
  public:
    explicit
    monotonic_buffer_resource(memory_resource* __upstream) noexcept
    __attribute__((__nonnull__))
    : _M_upstream(__upstream)
    { _GLIBCXX_DEBUG_ASSERT(__upstream != nullptr); }

monotonic_buffer_resource(size_t __initial_size,
			      memory_resource* __upstream) noexcept
    __attribute__((__nonnull__))
    : _M_next_bufsiz(__initial_size),
      _M_upstream(__upstream)
    {
      _GLIBCXX_DEBUG_ASSERT(__upstream != nullptr);
      _GLIBCXX_DEBUG_ASSERT(__initial_size > 0);
    }

monotonic_buffer_resource(void* __buffer, size_t __buffer_size,
			      memory_resource* __upstream) noexcept
    __attribute__((__nonnull__(4)))
    : _M_current_buf(__buffer), _M_avail(__buffer_size),
      _M_next_bufsiz(_S_next_bufsize(__buffer_size)),
      _M_upstream(__upstream),
      _M_orig_buf(__buffer), _M_orig_size(__buffer_size)
    {
      _GLIBCXX_DEBUG_ASSERT(__upstream != nullptr);
      _GLIBCXX_DEBUG_ASSERT(__buffer != nullptr || __buffer_size == 0);
    }

monotonic_buffer_resource() noexcept
    : monotonic_buffer_resource(get_default_resource())
    { }

explicit
    monotonic_buffer_resource(size_t __initial_size) noexcept
    : monotonic_buffer_resource(__initial_size, get_default_resource())
    { }

monotonic_buffer_resource(void* __buffer, size_t __buffer_size) noexcept
    : monotonic_buffer_resource(__buffer, __buffer_size, get_default_resource())
    { }

monotonic_buffer_resource(const monotonic_buffer_resource&) = delete;

virtual ~monotonic_buffer_resource(); // key function

monotonic_buffer_resource&
    operator=(const monotonic_buffer_resource&) = delete;

void
    release() noexcept
    {
      if (_M_head)
	_M_release_buffers();

// reset to initial state at contruction:
      if ((_M_current_buf = _M_orig_buf))
	{
	  _M_avail = _M_orig_size;
	  _M_next_bufsiz = _S_next_bufsize(_M_orig_size);
	}
      else
	{
	  _M_avail = 0;
	  _M_next_bufsiz = _M_orig_size;
	}
    }

memory_resource*
    upstream_resource() const noexcept
    __attribute__((__returns_nonnull__))
    { return _M_upstream; }

protected:
    void*
    do_allocate(size_t __bytes, size_t __alignment) override
    {
      if (__builtin_expect(__bytes == 0, false))
	__bytes = 1; // Ensures we don't return the same pointer twice.

void* __p = std::align(__alignment, __bytes, _M_current_buf, _M_avail);
      if (__builtin_expect(__p == nullptr, false))
	{
	  _M_new_buffer(__bytes, __alignment);
	  __p = _M_current_buf;
	}
      _M_current_buf = (char*)_M_current_buf + __bytes;
      _M_avail -= __bytes;
      return __p;
    }

void
    do_deallocate(void*, size_t, size_t) override
    { }

bool
    do_is_equal(const memory_resource& __other) const noexcept override
    { return this == &__other; }

private:
    // Update _M_current_buf and _M_avail to refer to a new buffer with
    // at least the specified size and alignment, allocated from upstream.
    void
    _M_new_buffer(size_t __bytes, size_t __alignment);

// Deallocate all buffers obtained from upstream.
    void
    _M_release_buffers() noexcept;

static size_t
    _S_next_bufsize(size_t __buffer_size) noexcept
    {
      if (__builtin_expect(__buffer_size == 0, false))
	__buffer_size = 1;
      return __buffer_size * _S_growth_factor;
    }

static constexpr size_t _S_init_bufsize = 128 * sizeof(void*);
    static constexpr float _S_growth_factor = 1.5;

void*	_M_current_buf = nullptr;
    size_t	_M_avail = 0;
    size_t	_M_next_bufsiz = _S_init_bufsize;

// Initial values set at construction and reused by release():
    memory_resource* const	_M_upstream;
    void* const			_M_orig_buf = nullptr;
    size_t const		_M_orig_size = _M_next_bufsiz;

class _Chunk;
    _Chunk* _M_head = nullptr;
  };

} // namespace pmr
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#endif // C++17
#endif // _GLIBCXX_MEMORY_RESOURCE

${this.title}

Code Editor : memory_resource