mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-13 19:14:30 +00:00
285 lines
8.1 KiB
C++
285 lines
8.1 KiB
C++
#pragma once
|
||
|
||
#include <string.h>
|
||
#include <malloc.h>
|
||
#include <cstddef>
|
||
#include <algorithm>
|
||
#include <memory>
|
||
|
||
#include <boost/noncopyable.hpp>
|
||
|
||
#include <Yandex/likely.h>
|
||
#include <Yandex/strong_typedef.h>
|
||
|
||
#include <DB/Core/Exception.h>
|
||
#include <DB/Core/ErrorCodes.h>
|
||
|
||
|
||
namespace DB
|
||
{
|
||
|
||
/** Динамический массив для POD-типов.
|
||
* Предназначен для небольшого количества больших массивов (а не большого количества маленьких).
|
||
* А точнее - для использования в ColumnVector.
|
||
* Отличается от std::vector тем, что не инициализирует элементы.
|
||
* Сделано noncopyable, чтобы не было случайных копий. Скопировать данные можно с помощью метода assign.
|
||
* Поддерживается только часть интерфейса std::vector.
|
||
*
|
||
* Если вставлять элементы push_back-ом, не делая reserve, то PODArray примерно в 2.5 раза быстрее std::vector.
|
||
*/
|
||
template <typename T>
|
||
class PODArray : private boost::noncopyable, private std::allocator<char> /// empty base optimization
|
||
{
|
||
private:
|
||
typedef std::allocator<char> Allocator;
|
||
static const size_t initial_size;
|
||
|
||
char * c_start;
|
||
char * c_end;
|
||
char * c_end_of_storage;
|
||
|
||
bool use_libc_realloc;
|
||
|
||
T * t_start() { return reinterpret_cast<T *>(c_start); }
|
||
T * t_end() { return reinterpret_cast<T *>(c_end); }
|
||
T * t_end_of_storage() { return reinterpret_cast<T *>(c_end_of_storage); }
|
||
|
||
const T * t_start() const { return reinterpret_cast<const T *>(c_start); }
|
||
const T * t_end() const { return reinterpret_cast<const T *>(c_end); }
|
||
const T * t_end_of_storage() const { return reinterpret_cast<const T *>(c_end_of_storage); }
|
||
|
||
size_t storage_size() const { return c_end_of_storage - c_start; }
|
||
static size_t byte_size(size_t n) { return n * sizeof(T); }
|
||
|
||
static size_t round_up_to_power_of_two(size_t n)
|
||
{
|
||
--n;
|
||
n |= n >> 1;
|
||
n |= n >> 2;
|
||
n |= n >> 4;
|
||
n |= n >> 8;
|
||
n |= n >> 16;
|
||
n |= n >> 32;
|
||
++n;
|
||
|
||
return n;
|
||
}
|
||
|
||
static size_t to_size(size_t n) { return byte_size(std::max(initial_size, round_up_to_power_of_two(n))); }
|
||
|
||
void alloc(size_t n)
|
||
{
|
||
size_t bytes_to_alloc = to_size(n);
|
||
c_start = c_end = Allocator::allocate(bytes_to_alloc);
|
||
c_end_of_storage = c_start + bytes_to_alloc;
|
||
|
||
//memset(c_start, 0, bytes_to_alloc);
|
||
}
|
||
|
||
void dealloc()
|
||
{
|
||
if (use_libc_realloc)
|
||
::free(c_start);
|
||
else
|
||
Allocator::deallocate(c_start, storage_size());
|
||
}
|
||
|
||
void realloc(size_t n)
|
||
{
|
||
// std::cerr << "realloc" << std::endl;
|
||
|
||
ptrdiff_t end_diff = c_end - c_start;
|
||
size_t bytes_to_alloc = to_size(n);
|
||
|
||
char * old_c_start = c_start;
|
||
char * old_c_end_of_storage = c_end_of_storage;
|
||
|
||
if (use_libc_realloc)
|
||
{
|
||
c_start = reinterpret_cast<char *>(::realloc(c_start, bytes_to_alloc));
|
||
|
||
if (NULL == c_start)
|
||
throwFromErrno("PODArray: cannot realloc", ErrorCodes::CANNOT_ALLOCATE_MEMORY);
|
||
}
|
||
else
|
||
{
|
||
c_start = reinterpret_cast<char *>(malloc(bytes_to_alloc));
|
||
|
||
if (NULL == c_start)
|
||
throwFromErrno("PODArray: cannot realloc", ErrorCodes::CANNOT_ALLOCATE_MEMORY);
|
||
|
||
memcpy(c_start, old_c_start, old_c_end_of_storage - old_c_start);
|
||
Allocator::deallocate(old_c_start, old_c_end_of_storage - old_c_start);
|
||
}
|
||
|
||
//memset(c_start + (old_c_end_of_storage - old_c_start), 0, bytes_to_alloc - (old_c_end_of_storage - old_c_start));
|
||
|
||
c_end = c_start + end_diff;
|
||
c_end_of_storage = c_start + bytes_to_alloc;
|
||
|
||
use_libc_realloc = true;
|
||
}
|
||
|
||
public:
|
||
typedef T value_type;
|
||
|
||
|
||
/// Просто typedef нельзя, так как возникает неоднозначность для конструкторов и функций assign.
|
||
class iterator
|
||
{
|
||
private:
|
||
T * ptr;
|
||
public:
|
||
iterator() {}
|
||
iterator(T * ptr_) : ptr(ptr_) {}
|
||
|
||
bool operator== (const iterator & rhs) const { return ptr == rhs.ptr; }
|
||
bool operator!= (const iterator & rhs) const { return ptr != rhs.ptr; }
|
||
|
||
iterator & operator++() { ++ptr; return *this; }
|
||
|
||
T & operator* () const { return *ptr; }
|
||
T * operator->() const { return ptr; }
|
||
|
||
iterator operator+ (ptrdiff_t diff) const { return ptr + diff; }
|
||
iterator operator- (ptrdiff_t diff) const { return ptr - diff; }
|
||
ptrdiff_t operator- (const iterator & rhs) const { return ptr - rhs.ptr; }
|
||
};
|
||
|
||
class const_iterator
|
||
{
|
||
private:
|
||
const T * ptr;
|
||
public:
|
||
const_iterator() {}
|
||
const_iterator(const T * ptr_) : ptr(ptr_) {}
|
||
|
||
bool operator== (const const_iterator & rhs) const { return ptr == rhs.ptr; }
|
||
bool operator!= (const const_iterator & rhs) const { return ptr != rhs.ptr; }
|
||
|
||
const_iterator & operator++() { ++ptr; return *this; }
|
||
|
||
const T & operator* () const { return *ptr; }
|
||
const T * operator->() const { return ptr; }
|
||
|
||
const_iterator operator+ (ptrdiff_t diff) const { return ptr + diff; }
|
||
const_iterator operator- (ptrdiff_t diff) const { return ptr - diff; }
|
||
ptrdiff_t operator- (const const_iterator & rhs) const { return ptr - rhs.ptr; }
|
||
};
|
||
|
||
|
||
PODArray() : use_libc_realloc(false) { alloc(initial_size); }
|
||
PODArray(size_t n) : use_libc_realloc(false) { alloc(n); c_end += byte_size(n); }
|
||
PODArray(size_t n, const T & x) : use_libc_realloc(false) { alloc(n); assign(n, x); }
|
||
PODArray(const_iterator from_begin, const_iterator from_end) : use_libc_realloc(false) { alloc(from_end - from_begin); insert(from_begin, from_end); }
|
||
~PODArray() { dealloc(); }
|
||
|
||
size_t size() const { return t_end() - t_start(); }
|
||
bool empty() const { return t_end() == t_start(); }
|
||
size_t capacity() const { return t_end_of_storage() - t_start(); }
|
||
|
||
T & operator[] (size_t n) { return t_start()[n]; }
|
||
const T & operator[] (size_t n) const { return t_start()[n]; }
|
||
|
||
T & front() { return t_start()[0]; }
|
||
T & back() { return t_end()[-1]; }
|
||
const T & front() const { return t_start()[0]; }
|
||
const T & back() const { return t_end()[-1]; }
|
||
|
||
iterator begin() { return t_start(); }
|
||
iterator end() { return t_end(); }
|
||
const_iterator begin() const { return t_start(); }
|
||
const_iterator end() const { return t_end(); }
|
||
|
||
void reserve(size_t n)
|
||
{
|
||
if (n > capacity())
|
||
realloc(n);
|
||
}
|
||
|
||
void reserve()
|
||
{
|
||
realloc(size() * 2);
|
||
}
|
||
|
||
void resize(size_t n)
|
||
{
|
||
reserve(n);
|
||
c_end = c_start + byte_size(n);
|
||
}
|
||
|
||
/// Как resize, но обнуляет новые элементы.
|
||
void resize_fill(size_t n)
|
||
{
|
||
size_t old_size = size();
|
||
if (n > old_size)
|
||
{
|
||
reserve(n);
|
||
memset(c_end, 0, n - old_size);
|
||
}
|
||
c_end = c_start + byte_size(n);
|
||
}
|
||
|
||
void clear()
|
||
{
|
||
c_end = c_start;
|
||
}
|
||
|
||
void push_back(const T & x)
|
||
{
|
||
if (unlikely(c_end == c_end_of_storage))
|
||
reserve();
|
||
|
||
*t_end() = x;
|
||
c_end += byte_size(1);
|
||
}
|
||
|
||
/// Не вставляйте в массив кусок самого себя. Потому что при ресайзе, итераторы на самого себя могут инвалидироваться.
|
||
void insert(const_iterator from_begin, const_iterator from_end)
|
||
{
|
||
size_t required_capacity = size() + (from_end - from_begin);
|
||
if (required_capacity > capacity())
|
||
reserve(round_up_to_power_of_two(required_capacity));
|
||
|
||
size_t bytes_to_copy = byte_size(from_end - from_begin);
|
||
memcpy(c_end, reinterpret_cast<const void *>(&*from_begin), bytes_to_copy);
|
||
c_end += bytes_to_copy;
|
||
}
|
||
|
||
void swap(PODArray<T> & rhs)
|
||
{
|
||
std::swap(c_start, rhs.c_start);
|
||
std::swap(c_end, rhs.c_end);
|
||
std::swap(c_end_of_storage, rhs.c_end_of_storage);
|
||
}
|
||
|
||
void assign(size_t n, const T & x)
|
||
{
|
||
resize(n);
|
||
std::fill(begin(), end(), x);
|
||
}
|
||
|
||
void assign(const_iterator from_begin, const_iterator from_end)
|
||
{
|
||
size_t required_capacity = from_end - from_begin;
|
||
if (required_capacity > capacity())
|
||
reserve(round_up_to_power_of_two(required_capacity));
|
||
|
||
size_t bytes_to_copy = byte_size(required_capacity);
|
||
memcpy(c_start, reinterpret_cast<const void *>(from_begin), bytes_to_copy);
|
||
c_end = c_start + bytes_to_copy;
|
||
}
|
||
|
||
void assign(const PODArray<T> & from)
|
||
{
|
||
assign(from.begin(), from.end());
|
||
}
|
||
};
|
||
|
||
template <typename T>
|
||
const size_t PODArray<T>::initial_size = 4096;
|
||
|
||
|
||
|
||
}
|