spdlog/include/spdlog/details/stack_buf.h
2014-11-21 11:23:55 +02:00

135 lines
4.3 KiB
C++

/*************************************************************************/
/* spdlog - an extremely fast and easy to use c++11 logging library. */
/* Copyright (c) 2014 Gabi Melman. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#pragma once
#include <algorithm>
#include <array>
#include <vector>
#include <cstring>
namespace spdlog
{
namespace details
{
// Fast memory storage on the stack when possible or in std::vector
template<unsigned short STACK_SIZE>
class stack_buf
{
public:
static const unsigned short stack_size = STACK_SIZE;
stack_buf() :_v(), _stack_size(0) {}
~stack_buf() = default;
stack_buf(const stack_buf& other) :stack_buf(other, delegate_copy_or_move {})
{}
stack_buf(stack_buf&& other) :stack_buf(other, delegate_copy_or_move {})
{
other.clear();
}
template<class T1>
stack_buf& operator=(T1&& other)
{
_stack_size = other._stack_size;
if (other.vector_used())
_v = std::forward<T1>(other)._v;
else
std::copy_n(other._stack_array.begin(), other._stack_size, _stack_array.begin());
return *this;
}
void append(const char* buf, std::size_t buf_size)
{
//If we are aleady using _v, forget about the stack
if (vector_used())
{
_v.insert(_v.end(), buf, buf + buf_size);
}
//Try use the stack
else
{
if (_stack_size + buf_size <= STACK_SIZE)
{
std::memcpy(&_stack_array[_stack_size], buf, buf_size);
_stack_size += buf_size;
}
//Not enough stack space. Copy all to _v
else
{
_v.reserve(_stack_size + buf_size);
_v.insert(_v.end(), _stack_array.begin(), _stack_array.begin() + _stack_size);
_v.insert(_v.end(), buf, buf + buf_size);
}
}
}
void clear()
{
_stack_size = 0;
_v.clear();
}
const char* data() const
{
if (vector_used())
return _v.data();
else
return _stack_array.data();
}
std::size_t size() const
{
if (vector_used())
return _v.size();
else
return _stack_size;
}
private:
struct delegate_copy_or_move {};
template<class T1>
stack_buf(T1&& other, delegate_copy_or_move)
{
_stack_size = other._stack_size;
if (other.vector_used())
_v = std::forward<T1>(other)._v;
else
std::copy_n(other._stack_array.begin(), other._stack_size, _stack_array.begin());
}
inline bool vector_used() const
{
return !(_v.empty());
}
std::vector<char> _v;
std::array<char, STACK_SIZE> _stack_array;
std::size_t _stack_size;
};
}
} //namespace spdlog { namespace details {