112 lines
2.6 KiB
C++
112 lines
2.6 KiB
C++
#pragma once
|
|
|
|
#include <algorithm>
|
|
#include <array>
|
|
#include <vector>
|
|
#include <cstring>
|
|
|
|
|
|
// Fast memory storage on the stack when possible or in std::vector
|
|
namespace c11log
|
|
{
|
|
namespace details
|
|
{
|
|
|
|
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_move {})
|
|
{}
|
|
|
|
stack_buf(stack_buf&& other):stack_buf(other, delegate_copy_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_move {};
|
|
template<class T1>
|
|
stack_buf(T1&& other, delegate_copy_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 c11log { namespace details {
|