spdlog/include/c11log/details/fast_buf.h
2014-03-22 16:37:48 +02:00

104 lines
2.4 KiB
C++

#pragma once
#include <array>
#include <vector>
#include <algorithm>
// Fast memory storage
// stores its contents on the stack when possible, in vector<char> otherwise
// NOTE: User should be remember that returned buffer might be on the stack!!
namespace c11log
{
namespace details
{
template<std::size_t STACK_SIZE=128>
class fast_buf
{
public:
fast_buf():_stack_size(0) {}
~fast_buf() {};
fast_buf(const bufpair_t& buf_to_copy):fast_buf()
{
append(buf_to_copy);
}
fast_buf(const fast_buf& other)
{
_stack_size = other._stack_size;
if(!other._v.empty())
_v = other._v;
else if(_stack_size)
std::copy(other._stack_buf.begin(), other._stack_buf.begin()+_stack_size, _stack_buf.begin());
}
fast_buf(fast_buf&& other)
{
_stack_size = other._stack_size;
if(!other._v.empty())
_v = other._v;
else if(_stack_size)
std::copy(other._stack_buf.begin(), other._stack_buf.begin()+_stack_size, _stack_buf.begin());
other.clear();
}
fast_buf& operator=(const fast_buf& other) = delete;
fast_buf& operator=(fast_buf&& other) = delete;
void append(const char* buf, std::size_t size)
{
//If we are aleady using _v, forget about the stack
if(!_v.empty())
{
_v.insert(_v.end(), buf, buf+ size);
}
//Try use the stack
else
{
if(_stack_size+size <= STACK_SIZE)
{
std::memcpy(&_stack_buf[_stack_size], buf, size);
_stack_size+=size;
}
//Not enough stack space. Copy all to _v
else
{
_v.reserve(_stack_size+size);
if(_stack_size)
_v.insert(_v.end(), _stack_buf.begin(), _stack_buf.begin() +_stack_size);
_v.insert(_v.end(), buf, buf+size);
}
}
}
void append(const bufpair_t &buf)
{
append(buf.first, buf.second);
}
void clear()
{
_stack_size = 0;
_v.clear();
}
bufpair_t get()
{
if(!_v.empty())
return bufpair_t(_v.data(), _v.size());
else
return bufpair_t(_stack_buf.data(), _stack_size);
}
private:
std::vector<char> _v;
std::array<char, STACK_SIZE> _stack_buf;
std::size_t _stack_size;
};
}
} //namespace c11log { namespace details {