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