88 lines
1.8 KiB
C++
88 lines
1.8 KiB
C++
#pragma once
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// Fast ostringstream like supprt which return its string by ref and nothing more
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#include<streambuf>
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#include<string>
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namespace c11log
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{
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namespace details
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{
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class str_devicebuf:public std::streambuf
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{
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public:
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str_devicebuf() = default;
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~str_devicebuf() = default;
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str_devicebuf(const str_devicebuf& other) = delete;
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str_devicebuf(str_devicebuf&& other) = delete;
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str_devicebuf& operator=(const str_devicebuf&) = delete;
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str_devicebuf& operator=(str_devicebuf&&) = delete;
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const std::string& str_ref() const
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{
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return _str;
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}
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void reset_str()
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{
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_str.clear();
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}
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protected:
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int sync() override
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{
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return 0;
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}
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// copy the give buffer into the accumulated string.
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// reserve initially 128 bytes which should be enough for common log lines
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std::streamsize xsputn(const char_type* s, std::streamsize count) override
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{
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if(_str.capacity() < k_initial_reserve)
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{
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_str.reserve(k_initial_reserve);
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}
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_str.append(s, static_cast<unsigned int>(count));
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return count;
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}
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int_type overflow(int_type ch) override
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{
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if (ch != traits_type::eof())
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xsputn((char*)&ch, 1);
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return 1;
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}
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private:
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std::string _str;
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static constexpr std::streamsize k_initial_reserve = 128;
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};
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class fast_oss:public std::ostream
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{
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public:
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fast_oss():std::ostream(&_dev) {}
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~fast_oss() = default;
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fast_oss(const fast_oss& other) = delete;
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fast_oss(fast_oss&& other) = delete;
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fast_oss& operator=(const fast_oss& other) = delete;
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const std::string& str_ref() const
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{
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return _dev.str_ref();
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}
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void reset_str()
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{
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_dev.reset_str();
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}
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private:
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str_devicebuf _dev;
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};
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}
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}
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