forked from OSchip/llvm-project
Speedup to_string and to_wstring for integers using stack buffer and SSO. Reviewed as https://reviews.llvm.org/D59178 Thanks to ivafanas for all his work on this patch.
llvm-svn: 362649
This commit is contained in:
Marshall Clow
parent
3975b15dba
commit
7ce7110e6d
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@ -7,12 +7,14 @@
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//===----------------------------------------------------------------------===//
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#include "string"
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#include "charconv"
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#include "cstdlib"
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#include "cwchar"
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#include "cerrno"
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#include "limits"
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#include "stdexcept"
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#include <stdio.h>
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#include "__debug"
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_LIBCPP_BEGIN_NAMESPACE_STD
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@ -171,7 +173,7 @@ as_integer( const string& func, const wstring& s, size_t* idx, int base )
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// as_float
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template<typename V, typename S, typename F>
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template<typename V, typename S, typename F>
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inline
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V
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as_float_helper(const string& func, const S& str, size_t* idx, F f )
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@ -375,11 +377,11 @@ as_string(P sprintf_like, S s, const typename S::value_type* fmt, V a)
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return s;
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}
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template <class S, class V, bool = is_floating_point<V>::value>
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template <class S>
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struct initial_string;
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template <class V, bool b>
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struct initial_string<string, V, b>
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template <>
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struct initial_string<string>
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{
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string
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operator()() const
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@ -390,23 +392,8 @@ struct initial_string<string, V, b>
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}
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};
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template <class V>
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struct initial_string<wstring, V, false>
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{
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wstring
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operator()() const
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{
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const size_t n = (numeric_limits<unsigned long long>::digits / 3)
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+ ((numeric_limits<unsigned long long>::digits % 3) != 0)
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+ 1;
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wstring s(n, wchar_t());
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s.resize(s.capacity());
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return s;
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}
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};
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template <class V>
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struct initial_string<wstring, V, true>
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template <>
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struct initial_string<wstring>
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{
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wstring
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operator()() const
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@ -430,95 +417,42 @@ get_swprintf()
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#endif
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}
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template <typename S, typename V>
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S i_to_string(const V v)
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{
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// numeric_limits::digits10 returns value less on 1 than desired for unsigned numbers.
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// For example, for 1-byte unsigned value digits10 is 2 (999 can not be represented),
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// so we need +1 here.
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constexpr size_t bufsize = numeric_limits<V>::digits10 + 2; // +1 for minus, +1 for digits10
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char buf[bufsize];
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const auto res = to_chars(buf, buf + bufsize, v);
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_LIBCPP_ASSERT(res.ec == errc(), "bufsize must be large enough to accomodate the value");
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return S(buf, res.ptr);
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}
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} // unnamed namespace
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string to_string(int val)
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{
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return as_string(snprintf, initial_string<string, int>()(), "%d", val);
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}
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string to_string (int val) { return i_to_string< string>(val); }
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string to_string (long val) { return i_to_string< string>(val); }
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string to_string (long long val) { return i_to_string< string>(val); }
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string to_string (unsigned val) { return i_to_string< string>(val); }
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string to_string (unsigned long val) { return i_to_string< string>(val); }
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string to_string (unsigned long long val) { return i_to_string< string>(val); }
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string to_string(unsigned val)
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{
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return as_string(snprintf, initial_string<string, unsigned>()(), "%u", val);
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}
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wstring to_wstring(int val) { return i_to_string<wstring>(val); }
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wstring to_wstring(long val) { return i_to_string<wstring>(val); }
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wstring to_wstring(long long val) { return i_to_string<wstring>(val); }
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wstring to_wstring(unsigned val) { return i_to_string<wstring>(val); }
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wstring to_wstring(unsigned long val) { return i_to_string<wstring>(val); }
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wstring to_wstring(unsigned long long val) { return i_to_string<wstring>(val); }
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string to_string(long val)
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{
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return as_string(snprintf, initial_string<string, long>()(), "%ld", val);
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}
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string to_string(unsigned long val)
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{
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return as_string(snprintf, initial_string<string, unsigned long>()(), "%lu", val);
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}
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string to_string (float val) { return as_string(snprintf, initial_string< string>()(), "%f", val); }
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string to_string (double val) { return as_string(snprintf, initial_string< string>()(), "%f", val); }
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string to_string (long double val) { return as_string(snprintf, initial_string< string>()(), "%Lf", val); }
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string to_string(long long val)
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{
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return as_string(snprintf, initial_string<string, long long>()(), "%lld", val);
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}
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wstring to_wstring(float val) { return as_string(get_swprintf(), initial_string<wstring>()(), L"%f", val); }
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wstring to_wstring(double val) { return as_string(get_swprintf(), initial_string<wstring>()(), L"%f", val); }
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wstring to_wstring(long double val) { return as_string(get_swprintf(), initial_string<wstring>()(), L"%Lf", val); }
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string to_string(unsigned long long val)
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{
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return as_string(snprintf, initial_string<string, unsigned long long>()(), "%llu", val);
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}
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string to_string(float val)
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{
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return as_string(snprintf, initial_string<string, float>()(), "%f", val);
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}
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string to_string(double val)
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{
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return as_string(snprintf, initial_string<string, double>()(), "%f", val);
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}
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string to_string(long double val)
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{
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return as_string(snprintf, initial_string<string, long double>()(), "%Lf", val);
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}
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wstring to_wstring(int val)
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{
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return as_string(get_swprintf(), initial_string<wstring, int>()(), L"%d", val);
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}
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wstring to_wstring(unsigned val)
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{
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return as_string(get_swprintf(), initial_string<wstring, unsigned>()(), L"%u", val);
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}
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wstring to_wstring(long val)
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{
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return as_string(get_swprintf(), initial_string<wstring, long>()(), L"%ld", val);
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}
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wstring to_wstring(unsigned long val)
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{
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return as_string(get_swprintf(), initial_string<wstring, unsigned long>()(), L"%lu", val);
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}
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wstring to_wstring(long long val)
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{
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return as_string(get_swprintf(), initial_string<wstring, long long>()(), L"%lld", val);
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}
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wstring to_wstring(unsigned long long val)
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{
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return as_string(get_swprintf(), initial_string<wstring, unsigned long long>()(), L"%llu", val);
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}
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wstring to_wstring(float val)
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{
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return as_string(get_swprintf(), initial_string<wstring, float>()(), L"%f", val);
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}
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wstring to_wstring(double val)
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{
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return as_string(get_swprintf(), initial_string<wstring, double>()(), L"%f", val);
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}
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wstring to_wstring(long double val)
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{
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return as_string(get_swprintf(), initial_string<wstring, long double>()(), L"%Lf", val);
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}
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_LIBCPP_END_NAMESPACE_STD
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