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Improve performance of http::string_to_verb

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`operator==` performs better than the hand-written comparison routine.

fix #1636

Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>
This commit is contained in:
Damian Jarek
2019-06-19 17:53:35 +02:00
parent ab55c4d21e
commit a0d5baf22a
7 changed files with 218 additions and 174 deletions
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include/boost/beast/core/string.hpp
+14 -88
View File
@@ -10,82 +10,17 @@
#ifndef BOOST_BEAST_STRING_HPP
#define BOOST_BEAST_STRING_HPP
#include <boost/beast/core/detail/config.hpp>
#include <boost/version.hpp>
#if defined(BOOST_BEAST_USE_STD_STRING_VIEW)
#include <string_view>
#else
#include <boost/utility/string_view.hpp>
#endif
#include <algorithm>
#include <boost/beast/core/detail/string.hpp>
namespace boost {
namespace beast {
#if defined(BOOST_BEAST_USE_STD_STRING_VIEW)
/// The type of string view used by the library
using string_view = std::string_view;
/// The type of string view used by the library
using detail::string_view;
/// The type of basic string view used by the library
template<class CharT, class Traits>
using basic_string_view =
std::basic_string_view<CharT, Traits>;
#else
/// The type of string view used by the library
using string_view = boost::string_view;
/// The type of basic string view used by the library
template<class CharT, class Traits>
using basic_string_view =
boost::basic_string_view<CharT, Traits>;
#endif
namespace detail {
inline
char
ascii_tolower(char c)
{
return ((static_cast<unsigned>(c) - 65U) < 26) ?
c + 'a' - 'A' : c;
}
template<class = void>
bool
iequals(
beast::string_view lhs,
beast::string_view rhs)
{
auto n = lhs.size();
if(rhs.size() != n)
return false;
auto p1 = lhs.data();
auto p2 = rhs.data();
char a, b;
// fast loop
while(n--)
{
a = *p1++;
b = *p2++;
if(a != b)
goto slow;
}
return true;
slow:
do
{
if(ascii_tolower(a) != ascii_tolower(b))
return false;
a = *p1++;
b = *p2++;
}
while(n--);
return true;
}
} // detail
/// The type of basic string view used by the library
template<class CharT, class Traits>
using basic_string_view = detail::basic_string_view<CharT, Traits>;
/** Returns `true` if two strings are equal, using a case-insensitive comparison.
@@ -95,14 +30,11 @@ slow:
@param rhs The string on the right side of the equality
*/
inline
BOOST_BEAST_DECL
bool
iequals(
beast::string_view lhs,
beast::string_view rhs)
{
return detail::iequals(lhs, rhs);
}
beast::string_view rhs);
/** A case-insensitive less predicate for strings.
@@ -110,21 +42,11 @@ iequals(
*/
struct iless
{
BOOST_BEAST_DECL
bool
operator()(
string_view lhs,
string_view rhs) const
{
using std::begin;
using std::end;
return std::lexicographical_compare(
begin(lhs), end(lhs), begin(rhs), end(rhs),
[](char c1, char c2)
{
return detail::ascii_tolower(c1) < detail::ascii_tolower(c2);
}
);
}
string_view rhs) const;
};
/** A case-insensitive equality predicate for strings.
@@ -145,4 +67,8 @@ struct iequal
} // beast
} // boost
#ifdef BOOST_BEAST_HEADER_ONLY
#include <boost/beast/core/impl/string.ipp>
#endif
#endif