parsing strings uses SSE2

bench/bench.cpp

@@ -444,7 +444,7 @@ main(
         //vi.emplace_back(new nlohmann_impl);
 
         benchParse(vs, vi);
-        benchSerialize(vs, vi);
+        //benchSerialize(vs, vi);
     }
     catch(system_error const& se)
     {

include/boost/json/detail/basic_parser.hpp

@@ -35,43 +35,6 @@ struct parser_base
             return 10 + c - 'a';
         return -1;
     }
-
-    static
-    int
-    utf8_encode(
-        char* dest,
-        unsigned long cp)
-    {
-        if(cp < 0x80)
-        {
-            dest[0] = static_cast<char>(cp);
-            return 1;
-        }
-
-        if(cp < 0x800)
-        {
-            dest[0] = static_cast<char>( (cp >> 6)          | 0xc0);
-            dest[1] = static_cast<char>( (cp & 0x3f)        | 0x80);
-            return 2;
-        }
-
-        if(cp < 0x10000)
-        {
-            dest[0] = static_cast<char>( (cp >> 12)         | 0xe0);
-            dest[1] = static_cast<char>(((cp >> 6) & 0x3f)  | 0x80);
-            dest[2] = static_cast<char>( (cp       & 0x3f)  | 0x80);
-            return 3;
-        }
-
-        {
-            dest[0] = static_cast<char>( (cp >> 18)         | 0xf0);
-            dest[1] = static_cast<char>(((cp >> 12) & 0x3f) | 0x80);
-            dest[2] = static_cast<char>(((cp >> 6)  & 0x3f) | 0x80);
-            dest[3] = static_cast<char>( (cp        & 0x3f) | 0x80);
-            return 4;
-        }
-    }
-
 };
 
 } // detail

include/boost/json/detail/config.hpp

@@ -52,8 +52,6 @@
 # endif
 #endif
 
-#define BOOST_JSON_VALUE_IS_TRIVIAL
-
 #ifndef BOOST_NO_EXCEPTIONS
 # define BOOST_JSON_THROW(x) throw(x)
 #else
@@ -62,4 +60,16 @@
 
 #define BOOST_JSON_STATIC_ASSERT( ... ) static_assert(__VA_ARGS__, #__VA_ARGS__)
 
+// optimizations
+
+#define BOOST_JSON_VALUE_IS_TRIVIAL
+
+#ifndef BOOST_JSON_NO_SSE2
+# if (defined(_M_IX86) && _M_IX86_FP == 2) || \
+      defined(_M_X64) || defined(__SSE2__)
+#  define BOOST_JSON_USE_SSE2
+# endif
+#endif
+
+
 #endif

include/boost/json/detail/sse2.hpp

@@ -0,0 +1,75 @@
+//
+// Copyright (c) 2018-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/vinniefalco/json
+//
+
+#ifndef BOOST_JSON_DETAIL_SSE2_HPP
+#define BOOST_JSON_DETAIL_SSE2_HPP
+
+#include <boost/json/detail/config.hpp>
+#ifdef BOOST_JSON_USE_SSE2
+#include <emmintrin.h>
+#include <xmmintrin.h>
+#endif
+
+namespace boost {
+namespace json {
+namespace detail {
+
+#ifdef BOOST_JSON_USE_SSE2
+inline
+unsigned long long
+count_unescaped(
+    char const* s,
+    unsigned long long n) noexcept
+{
+    __m128i const q1 = _mm_set1_epi8( '"' );
+    __m128i const q2 = _mm_set1_epi8( '\\' );
+    __m128i const q3 = _mm_set1_epi8( 0x20 );
+
+    char const * s0 = s;
+
+    while( n >= 16 )
+    {
+        __m128i v1 = _mm_loadu_si128( (__m128i const*)s );
+
+        __m128i v2 = _mm_cmpeq_epi8( v1, q1 );
+        __m128i v3 = _mm_cmpeq_epi8( v1, q2 );
+        __m128i v4 = _mm_cmplt_epi8( v1, q3 );
+
+        __m128i v5 = _mm_or_si128( v2, v3 );
+        __m128i v6 = _mm_or_si128( v5, v4 );
+
+        int w = _mm_movemask_epi8( v6 );
+
+        if( w != 0 ) break;
+
+        s += 16;
+        n -= 16;
+    }
+
+    return s - s0;
+};
+
+#else
+
+inline
+unsigned long long
+count_unescaped(
+    char const*,
+    unsigned long long) noexcept
+{
+    return 0;
+}
+
+#endif
+
+} // detail
+} // json
+} // boost
+
+#endif

include/boost/json/impl/basic_parser.ipp

@@ -12,8 +12,9 @@
 
 #include <boost/json/basic_parser.hpp>
 #include <boost/json/error.hpp>
-#include <boost/json/detail/buffer.hpp>
 #include <boost/json/detail/assert.hpp>
+#include <boost/json/detail/buffer.hpp>
+#include <boost/json/detail/sse2.hpp>
 
 namespace boost {
 namespace json {
@@ -516,6 +517,7 @@ loop_string:
         auto const start = p;
         while(p < p1)
         {
+            p += detail::count_unescaped(p, p1 - p);
             if(*p == '\"')
             {
                 if(is_key_)