Added tuple interface to json_value_iterator_pair

beached · Aug 28, 2020 · 7afd49a · 7afd49a
1 parent 50cfd44
commit 7afd49a
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Showing 4 changed files with 74 additions and 16 deletions.
diff --git a/include/daw/json/impl/daw_json_value.h b/include/daw/json/impl/daw_json_value.h
@@ -11,6 +11,8 @@
 #include "daw_arrow_proxy.h"
 #include "daw_json_parse_name.h"
 
+#include <tuple>
+
 namespace daw::json {
 	template<typename Range>
 	class basic_json_value;
@@ -25,6 +27,56 @@ namespace daw::json {
 		basic_json_value<Range> value;
 	};
 
+	template<std::size_t Idx, typename Range>
+	constexpr decltype( auto ) get( basic_json_pair<Range> const & rng ) {
+		static_assert( Idx < 2 );
+		if constexpr( Idx == 0 ) {
+			return rng.name;
+		} else {
+			return rng.value;
+		}
+	}
+
+	template<std::size_t Idx, typename Range>
+	constexpr decltype( auto ) get( basic_json_pair<Range> & rng ) {
+		static_assert( Idx < 2 );
+		if constexpr( Idx == 0 ) {
+			return rng.name;
+		} else {
+			return rng.value;
+		}
+	}
+
+	template<std::size_t Idx, typename Range>
+	constexpr decltype( auto ) get( basic_json_pair<Range> && rng ) {
+		static_assert( Idx < 2 );
+		if constexpr( Idx == 0 ) {
+			return std::move( rng.name );
+		} else {
+			return std::move( rng.value );
+		}
+	}
+} // namespace daw::json
+
+namespace std {
+	template<typename Range>
+	class tuple_element<0, daw::json::basic_json_pair<Range>> {
+	public:
+		using type = std::optional<std::string_view>;
+	};
+
+	template<typename Range>
+	class tuple_element<1, daw::json::basic_json_pair<Range>> {
+	public:
+		using type = daw::json::basic_json_value<Range>;
+	};
+
+	template<typename Range>
+	class std::tuple_size<daw::json::basic_json_pair<Range>>
+	  : public std::integral_constant<std::size_t, 2> {};
+} // namespace std
+
+namespace daw::json {
 	/***
 	 * Iterator for iterating over arbutrary JSON members and array elements
 	 * @tparam Range see IteratorRange

diff --git a/include/daw/json/impl/daw_murmur3.h b/include/daw/json/impl/daw_murmur3.h
@@ -24,39 +24,42 @@ namespace daw {
 			return result;
 		}
 
-		static inline constexpr uint32_t rotl( std::uint32_t n, unsigned c ) {
-			constexpr unsigned mask = ( CHAR_BIT * sizeof( n ) - 1 );
-			c &= mask;
-			return ( n << c ) | ( n >> ( ( -c ) & mask ) );
+		template<unsigned r>
+		DAW_ATTRIBUTE_FLATTEN [[nodiscard]] static inline constexpr uint32_t
+		rotl( std::uint32_t n ) {
+			return ( n << r ) | ( n >> r );
 		}
 
-		inline constexpr std::uint32_t
+		[[nodiscard]] inline constexpr std::uint32_t
 		murmur3_32_scramble( std::uint32_t k ) noexcept {
 			k *= 0xcc9e'2d51ULL;
-			rotl( k, 15 );
+			k = rotl<15>( k );
 			k *= 0x1b87'3593ULL;
 			return k;
 		}
 	} // namespace murmur3_details
 
 	template<typename String>
-	constexpr std::uint32_t murmur3_32( String const &key ) noexcept {
-		std::uint32_t h = 0; // seed
-		auto const len = static_cast<uint32_t>( key.size( ) );
+	[[nodiscard]] constexpr std::uint32_t
+	murmur3_32( String const &key, std::uint32_t seed = 0 ) noexcept {
+
+		std::uint32_t h = seed;
+		std::uint32_t const len = static_cast<uint32_t>( key.size( ) );
 		char const *first = key.data( );
 		char const *const last = key.data( ) + len;
+		std::uint32_t k = 0U;
 		while( ( last - first ) >= 4U ) {
 			// Here is a source of differing results across endiannesses.
 			// A swap here has no effects on hash properties though.
-			std::uint32_t k = murmur3_details::to_u32( first );
+			k = murmur3_details::to_u32( first );
 			h ^= murmur3_details::murmur3_32_scramble( k );
-			h = murmur3_details::rotl( h, 13 );
+			h = murmur3_details::rotl<13>( h );
 			h = h * 5U + 0xe654'6b64ULL;
 			first += 4;
 		}
 
 		// Anything left over
-		std::uint32_t k = 0U;
+		k = 0;
 		for( auto d = ( last - first ); d > 0; --d ) {
 			k <<= 8U;
 			char const c = *( first + ( d - 1 ) );

diff --git a/tests/canada_test_basic.cpp b/tests/canada_test_basic.cpp
@@ -27,8 +27,9 @@ int main( int argc, char **argv ) try {
 	auto json_data =
 	  std::string( daw::filesystem::memory_mapped_file_t<>( argv[1] ) );
 
-	auto const canada_result =
-	  daw::json::from_json<daw::geojson::FeatureCollection>( json_data );
+	auto const canada_result = daw::json::from_json<
+	  daw::geojson::FeatureCollection,
+	  daw::json::SIMDNoCommentSkippingPolicyChecked<simd_exec_tag>>( json_data );
 	daw::do_not_optimize( canada_result );
 
 	auto new_json_result = std::string( );

diff --git a/tests/daw_murmur3_test.cpp b/tests/daw_murmur3_test.cpp
@@ -24,8 +24,10 @@ int main( int, char ** ) {
 	daw::expecting( t0_b == 0x04030201 );
 	test( "", 0, 0 );
 	test( "", 1, 0x514E'28B7ULL );
-	test( "", 0xFFFF'FFFF, 0x81F1'6F39ULL );
-	test( "\xFF\xFF\xFF\xFF", 0, 0x7629'3B50ULL );
+	test( "", 0xFFFF'FFFF, 0x81F1'6F39ULL ); // make sure your seed uses unsigned 32-bit math
+	test( "\xFF\xFF\xFF\xFF", 0, 0x7629'3B50ULL ); // make sure 4-byte chunks use unsigned math
+	test( "\x21\x43\x65\x87", 0, 0xF55B'516BULL );
+	test( "\x21\x43\x65\x87", 0x5082'EDEE, 0x2362'F9DE );
 
 	test( "aaaa", 0x9747b28c, 0x5A97808A ); // one full chunk
 	test( "aaa", 0x9747b28c, 0x283E0130 );  // three characters