From 5ed80d308d3b33ae251f85c3f799fbbfeb0cc46d Mon Sep 17 00:00:00 2001
From: Niels <niels.lohmann@gmail.com>
Date: Sat, 9 May 2015 22:49:21 +0200
Subject: [PATCH] some parsing performance improvements
---
src/json.hpp | 158 ++++++++++++++++++++++++----------------------
src/json.hpp.re2c | 158 ++++++++++++++++++++++++----------------------
test/unit.cpp | 2 +-
3 files changed, 167 insertions(+), 151 deletions(-)
diff --git a/src/json.hpp b/src/json.hpp
index 87faa027..30b8f117 100644
--- a/src/json.hpp
+++ b/src/json.hpp
@@ -147,6 +147,23 @@ class basic_json
using list_init_t = std::initializer_list<basic_json>;
+ /////////////////////////////////
+ // JSON value type enumeration //
+ /////////////////////////////////
+
+ /// JSON value type enumeration
+ enum class value_t : uint8_t
+ {
+ null, ///< null value
+ object, ///< object (unordered set of name/value pairs)
+ array, ///< array (ordered collection of values)
+ string, ///< string value
+ boolean, ///< boolean value
+ number_integer, ///< number value (integer)
+ number_float, ///< number value (floating-point)
+ discarded ///< (internal) indicates the parser callback chose not to keep the value
+ };
+
////////////////////////
// JSON value storage //
////////////////////////
@@ -175,24 +192,60 @@ class basic_json
json_value(number_integer_t v) : number_integer(v) {}
/// constructor for numbers (floating-point)
json_value(number_float_t v) : number_float(v) {}
- };
+ /// constructor for empty values of a given type
+ json_value(value_t t)
+ {
+ switch (t)
+ {
+ case (value_t::null):
+ case (value_t::discarded):
+ {
+ break;
+ }
+ case (value_t::object):
+ {
+ AllocatorType<object_t> alloc;
+ object = alloc.allocate(1);
+ alloc.construct(object);
+ break;
+ }
- /////////////////////////////////
- // JSON value type enumeration //
- /////////////////////////////////
+ case (value_t::array):
+ {
+ AllocatorType<array_t> alloc;
+ array = alloc.allocate(1);
+ alloc.construct(array);
+ break;
+ }
- /// JSON value type enumeration
- enum class value_t : uint8_t
- {
- null, ///< null value
- object, ///< object (unordered set of name/value pairs)
- array, ///< array (ordered collection of values)
- string, ///< string value
- boolean, ///< boolean value
- number_integer, ///< number value (integer)
- number_float, ///< number value (floating-point)
- discarded ///< (internal) indicates the parser callback chose not to keep the value
+ case (value_t::string):
+ {
+ AllocatorType<string_t> alloc;
+ string = alloc.allocate(1);
+ alloc.construct(string, "");
+ break;
+ }
+
+ case (value_t::boolean):
+ {
+ boolean = boolean_t(false);
+ break;
+ }
+
+ case (value_t::number_integer):
+ {
+ number_integer = number_integer_t(0);
+ break;
+ }
+
+ case (value_t::number_float):
+ {
+ number_float = number_float_t(0.0);
+ break;
+ }
+ }
+ }
};
//////////////////////////
@@ -261,59 +314,8 @@ class basic_json
@exception std::bad_alloc if allocation for object, array, or string fails.
*/
inline basic_json(const value_t value)
- : m_type(value)
- {
- switch (m_type)
- {
- case (value_t::null):
- case (value_t::discarded):
- {
- break;
- }
-
- case (value_t::object):
- {
- AllocatorType<object_t> alloc;
- m_value.object = alloc.allocate(1);
- alloc.construct(m_value.object);
- break;
- }
-
- case (value_t::array):
- {
- AllocatorType<array_t> alloc;
- m_value.array = alloc.allocate(1);
- alloc.construct(m_value.array);
- break;
- }
-
- case (value_t::string):
- {
- AllocatorType<string_t> alloc;
- m_value.string = alloc.allocate(1);
- alloc.construct(m_value.string, "");
- break;
- }
-
- case (value_t::boolean):
- {
- m_value.boolean = boolean_t(false);
- break;
- }
-
- case (value_t::number_integer):
- {
- m_value.number_integer = number_integer_t(0);
- break;
- }
-
- case (value_t::number_float):
- {
- m_value.number_float = number_float_t(0.0);
- break;
- }
- }
- }
+ : m_type(value), m_value(value)
+ {}
/*!
@brief create a null object (implicitly)
@@ -4629,7 +4631,8 @@ basic_json_parser_59:
if (keep and (keep = callback(depth++, parse_event_t::object_start, result)))
{
// explicitly set result to object to cope with {}
- result = basic_json(value_t::object);
+ result.m_type = value_t::object;
+ result.m_value = json_value(value_t::object);
}
// read next token
@@ -4698,7 +4701,8 @@ basic_json_parser_59:
if (keep and (keep = callback(depth++, parse_event_t::array_start, result)))
{
// explicitly set result to object to cope with []
- result = basic_json(value_t::array);
+ result.m_type = value_t::array;
+ result.m_value = json_value(value_t::array);
}
// read next token
@@ -4750,7 +4754,7 @@ basic_json_parser_59:
case (lexer::token_type::literal_null):
{
get_token();
- result = basic_json(nullptr);
+ result.m_type = value_t::null;
break;
}
@@ -4765,14 +4769,16 @@ basic_json_parser_59:
case (lexer::token_type::literal_true):
{
get_token();
- result = basic_json(true);
+ result.m_type = value_t::boolean;
+ result.m_value = true;
break;
}
case (lexer::token_type::literal_false):
{
get_token();
- result = basic_json(false);
+ result.m_type = value_t::boolean;
+ result.m_value = false;
break;
}
@@ -4795,12 +4801,14 @@ basic_json_parser_59:
if (approx(float_val, static_cast<number_float_t>(int_val)))
{
// we basic_json not lose precision -> return int
- result = basic_json(int_val);
+ result.m_type = value_t::number_integer;
+ result.m_value = int_val;
}
else
{
// we would lose precision -> returnfloat
- result = basic_json(float_val);
+ result.m_type = value_t::number_float;
+ result.m_value = float_val;
}
break;
}
diff --git a/src/json.hpp.re2c b/src/json.hpp.re2c
index f456e90f..e5534daa 100644
--- a/src/json.hpp.re2c
+++ b/src/json.hpp.re2c
@@ -147,6 +147,23 @@ class basic_json
using list_init_t = std::initializer_list<basic_json>;
+ /////////////////////////////////
+ // JSON value type enumeration //
+ /////////////////////////////////
+
+ /// JSON value type enumeration
+ enum class value_t : uint8_t
+ {
+ null, ///< null value
+ object, ///< object (unordered set of name/value pairs)
+ array, ///< array (ordered collection of values)
+ string, ///< string value
+ boolean, ///< boolean value
+ number_integer, ///< number value (integer)
+ number_float, ///< number value (floating-point)
+ discarded ///< (internal) indicates the parser callback chose not to keep the value
+ };
+
////////////////////////
// JSON value storage //
////////////////////////
@@ -175,24 +192,60 @@ class basic_json
json_value(number_integer_t v) : number_integer(v) {}
/// constructor for numbers (floating-point)
json_value(number_float_t v) : number_float(v) {}
- };
+ /// constructor for empty values of a given type
+ json_value(value_t t)
+ {
+ switch (t)
+ {
+ case (value_t::null):
+ case (value_t::discarded):
+ {
+ break;
+ }
+ case (value_t::object):
+ {
+ AllocatorType<object_t> alloc;
+ object = alloc.allocate(1);
+ alloc.construct(object);
+ break;
+ }
- /////////////////////////////////
- // JSON value type enumeration //
- /////////////////////////////////
+ case (value_t::array):
+ {
+ AllocatorType<array_t> alloc;
+ array = alloc.allocate(1);
+ alloc.construct(array);
+ break;
+ }
- /// JSON value type enumeration
- enum class value_t : uint8_t
- {
- null, ///< null value
- object, ///< object (unordered set of name/value pairs)
- array, ///< array (ordered collection of values)
- string, ///< string value
- boolean, ///< boolean value
- number_integer, ///< number value (integer)
- number_float, ///< number value (floating-point)
- discarded ///< (internal) indicates the parser callback chose not to keep the value
+ case (value_t::string):
+ {
+ AllocatorType<string_t> alloc;
+ string = alloc.allocate(1);
+ alloc.construct(string, "");
+ break;
+ }
+
+ case (value_t::boolean):
+ {
+ boolean = boolean_t(false);
+ break;
+ }
+
+ case (value_t::number_integer):
+ {
+ number_integer = number_integer_t(0);
+ break;
+ }
+
+ case (value_t::number_float):
+ {
+ number_float = number_float_t(0.0);
+ break;
+ }
+ }
+ }
};
//////////////////////////
@@ -261,59 +314,8 @@ class basic_json
@exception std::bad_alloc if allocation for object, array, or string fails.
*/
inline basic_json(const value_t value)
- : m_type(value)
- {
- switch (m_type)
- {
- case (value_t::null):
- case (value_t::discarded):
- {
- break;
- }
-
- case (value_t::object):
- {
- AllocatorType<object_t> alloc;
- m_value.object = alloc.allocate(1);
- alloc.construct(m_value.object);
- break;
- }
-
- case (value_t::array):
- {
- AllocatorType<array_t> alloc;
- m_value.array = alloc.allocate(1);
- alloc.construct(m_value.array);
- break;
- }
-
- case (value_t::string):
- {
- AllocatorType<string_t> alloc;
- m_value.string = alloc.allocate(1);
- alloc.construct(m_value.string, "");
- break;
- }
-
- case (value_t::boolean):
- {
- m_value.boolean = boolean_t(false);
- break;
- }
-
- case (value_t::number_integer):
- {
- m_value.number_integer = number_integer_t(0);
- break;
- }
-
- case (value_t::number_float):
- {
- m_value.number_float = number_float_t(0.0);
- break;
- }
- }
- }
+ : m_type(value), m_value(value)
+ {}
/*!
@brief create a null object (implicitly)
@@ -3935,7 +3937,8 @@ class basic_json
if (keep and (keep = callback(depth++, parse_event_t::object_start, result)))
{
// explicitly set result to object to cope with {}
- result = basic_json(value_t::object);
+ result.m_type = value_t::object;
+ result.m_value = json_value(value_t::object);
}
// read next token
@@ -4004,7 +4007,8 @@ class basic_json
if (keep and (keep = callback(depth++, parse_event_t::array_start, result)))
{
// explicitly set result to object to cope with []
- result = basic_json(value_t::array);
+ result.m_type = value_t::array;
+ result.m_value = json_value(value_t::array);
}
// read next token
@@ -4056,7 +4060,7 @@ class basic_json
case (lexer::token_type::literal_null):
{
get_token();
- result = basic_json(nullptr);
+ result.m_type = value_t::null;
break;
}
@@ -4071,14 +4075,16 @@ class basic_json
case (lexer::token_type::literal_true):
{
get_token();
- result = basic_json(true);
+ result.m_type = value_t::boolean;
+ result.m_value = true;
break;
}
case (lexer::token_type::literal_false):
{
get_token();
- result = basic_json(false);
+ result.m_type = value_t::boolean;
+ result.m_value = false;
break;
}
@@ -4101,12 +4107,14 @@ class basic_json
if (approx(float_val, static_cast<number_float_t>(int_val)))
{
// we basic_json not lose precision -> return int
- result = basic_json(int_val);
+ result.m_type = value_t::number_integer;
+ result.m_value = int_val;
}
else
{
// we would lose precision -> returnfloat
- result = basic_json(float_val);
+ result.m_type = value_t::number_float;
+ result.m_value = float_val;
}
break;
}
diff --git a/test/unit.cpp b/test/unit.cpp
index b41c3846..d304934c 100644
--- a/test/unit.cpp
+++ b/test/unit.cpp
@@ -8662,7 +8662,7 @@ TEST_CASE("compliance tests from nativejson-benchmark")
TEST_STRING("[\"\\u20AC\"]", "\xE2\x82\xAC"); // Euro sign U+20AC
TEST_STRING("[\"\\uD834\\uDD1E\"]", "\xF0\x9D\x84\x9E"); // G clef sign U+1D11E
}
-
+
SECTION("roundtrip")
{
// test cases are from https://github.com/miloyip/nativejson-benchmark/tree/master/data/roundtrip