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🔨 added a SAX-DOM-Parser

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Niels Lohmann 2018-02-26 23:39:23 +01:00
parent 21352c4d8e
commit 3ff9455332
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GPG Key ID: 7F3CEA63AE251B69
7 changed files with 177 additions and 44 deletions
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15
include/nlohmann/detail/input/json_sax.hpp
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@ -20,6 +20,9 @@ struct json_sax
/// type for floating-point numbers
using number_float_t = typename BasicJsonType::number_float_t;
/// constant to indicate that no size limit is given for array or object
static constexpr auto no_limit = std::size_t(-1);
/*!
@brief a null value was read
@return whether parsing should proceed
@ -60,22 +63,22 @@ struct json_sax
@param[in] val string value
@return whether parsing should proceed
*/
virtual bool string(const std::string& val) = 0;
virtual bool string(std::string&& val) = 0;
/*!
@brief the beginning of an object was read
@param[in] elements number of object elements or -1 if unknown
@param[in] elements number of object elements or no_limit if unknown
@return whether parsing should proceed
@note binary formats may report the number of elements
*/
virtual bool start_object(std::size_t elements) = 0;
virtual bool start_object(std::size_t elements = no_limit) = 0;
/*!
@brief an object key was read
@param[in] val object key
@return whether parsing should proceed
*/
virtual bool key(const std::string& val) = 0;
virtual bool key(std::string&& val) = 0;
/*!
@brief the end of an object was read
@ -85,11 +88,11 @@ struct json_sax
/*!
@brief the beginning of an array was read
@param[in] elements number of array elements or -1 if unknown
@param[in] elements number of array elements or no_limit if unknown
@return whether parsing should proceed
@note binary formats may report the number of elements
*/
virtual bool start_array(std::size_t elements) = 0;
virtual bool start_array(std::size_t elements = no_limit) = 0;
/*!
@brief the end of an array was read

2
include/nlohmann/detail/input/lexer.hpp
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@ -1130,7 +1130,7 @@ scan_number_done:
}
/// return current string value (implicitly resets the token; useful only once)
std::string move_string()
std::string&& move_string()
{
return std::move(token_buffer);
}

10
include/nlohmann/detail/input/parser.hpp
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@ -53,7 +53,7 @@ class parser
value
};
using json_sax = json_sax<BasicJsonType>;
using json_sax_t = json_sax<BasicJsonType>;
using parser_callback_t =
std::function<bool(int depth, parse_event_t event, BasicJsonType& parsed)>;
@ -65,7 +65,7 @@ class parser
: callback(cb), m_lexer(adapter), allow_exceptions(allow_exceptions_)
{}
parser(detail::input_adapter_t adapter, json_sax* s)
parser(detail::input_adapter_t adapter, json_sax_t* s)
: m_lexer(adapter), sax(s)
{}
@ -541,7 +541,7 @@ class parser
{
case token_type::begin_object:
{
if (not sax->start_object(std::size_t(-1)))
if (not sax->start_object())
{
return false;
}
@ -610,7 +610,7 @@ class parser
case token_type::begin_array:
{
if (not sax->start_array(std::size_t(-1)))
if (not sax->start_array())
{
return false;
}
@ -772,7 +772,7 @@ class parser
/// whether to throw exceptions in case of errors
const bool allow_exceptions = true;
/// associated SAX parse event receiver
json_sax* sax = nullptr;
json_sax_t* sax = nullptr;
};
}
}

8
include/nlohmann/json.hpp
View File

@ -1105,7 +1105,7 @@ class basic_json
*/
using parser_callback_t = typename parser::parser_callback_t;
using json_sax = typename parser::json_sax;
using json_sax_t = typename parser::json_sax_t;
//////////////////
// constructors //
@ -5926,12 +5926,12 @@ class basic_json
return parser(i).accept(true);
}
static bool sax_parse(detail::input_adapter i, json_sax* sax)
static bool sax_parse(detail::input_adapter i, json_sax_t* sax)
{
return parser(i, sax).sax_parse();
}
static bool sax_parse(detail::input_adapter& i, json_sax* sax)
static bool sax_parse(detail::input_adapter& i, json_sax_t* sax)
{
return parser(i, sax).sax_parse();
}
@ -6009,7 +6009,7 @@ class basic_json
std::is_base_of<
std::random_access_iterator_tag,
typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
static bool sax_parse(IteratorType first, IteratorType last, json_sax* sax)
static bool sax_parse(IteratorType first, IteratorType last, json_sax_t* sax)
{
return parser(detail::input_adapter(first, last), sax).sax_parse();
}

35
single_include/nlohmann/json.hpp
View File

@ -2969,7 +2969,7 @@ scan_number_done:
}
/// return current string value (implicitly resets the token; useful only once)
std::string move_string()
std::string&& move_string()
{
return std::move(token_buffer);
}
@ -3154,6 +3154,9 @@ struct json_sax
/// type for floating-point numbers
using number_float_t = typename BasicJsonType::number_float_t;
/// constant to indicate that no size limit is given for array or object
static constexpr auto no_limit = std::size_t(-1);
/*!
@brief a null value was read
@return whether parsing should proceed
@ -3194,22 +3197,22 @@ struct json_sax
@param[in] val string value
@return whether parsing should proceed
*/
virtual bool string(const std::string& val) = 0;
virtual bool string(std::string&& val) = 0;
/*!
@brief the beginning of an object was read
@param[in] elements number of object elements or -1 if unknown
@param[in] elements number of object elements or no_limit if unknown
@return whether parsing should proceed
@note binary formats may report the number of elements
*/
virtual bool start_object(std::size_t elements) = 0;
virtual bool start_object(std::size_t elements = no_limit) = 0;
/*!
@brief an object key was read
@param[in] val object key
@return whether parsing should proceed
*/
virtual bool key(const std::string& val) = 0;
virtual bool key(std::string&& val) = 0;
/*!
@brief the end of an object was read
@ -3219,11 +3222,11 @@ struct json_sax
/*!
@brief the beginning of an array was read
@param[in] elements number of array elements or -1 if unknown
@param[in] elements number of array elements or no_limit if unknown
@return whether parsing should proceed
@note binary formats may report the number of elements
*/
virtual bool start_array(std::size_t elements) = 0;
virtual bool start_array(std::size_t elements = no_limit) = 0;
/*!
@brief the end of an array was read
@ -3297,7 +3300,7 @@ class parser
value
};
using json_sax = json_sax<BasicJsonType>;
using json_sax_t = json_sax<BasicJsonType>;
using parser_callback_t =
std::function<bool(int depth, parse_event_t event, BasicJsonType& parsed)>;
@ -3309,7 +3312,7 @@ class parser
: callback(cb), m_lexer(adapter), allow_exceptions(allow_exceptions_)
{}
parser(detail::input_adapter_t adapter, json_sax* s)
parser(detail::input_adapter_t adapter, json_sax_t* s)
: m_lexer(adapter), sax(s)
{}
@ -3785,7 +3788,7 @@ class parser
{
case token_type::begin_object:
{
if (not sax->start_object(std::size_t(-1)))
if (not sax->start_object())
{
return false;
}
@ -3854,7 +3857,7 @@ class parser
case token_type::begin_array:
{
if (not sax->start_array(std::size_t(-1)))
if (not sax->start_array())
{
return false;
}
@ -4016,7 +4019,7 @@ class parser
/// whether to throw exceptions in case of errors
const bool allow_exceptions = true;
/// associated SAX parse event receiver
json_sax* sax = nullptr;
json_sax_t* sax = nullptr;
};
}
}
@ -11013,7 +11016,7 @@ class basic_json
*/
using parser_callback_t = typename parser::parser_callback_t;
using json_sax = typename parser::json_sax;
using json_sax_t = typename parser::json_sax_t;
//////////////////
// constructors //
@ -15834,12 +15837,12 @@ class basic_json
return parser(i).accept(true);
}
static bool sax_parse(detail::input_adapter i, json_sax* sax)
static bool sax_parse(detail::input_adapter i, json_sax_t* sax)
{
return parser(i, sax).sax_parse();
}
static bool sax_parse(detail::input_adapter& i, json_sax* sax)
static bool sax_parse(detail::input_adapter& i, json_sax_t* sax)
{
return parser(i, sax).sax_parse();
}
@ -15917,7 +15920,7 @@ class basic_json
std::is_base_of<
std::random_access_iterator_tag,
typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
static bool sax_parse(IteratorType first, IteratorType last, json_sax* sax)
static bool sax_parse(IteratorType first, IteratorType last, json_sax_t* sax)
{
return parser(detail::input_adapter(first, last), sax).sax_parse();
}

139
test/src/unit-class_parser.cpp
View File

@ -34,7 +34,7 @@ using nlohmann::json;
#include <valarray>
class SaxEventLogger : public nlohmann::json::json_sax
class SaxEventLogger : public nlohmann::json::json_sax_t
{
public:
bool null() override
@ -67,7 +67,7 @@ class SaxEventLogger : public nlohmann::json::json_sax
return true;
}
bool string(const std::string& val) override
bool string(std::string&& val) override
{
events.push_back("string(" + val + ")");
return true;
@ -75,7 +75,7 @@ class SaxEventLogger : public nlohmann::json::json_sax
bool start_object(std::size_t elements) override
{
if (elements == std::size_t(-1))
if (elements == no_limit)
{
events.push_back("start_object()");
}
@ -86,13 +86,13 @@ class SaxEventLogger : public nlohmann::json::json_sax
return true;
}
bool key(const std::string& val) override
bool key(std::string&& val) override
{
events.push_back("key(" + val + ")");
return true;
}
bool end_object()override
bool end_object() override
{
events.push_back("end_object()");
return true;
@ -100,7 +100,7 @@ class SaxEventLogger : public nlohmann::json::json_sax
bool start_array(std::size_t elements) override
{
if (elements == std::size_t(-1))
if (elements == no_limit)
{
events.push_back("start_array()");
}
@ -134,6 +134,129 @@ class SaxEventLogger : public nlohmann::json::json_sax
bool errored = false;
};
class SaxDomParser : public nlohmann::json::json_sax_t
{
public:
bool null() override
{
handle_value(nullptr);
return true;
}
bool boolean(bool val) override
{
handle_value(val);
return true;
}
bool number_integer(json::number_integer_t val) override
{
handle_value(val);
return true;
}
bool number_unsigned(json::number_unsigned_t val) override
{
handle_value(val);
return true;
}
bool number_float(json::number_float_t val, const std::string&) override
{
handle_value(val);
return true;
}
bool string(std::string&& val) override
{
handle_value(val);
return true;
}
bool start_object(std::size_t) override
{
ref_stack.push_back(handle_value(json::value_t::object));
return true;
}
bool key(std::string&& val) override
{
last_key = val;
return true;
}
bool end_object() override
{
ref_stack.pop_back();
return true;
}
bool start_array(std::size_t) override
{
ref_stack.push_back(handle_value(json::value_t::array));
return true;
}
bool end_array() override
{
ref_stack.pop_back();
return true;
}
bool binary(const std::vector<uint8_t>&) override
{
return true;
}
bool parse_error(std::size_t position, const std::string&) override
{
return false;
}
json& get_value()
{
return root;
}
private:
/// the parsed JSON value
json root;
/// stack to model hierarchy of values
std::vector<json*> ref_stack;
/// helper variable for object keys
std::string last_key;
/*!
@invariant If the ref stack is empty, then the passed value will be the new
root.
@invariant If the ref stack contains a value, then it is an array or an
object to which we can add elements
*/
json* handle_value(json&& j)
{
if (ref_stack.empty())
{
assert(root.is_null());
root = j;
return &root;
}
else
{
assert(ref_stack.back()->is_array() or ref_stack.back()->is_object());
if (ref_stack.back()->is_array())
{
ref_stack.back()->push_back(j);
return &(ref_stack.back()->back());
}
else
{
json& r = ref_stack.back()->operator[](last_key) = j;
return &r;
}
}
}
};
json parser_helper(const std::string& s);
bool accept_helper(const std::string& s);
@ -148,6 +271,10 @@ json parser_helper(const std::string& s)
CHECK_NOTHROW(json::parser(nlohmann::detail::input_adapter(s), nullptr, false).parse(true, j_nothrow));
CHECK(j_nothrow == j);
SaxDomParser sdp;
json::sax_parse(s, &sdp);
CHECK(sdp.get_value() == j);
return j;
}

12
test/src/unit-deserialization.cpp
View File

@ -34,7 +34,7 @@ using nlohmann::json;
#include <iostream>
#include <valarray>
struct SaxEventLogger : public nlohmann::json::json_sax
struct SaxEventLogger : public nlohmann::json::json_sax_t
{
bool null() override
{
@ -66,7 +66,7 @@ struct SaxEventLogger : public nlohmann::json::json_sax
return true;
}
bool string(const std::string& val) override
bool string(std::string&& val) override
{
events.push_back("string(" + val + ")");
return true;
@ -85,7 +85,7 @@ struct SaxEventLogger : public nlohmann::json::json_sax
return true;
}
bool key(const std::string& val) override
bool key(std::string&& val) override
{
events.push_back("key(" + val + ")");
return true;
@ -135,7 +135,7 @@ struct SaxEventLoggerExitAfterStartObject : public SaxEventLogger
{
bool start_object(std::size_t elements) override
{
if (elements == std::size_t(-1))
if (elements == no_limit)
{
events.push_back("start_object()");
}
@ -149,7 +149,7 @@ struct SaxEventLoggerExitAfterStartObject : public SaxEventLogger
struct SaxEventLoggerExitAfterKey : public SaxEventLogger
{
bool key(const std::string& val) override
bool key(std::string&& val) override
{
events.push_back("key(" + val + ")");
return false;
@ -160,7 +160,7 @@ struct SaxEventLoggerExitAfterStartArray : public SaxEventLogger
{
bool start_array(std::size_t elements) override
{
if (elements == std::size_t(-1))
if (elements == no_limit)
{
events.push_back("start_array()");
}