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Unverified Commit c7a69ae0 by Niels Lohmann
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⚡ started working on parser with provded result reference #418

Internally, the parser now writes its result into a JSON value provided as a reference. To be usable, the public interfaces need to be extended.
parent f513c467
Showing with 53 additions and 47 deletions
src/json.hpp
......@@ -3107,19 +3107,19 @@ class parser
/*!
@brief public parser interface
@param[in] strict whether to expect the last token to be EOF
@return parsed JSON value
@param[in] strict whether to expect the last token to be EOF
@param[in,out] result parsed JSON value
@throw parse_error.101 in case of an unexpected token
@throw parse_error.102 if to_unicode fails or surrogate error
@throw parse_error.103 if to_unicode fails
*/
BasicJsonType parse(const bool strict = true)
void parse(const bool strict, BasicJsonType& result)
{
// read first token
get_token();
BasicJsonType result = parse_internal(true);
parse_internal(true, result);
result.assert_invariant();
if (strict)
......@@ -3128,9 +3128,12 @@ class parser
expect(token_type::end_of_input);
}
// return parser result and replace it with null in case the
// top-level value was discarded by the callback function
return result.is_discarded() ? BasicJsonType() : std::move(result);
// set top-level value to null if it was discarded by the callback
// function
if (result.is_discarded())
{
result = nullptr;
}
}
/*!
......@@ -3164,17 +3167,19 @@ class parser
@throw parse_error.102 if to_unicode fails or surrogate error
@throw parse_error.103 if to_unicode fails
*/
BasicJsonType parse_internal(bool keep)
void parse_internal(bool keep, BasicJsonType& result)
{
auto result = BasicJsonType(value_t::discarded);
// start with a discarded value
if (not result.is_discarded())
{
result.m_type = value_t::discarded;
}
switch (last_token)
{
case token_type::begin_object:
{
if (keep and (not callback or
((keep = callback(depth++, parse_event_t::object_start,
result)) != 0)))
if (keep and (not callback or ((keep = callback(depth++, parse_event_t::object_start, result)))))
{
// explicitly set result to object to cope with {}
result.m_type = value_t::object;
......@@ -3187,15 +3192,15 @@ class parser
// closing } -> we are done
if (last_token == token_type::end_object)
{
if (keep and callback and
not callback(--depth, parse_event_t::object_end, result))
if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
{
result = BasicJsonType(value_t::discarded);
result.m_type = value_t::discarded;
}
return result;
break;
}
// parse values
BasicJsonType value;
while (true)
{
// store key
......@@ -3222,7 +3227,8 @@ class parser
// parse and add value
get_token();
auto value = parse_internal(keep);
value = value_t::discarded;
parse_internal(keep, value);
if (keep and keep_tag and not value.is_discarded())
{
result[key] = std::move(value);
......@@ -3241,20 +3247,16 @@ class parser
break;
}
if (keep and callback and
not callback(--depth, parse_event_t::object_end, result))
if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
{
result = BasicJsonType(value_t::discarded);
result.m_type = value_t::discarded;
}
return result;
break;
}
case token_type::begin_array:
{
if (keep and (not callback or
((keep = callback(depth++, parse_event_t::array_start,
result)) != 0)))
if (keep and (not callback or ((keep = callback(depth++, parse_event_t::array_start, result)))))
{
// explicitly set result to object to cope with []
result.m_type = value_t::array;
......@@ -3267,19 +3269,19 @@ class parser
// closing ] -> we are done
if (last_token == token_type::end_array)
{
if (callback and
not callback(--depth, parse_event_t::array_end, result))
if (callback and not callback(--depth, parse_event_t::array_end, result))
{
result = BasicJsonType(value_t::discarded);
result.m_type = value_t::discarded;
}
return result;
break;
}
// parse values
BasicJsonType value;
while (true)
{
// parse value
auto value = parse_internal(keep);
parse_internal(keep, value);
if (keep and not value.is_discarded())
{
result.push_back(std::move(value));
......@@ -3298,13 +3300,11 @@ class parser
break;
}
if (keep and callback and
not callback(--depth, parse_event_t::array_end, result))
if (keep and callback and not callback(--depth, parse_event_t::array_end, result))
{
result = BasicJsonType(value_t::discarded);
result.m_type = value_t::discarded;
}
return result;
break;
}
case token_type::literal_null:
......@@ -3315,7 +3315,8 @@ class parser
case token_type::value_string:
{
result = BasicJsonType(m_lexer.get_string());
result.m_type = value_t::string;
result.m_value = m_lexer.get_string();
break;
}
......@@ -3359,7 +3360,6 @@ class parser
m_lexer.get_token_string() +
"'"));
}
break;
}
......@@ -3378,12 +3378,10 @@ class parser
}
}
if (keep and callback and
not callback(depth, parse_event_t::value, result))
if (keep and callback and not callback(depth, parse_event_t::value, result))
{
result = BasicJsonType(value_t::discarded);
result.m_type = value_t::discarded;
}
return result;
}
/*!
......@@ -12892,7 +12890,9 @@ class basic_json
static basic_json parse(const CharT s,
const parser_callback_t cb = nullptr)
{
return parser(detail::input_adapter_factory::create(s), cb).parse(true);
basic_json result;
parser(detail::input_adapter_factory::create(s), cb).parse(true, result);
return result;
}
template<typename CharT, typename std::enable_if<
......@@ -12935,7 +12935,9 @@ class basic_json
static basic_json parse(std::istream& i,
const parser_callback_t cb = nullptr)
{
return parser(detail::input_adapter_factory::create(i), cb).parse(true);
basic_json result;
parser(detail::input_adapter_factory::create(i), cb).parse(true, result);
return result;
}
static bool accept(std::istream& i)
......@@ -12949,7 +12951,9 @@ class basic_json
static basic_json parse(std::istream&& i,
const parser_callback_t cb = nullptr)
{
return parser(detail::input_adapter_factory::create(i), cb).parse(true);
basic_json result;
parser(detail::input_adapter_factory::create(i), cb).parse(true, result);
return result;
}
static bool accept(std::istream&& i)
......@@ -13009,7 +13013,9 @@ class basic_json
static basic_json parse(IteratorType first, IteratorType last,
const parser_callback_t cb = nullptr)
{
return parser(detail::input_adapter_factory::create(first, last), cb).parse(true);
basic_json result;
parser(detail::input_adapter_factory::create(first, last), cb).parse(true, result);
return result;
}
template<class IteratorType, typename std::enable_if<
......@@ -13100,7 +13106,7 @@ class basic_json
JSON_DEPRECATED
friend std::istream& operator<<(basic_json& j, std::istream& i)
{
j = parser(detail::input_adapter_factory::create(i)).parse(false);
parser(detail::input_adapter_factory::create(i)).parse(false, j);
return i;
}
......@@ -13131,7 +13137,7 @@ class basic_json
*/
friend std::istream& operator>>(std::istream& i, basic_json& j)
{
j = parser(detail::input_adapter_factory::create(i)).parse(false);
parser(detail::input_adapter_factory::create(i)).parse(false, j);
return i;
}
......
test/src/unit-class_parser.cpp
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