14cd019861
* Rename 'develop' folder to 'include/nlohmann' * Rename 'src' folder to 'single_include/nlohmann' * Use <nlohmann/*> headers in sources and tests * Change amalgamate config file
590 lines
17 KiB
C++
590 lines
17 KiB
C++
#pragma once
|
|
|
|
#include <cassert> // assert
|
|
#include <cmath> // isfinite
|
|
#include <cstdint> // uint8_t
|
|
#include <functional> // function
|
|
#include <string> // string
|
|
#include <utility> // move
|
|
|
|
#include <nlohmann/detail/exceptions.hpp>
|
|
#include <nlohmann/detail/macro_scope.hpp>
|
|
#include <nlohmann/detail/input/input_adapters.hpp>
|
|
#include <nlohmann/detail/input/lexer.hpp>
|
|
#include <nlohmann/detail/value_t.hpp>
|
|
|
|
namespace nlohmann
|
|
{
|
|
namespace detail
|
|
{
|
|
////////////
|
|
// parser //
|
|
////////////
|
|
|
|
/*!
|
|
@brief syntax analysis
|
|
|
|
This class implements a recursive decent parser.
|
|
*/
|
|
template<typename BasicJsonType>
|
|
class parser
|
|
{
|
|
using number_integer_t = typename BasicJsonType::number_integer_t;
|
|
using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
|
|
using number_float_t = typename BasicJsonType::number_float_t;
|
|
using lexer_t = lexer<BasicJsonType>;
|
|
using token_type = typename lexer_t::token_type;
|
|
|
|
public:
|
|
enum class parse_event_t : uint8_t
|
|
{
|
|
/// the parser read `{` and started to process a JSON object
|
|
object_start,
|
|
/// the parser read `}` and finished processing a JSON object
|
|
object_end,
|
|
/// the parser read `[` and started to process a JSON array
|
|
array_start,
|
|
/// the parser read `]` and finished processing a JSON array
|
|
array_end,
|
|
/// the parser read a key of a value in an object
|
|
key,
|
|
/// the parser finished reading a JSON value
|
|
value
|
|
};
|
|
|
|
using parser_callback_t =
|
|
std::function<bool(int depth, parse_event_t event, BasicJsonType& parsed)>;
|
|
|
|
/// a parser reading from an input adapter
|
|
explicit parser(detail::input_adapter_t adapter,
|
|
const parser_callback_t cb = nullptr,
|
|
const bool allow_exceptions_ = true)
|
|
: callback(cb), m_lexer(adapter), allow_exceptions(allow_exceptions_)
|
|
{}
|
|
|
|
/*!
|
|
@brief public parser interface
|
|
|
|
@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
|
|
*/
|
|
void parse(const bool strict, BasicJsonType& result)
|
|
{
|
|
// read first token
|
|
get_token();
|
|
|
|
parse_internal(true, result);
|
|
result.assert_invariant();
|
|
|
|
// in strict mode, input must be completely read
|
|
if (strict)
|
|
{
|
|
get_token();
|
|
expect(token_type::end_of_input);
|
|
}
|
|
|
|
// in case of an error, return discarded value
|
|
if (errored)
|
|
{
|
|
result = value_t::discarded;
|
|
return;
|
|
}
|
|
|
|
// set top-level value to null if it was discarded by the callback
|
|
// function
|
|
if (result.is_discarded())
|
|
{
|
|
result = nullptr;
|
|
}
|
|
}
|
|
|
|
/*!
|
|
@brief public accept interface
|
|
|
|
@param[in] strict whether to expect the last token to be EOF
|
|
@return whether the input is a proper JSON text
|
|
*/
|
|
bool accept(const bool strict = true)
|
|
{
|
|
// read first token
|
|
get_token();
|
|
|
|
if (not accept_internal())
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// strict => last token must be EOF
|
|
return not strict or (get_token() == token_type::end_of_input);
|
|
}
|
|
|
|
private:
|
|
/*!
|
|
@brief the actual parser
|
|
@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
|
|
*/
|
|
void parse_internal(bool keep, BasicJsonType& result)
|
|
{
|
|
// never parse after a parse error was detected
|
|
assert(not errored);
|
|
|
|
// start with a discarded value
|
|
if (not result.is_discarded())
|
|
{
|
|
result.m_value.destroy(result.m_type);
|
|
result.m_type = value_t::discarded;
|
|
}
|
|
|
|
switch (last_token)
|
|
{
|
|
case token_type::begin_object:
|
|
{
|
|
if (keep)
|
|
{
|
|
if (callback)
|
|
{
|
|
keep = callback(depth++, parse_event_t::object_start, result);
|
|
}
|
|
|
|
if (not callback or keep)
|
|
{
|
|
// explicitly set result to object to cope with {}
|
|
result.m_type = value_t::object;
|
|
result.m_value = value_t::object;
|
|
}
|
|
}
|
|
|
|
// read next token
|
|
get_token();
|
|
|
|
// 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))
|
|
{
|
|
result.m_value.destroy(result.m_type);
|
|
result.m_type = value_t::discarded;
|
|
}
|
|
break;
|
|
}
|
|
|
|
// parse values
|
|
std::string key;
|
|
BasicJsonType value;
|
|
while (true)
|
|
{
|
|
// store key
|
|
if (not expect(token_type::value_string))
|
|
{
|
|
return;
|
|
}
|
|
key = m_lexer.move_string();
|
|
|
|
bool keep_tag = false;
|
|
if (keep)
|
|
{
|
|
if (callback)
|
|
{
|
|
BasicJsonType k(key);
|
|
keep_tag = callback(depth, parse_event_t::key, k);
|
|
}
|
|
else
|
|
{
|
|
keep_tag = true;
|
|
}
|
|
}
|
|
|
|
// parse separator (:)
|
|
get_token();
|
|
if (not expect(token_type::name_separator))
|
|
{
|
|
return;
|
|
}
|
|
|
|
// parse and add value
|
|
get_token();
|
|
value.m_value.destroy(value.m_type);
|
|
value.m_type = value_t::discarded;
|
|
parse_internal(keep, value);
|
|
|
|
if (JSON_UNLIKELY(errored))
|
|
{
|
|
return;
|
|
}
|
|
|
|
if (keep and keep_tag and not value.is_discarded())
|
|
{
|
|
result.m_value.object->emplace(std::move(key), std::move(value));
|
|
}
|
|
|
|
// comma -> next value
|
|
get_token();
|
|
if (last_token == token_type::value_separator)
|
|
{
|
|
get_token();
|
|
continue;
|
|
}
|
|
|
|
// closing }
|
|
if (not expect(token_type::end_object))
|
|
{
|
|
return;
|
|
}
|
|
break;
|
|
}
|
|
|
|
if (keep and callback and not callback(--depth, parse_event_t::object_end, result))
|
|
{
|
|
result.m_value.destroy(result.m_type);
|
|
result.m_type = value_t::discarded;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case token_type::begin_array:
|
|
{
|
|
if (keep)
|
|
{
|
|
if (callback)
|
|
{
|
|
keep = callback(depth++, parse_event_t::array_start, result);
|
|
}
|
|
|
|
if (not callback or keep)
|
|
{
|
|
// explicitly set result to array to cope with []
|
|
result.m_type = value_t::array;
|
|
result.m_value = value_t::array;
|
|
}
|
|
}
|
|
|
|
// read next token
|
|
get_token();
|
|
|
|
// closing ] -> we are done
|
|
if (last_token == token_type::end_array)
|
|
{
|
|
if (callback and not callback(--depth, parse_event_t::array_end, result))
|
|
{
|
|
result.m_value.destroy(result.m_type);
|
|
result.m_type = value_t::discarded;
|
|
}
|
|
break;
|
|
}
|
|
|
|
// parse values
|
|
BasicJsonType value;
|
|
while (true)
|
|
{
|
|
// parse value
|
|
value.m_value.destroy(value.m_type);
|
|
value.m_type = value_t::discarded;
|
|
parse_internal(keep, value);
|
|
|
|
if (JSON_UNLIKELY(errored))
|
|
{
|
|
return;
|
|
}
|
|
|
|
if (keep and not value.is_discarded())
|
|
{
|
|
result.m_value.array->push_back(std::move(value));
|
|
}
|
|
|
|
// comma -> next value
|
|
get_token();
|
|
if (last_token == token_type::value_separator)
|
|
{
|
|
get_token();
|
|
continue;
|
|
}
|
|
|
|
// closing ]
|
|
if (not expect(token_type::end_array))
|
|
{
|
|
return;
|
|
}
|
|
break;
|
|
}
|
|
|
|
if (keep and callback and not callback(--depth, parse_event_t::array_end, result))
|
|
{
|
|
result.m_value.destroy(result.m_type);
|
|
result.m_type = value_t::discarded;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case token_type::literal_null:
|
|
{
|
|
result.m_type = value_t::null;
|
|
break;
|
|
}
|
|
|
|
case token_type::value_string:
|
|
{
|
|
result.m_type = value_t::string;
|
|
result.m_value = m_lexer.move_string();
|
|
break;
|
|
}
|
|
|
|
case token_type::literal_true:
|
|
{
|
|
result.m_type = value_t::boolean;
|
|
result.m_value = true;
|
|
break;
|
|
}
|
|
|
|
case token_type::literal_false:
|
|
{
|
|
result.m_type = value_t::boolean;
|
|
result.m_value = false;
|
|
break;
|
|
}
|
|
|
|
case token_type::value_unsigned:
|
|
{
|
|
result.m_type = value_t::number_unsigned;
|
|
result.m_value = m_lexer.get_number_unsigned();
|
|
break;
|
|
}
|
|
|
|
case token_type::value_integer:
|
|
{
|
|
result.m_type = value_t::number_integer;
|
|
result.m_value = m_lexer.get_number_integer();
|
|
break;
|
|
}
|
|
|
|
case token_type::value_float:
|
|
{
|
|
result.m_type = value_t::number_float;
|
|
result.m_value = m_lexer.get_number_float();
|
|
|
|
// throw in case of infinity or NAN
|
|
if (JSON_UNLIKELY(not std::isfinite(result.m_value.number_float)))
|
|
{
|
|
if (allow_exceptions)
|
|
{
|
|
JSON_THROW(out_of_range::create(406, "number overflow parsing '" +
|
|
m_lexer.get_token_string() + "'"));
|
|
}
|
|
expect(token_type::uninitialized);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case token_type::parse_error:
|
|
{
|
|
// using "uninitialized" to avoid "expected" message
|
|
if (not expect(token_type::uninitialized))
|
|
{
|
|
return;
|
|
}
|
|
break; // LCOV_EXCL_LINE
|
|
}
|
|
|
|
default:
|
|
{
|
|
// the last token was unexpected; we expected a value
|
|
if (not expect(token_type::literal_or_value))
|
|
{
|
|
return;
|
|
}
|
|
break; // LCOV_EXCL_LINE
|
|
}
|
|
}
|
|
|
|
if (keep and callback and not callback(depth, parse_event_t::value, result))
|
|
{
|
|
result.m_type = value_t::discarded;
|
|
}
|
|
}
|
|
|
|
/*!
|
|
@brief the actual acceptor
|
|
|
|
@invariant 1. The last token is not yet processed. Therefore, the caller
|
|
of this function must make sure a token has been read.
|
|
2. When this function returns, the last token is processed.
|
|
That is, the last read character was already considered.
|
|
|
|
This invariant makes sure that no token needs to be "unput".
|
|
*/
|
|
bool accept_internal()
|
|
{
|
|
switch (last_token)
|
|
{
|
|
case token_type::begin_object:
|
|
{
|
|
// read next token
|
|
get_token();
|
|
|
|
// closing } -> we are done
|
|
if (last_token == token_type::end_object)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
// parse values
|
|
while (true)
|
|
{
|
|
// parse key
|
|
if (last_token != token_type::value_string)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// parse separator (:)
|
|
get_token();
|
|
if (last_token != token_type::name_separator)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// parse value
|
|
get_token();
|
|
if (not accept_internal())
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// comma -> next value
|
|
get_token();
|
|
if (last_token == token_type::value_separator)
|
|
{
|
|
get_token();
|
|
continue;
|
|
}
|
|
|
|
// closing }
|
|
return (last_token == token_type::end_object);
|
|
}
|
|
}
|
|
|
|
case token_type::begin_array:
|
|
{
|
|
// read next token
|
|
get_token();
|
|
|
|
// closing ] -> we are done
|
|
if (last_token == token_type::end_array)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
// parse values
|
|
while (true)
|
|
{
|
|
// parse value
|
|
if (not accept_internal())
|
|
{
|
|
return false;
|
|
}
|
|
|
|
// comma -> next value
|
|
get_token();
|
|
if (last_token == token_type::value_separator)
|
|
{
|
|
get_token();
|
|
continue;
|
|
}
|
|
|
|
// closing ]
|
|
return (last_token == token_type::end_array);
|
|
}
|
|
}
|
|
|
|
case token_type::value_float:
|
|
{
|
|
// reject infinity or NAN
|
|
return std::isfinite(m_lexer.get_number_float());
|
|
}
|
|
|
|
case token_type::literal_false:
|
|
case token_type::literal_null:
|
|
case token_type::literal_true:
|
|
case token_type::value_integer:
|
|
case token_type::value_string:
|
|
case token_type::value_unsigned:
|
|
return true;
|
|
|
|
default: // the last token was unexpected
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/// get next token from lexer
|
|
token_type get_token()
|
|
{
|
|
return (last_token = m_lexer.scan());
|
|
}
|
|
|
|
/*!
|
|
@throw parse_error.101 if expected token did not occur
|
|
*/
|
|
bool expect(token_type t)
|
|
{
|
|
if (JSON_UNLIKELY(t != last_token))
|
|
{
|
|
errored = true;
|
|
expected = t;
|
|
if (allow_exceptions)
|
|
{
|
|
throw_exception();
|
|
}
|
|
else
|
|
{
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
[[noreturn]] void throw_exception() const
|
|
{
|
|
std::string error_msg = "syntax error - ";
|
|
if (last_token == token_type::parse_error)
|
|
{
|
|
error_msg += std::string(m_lexer.get_error_message()) + "; last read: '" +
|
|
m_lexer.get_token_string() + "'";
|
|
}
|
|
else
|
|
{
|
|
error_msg += "unexpected " + std::string(lexer_t::token_type_name(last_token));
|
|
}
|
|
|
|
if (expected != token_type::uninitialized)
|
|
{
|
|
error_msg += "; expected " + std::string(lexer_t::token_type_name(expected));
|
|
}
|
|
|
|
JSON_THROW(parse_error::create(101, m_lexer.get_position(), error_msg));
|
|
}
|
|
|
|
private:
|
|
/// current level of recursion
|
|
int depth = 0;
|
|
/// callback function
|
|
const parser_callback_t callback = nullptr;
|
|
/// the type of the last read token
|
|
token_type last_token = token_type::uninitialized;
|
|
/// the lexer
|
|
lexer_t m_lexer;
|
|
/// whether a syntax error occurred
|
|
bool errored = false;
|
|
/// possible reason for the syntax error
|
|
token_type expected = token_type::uninitialized;
|
|
/// whether to throw exceptions in case of errors
|
|
const bool allow_exceptions = true;
|
|
};
|
|
}
|
|
}
|