JSONParser Class Reference

JSON implementation of the IParser interface. More...

#include <JsonParser.h>

Inheritance diagram for JSONParser:

Collaboration diagram for JSONParser:

Public Member Functions
std::shared_ptr< DBNode >	parse (const std::string &input) const override
	Parses a JSON document from an in-memory string.
void	writeToFile (const std::string &filename, const std::shared_ptr< DBNode > &root) const override
	Serializes a DBNode tree to a JSON file.
std::shared_ptr< DBNode >	readFromFile (const std::string &filename) const override
	Reads a JSON file and parses it into a DBNode tree.
std::shared_ptr< DBNode >	parseObject (const std::string &input, size_t &index) const
	Parses a JSON object starting at the given index.
std::string	parseString (const std::string &input, size_t &index) const
	Parses a JSON string literal.
DBNode::Value	parseValue (const std::string &input, size_t &index) const
	Parses any JSON value at the current position.
double	parseNumber (const std::string &input, size_t &index) const
	Parses a JSON number (integer or floating point).
void	skipWhitespace (const std::string &input, size_t &index) const
	Skips whitespace characters in the input string.
std::shared_ptr< DBNode >	parseArray (const std::string &input, size_t &index) const
	Parses a JSON array starting at the current position.
Public Member Functions inherited from IParser
virtual	~IParser ()=default
	Virtual destructor to allow proper cleanup via base pointer.

Detailed Description

JSON implementation of the IParser interface.

JSONParser can:

• parse a JSON string into a DBNode tree,
• serialize a DBNode tree to JSON and write it to a file (via DBNode::printJSONToStream),
• read JSON from a file and convert it back into a DBNode tree.

The parser is intentionally simple and does not support the full JSON standard (e.g. no null literal, no escape sequences in strings).

Definition at line 42 of file JsonParser.h.

Member Function Documentation

parse()

std::shared_ptr< DBNode > JSONParser::parse ( const std::string &  input ) const

overridevirtual

Parses a JSON document from an in-memory string.

The top-level JSON value is expected to be an object ({ ... }).

Parameters

input

JSON text buffer.

Returns

Shared pointer to the root DBNode representing the JSON object.

Exceptions

std::runtime_error

on malformed JSON or conversion errors.

Implements IParser.

Definition at line 3 of file JsonParser.cpp.

parseArray()

std::shared_ptr< DBNode > JSONParser::parseArray	(	const std::string &	input,
		size_t &	index
	)		const

Parses a JSON array starting at the current position.

Expects input[index] to point to '['. Elements are parsed using parseValue() and stored in a DBNode with numeric string keys: 0, 1, 2, ...

On return, index is advanced past the closing ']'.

Parameters

input	JSON string.
index	Reference to the current position; advanced as parsing proceeds.

Returns

Shared pointer to the DBNode representing the array.

Exceptions

std::runtime_error

on invalid syntax.

Definition at line 57 of file JsonParser.cpp.

parseNumber()

double JSONParser::parseNumber	(	const std::string &	input,
		size_t &	index
	)		const

Parses a JSON number (integer or floating point).

Accepts the typical JSON number syntax:

• optional minus sign,
• digits,
• optional decimal part,
• optional exponent (e/E with optional sign).

Parameters

input	JSON string.
index	Reference to the current position; advanced past the end of the numeric token.

Returns

Parsed double value.

Exceptions

std::runtime_error

if the token cannot be converted to double.

Definition at line 74 of file JsonParser.cpp.

parseObject()

std::shared_ptr< DBNode > JSONParser::parseObject	(	const std::string &	input,
		size_t &	index
	)		const

Parses a JSON object starting at the given index.

Expects input[index] to point to a '{', and consumes the entire object, returning a DBNode where each key becomes a child entry.

Example JSON: { "a": 1, "b": true }

becomes a DBNode with:

• key "a" -> 1
• key "b" -> true

Parameters

input	JSON string.
index	Reference to the current position in the string; advanced past the closing '}' on success.

Returns

Shared pointer to the DBNode representing the object.

Exceptions

std::runtime_error

on invalid syntax.

Definition at line 9 of file JsonParser.cpp.

parseString()

std::string JSONParser::parseString	(	const std::string &	input,
		size_t &	index
	)		const

Parses a JSON string literal.

Expects input[index] to point to the opening double quote ("</tt>). Reads until the next unescaped <tt>". Escape sequences are not currently interpreted; characters are copied verbatim.

Parameters

input	JSON string.
index	Reference to the current position; on return, points just after the closing ".

Returns

The extracted string value (without quotes).

Exceptions

std::runtime_error

if the expected quotes are missing.

Definition at line 31 of file JsonParser.cpp.

parseValue()

DBNode::Value JSONParser::parseValue	(	const std::string &	input,
		size_t &	index
	)		const

Parses any JSON value at the current position.

Supported value types:

• object: { ... }
• array: [ ... ]
• string: "..."
• number: integer or floating-point
• boolean: true / false

The result is converted into a DBNode::Value:

• objects and arrays become DBNode subtrees,
• scalars become int/double/bool/string stored in the variant.

Parameters

input	JSON string.
index	Reference to the current position; advanced past the parsed value on success.

Returns

Parsed DBNode::Value.

Exceptions

std::runtime_error

if the value is invalid or unsupported.

Definition at line 43 of file JsonParser.cpp.

readFromFile()

std::shared_ptr< DBNode > JSONParser::readFromFile ( const std::string &  filename ) const

overridevirtual

Reads a JSON file and parses it into a DBNode tree.

The entire file content is loaded into memory and passed to parse().

Parameters

filename

Source file name.

Returns

Shared pointer to the root DBNode representing the JSON document.

Exceptions

std::runtime_error

if the file cannot be opened or parsing fails.

Implements IParser.

Definition at line 113 of file JsonParser.cpp.

skipWhitespace()

void JSONParser::skipWhitespace	(	const std::string &	input,
		size_t &	index
	)		const

Skips whitespace characters in the input string.

Advances index while input[index] is a whitespace character as reported by std::isspace.

Parameters

input	JSON string.
index	Reference to the current position; updated in place.

Definition at line 99 of file JsonParser.cpp.

writeToFile()

void JSONParser::writeToFile ( const std::string &  filename, const std::shared_ptr< DBNode > &  root  ) const

overridevirtual

Serializes a DBNode tree to a JSON file.

Internally uses DBNode::printJSONToStream() to produce a JSON-like representation and writes it to filename.

Parameters

filename	Target file name.
root	Root DBNode to serialize.

Exceptions

std::runtime_error

if the file cannot be opened or a write error occurs.

Implements IParser.

Definition at line 103 of file JsonParser.cpp.

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The documentation for this class was generated from the following files:

• /home/runner/work/Hyperiso/Hyperiso/Hyperiso/Hyperiso/core/src/DataBase/adapters/JsonParser.h
• /home/runner/work/Hyperiso/Hyperiso/Hyperiso/Hyperiso/core/src/DataBase/adapters/JsonParser.cpp