Util: Add JSON parser

2022-06-07 12:46:13 +02:00
parent 0880d98fe0
commit 5188d57d19
2 changed files with 323 additions and 0 deletions
@@ -0,0 +1,277 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstddef> // size_t
+#include <cstdint> // uint32_t
+#include <cstdio>  // printf
+#include <map>
+#include <string> // stod
+
+#include "util/json/array.h"
+#include "util/json/lexer.h"
+#include "util/json/object.h"
+#include "util/json/parser.h"
+
+namespace Json {
+
+Parser::Parser(const std::string& input)
+	: m_input(input)
+{
+}
+
+Parser::~Parser()
+{
+}
+
+// -----------------------------------------
+
+void Parser::parse()
+{
+	Lexer lexer(m_input);
+	lexer.analyze();
+	m_tokens = lexer.tokens();
+
+	printf("---------\n");
+	printf("Parsing:\n");
+
+	Value result;
+
+	Token token;
+	while (m_index < m_tokens.size()) {
+		token = peek();
+
+		switch (token.type) {
+		case Token::Type::Literal:
+			if (token.symbol == "null") {
+				result = Value {};
+			}
+			else if (token.symbol == "true") {
+				result = Value { true };
+			}
+			else if (token.symbol == "false") {
+				result = Value { false };
+			}
+			m_index++;
+			break;
+		case Token::Type::Number:
+			result = Value { std::stod(token.symbol) };
+			m_index++;
+			break;
+		case Token::Type::String:
+			result = Value { token.symbol };
+			m_index++;
+			break;
+		case Token::Type::BracketOpen:
+			result = getArray();
+			break;
+		case Token::Type::BraceOpen:
+			result = getObject();
+			break;
+		case Token::Type::Comma:
+			// Error!
+			// Multiple JSON root elements
+			break;
+		default:
+			// Error!
+			break;
+		}
+
+		break;
+	}
+}
+
+// -----------------------------------------
+
+Token Parser::peek()
+{
+	return m_tokens[m_index];
+}
+
+Token Parser::consume()
+{
+	Token token = peek();
+	m_index++;
+	return token;
+}
+
+bool Parser::consumeSpecific(Token::Type type)
+{
+	if (peek().type != type) {
+		return false;
+	}
+
+	m_index++;
+	return true;
+}
+
+Value Parser::getArray()
+{
+	size_t index = m_index;
+	m_index++;
+
+	Array array;
+
+	Token token;
+	for (;;) {
+		token = consume();
+
+		switch (token.type) {
+		case Token::Type::Literal:
+			printf("Adding literal to array.. v:{%s}, t:{%d}\n", token.symbol.c_str(), (int)token.type);
+			if (token.symbol == "null") {
+				array.emplace(Value {});
+			}
+			else if (token.symbol == "true") {
+				array.emplace(Value { true });
+			}
+			else if (token.symbol == "false") {
+				array.emplace(Value { false });
+			}
+			break;
+		case Token::Type::Number:
+			printf("Adding number to array.. v:{%s}, t:{%d} -> %f\n", token.symbol.c_str(), (int)token.type, std::stod(token.symbol));
+			array.emplace(Value { std::stod(token.symbol) });
+			break;
+		case Token::Type::String:
+			printf("Adding string to array.. v:{%s}, t:{%d}\n", token.symbol.c_str(), (int)token.type);
+			array.emplace(Value { token.symbol });
+			break;
+		case Token::Type::BracketOpen:
+			m_index--;
+			array.emplace(Value { getArray() });
+			break;
+		case Token::Type::BraceOpen:
+			m_index--;
+			array.emplace(Value { getObject() });
+			break;
+		default:
+			// Error!
+			printf("Invalid JSON! array:1\n");
+			break;
+		}
+
+		// Find , or }
+		token = consume();
+		if (token.type == Token::Type::Comma) {
+			continue;
+		}
+		else if (token.type == Token::Type::BracketClose) {
+			break;
+		}
+		else {
+			// Error!
+			printf("Invalid JSON! array:2\n");
+			break;
+		}
+	}
+
+	return Value { array };
+}
+
+Value Parser::getObject()
+{
+	size_t index = m_index;
+	m_index++;
+
+	Object object;
+
+	Token token;
+	std::string key;
+	std::map<std::string, uint32_t> unique;
+	for (;;) {
+		// Find string key
+		token = consume();
+		if (token.type != Token::Type::String) {
+			// Error!
+			printf("Invalid JSON! 1\n");
+			break;
+		}
+
+		// Check if key exists in hashmap
+		key = token.symbol;
+		if (unique.find(key) != unique.end()) {
+			// If exists, unique key fail!
+			// Error!
+			printf("Invalid JSON! 2\n");
+			break;
+		}
+		// Add key to hashmap
+		unique.insert({ key, 0 });
+
+		// Find :
+		if (!consumeSpecific(Token::Type::Colon)) {
+			// Error!
+			printf("Invalid JSON! 3\n");
+			break;
+		}
+
+		// Find string/number/literal value
+		token = consume();
+		if (token.type != Token::Type::String
+		    && token.type != Token::Type::Number
+		    && token.type != Token::Type::Literal
+		    && token.type != Token::Type::BracketOpen
+		    && token.type != Token::Type::BraceOpen) {
+			// Error!
+			printf("Invalid JSON! 4\n");
+			break;
+		}
+
+		// Add member to object
+		switch (token.type) {
+		case Token::Type::Literal:
+			printf("Adding literal to object.. k:{%s}, v:{%s}, t:{%d}\n", key.c_str(), token.symbol.c_str(), (int)token.type);
+			if (token.symbol == "null") {
+				object.emplace(key, Value {});
+			}
+			else if (token.symbol == "true") {
+				object.emplace(key, Value { true });
+			}
+			else if (token.symbol == "false") {
+				object.emplace(key, Value { false });
+			}
+			break;
+		case Token::Type::Number:
+			printf("Adding number to object.. k:{%s}, v:{%s}, t:{%d} -> %f\n", key.c_str(), token.symbol.c_str(), (int)token.type, std::stod(token.symbol));
+			object.emplace(key, Value { std::stod(token.symbol) });
+			break;
+		case Token::Type::String:
+			printf("Adding string to object.. k:{%s}, v:{%s}, t:{%d}\n", key.c_str(), token.symbol.c_str(), (int)token.type);
+			object.emplace(key, Value { token.symbol });
+			break;
+		case Token::Type::BracketOpen:
+			m_index--;
+			object.emplace(key, Value { getArray() });
+			break;
+		case Token::Type::BraceOpen:
+			m_index--;
+			object.emplace(key, Value { getObject() });
+			break;
+		default:
+			// Error!
+			printf("Invalid JSON! 5\n");
+			break;
+		}
+
+		// Find , or }
+		token = consume();
+		if (token.type == Token::Type::Comma) {
+			continue;
+		}
+		else if (token.type == Token::Type::BraceClose) {
+			break;
+		}
+		else {
+			// Error!
+			printf("Invalid JSON! 6\n");
+			break;
+		}
+	}
+
+	return Value { object };
+}
+
+} // namespace Json
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_PARSER_H
+#define JSON_PARSER_H
+
+#include <cstddef> // size_t
+#include <map>
+#include <string>
+#include <type_traits>
+#include <typeinfo>
+#include <vector>
+
+#include "util/json/lexer.h"
+#include "util/json/value.h"
+
+namespace Json {
+
+class Parser {
+public:
+	Parser(const std::string& input);
+	virtual ~Parser();
+
+	void parse();
+
+private:
+	Token peek();
+
+	Token consume();
+	bool consumeSpecific(Token::Type type);
+
+	Value getArray();
+	Value getObject();
+
+	std::string m_input;
+
+	std::vector<Token> m_tokens;
+	size_t m_index { 0 };
+};
+
+} // namespace Json
+
+#endif // JSON_PARSER_H