Util: Add JSON lexical analyzer

src/util/json/lexer.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef JSON_LEXER_H
+#define JSON_LEXER_H
+
+// The JavaScript Object Notation (JSON) Data Interchange Format
+// home/rick/code/cpp/manafiles/ https://www.rfc-editor.org/rfc/pdfrfc/rfc8259.txt.pdf
+
+#include <cstddef> // size_t
+#include <string>
+#include <vector>
+
+namespace Json {
+
+struct Token {
+	enum class Type {
+		None,
+		BraceOpen,    // {
+		BraceClose,   // }
+		BracketOpen,  // [
+		BracketClose, // ]
+		Colon,        // :
+		Comma,        // ,
+		String,       // "foobar"
+		Number,       // 123.456
+		Literal,      // false/null/true (case sensitive)
+	};
+
+	Type type { Type::None };
+	size_t line { 0 };
+	size_t column { 0 };
+	std::string symbol;
+};
+
+// Lexical analyzer
+class Lexer {
+public:
+	Lexer(const std::string& input);
+	virtual ~Lexer();
+
+	void analyze();
+
+	const std::vector<Token>& tokens() const { return m_tokens; }
+
+private:
+	char peek();
+	char peekNext();
+
+	char consume();
+	bool consumeSpecific(char character);
+
+	bool getString();
+	bool getNumber();
+	bool getLiteral();
+
+	std::string m_input;
+	size_t m_index { 0 };
+	size_t m_column { 1 };
+	size_t m_line { 1 };
+
+	std::vector<Token> m_tokens;
+};
+
+} // namespace Json
+
+#endif // JSON_LEXER_H