Util+Test: Add code snapshot from the riyyi/manafiles project

Add all utility and unit test code from the riyyi/manafiles project at
commit 6f0e3d6063ab75ad81899135689569e440ddb813, link at:
github.com/riyyi/manafiles/tree/6f0e3d6063ab75ad81899135689569e440ddb813

src/util/argparser.cpp

@@ -0,0 +1,568 @@
+/*
+ * Copyright (C) 2021-2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // find_if
+#include <cstddef>   // size_t
+#include <cstdint>   // uint8_t
+#include <cstdio>    // printf
+#include <cstring>   // strcmp
+#include <limits>    // numeric_limits
+#include <string>    // stod, stoi, stoul
+#include <string_view>
+#include <vector>
+
+#include "util/argparser.h"
+
+namespace Util {
+
+ArgParser::ArgParser()
+{
+}
+
+ArgParser::~ArgParser()
+{
+}
+
+void ArgParser::printError(char parameter, Error error)
+{
+	char tmp[] { parameter, '\0' };
+	printError(tmp, error, false);
+}
+
+void ArgParser::printError(const char* parameter, Error error, bool longName)
+{
+	if (!m_errorReporting) {
+		return;
+	}
+
+	if (error == Error::OptionInvalid) {
+		printf("%s: invalid option -- '%s'\n", m_name, parameter);
+	}
+	else if (error == Error::OptionUnrecognized) {
+		printf("%s: unrecognized option -- '%s'\n", m_name, parameter);
+	}
+	else if (error == Error::OptionDoesntAllowArgument) {
+		printf("%s: option '--%s' doesn't allow an argument\n", m_name, parameter);
+	}
+	else if (error == Error::OptionRequiresArgument) {
+		if (longName) {
+			printf("%s: option '--%s' requires an argument\n", m_name, parameter);
+		}
+		else {
+			printf("%s: option requires an argument -- '%s'\n", m_name, parameter);
+		}
+	}
+	else if (error == Error::OptionInvalidArgumentType) {
+		if (longName) {
+			printf("%s: option '--%s' invalid type\n", m_name, parameter);
+		}
+		else {
+			printf("%s: option invalid type -- '%s'\n", m_name, parameter);
+		}
+	}
+	else if (error == Error::ArgumentExtraOperand) {
+		printf("%s: extra operand '%s'\n", m_name, parameter);
+	}
+	else if (error == Error::ArgumentRequired) {
+		printf("%s: missing required argument '%s'\n", m_name, parameter);
+	}
+	else if (error == Error::ArgumentInvalidType) {
+		printf("%s: invalid argument type '%s'\n", m_name, parameter);
+	}
+
+	// TODO: Print command usage, if it's enabled.
+}
+
+// Required: directly after || separated by space
+// Optional: directly after
+bool ArgParser::parseShortOption(std::string_view option, std::string_view next)
+{
+	bool result = true;
+
+#ifndef NDEBUG
+	printf("Parsing short option: '%s'\n", option.data());
+#endif
+
+	char c;
+	std::string_view value;
+	for (size_t i = 0; i < option.size(); ++i) {
+		c = option.at(i);
+
+#ifndef NDEBUG
+		printf("short '%c'\n", c);
+#endif
+
+		auto foundOption = std::find_if(m_options.begin(), m_options.end(), [&c](Option& it) -> bool {
+			return it.shortName == c;
+		});
+
+		// Option does not exist
+		if (foundOption == m_options.cend()) {
+			printError(c, Error::OptionInvalid);
+
+			if (m_exitOnFirstError) {
+				return false;
+			}
+		}
+		else if (foundOption->requiresArgument == Required::No) {
+			// FIXME: Figure out why providing a nullptr breaks the lambda here.
+			result = foundOption->acceptValue("");
+		}
+		else if (foundOption->requiresArgument == Required::Yes) {
+			value = option.substr(i + 1);
+			if (value.empty() && next.empty()) {
+				foundOption->error = Error::OptionRequiresArgument;
+				printError(c, Error::OptionRequiresArgument);
+				result = false;
+			}
+			else if (!value.empty()) {
+				result = foundOption->acceptValue(value.data());
+				if (!result) {
+					printError(c, Error::OptionInvalidArgumentType);
+				}
+			}
+			else if (next[0] == '-') {
+				foundOption->error = Error::OptionRequiresArgument;
+				printError(c, Error::OptionRequiresArgument);
+				result = false;
+			}
+			else {
+				result = foundOption->acceptValue(next.data());
+				m_optionIndex++;
+				if (!result) {
+					printError(c, Error::OptionInvalidArgumentType);
+				}
+			}
+
+			break;
+		}
+		else if (foundOption->requiresArgument == Required::Optional) {
+			value = option.substr(i + 1);
+			if (!value.empty()) {
+				result = foundOption->acceptValue(value.data());
+				if (!result) {
+					printError(c, Error::OptionInvalidArgumentType);
+				}
+				break;
+			}
+		}
+	}
+
+	return result;
+}
+
+// Required: directly after, separated by '=' || separated by space
+// Optional: directly after, separated by '='
+bool ArgParser::parseLongOption(std::string_view option, std::string_view next)
+{
+	std::string name = std::string(option.substr(0, option.find_first_of('=')));
+	std::string_view value = option.substr(option.find_first_of('=') + 1);
+
+	auto foundOption = std::find_if(m_options.begin(), m_options.end(), [&name](Option& it) -> bool {
+		return it.longName && it.longName == name;
+	});
+
+	if (foundOption == m_options.cend()) {
+		printError(name.data(), Error::OptionUnrecognized);
+		return false;
+	}
+
+	enum class ArgumentProvided : uint8_t {
+		No,
+		DirectlyAfter,
+		Seperated,
+	};
+
+	auto argument = ArgumentProvided::No;
+	if (name != value || option.find('=') != std::string_view::npos) {
+		argument = ArgumentProvided::DirectlyAfter;
+	}
+	else if (!next.empty() && next[0] != '-') {
+		argument = ArgumentProvided::Seperated;
+		value = next;
+	}
+
+	bool result = true;
+
+	if (foundOption->requiresArgument == Required::No) {
+		if (argument == ArgumentProvided::DirectlyAfter) {
+			foundOption->error = Error::OptionDoesntAllowArgument;
+			printError(name.data(), Error::OptionDoesntAllowArgument);
+			return false;
+		}
+
+		result = foundOption->acceptValue("");
+	}
+	else if (foundOption->requiresArgument == Required::Yes) {
+		if (argument == ArgumentProvided::No) {
+			foundOption->error = Error::OptionRequiresArgument;
+			printError(name.data(), Error::OptionRequiresArgument);
+			return false;
+		}
+
+		result = foundOption->acceptValue(value.data());
+		if (!result) {
+			printError(name.data(), Error::OptionInvalidArgumentType);
+		}
+
+		if (argument == ArgumentProvided::Seperated) {
+			m_optionIndex++;
+		}
+	}
+	else if (foundOption->requiresArgument == Required::Optional) {
+		if (argument == ArgumentProvided::DirectlyAfter) {
+			result = foundOption->acceptValue(value.data());
+			if (!result) {
+				printError(name.data(), Error::OptionInvalidArgumentType);
+			}
+		}
+	}
+
+	return result;
+}
+
+bool ArgParser::parseArgument(std::string_view argument)
+{
+	bool result = true;
+
+	for (;;) {
+		// Run out of argument handlers
+		if (m_argumentIndex >= m_arguments.size()) {
+			printError(argument.data(), Error::ArgumentExtraOperand);
+			return false;
+		}
+
+		Argument& currentArgument = m_arguments.at(m_argumentIndex);
+		result = currentArgument.acceptValue(argument.data());
+
+		if (result) {
+			currentArgument.addedValues++;
+			if (currentArgument.addedValues >= currentArgument.maxValues) {
+				m_argumentIndex++;
+			}
+		}
+		else if (currentArgument.minValues == 0) {
+			m_argumentIndex++;
+			continue;
+		}
+		else {
+			printError(argument.data(), Error::ArgumentInvalidType);
+		}
+
+		break;
+	}
+
+	return result;
+}
+
+bool ArgParser::parse(int argc, const char* argv[])
+{
+	bool result = true;
+
+	// Set looping indices
+	m_optionIndex = 1;
+	m_argumentIndex = 0;
+
+	// By default parse all '-' prefixed parameters as options
+	m_nonOptionMode = false;
+
+	// Get program name
+	m_name = argv[0] + std::string_view(argv[0]).find_last_of('/') + 1;
+
+	std::string_view argument;
+	std::string_view next;
+	for (; m_optionIndex < (size_t)argc; ++m_optionIndex) {
+
+#ifndef NDEBUG
+		printf("argv[%zu]: %s\n", m_optionIndex, argv[m_optionIndex]);
+#endif
+
+		// Get the current and next parameter
+		argument = argv[m_optionIndex];
+		if (m_optionIndex + 1 < (size_t)argc && argv[m_optionIndex + 1][0] != '-') {
+			next = argv[m_optionIndex + 1];
+		}
+		else {
+			next = {};
+		}
+
+		// Stop parsing '-' prefixed parameters as options afer '--'
+		if (argument.compare("--") == 0) {
+			m_nonOptionMode = true;
+			continue;
+		}
+
+		// Long Option
+		if (!m_nonOptionMode && argument[0] == '-' && argument[1] == '-') {
+			argument = argument.substr(argument.find_first_not_of('-'));
+			if (!parseLongOption(argument, next)) {
+				result = false;
+			}
+		}
+		// Short Option
+		else if (!m_nonOptionMode && argument[0] == '-') {
+			argument = argument.substr(argument.find_first_not_of('-'));
+			if (!parseShortOption(argument, next)) {
+				result = false;
+			}
+		}
+		// Argument
+		else {
+			if (m_stopParsingOnFirstNonOption) {
+				m_nonOptionMode = true;
+			}
+			if (!parseArgument(argument)) {
+				result = false;
+			}
+		}
+
+		if (m_exitOnFirstError && !result) {
+			break;
+		}
+	}
+
+	// Check any leftover arguments for required
+	for (; m_argumentIndex < m_arguments.size(); ++m_argumentIndex) {
+		Argument& currentArgument = m_arguments.at(m_argumentIndex);
+		if (currentArgument.minValues > currentArgument.addedValues) {
+			result = false;
+			printError(currentArgument.name ? currentArgument.name : "", Error::ArgumentRequired);
+		}
+	}
+
+	if (result) {
+		return true;
+	}
+
+	for (auto& option : m_options) {
+		if (option.longName && strcmp(option.longName, "help") == 0) {
+			printf("Try '%s --help' for more information.\n", m_name);
+			break;
+		}
+		if (option.shortName == 'h') {
+			printf("Try '%s -h' for more information.\n", m_name);
+			break;
+		}
+	}
+
+	return false;
+}
+
+// -----------------------------------------
+
+void ArgParser::addOption(Option&& option)
+{
+	m_options.push_back(option);
+}
+
+void ArgParser::addOption(bool& value, char shortName, const char* longName, const char* usageString, const char* manString)
+{
+	addOption({ shortName, longName, nullptr, usageString, manString, Required::No, getAcceptFunction(value) });
+}
+
+void ArgParser::addOption(const char*& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName, Required requiresArgument)
+{
+	addOption({ shortName, longName, argumentName, usageString, manString, requiresArgument, getAcceptFunction(value) });
+}
+
+void ArgParser::addOption(std::string& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName, Required requiresArgument)
+{
+	addOption({ shortName, longName, argumentName, usageString, manString, requiresArgument, getAcceptFunction(value) });
+}
+
+void ArgParser::addOption(std::string_view& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName, Required requiresArgument)
+{
+	addOption({ shortName, longName, argumentName, usageString, manString, requiresArgument, getAcceptFunction(value) });
+}
+
+void ArgParser::addOption(int& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName, Required requiresArgument)
+{
+	addOption({ shortName, longName, argumentName, usageString, manString, requiresArgument, getAcceptFunction(value) });
+}
+
+void ArgParser::addOption(unsigned int& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName, Required requiresArgument)
+{
+	addOption({ shortName, longName, argumentName, usageString, manString, requiresArgument, getAcceptFunction(value) });
+}
+
+void ArgParser::addOption(double& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName, Required requiresArgument)
+{
+	addOption({ shortName, longName, argumentName, usageString, manString, requiresArgument, getAcceptFunction(value) });
+}
+
+void ArgParser::addOption(std::vector<std::string>& values, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName, Required requiresArgument)
+{
+	addOption({ shortName, longName, argumentName, usageString, manString, requiresArgument, getAcceptFunction(values) });
+}
+
+// -----------------------------------------
+
+void ArgParser::addArgument(Argument&& argument)
+{
+	m_arguments.push_back(argument);
+}
+
+void ArgParser::addArgument(bool& value, const char* name, const char* usageString, const char* manString, Required required)
+{
+	size_t minValues = required == Required::Yes ? 1 : 0;
+	addArgument({ name, usageString, manString, minValues, 1, 0, getAcceptFunction(value) });
+}
+
+void ArgParser::addArgument(const char*& value, const char* name, const char* usageString, const char* manString, Required required)
+{
+	size_t minValues = required == Required::Yes ? 1 : 0;
+	addArgument({ name, usageString, manString, minValues, 1, 0, getAcceptFunction(value) });
+}
+
+void ArgParser::addArgument(std::string& value, const char* name, const char* usageString, const char* manString, Required required)
+{
+	size_t minValues = required == Required::Yes ? 1 : 0;
+	addArgument({ name, usageString, manString, minValues, 1, 0, getAcceptFunction(value) });
+}
+
+void ArgParser::addArgument(std::string_view& value, const char* name, const char* usageString, const char* manString, Required required)
+{
+	size_t minValues = required == Required::Yes ? 1 : 0;
+	addArgument({ name, usageString, manString, minValues, 1, 0, getAcceptFunction(value) });
+}
+
+void ArgParser::addArgument(int& value, const char* name, const char* usageString, const char* manString, Required required)
+{
+	size_t minValues = required == Required::Yes ? 1 : 0;
+	addArgument({ name, usageString, manString, minValues, 1, 0, getAcceptFunction(value) });
+}
+
+void ArgParser::addArgument(unsigned int& value, const char* name, const char* usageString, const char* manString, Required required)
+{
+	size_t minValues = required == Required::Yes ? 1 : 0;
+	addArgument({ name, usageString, manString, minValues, 1, 0, getAcceptFunction(value) });
+}
+
+void ArgParser::addArgument(double& value, const char* name, const char* usageString, const char* manString, Required required)
+{
+	size_t minValues = required == Required::Yes ? 1 : 0;
+	addArgument({ name, usageString, manString, minValues, 1, 0, getAcceptFunction(value) });
+}
+
+void ArgParser::addArgument(std::vector<std::string>& values, const char* name, const char* usageString, const char* manString, Required required)
+{
+	size_t minValues = required == Required::Yes ? 1 : 0;
+	addArgument({ name, usageString, manString, minValues, values.max_size(), 0, getAcceptFunction(values) });
+}
+
+// -----------------------------------------
+
+AcceptFunction ArgParser::getAcceptFunction(bool& value)
+{
+	return [&value](const char*) -> bool {
+		value = true;
+		return true;
+	};
+}
+
+AcceptFunction ArgParser::getAcceptFunction(const char*& value)
+{
+	return [&value](const char* input) -> bool {
+		value = input;
+		return true;
+	};
+}
+
+AcceptFunction ArgParser::getAcceptFunction(std::string& value)
+{
+	return [&value](const char* input) -> bool {
+		value = input;
+		return true;
+	};
+}
+
+AcceptFunction ArgParser::getAcceptFunction(std::string_view& value)
+{
+	return [&value](const char* input) -> bool {
+		value = input;
+		return true;
+	};
+}
+
+AcceptFunction ArgParser::getAcceptFunction(int& value)
+{
+	return [&value](const char* input) -> bool {
+		const char* validate = input;
+		for (; *validate != '\0'; ++validate) {
+			// - [0-9]
+			if (*validate != 45 && (*validate < 48 || *validate > 57)) {
+				return false;
+			}
+		}
+
+		try {
+			value = std::stoi(input);
+			return true;
+		}
+		catch (...) {
+			return false;
+		}
+	};
+}
+
+AcceptFunction ArgParser::getAcceptFunction(unsigned int& value)
+{
+	return [&value](const char* input) -> bool {
+		const char* validate = input;
+		for (; *validate != '\0'; ++validate) {
+			// [0-9]
+			if (*validate < 48 || *validate > 57) {
+				return false;
+			}
+		}
+
+		unsigned long convert = 0;
+		try {
+			convert = std::stoul(input);
+		}
+		catch (...) {
+			return false;
+		}
+
+		if (convert <= std::numeric_limits<unsigned int>::max()) {
+			value = static_cast<unsigned int>(convert);
+			return true;
+		}
+
+		return false;
+	};
+}
+
+AcceptFunction ArgParser::getAcceptFunction(double& value)
+{
+	return [&value](const char* input) -> bool {
+		const char* validate = input;
+		for (; *validate != '\0'; ++validate) {
+			// . [0-9]
+			if (*validate != 46 && (*validate < 48 || *validate > 57)) {
+				return false;
+			}
+		}
+
+		try {
+			value = std::stod(input);
+			return true;
+		}
+		catch (...) {
+			return false;
+		}
+	};
+}
+
+AcceptFunction ArgParser::getAcceptFunction(std::vector<std::string>& value)
+{
+	return [&value](const char* input) -> bool {
+		value.push_back(input);
+		return true;
+	};
+}
+
+} // namespace Util

src/util/argparser.h

@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef>    // size_t
+#include <cstdint>    // uint8_t
+#include <functional> // function
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace Util {
+
+using AcceptFunction = std::function<bool(const char*)>;
+
+class ArgParser final {
+public:
+	ArgParser();
+	virtual ~ArgParser();
+
+	enum class Required : uint8_t {
+		No,
+		Yes,
+		Optional,
+	};
+
+	enum class Error : uint8_t {
+		None,
+		OptionInvalid,      // For short options
+		OptionUnrecognized, // For long options
+		OptionDoesntAllowArgument,
+		OptionRequiresArgument,
+		OptionInvalidArgumentType,
+		ArgumentExtraOperand,
+		ArgumentRequired,
+		ArgumentInvalidType,
+	};
+
+	struct Option {
+		char shortName { 0 };
+		const char* longName { nullptr };
+		const char* argumentName { nullptr };
+		const char* usageString { nullptr };
+		const char* manString { nullptr };
+		Required requiresArgument;
+		AcceptFunction acceptValue;
+
+		Error error = Error::None;
+	};
+
+	struct Argument {
+		const char* name { nullptr };
+		const char* usageString { nullptr };
+		const char* manString { nullptr };
+		size_t minValues { 0 };
+		size_t maxValues { 1 };
+		size_t addedValues { 0 };
+		AcceptFunction acceptValue;
+	};
+
+	bool parse(int argc, const char* argv[]);
+
+	void addOption(Option&& option);
+	void addOption(bool& value, char shortName, const char* longName, const char* usageString, const char* manString);
+	void addOption(const char*& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName = "", Required requiresArgument = Required::No);
+	void addOption(std::string& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName = "", Required requiresArgument = Required::No);
+	void addOption(std::string_view& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName = "", Required requiresArgument = Required::No);
+	void addOption(int& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName = "", Required requiresArgument = Required::No);
+	void addOption(unsigned int& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName = "", Required requiresArgument = Required::No);
+	void addOption(double& value, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName = "", Required requiresArgument = Required::No);
+	void addOption(std::vector<std::string>& values, char shortName, const char* longName, const char* usageString, const char* manString, const char* argumentName = "", Required requiresArgument = Required::No);
+
+	void addArgument(Argument&& argument);
+	void addArgument(bool& value, const char* name, const char* usageString, const char* manString, Required required = Required::No);
+	void addArgument(const char*& value, const char* name, const char* usageString, const char* manString, Required required = Required::No);
+	void addArgument(std::string& value, const char* name, const char* usageString, const char* manString, Required required = Required::No);
+	void addArgument(std::string_view& value, const char* name, const char* usageString, const char* manString, Required required = Required::No);
+	void addArgument(int& value, const char* name, const char* usageString, const char* manString, Required required = Required::No);
+	void addArgument(unsigned int& value, const char* name, const char* usageString, const char* manString, Required required = Required::No);
+	void addArgument(double& value, const char* name, const char* usageString, const char* manString, Required required = Required::No);
+	void addArgument(std::vector<std::string>& values, const char* name, const char* usageString, const char* manString, Required required = Required::No);
+
+	void setErrorReporting(bool state) { m_errorReporting = state; }
+	void setExitOnFirstError(bool state) { m_exitOnFirstError = state; }
+	void setStopParsingOnFirstNonOption(bool state) { m_stopParsingOnFirstNonOption = state; }
+
+private:
+	void printError(char parameter, Error error);
+	void printError(const char* parameter, Error error, bool longName = true);
+	bool parseShortOption(std::string_view option, std::string_view next);
+	bool parseLongOption(std::string_view option, std::string_view next);
+	bool parseArgument(std::string_view argument);
+
+	AcceptFunction getAcceptFunction(bool& value);
+	AcceptFunction getAcceptFunction(const char*& value);
+	AcceptFunction getAcceptFunction(std::string& value);
+	AcceptFunction getAcceptFunction(std::string_view& value);
+	AcceptFunction getAcceptFunction(int& value);
+	AcceptFunction getAcceptFunction(unsigned int& value);
+	AcceptFunction getAcceptFunction(double& value);
+	AcceptFunction getAcceptFunction(std::vector<std::string>& value);
+
+	bool m_errorReporting { true };
+	bool m_exitOnFirstError { true };
+	bool m_stopParsingOnFirstNonOption { false };
+
+	size_t m_optionIndex { 1 };
+	size_t m_argumentIndex { 0 };
+	bool m_nonOptionMode { false };
+
+	const char* m_name { nullptr };
+	std::vector<Option> m_options;
+	std::vector<Argument> m_arguments;
+};
+
+} // namespace Util

src/util/file.cpp

@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2021-2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdint> // int32_t
+#include <filesystem>
+#include <fstream> // ifstream, ios, ofstream
+#include <memory>  // make_unique
+#include <string>
+
+#include "util/file.h"
+#include "util/meta/assert.h"
+
+namespace Util {
+
+File::File(const std::string& path)
+	: m_path(path)
+{
+	// Create input stream object and open file
+	std::ifstream file(path, std::ios::in);
+	VERIFY(file.is_open(), "failed to open file: '{}'", path);
+
+	// Get length of the file
+	file.seekg(0, std::ios::end);
+	int32_t size = file.tellg();
+	file.seekg(0, std::ios::beg);
+	VERIFY(size != -1, "failed to read file length: '{}', path");
+
+	// Allocate memory filled with zeros
+	auto buffer = std::make_unique<char[]>(size);
+
+	// Fill buffer with file contents
+	file.read(buffer.get(), size);
+	file.close();
+
+	m_data = std::string(buffer.get(), size);
+}
+
+File::~File()
+{
+}
+
+// -----------------------------------------
+
+File File::create(const std::string& path)
+{
+	if (!std::filesystem::exists(path)) {
+		std::ofstream { path };
+	}
+
+	return Util::File(path);
+}
+
+// -----------------------------------------
+
+void File::clear()
+{
+	m_data.clear();
+}
+
+File& File::append(const std::string& data)
+{
+	m_data.append(data);
+
+	return *this;
+}
+
+File& File::replace(size_t index, size_t length, const std::string& data)
+{
+	m_data.replace(index, length, data);
+
+	return *this;
+}
+
+File& File::flush()
+{
+	// Create output stream object and open file
+	std::ofstream file(m_path, std::ios::out | std::ios::trunc);
+	VERIFY(file.is_open(), "failed to open file: '{}'", m_path);
+
+	// Write data to disk
+	file.write(m_data.c_str(), m_data.size());
+
+	return *this;
+}
+
+} // namespace Util

src/util/file.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2021-2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <string>
+
+namespace Util {
+
+class File {
+public:
+	File(const std::string& path);
+	virtual ~File();
+
+	static File create(const std::string& path);
+
+	void clear();
+	File& append(const std::string& data);
+	File& replace(size_t index, size_t length, const std::string& data);
+	File& flush();
+
+	const char* c_str() const { return m_data.c_str(); }
+	const std::string& data() const { return m_data; }
+	const std::string& path() const { return m_path; }
+
+private:
+	std::string m_path;
+	std::string m_data;
+};
+
+} // namespace Util

src/util/format/.clang-tidy

@@ -0,0 +1,6 @@
+# -*- yaml -*-
+
+---
+# FIXME: Figure out why NOLINTBEGIN/NOLINTEND doesnt work
+Checks: -misc-unused-using-decls
+...

src/util/format/builder.cpp

@@ -0,0 +1,222 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // min
+#include <cstddef>   // size_t
+#include <cstdint>   // uint8_t, uint16_t, uint32_t, uint64_t
+#include <iomanip>   // setprecision
+#include <ios>       // defaultfloat, fixed
+#include <limits>    // numeric_limits
+#include <sstream>   // stringstream
+#include <string>
+#include <string_view>
+
+#include "util/format/builder.h"
+#include "util/format/parser.h"
+#include "util/meta/assert.h"
+
+namespace Util::Format {
+
+void Builder::putLiteral(std::string_view literal)
+{
+	for (size_t i = 0; i < literal.length(); ++i) {
+		putCharacter(literal[i]);
+		if (literal[i] == '{' || literal[i] == '}') {
+			++i;
+		}
+	}
+}
+
+static constexpr std::string numberToString(size_t value, uint8_t base, bool uppercase)
+{
+	std::string result;
+
+	if (value > std::numeric_limits<uint32_t>::max()) {
+		result.reserve(64);
+	}
+	else if (value > std::numeric_limits<uint16_t>::max()) {
+		result.reserve(32);
+	}
+
+	constexpr const auto& lookupLowercase = "0123456789abcdef";
+	constexpr const auto& lookupUppercase = "0123456789ABCDEF";
+
+	if (value == 0) {
+		result = '0';
+	}
+	else if (uppercase) {
+		while (value > 0) {
+			result.insert(0, 1, lookupUppercase[value % base]);
+			value /= base;
+		}
+	}
+	else {
+		while (value > 0) {
+			result.insert(0, 1, lookupLowercase[value % base]);
+			value /= base;
+		}
+	}
+
+	return result;
+}
+
+void Builder::putU64(size_t value,
+                     uint8_t base,
+                     bool uppercase,
+                     char fill,
+                     Align align,
+                     Sign sign,
+                     bool alternativeForm,
+                     bool zeroPadding,
+                     size_t width,
+                     bool isNegative) const
+{
+	std::string number = numberToString(value, base, uppercase);
+
+	// Sign
+	std::string prefix = "";
+	switch (sign) {
+	case Sign::None:
+	case Sign::Negative:
+		if (isNegative) {
+			prefix = '-';
+		}
+		break;
+	case Sign::Both:
+		prefix = (isNegative) ? '-' : '+';
+		break;
+	case Sign::Space:
+		prefix = (isNegative) ? '-' : ' ';
+		break;
+	default:
+		VERIFY_NOT_REACHED();
+	};
+
+	// Alternative form
+	if (alternativeForm) {
+		switch (base) {
+		case 2:
+			prefix += (uppercase) ? "0B" : "0b";
+			break;
+		case 8:
+			prefix += '0';
+			break;
+		case 10:
+			break;
+		case 16:
+			prefix += (uppercase) ? "0X" : "0x";
+			break;
+		default:
+			VERIFY_NOT_REACHED();
+		}
+	}
+
+	if (!zeroPadding) {
+		number.insert(0, prefix);
+	}
+	else {
+		if (align != Builder::Align::None) {
+			number.insert(0, prefix);
+		}
+		fill = '0';
+	}
+
+	size_t length = number.length();
+	if (width < length) {
+		m_builder.write(number.data(), length);
+		return;
+	}
+
+	switch (align) {
+	case Align::Left:
+		m_builder.write(number.data(), length);
+		m_builder << std::string(width - length, fill);
+		break;
+	case Align::Center: {
+		size_t half = (width - length) / 2;
+		m_builder << std::string(half, fill);
+		m_builder.write(number.data(), length);
+		m_builder << std::string(width - half - length, fill);
+		break;
+	}
+	case Align::Right:
+		m_builder << std::string(width - length, fill);
+		m_builder.write(number.data(), length);
+		break;
+	case Align::None:
+		if (zeroPadding) {
+			m_builder << prefix;
+			m_builder << std::string(width - length - prefix.length(), fill);
+		}
+		else {
+			m_builder << std::string(width - length, fill);
+		}
+		m_builder.write(number.data(), length);
+		break;
+	default:
+		VERIFY_NOT_REACHED();
+	};
+}
+
+void Builder::putI64(int64_t value,
+                     uint8_t base,
+                     bool uppercase,
+                     char fill,
+                     Align align,
+                     Sign sign,
+                     bool alternativeForm,
+                     bool zeroPadding,
+                     size_t width) const
+{
+	bool isNegative = value < 0;
+	value = isNegative ? -value : value;
+	putU64(static_cast<uint64_t>(value), base, uppercase, fill, align, sign, alternativeForm, zeroPadding, width, isNegative);
+}
+
+void Builder::putF64(double number, uint8_t precision) const
+{
+	precision = std::min(precision, static_cast<uint8_t>(std::numeric_limits<double>::digits10));
+
+	std::stringstream stream;
+	stream
+		<< std::fixed << std::setprecision(precision)
+		<< number
+		<< std::defaultfloat << std::setprecision(6);
+	std::string string = stream.str();
+	m_builder << string;
+}
+
+void Builder::putString(std::string_view string, char fill, Align align, size_t width) const
+{
+	size_t length = string.length();
+	if (width < length) {
+		m_builder.write(string.data(), length);
+		return;
+	}
+
+	switch (align) {
+	case Align::None:
+	case Align::Left:
+		m_builder.write(string.data(), length);
+		m_builder << std::string(width - length, fill);
+		break;
+	case Align::Center: {
+		size_t half = (width - length) / 2;
+		m_builder << std::string(half, fill);
+		m_builder.write(string.data(), length);
+		m_builder << std::string(width - half - length, fill);
+		break;
+	}
+	case Align::Right:
+		m_builder << std::string(width - length, fill);
+		m_builder.write(string.data(), length);
+		break;
+	default:
+		VERIFY_NOT_REACHED();
+	};
+}
+
+} // namespace Util::Format

src/util/format/builder.h

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <cstdint> // int32_t, int64_t, uint8_t, uint32_t
+#include <sstream> // stringstream
+#include <string_view>
+
+namespace Util::Format {
+
+class Builder {
+public:
+	enum class Align : uint8_t {
+		None,
+		Left = '<',
+		Right = '>',
+		Center = '^',
+	};
+
+	enum class Sign : uint8_t {
+		None,
+		Negative = '-',
+		Both = '+',
+		Space = ' ',
+	};
+
+	explicit Builder(std::stringstream& builder)
+		: m_builder(builder)
+	{
+	}
+
+	void putLiteral(std::string_view literal);
+
+	void putU64(size_t value,
+	            uint8_t base = 10,
+	            bool uppercase = false,
+	            char fill = ' ',
+	            Align align = Align::Right,
+	            Sign sign = Sign::Negative,
+	            bool alternativeForm = false,
+	            bool zeroPadding = false,
+	            size_t width = 0,
+	            bool isNegative = false) const;
+
+	void putI64(int64_t value,
+	            uint8_t base = 10,
+	            bool uppercase = false,
+	            char fill = ' ',
+	            Align align = Align::Right,
+	            Sign sign = Sign::Negative,
+	            bool alternativeForm = false,
+	            bool zeroPadding = false,
+	            size_t width = 0) const;
+
+	void putF64(double number, uint8_t precision = 6) const;
+	void putCharacter(char character) const { m_builder.write(&character, 1); }
+	void putString(std::string_view string, char fill = ' ', Align align = Align::Left, size_t width = 0) const;
+
+	const std::stringstream& builder() const { return m_builder; }
+	std::stringstream& builder() { return m_builder; }
+
+private:
+	std::stringstream& m_builder;
+};
+
+} // namespace Util::Format
+
+#if 0
+	// Defaults based on type
+	switch (type) {
+	case SpecifierType::Integral:
+		specifier.align = Builder::Align::Right;
+		specifier.type = PresentationType::Decimal;
+		break;
+	case SpecifierType::FloatingPoint:
+		specifier.align = Builder::Align::Right;
+		specifier.type = PresentationType::General;
+		break;
+	}
+#endif

src/util/format/color.cpp

@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdint> // uint8_t
+#include <cstdio>  // FILE, fputs, stdout
+#include <sstream> // stringstream
+#include <string>
+#include <string_view>
+
+#include "util/format/color.h"
+#include "util/format/format.h"
+#include "util/meta/assert.h"
+
+namespace Util::Format {
+
+TextStyle::TextStyle(Emphasis emphasis)
+	: m_emphasis(emphasis)
+{
+}
+
+TextStyle::TextStyle(bool isForeground, TerminalColor color)
+{
+	if (isForeground) {
+		m_foregroundColor = color;
+	}
+	else {
+		m_backgroundColor = color;
+	}
+}
+
+// -----------------------------------------
+
+TextStyle& TextStyle::operator|=(const TextStyle& rhs)
+{
+	if (m_foregroundColor == TerminalColor::None) {
+		m_foregroundColor = rhs.m_foregroundColor;
+	}
+	else {
+		VERIFY(rhs.m_foregroundColor == TerminalColor::None, "can't OR a terminal color");
+	}
+
+	if (m_backgroundColor == TerminalColor::None) {
+		m_backgroundColor = rhs.m_backgroundColor;
+	}
+	else {
+		VERIFY(rhs.m_backgroundColor == TerminalColor::None, "can't OR a terminal color");
+	}
+
+	m_emphasis = static_cast<Emphasis>(static_cast<uint8_t>(m_emphasis) | static_cast<uint8_t>(rhs.m_emphasis));
+
+	return *this;
+}
+
+TextStyle fg(TerminalColor foreground)
+{
+	return TextStyle(true, foreground);
+}
+
+TextStyle bg(TerminalColor background)
+{
+	return TextStyle(false, background);
+}
+
+TextStyle operator|(TextStyle lhs, const TextStyle& rhs)
+{
+	return lhs |= rhs;
+}
+
+TextStyle operator|(Emphasis lhs, Emphasis rhs)
+{
+	return TextStyle { lhs } | rhs;
+}
+
+bool operator&(Emphasis lhs, Emphasis rhs)
+{
+	return static_cast<uint8_t>(lhs) & static_cast<uint8_t>(rhs);
+}
+
+// -----------------------------------------
+
+void setDisplayAttributes(std::stringstream& stream, const TextStyle& style)
+{
+	bool hasForeground = style.foregroundColor() != TerminalColor::None;
+	bool hasBackground = style.backgroundColor() != TerminalColor::None;
+	bool hasEmphasis = style.emphasis() != Emphasis::None;
+	if (!hasForeground && !hasBackground && !hasEmphasis) {
+		return;
+	}
+
+	stream.write("\033[", 2);
+
+	if (hasForeground) {
+		stream << format("{}", static_cast<uint8_t>(style.foregroundColor()));
+	}
+
+	if (hasBackground) {
+		if (hasForeground) {
+			stream.write(";", 1);
+		}
+		stream << format("{}", static_cast<uint8_t>(style.backgroundColor()) + 10);
+	}
+
+	stream.write("m", 1);
+
+	if (hasEmphasis) {
+
+#define ESCAPE_ATTRIBUTE(escape, attribute) \
+	if (style.emphasis() & escape) {        \
+		stream.write("\033[", 2);           \
+		stream.write(attribute, 1);         \
+		stream.write("m", 1);               \
+	}
+
+		ESCAPE_ATTRIBUTE(Emphasis::Bold, "1");
+		ESCAPE_ATTRIBUTE(Emphasis::Faint, "2");
+		ESCAPE_ATTRIBUTE(Emphasis::Italic, "3");
+		ESCAPE_ATTRIBUTE(Emphasis::Underline, "4");
+		ESCAPE_ATTRIBUTE(Emphasis::Blink, "5");
+		ESCAPE_ATTRIBUTE(Emphasis::Reverse, "7");
+		ESCAPE_ATTRIBUTE(Emphasis::Conceal, "8");
+		ESCAPE_ATTRIBUTE(Emphasis::Strikethrough, "9");
+	}
+}
+
+void coloredVariadicFormat(std::stringstream& stream, const TextStyle& style, std::string_view format, TypeErasedParameters& parameters)
+{
+	setDisplayAttributes(stream, style);
+	variadicFormat(stream, format, parameters);
+	stream.write("\033[0m", 4);
+}
+
+// -----------------------------------------
+
+void coloredVariadicPrint(FILE* file, const TextStyle& style, std::string_view format, TypeErasedParameters& parameters)
+{
+	std::stringstream stream;
+	setDisplayAttributes(stream, style);
+	variadicFormat(stream, format, parameters);
+	stream.write("\033[0m", 4);
+
+	std::string string = stream.str();
+	fputs(string.c_str(), file);
+}
+
+// -----------------------------------------
+
+ColorPrintOperatorStyle::ColorPrintOperatorStyle(FILE* file, const TextStyle& style)
+	: m_file(file)
+	, m_style(style)
+	, m_stream()
+	, m_builder(m_stream)
+{
+	setDisplayAttributes(m_stream, style);
+}
+
+ColorPrintOperatorStyle::~ColorPrintOperatorStyle()
+{
+	m_stream.write("\033[0m", 4);
+	std::string string = m_stream.str();
+	fputs(string.c_str(), m_file);
+}
+
+ColorPrintOperatorStyle print(const TextStyle& style)
+{
+	return ColorPrintOperatorStyle(stdout, style);
+}
+
+ColorPrintOperatorStyle print(FILE* file, const TextStyle& style)
+{
+	return ColorPrintOperatorStyle(file, style);
+}
+
+} // namespace Util::Format

src/util/format/color.h

@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t
+#include <cstdio>  // FILE, stdout
+#include <sstream> // stringstream
+#include <string_view>
+
+#include "util/format/format.h"
+
+namespace Util::Format {
+
+enum class TerminalColor : uint8_t {
+	None = 0,
+	Black = 30,
+	Red,
+	Green,
+	Yellow,
+	Blue,
+	Magenta,
+	Cyan,
+	White,
+	BrightBlack = 90,
+	BrightRed,
+	BrightGreen,
+	BrightYellow,
+	BrightBlue,
+	BrightMagenta,
+	BrightCyan,
+	BrightWhite
+};
+
+// Bit field
+enum class Emphasis : uint8_t {
+	None = 0,               // Attribute 0
+	Bold = 1,               // Attribute 1
+	Faint = 1 << 1,         // Attribute 2
+	Italic = 1 << 2,        // Attribute 3
+	Underline = 1 << 3,     // Attribute 4
+	Blink = 1 << 4,         // Attribute 5
+	Reverse = 1 << 5,       // Attribute 7
+	Conceal = 1 << 6,       // Attribute 8
+	Strikethrough = 1 << 7, // Attribute 9
+};
+
+class TextStyle {
+private:
+	friend TextStyle fg(TerminalColor foreground);
+	friend TextStyle bg(TerminalColor background);
+
+public:
+	TextStyle(Emphasis emphasis);
+
+	// Operator pipe equal, reads the same way as +=
+	TextStyle& operator|=(const TextStyle& rhs);
+
+	TerminalColor foregroundColor() const { return m_foregroundColor; }
+	TerminalColor backgroundColor() const { return m_backgroundColor; }
+	Emphasis emphasis() const { return m_emphasis; }
+
+private:
+	TextStyle(bool isForeground, TerminalColor color);
+
+	TerminalColor m_foregroundColor { TerminalColor::None };
+	TerminalColor m_backgroundColor { TerminalColor::None };
+	Emphasis m_emphasis { 0 };
+};
+
+TextStyle fg(TerminalColor foreground);
+TextStyle bg(TerminalColor background);
+TextStyle operator|(TextStyle lhs, const TextStyle& rhs);
+TextStyle operator|(Emphasis lhs, Emphasis rhs);
+bool operator&(Emphasis lhs, Emphasis rhs);
+
+// -----------------------------------------
+
+void coloredVariadicFormat(std::stringstream& stream, const TextStyle& style, std::string_view format, TypeErasedParameters& parameters);
+
+template<typename... Parameters>
+std::string format(const TextStyle& style, std::string_view format, const Parameters&... parameters)
+{
+	std::stringstream stream;
+	VariadicParameters variadicParameters { parameters... };
+	coloredVariadicFormat(stream, style, format, variadicParameters);
+	return stream.str();
+}
+
+template<typename... Parameters>
+void formatTo(std::string& output, const TextStyle& style, std::string_view format, const Parameters&... parameters)
+{
+	std::stringstream stream;
+	VariadicParameters variadicParameters { parameters... };
+	coloredVariadicFormat(stream, style, format, variadicParameters);
+	output += stream.str();
+}
+
+// -----------------------------------------
+
+void coloredVariadicPrint(FILE* file, const TextStyle& style, std::string_view format, TypeErasedParameters& parameters);
+
+template<size_t N, typename... Parameters>
+void print(const TextStyle& style, const char (&format)[N], const Parameters&... parameters)
+{
+	VariadicParameters variadicParameters { parameters... };
+	coloredVariadicPrint(stdout, style, { format, N - 1 }, variadicParameters);
+}
+
+template<size_t N, typename... Parameters>
+void print(FILE* file, const TextStyle& style, const char (&format)[N], const Parameters&... parameters)
+{
+	VariadicParameters variadicParameters { parameters... };
+	coloredVariadicPrint(file, style, { format, N - 1 }, variadicParameters);
+}
+
+// -----------------------------------------
+
+class ColorPrintOperatorStyle {
+public:
+	ColorPrintOperatorStyle(FILE* file, const TextStyle& style);
+	virtual ~ColorPrintOperatorStyle();
+
+	Builder& builder() { return m_builder; }
+
+private:
+	FILE* m_file;
+	TextStyle m_style;
+
+	std::stringstream m_stream;
+	Builder m_builder;
+};
+
+template<typename T>
+const ColorPrintOperatorStyle& operator<<(const ColorPrintOperatorStyle& colorPrintOperatorStyle, const T& value)
+{
+	_format(const_cast<ColorPrintOperatorStyle&>(colorPrintOperatorStyle).builder(), value);
+	return colorPrintOperatorStyle;
+}
+
+ColorPrintOperatorStyle print(const TextStyle& style);
+ColorPrintOperatorStyle print(FILE* file, const TextStyle& style);
+
+} // namespace Util::Format
+
+namespace Util {
+
+using Util::Format::format;
+using Util::Format::formatTo;
+using Util::Format::print;
+
+} // namespace Util

src/util/format/format.cpp

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <sstream> // stringstream
+#include <string>
+#include <string_view>
+
+#include "util/format/builder.h"
+#include "util/format/format.h"
+#include "util/format/parser.h"
+#include "util/meta/assert.h"
+
+namespace Util::Format {
+
+void variadicFormatImpl(Builder& builder, Parser& parser, TypeErasedParameters& parameters)
+{
+	// Consume everything until '{' or EOF
+	const auto literal = parser.consumeLiteral();
+	builder.putLiteral(literal);
+
+	// Reached end of format string
+	if (parser.isEOF()) {
+		return;
+	}
+
+	// Consume index + ':'
+	auto indexMaybe = parser.consumeIndex();
+
+	// Get parameter at index, or next
+	size_t index = indexMaybe.has_value() ? indexMaybe.value() : parameters.tell();
+	VERIFY(index < parameters.size(), "argument not found at index '%zu'", index);
+	auto& parameter = parameters.parameter(index);
+
+	// Format the parameter
+	parameter.format(builder, parser, parameter.value);
+
+	// Go to next parameter
+	parameters.ignore();
+
+	// Recurse
+	if (!parser.isEOF()) {
+		variadicFormatImpl(builder, parser, parameters);
+	}
+}
+
+void variadicFormat(std::stringstream& stream, std::string_view format, TypeErasedParameters& parameters)
+{
+	Builder builder { stream };
+	Parser parser { format, parameters.size() };
+
+	variadicFormatImpl(builder, parser, parameters);
+}
+
+// -----------------------------------------
+
+FormatOperatorStyle::FormatOperatorStyle(std::string& output)
+	: m_output(output)
+	, m_stream()
+	, m_builder(m_stream)
+{
+}
+
+FormatOperatorStyle::~FormatOperatorStyle()
+{
+	m_output = m_stream.str();
+}
+
+FormatOperatorStyle formatTo(std::string& output)
+{
+	return FormatOperatorStyle(output);
+}
+
+} // namespace Util::Format

src/util/format/format.h

@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <span>
+#include <sstream> // stringstream
+#include <string>
+#include <string_view>
+
+#include "util/format/formatter.h"
+
+namespace Util::Format {
+
+class Builder;
+class Parser;
+
+struct Parameter {
+	const void* value;
+	void (*format)(Builder& builder, Parser& parser, const void* value);
+};
+
+template<typename T>
+void formatParameterValue(Builder& builder, Parser& parser, const void* value)
+{
+	Formatter<T> formatter;
+	formatter.parse(parser);
+	formatter.format(builder, *static_cast<const T*>(value));
+}
+
+// Type erasure improves both compile time and binary size significantly
+class TypeErasedParameters {
+public:
+	const Parameter parameter(size_t index) { return m_parameters[index]; }
+
+	size_t tell() const { return m_index; }
+	size_t size() const { return m_parameters.size(); }
+	bool isEOF() const { return m_index >= m_parameters.size(); }
+	void ignore() { m_index++; }
+
+protected:
+	size_t m_index { 0 };
+	std::span<const Parameter> m_parameters;
+};
+
+template<typename... Parameters>
+class VariadicParameters final : public TypeErasedParameters {
+public:
+	VariadicParameters(const Parameters&... parameters)
+		: m_templatedParameters({ { &parameters, formatParameterValue<Parameters> }... })
+	{
+		m_parameters = m_templatedParameters;
+	}
+
+private:
+	std::array<Parameter, sizeof...(Parameters)> m_templatedParameters;
+};
+
+// -----------------------------------------
+
+void variadicFormatImpl(Builder& builder, Parser& parser, TypeErasedParameters& parameters);
+void variadicFormat(std::stringstream& stream, std::string_view format, TypeErasedParameters& parameters);
+
+// -----------------------------------------
+
+template<typename... Parameters>
+std::string format(std::string_view format, const Parameters&... parameters)
+{
+	std::stringstream stream;
+	VariadicParameters variadicParameters { parameters... };
+	variadicFormat(stream, format, variadicParameters);
+	return stream.str();
+}
+
+template<typename... Parameters>
+void formatTo(std::string& output, std::string_view format, const Parameters&... parameters)
+{
+	std::stringstream stream;
+	VariadicParameters variadicParameters { parameters... };
+	variadicFormat(stream, format, variadicParameters);
+	output += stream.str();
+}
+
+// -----------------------------------------
+
+class FormatOperatorStyle {
+public:
+	FormatOperatorStyle(std::string& output);
+	virtual ~FormatOperatorStyle();
+
+	Builder& builder() { return m_builder; }
+
+private:
+	std::string& m_output;
+	std::stringstream m_stream;
+	Builder m_builder;
+};
+
+template<typename T>
+const FormatOperatorStyle& operator<<(const FormatOperatorStyle& formatOperatorStyle, const T& value)
+{
+	_format(const_cast<FormatOperatorStyle&>(formatOperatorStyle).builder(), value);
+	return formatOperatorStyle;
+}
+
+FormatOperatorStyle formatTo(std::string& output);
+
+} // namespace Util::Format
+
+namespace Util {
+
+using Util::Format::format;
+using Util::Format::formatTo;
+
+} // namespace Util

src/util/format/formatter.cpp

@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdint> // uint8_t
+#include <cstring> // strlen
+#include <string>
+#include <string_view>
+
+#include "util/format/builder.h"
+#include "util/format/formatter.h"
+#include "util/format/parser.h"
+
+namespace Util::Format {
+
+// Char
+
+template<>
+void Formatter<char>::format(Builder& builder, char value) const
+{
+	if (specifier.type != PresentationType::None && specifier.type != PresentationType::Character) {
+		// "Type char is a distinct type that has an implementation-defined
+		// choice of “signed char” or “unsigned char” as its underlying type."
+		// http://eel.is/c++draft/basic#fundamental
+		Formatter<signed char> formatter { .specifier = specifier };
+		return formatter.format(builder, static_cast<signed char>(value));
+	}
+
+	Formatter<std::string_view> formatter { .specifier = specifier };
+	return formatter.format(builder, { &value, 1 });
+}
+
+template<>
+void Formatter<bool>::format(Builder& builder, bool value) const
+{
+	switch (specifier.type) {
+	case PresentationType::Binary:
+	case PresentationType::BinaryUppercase:
+	case PresentationType::Character:
+	case PresentationType::Decimal:
+	case PresentationType::Octal:
+	case PresentationType::Hex:
+	case PresentationType::HexUppercase: {
+		Formatter<uint8_t> formatter { .specifier = specifier };
+		return formatter.format(builder, static_cast<uint8_t>(value));
+	}
+	default:
+		break;
+	};
+
+	Formatter<std::string_view> formatter { .specifier = specifier };
+	formatter.format(builder, value ? "true" : "false");
+}
+
+// String
+
+template<>
+void Formatter<std::string_view>::format(Builder& builder, std::string_view value) const
+{
+	builder.putString(value, specifier.fill, specifier.align, specifier.width);
+}
+
+void Formatter<const char*>::parse(Parser& parser)
+{
+	parser.parseSpecifier(specifier, Parser::ParameterType::CString);
+}
+
+void Formatter<const char*>::format(Builder& builder, const char* value) const
+{
+	if (specifier.type == PresentationType::Pointer) {
+		Formatter<uintptr_t> formatter { .specifier = specifier };
+		formatter.specifier.alternativeForm = true;
+		formatter.specifier.type = PresentationType::Hex;
+		return formatter.format(builder, reinterpret_cast<uintptr_t>(value));
+	}
+
+	Formatter<std::string_view>::format(
+		builder,
+		value != nullptr ? std::string_view { value, strlen(value) } : "nullptr");
+}
+
+// Pointer
+
+void Formatter<std::nullptr_t>::format(Builder& builder, std::nullptr_t) const
+{
+	Formatter<const void*>::format(builder, 0);
+}
+
+// For debugging
+
+void Formatter<Specifier>::format(Builder& builder, Specifier value) const
+{
+	char result[255];
+	sprintf(result, R"(
+fill:            {%c}
+align:           {%c}
+sign:            {%c}
+alternativeForm: {%d}
+zeroPadding:     {%d}
+width:           {%zu}
+precision:       {%d}
+type:            {%c}
+)",
+	        value.fill,
+	        static_cast<char>(value.align),
+	        static_cast<char>(value.sign),
+	        value.alternativeForm,
+	        value.zeroPadding,
+	        value.width,
+	        value.precision,
+	        static_cast<char>(value.type));
+	builder.putString(std::string_view(result));
+}
+
+} // namespace Util::Format

src/util/format/formatter.h

@@ -0,0 +1,325 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cassert>
+#include <cstddef> // size_t
+#include <cstdint> // int8_t, uint8_t, uintptr_t
+#include <map>
+#include <string>
+#include <string_view>
+#include <type_traits> // is_integral_v, is_same
+#include <unordered_map>
+#include <vector>
+
+#include "util/format/builder.h"
+#include "util/format/parser.h"
+#include "util/meta/concepts.h"
+
+namespace Util::Format {
+
+enum class PresentationType : uint8_t {
+	None,
+	// Interger
+	Binary = 'b',
+	BinaryUppercase = 'B',
+	Decimal = 'd',
+	Octal = 'o',
+	Hex = 'x',
+	HexUppercase = 'X',
+	// Floating-point
+	Hexfloat = 'a',
+	HexfloatUppercase = 'A',
+	Exponent = 'e',
+	ExponentUppercase = 'E',
+	FixedPoint = 'f',
+	FixedPointUppercase = 'F',
+	General = 'g',
+	GeneralUppercase = 'G',
+	// Character
+	Character = 'c',
+	// String
+	String = 's',
+	// Pointer
+	Pointer = 'p',
+	// Container
+	Container = 'C',
+};
+
+struct Specifier {
+	char fill = ' ';
+	Builder::Align align = Builder::Align::None;
+
+	Builder::Sign sign = Builder::Sign::None;
+
+	bool alternativeForm = false;
+	bool zeroPadding = false;
+	size_t width = 0;
+	int8_t precision = -1;
+
+	PresentationType type = PresentationType::None;
+};
+
+template<typename T>
+struct Formatter {
+	Specifier specifier;
+
+	void parse(Parser& parser)
+	{
+		if constexpr (std::is_same_v<T, char>) {
+			parser.parseSpecifier(specifier, Parser::ParameterType::Char);
+		}
+		else if (std::is_same_v<T, bool>) {
+			parser.parseSpecifier(specifier, Parser::ParameterType::Char);
+		}
+		else if (std::is_same_v<T, std::string_view>) {
+			parser.parseSpecifier(specifier, Parser::ParameterType::String);
+		}
+	}
+
+	void format(Builder&, T) const {}
+};
+
+// Integral
+
+template<Integral T>
+struct Formatter<T> {
+	Specifier specifier;
+
+	void parse(Parser& parser)
+	{
+		parser.parseSpecifier(specifier, Parser::ParameterType::Integral);
+	}
+
+	void format(Builder& builder, T value) const
+	{
+		if (specifier.type == PresentationType::Character) {
+			assert(value >= 0 && value <= 127);
+
+			Formatter<std::string_view> formatter { .specifier = specifier };
+			formatter.specifier.type = PresentationType::String;
+			return formatter.format(builder, { reinterpret_cast<const char*>(&value), 1 });
+		}
+
+		uint8_t base = 0;
+		bool uppercase = false;
+		switch (specifier.type) {
+		case PresentationType::BinaryUppercase:
+			uppercase = true;
+		case PresentationType::Binary:
+			base = 2;
+			break;
+		case PresentationType::Octal:
+			base = 8;
+			break;
+		case PresentationType::None:
+		case PresentationType::Decimal:
+			base = 10;
+			break;
+		case PresentationType::HexUppercase:
+			uppercase = true;
+		case PresentationType::Hex:
+			base = 16;
+			break;
+		default:
+			assert(false);
+		};
+
+		if constexpr (std::is_unsigned_v<T>) {
+			builder.putU64(
+				value, base, uppercase, specifier.fill, specifier.align, specifier.sign,
+				specifier.alternativeForm, specifier.zeroPadding, specifier.width);
+		}
+		else {
+			builder.putI64(
+				value, base, uppercase, specifier.fill, specifier.align, specifier.sign,
+				specifier.alternativeForm, specifier.zeroPadding, specifier.width);
+		}
+	}
+};
+
+// Floating point
+
+template<FloatingPoint T>
+struct Formatter<T> {
+	Specifier specifier;
+
+	void parse(Parser& parser)
+	{
+		parser.parseSpecifier(specifier, Parser::ParameterType::FloatingPoint);
+	}
+
+	void format(Builder& builder, T value) const
+	{
+		if (specifier.precision < 0) {
+			builder.putF64(value);
+			return;
+		}
+
+		builder.putF64(value, specifier.precision);
+	}
+};
+
+// Char
+
+template<>
+void Formatter<char>::format(Builder& builder, char value) const;
+
+template<>
+void Formatter<bool>::format(Builder& builder, bool value) const;
+
+// String
+
+template<>
+void Formatter<std::string_view>::format(Builder& builder, std::string_view value) const;
+
+template<>
+struct Formatter<std::string> : Formatter<std::string_view> {
+};
+
+template<>
+struct Formatter<const char*> : Formatter<std::string_view> {
+	void parse(Parser& parser);
+	void format(Builder& builder, const char* value) const;
+};
+
+template<>
+struct Formatter<char*> : Formatter<const char*> {
+};
+
+template<size_t N>
+struct Formatter<char[N]> : Formatter<const char*> {
+};
+
+// Pointer
+
+template<typename T>
+struct Formatter<T*> : Formatter<uintptr_t> {
+	void parse(Parser& parser)
+	{
+		parser.parseSpecifier(specifier, Parser::ParameterType::Pointer);
+		specifier.alternativeForm = true;
+		specifier.type = PresentationType::Hex;
+	}
+
+	void format(Builder& builder, T* value) const
+	{
+		Formatter<uintptr_t>::format(builder, reinterpret_cast<uintptr_t>(value));
+	}
+};
+
+template<>
+struct Formatter<std::nullptr_t> : Formatter<const void*> {
+	void format(Builder& builder, std::nullptr_t) const;
+};
+
+// Container
+
+template<typename T>
+struct Formatter<std::vector<T>> : Formatter<T> {
+	Specifier specifier;
+
+	void parse(Parser& parser)
+	{
+		parser.parseSpecifier(specifier, Parser::ParameterType::Container);
+	}
+
+	void format(Builder& builder, const std::vector<T>& value) const
+	{
+		std::string indent = std::string(specifier.width, specifier.fill);
+
+		builder.putCharacter('{');
+		if (specifier.alternativeForm) {
+			builder.putCharacter('\n');
+		}
+		for (auto it = value.cbegin(); it != value.cend(); ++it) {
+			builder.putString(indent);
+
+			Formatter<T>::format(builder, *it);
+
+			// Add comma, except after the last element
+			if (it != std::prev(value.end(), 1)) {
+				builder.putCharacter(',');
+			}
+			else if (!specifier.alternativeForm) {
+				builder.putString(indent);
+			}
+
+			if (specifier.alternativeForm) {
+				builder.putCharacter('\n');
+			}
+		}
+		builder.putCharacter('}');
+	}
+};
+
+#define UTIL_FORMAT_FORMAT_AS_MAP(type)                                         \
+	template<typename K, typename V>                                            \
+	struct Formatter<type<K, V>>                                                \
+		: Formatter<K>                                                          \
+		, Formatter<V> {                                                        \
+		Specifier specifier;                                                    \
+                                                                                \
+		void parse(Parser& parser)                                              \
+		{                                                                       \
+			parser.parseSpecifier(specifier, Parser::ParameterType::Container); \
+		}                                                                       \
+                                                                                \
+		void format(Builder& builder, const type<K, V>& value) const            \
+		{                                                                       \
+			std::string indent = std::string(specifier.width, specifier.fill);  \
+                                                                                \
+			builder.putCharacter('{');                                          \
+			if (specifier.alternativeForm) {                                    \
+				builder.putCharacter('\n');                                     \
+			}                                                                   \
+			auto last = value.end();                                            \
+			for (auto it = value.begin(); it != last; ++it) {                   \
+				builder.putString(indent);                                      \
+				builder.putCharacter('"');                                      \
+				Formatter<K>::format(builder, it->first);                       \
+				builder.putCharacter('"');                                      \
+				builder.putString((specifier.width > 0) ? ": " : ":");          \
+				Formatter<V>::format(builder, it->second);                      \
+                                                                                \
+				/* Add comma, except after the last element */                  \
+				if (std::next(it) != last) {                                    \
+					builder.putCharacter(',');                                  \
+				}                                                               \
+				else if (!specifier.alternativeForm) {                          \
+					builder.putString(indent);                                  \
+				}                                                               \
+                                                                                \
+				if (specifier.alternativeForm) {                                \
+					builder.putCharacter('\n');                                 \
+				}                                                               \
+			}                                                                   \
+			builder.putCharacter('}');                                          \
+		}                                                                       \
+	}
+
+UTIL_FORMAT_FORMAT_AS_MAP(std::map);
+UTIL_FORMAT_FORMAT_AS_MAP(std::unordered_map);
+
+// For debugging
+
+template<>
+struct Formatter<Specifier> : Formatter<std::nullptr_t> {
+	void format(Builder& builder, Specifier value) const;
+};
+
+} // namespace Util::Format
+
+#if 0
+
+TODO:
+- Split assert.h so it can work in format headers! (formatter.h)
+v Add unit tests
+- Expand Builder::putf60
+- Add Builder::putf80 (?)
+
+#endif

src/util/format/log.cpp

@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdio> // FILE
+#include <string>
+
+#include "util/format/color.h"
+#include "util/format/log.h"
+
+namespace Util::Format {
+
+std::string formatTimeElapsed()
+{
+	return format("{:.3}s ", s_timer.elapsedNanoseconds() / 1000000000.0);
+}
+
+std::string formatType(LogType type)
+{
+	std::string output;
+
+	formatTo(output, "[");
+	switch (type) {
+	case LogType::Trace:
+		formatTo(output, "trace");
+		break;
+	case LogType::Debug:
+		formatTo(output, fg(TerminalColor::Magenta), "debug");
+		break;
+	case LogType::Success:
+		formatTo(output, fg(TerminalColor::Green), "success");
+		break;
+	case LogType::Info:
+		formatTo(output, fg(TerminalColor::Blue), "info");
+		break;
+	case LogType::Warn:
+		formatTo(output, Emphasis::Bold | fg(TerminalColor::Yellow), "warn");
+		break;
+	case LogType::Error:
+		formatTo(output, Emphasis::Bold | fg(TerminalColor::Red), "error");
+		break;
+	case LogType::Critical:
+		formatTo(output, Emphasis::Bold | fg(TerminalColor::White) | bg(TerminalColor::Red), "critical");
+		break;
+	default:
+		break;
+	};
+	formatTo(output, "] ");
+
+	return output;
+}
+
+// -----------------------------------------
+
+LogOperatorStyle::LogOperatorStyle(FILE* file, LogType type)
+	: m_file(file)
+	, m_type(type)
+	, m_stream()
+	, m_builder(m_stream)
+{
+	m_stream << formatTimeElapsed();
+	m_stream << formatType(type);
+}
+
+LogOperatorStyle::~LogOperatorStyle()
+{
+	m_stream.write("\n", 1);
+	std::string string = m_stream.str();
+	fputs(string.c_str(), m_file);
+}
+
+LogOperatorStyle trace()
+{
+	return LogOperatorStyle(stdout, LogType::Trace);
+}
+
+LogOperatorStyle debug()
+{
+	return LogOperatorStyle(stdout, LogType::Debug);
+}
+
+LogOperatorStyle success()
+{
+	return LogOperatorStyle(stdout, LogType::Success);
+}
+
+LogOperatorStyle info()
+{
+	return LogOperatorStyle(stdout, LogType::Info);
+}
+
+LogOperatorStyle warn()
+{
+	return LogOperatorStyle(stderr, LogType::Warn);
+}
+
+LogOperatorStyle error()
+{
+	return LogOperatorStyle(stderr, LogType::Error);
+}
+
+LogOperatorStyle critical()
+{
+	return LogOperatorStyle(stderr, LogType::Critical);
+}
+
+} // namespace Util::Format

src/util/format/log.h

@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstdio> // FILE, stderr, stdout
+#include <string>
+#include <string_view>
+
+#include "util/format/format.h"
+#include "util/format/print.h"
+#include "util/timer.h"
+
+namespace Util::Format {
+
+static Util::Timer s_timer;
+
+enum class LogType : uint8_t {
+	Trace,    // White
+	Debug,    // Purple
+	Success,  // Green
+	Info,     // Blue
+	Warn,     // Bold yellow
+	Error,    // Bold red
+	Critical, // Bold on red
+};
+
+std::string formatTimeElapsed();
+std::string formatType(LogType type);
+
+#define LOG_FUNCTION(name, file, type)                                 \
+	template<size_t N, typename... Parameters>                         \
+	void name(const char(&format)[N], const Parameters&... parameters) \
+	{                                                                  \
+		print(file, "{}", formatTimeElapsed());                        \
+		print(file, "{}", formatType(type));                           \
+		VariadicParameters variadicParameters { parameters... };       \
+		print(file, format, variadicParameters);                       \
+		print(file, "\n");                                             \
+	}
+
+LOG_FUNCTION(trace, stdout, LogType::Trace);
+LOG_FUNCTION(debug, stdout, LogType::Debug);
+LOG_FUNCTION(success, stdout, LogType::Success);
+LOG_FUNCTION(info, stdout, LogType::Info);
+LOG_FUNCTION(warn, stderr, LogType::Warn);
+LOG_FUNCTION(error, stderr, LogType::Error);
+LOG_FUNCTION(critical, stderr, LogType::Critical);
+
+// -----------------------------------------
+
+class LogOperatorStyle {
+public:
+	LogOperatorStyle(FILE* file, LogType type);
+	virtual ~LogOperatorStyle();
+
+	Builder& builder() { return m_builder; }
+
+private:
+	FILE* m_file;
+	LogType m_type;
+
+	std::stringstream m_stream;
+	Builder m_builder;
+};
+
+template<typename T>
+const LogOperatorStyle& operator<<(const LogOperatorStyle& logOperatorStyle, const T& value)
+{
+	_format(const_cast<LogOperatorStyle&>(logOperatorStyle).builder(), value);
+	return logOperatorStyle;
+}
+
+LogOperatorStyle trace();
+LogOperatorStyle debug();
+LogOperatorStyle success();
+LogOperatorStyle info();
+LogOperatorStyle warn();
+LogOperatorStyle error();
+LogOperatorStyle critical();
+
+} // namespace Util::Format
+
+namespace Util {
+
+using Util::Format::critical;
+using Util::Format::debug;
+using Util::Format::error;
+using Util::Format::info;
+using Util::Format::success;
+using Util::Format::trace;
+using Util::Format::warn;
+
+} // namespace Util

src/util/format/parser.cpp

@@ -0,0 +1,419 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // replace
+#include <cstddef>   // size_t
+#include <cstdint>   // int8_t
+#include <limits>    // numeric_limits
+#include <string>
+#include <string_view>
+
+#include "util/format/builder.h"
+#include "util/format/formatter.h"
+#include "util/format/parser.h"
+#include "util/format/print.h"
+#include "util/meta/assert.h"
+
+namespace Util::Format {
+
+Parser::Parser(std::string_view format, size_t parameterCount)
+	: GenericLexer(format)
+	, m_parameterCount(parameterCount)
+{
+	checkFormatParameterConsistency();
+}
+
+Parser::~Parser()
+{
+}
+
+// -----------------------------------------
+
+void Parser::checkFormatParameterConsistency()
+{
+	size_t braceOpen = 0;
+	size_t braceClose = 0;
+	while (!isEOF()) {
+		char peek0 = peek();
+		char peek1 = peek(1);
+
+		if (peek0 == '{' && peek1 == '{') {
+			ignore(2);
+			continue;
+		}
+
+		if (peek0 == '}' && peek1 == '}') {
+			ignore(2);
+			continue;
+		}
+
+		if (peek0 == '{') {
+			braceOpen++;
+
+			if (peek1 >= '0' && peek1 <= '9') {
+				m_mode = ArgumentIndexingMode::Manual;
+			}
+		}
+		if (peek0 == '}') {
+			braceClose++;
+		}
+
+		ignore();
+	}
+	m_index = 0;
+
+	VERIFY(!(braceOpen < braceClose), "extra open braces in format string");
+	VERIFY(!(braceOpen > braceClose), "extra closing braces in format string");
+
+	if (m_mode == ArgumentIndexingMode::Automatic) {
+		VERIFY(!(braceOpen < m_parameterCount), "format string does not reference all passed parameters");
+		VERIFY(!(braceOpen > m_parameterCount), "format string references nonexistent parameter");
+	}
+}
+
+size_t Parser::stringToNumber(std::string_view value)
+{
+	size_t result = 0;
+
+	for (size_t i = 0; i < value.length(); ++i) {
+		VERIFY(value[i] >= '0' && value[i] <= '9', "unexpected '%c'", value[i]);
+		result *= 10;
+		result += value[i] - '0'; // Subtract ASCII 48 to get the number
+	}
+
+	return result;
+}
+
+std::string_view Parser::consumeLiteral()
+{
+	const auto begin = tell();
+
+	while (!isEOF()) {
+		char peek0 = peek();
+		char peek1 = peek(1);
+
+		if (peek0 == '{' && peek1 == '{') {
+			ignore(2);
+			continue;
+		}
+
+		if (peek0 == '}' && peek1 == '}') {
+			ignore(2);
+			continue;
+		}
+
+		// Get literal before the specifier {}
+		if (peek0 == '{' || peek0 == '}') {
+			return m_input.substr(begin, tell() - begin);
+		}
+
+		ignore();
+	}
+
+	return m_input.substr(begin);
+}
+
+std::optional<size_t> Parser::consumeIndex()
+{
+	if (!consumeSpecific('{')) {
+		VERIFY_NOT_REACHED();
+		return {};
+	}
+
+	switch (m_mode) {
+	case ArgumentIndexingMode::Automatic: {
+		VERIFY(consumeSpecific(':') || peek() == '}', "expecting ':' or '}', not '%c'", peek());
+		return {};
+	}
+	case ArgumentIndexingMode::Manual: {
+		const auto begin = tell();
+
+		while (!isEOF()) {
+			char peek0 = peek();
+			if (peek0 == '}' || peek0 == ':') {
+				break;
+			}
+
+			VERIFY(peek0 >= '0' && peek0 <= '9', "expecting number, not '%c'", peek0);
+
+			ignore();
+		}
+
+		size_t result = stringToNumber(m_input.substr(begin, tell() - begin));
+
+		if (peek() == ':') {
+			ignore();
+		}
+
+		return result;
+	}
+	};
+
+	VERIFY_NOT_REACHED();
+}
+
+void Parser::parseSpecifier(Specifier& specifier, ParameterType type)
+{
+	if (consumeSpecific('}') || isEOF()) {
+		return;
+	}
+
+	// Alignment
+	char peek0 = peek();
+	char peek1 = peek(1);
+	if (peek1 == '<' || peek1 == '>' || peek1 == '^') {
+		specifier.fill = peek0;
+		specifier.align = static_cast<Builder::Align>(peek1);
+		ignore(2);
+	}
+
+	enum State {
+		AfterAlign,
+		AfterSign,
+		AfterAlternativeForm,
+		AfterZeroPadding,
+		AfterWidth,
+		AfterDot,
+		AfterPrecision,
+		AfterType,
+	} state { State::AfterAlign };
+
+	size_t widthBegin = std::numeric_limits<size_t>::max();
+	size_t precisionBegin = std::numeric_limits<size_t>::max();
+	size_t widthEnd = 0;
+	size_t precisionEnd = 0;
+	std::string_view acceptedTypes = "bdoxaefgscpBXAFG";
+
+	static int p = 1;
+
+	while (true) {
+		char peek0 = peek();
+
+		if (peek0 == '}') {
+			ignore();
+			break;
+		}
+		if (isEOF()) {
+			break;
+		}
+
+		// Sign is only valid for numeric types
+		if (peek0 == '+' || peek0 == '-' || peek0 == ' ') {
+			VERIFY(state < State::AfterSign, "unexpected '%c' at this position", peek0);
+			state = State::AfterSign;
+			specifier.sign = static_cast<Builder::Sign>(peek0);
+		}
+
+		// Alternative form is only valid for numeric types
+		if (peek0 == '#') {
+			VERIFY(state < State::AfterAlternativeForm, "unexpected '#' at this position");
+			state = State::AfterAlternativeForm;
+			specifier.alternativeForm = true;
+		}
+
+		// Sign aware zero padding is only valid for numeric types
+		if (peek0 == '0') {
+			if (state < State::AfterWidth) {
+				VERIFY(state < State::AfterZeroPadding, "unexpected '0' at this position");
+				state = State::AfterZeroPadding;
+				specifier.zeroPadding = true;
+			}
+		}
+
+		if (peek0 >= '0' && peek0 <= '9') {
+			if (widthBegin == std::numeric_limits<size_t>::max() && state < State::AfterDot) {
+				VERIFY(state < State::AfterWidth, "unexpected '%c' at this position", peek0);
+				state = State::AfterWidth;
+				widthBegin = tell();
+			}
+			if (precisionBegin == std::numeric_limits<size_t>::max() && state == State::AfterDot) {
+				state = State::AfterPrecision;
+				precisionBegin = tell();
+			}
+		}
+
+		if (peek0 == '.') {
+			if (state == State::AfterWidth) {
+				widthEnd = tell();
+			}
+
+			VERIFY(state < State::AfterDot, "unexpected '.' at this position");
+			state = State::AfterDot;
+		}
+
+		if ((peek0 >= 'a' && peek0 <= 'z')
+		    || (peek0 >= 'A' && peek0 <= 'Z')) {
+			if (state == State::AfterWidth) {
+				widthEnd = tell();
+			}
+			if (state == State::AfterPrecision) {
+				precisionEnd = tell();
+			}
+
+			VERIFY(state < State::AfterType, "unexpected '%c' at this position", peek0);
+			state = State::AfterType;
+			VERIFY(acceptedTypes.find(peek0) != std::string_view::npos, "unexpected '%c' at this position", peek0);
+			specifier.type = static_cast<PresentationType>(peek0);
+		}
+
+		ignore();
+	}
+
+	if (widthBegin != std::numeric_limits<size_t>::max()) {
+		if (widthEnd == 0) {
+			// We parse until after the closing '}', so take this into account
+			widthEnd = tell() - 1;
+		}
+		specifier.width = stringToNumber(m_input.substr(widthBegin, widthEnd - widthBegin));
+	}
+
+	if (precisionBegin != std::numeric_limits<size_t>::max()) {
+		if (precisionEnd == 0) {
+			// We parse until after the closing '}', so take this into account
+			precisionEnd = tell() - 1;
+		}
+		specifier.precision = static_cast<int8_t>(stringToNumber(m_input.substr(precisionBegin, precisionEnd - precisionBegin)));
+	}
+
+	checkSpecifierType(specifier, type);
+
+	if (!p) {
+		p++;
+		Util::Format::print("{}\n", specifier);
+	}
+}
+
+constexpr void Parser::checkSpecifierIntegralType(const Specifier& specifier)
+{
+	switch (specifier.type) {
+	case PresentationType::None:
+	case PresentationType::Binary:
+	case PresentationType::BinaryUppercase:
+	case PresentationType::Character:
+	case PresentationType::Decimal:
+	case PresentationType::Octal:
+	case PresentationType::Hex:
+	case PresentationType::HexUppercase:
+		break;
+	default:
+		VERIFY(false, "invalid type specifier");
+	};
+
+	// Invalid: precision
+	VERIFY(specifier.precision == -1, "invalid specifier option");
+}
+
+constexpr void Parser::checkSpecifierFloatingPointType(const Specifier& specifier)
+{
+	switch (specifier.type) {
+	case PresentationType::None:
+	case PresentationType::Hexfloat:
+	case PresentationType::HexfloatUppercase:
+	case PresentationType::Exponent:
+	case PresentationType::ExponentUppercase:
+	case PresentationType::FixedPoint:
+	case PresentationType::FixedPointUppercase:
+	case PresentationType::General:
+	case PresentationType::GeneralUppercase:
+		break;
+	default:
+		VERIFY(false, "invalid type specifier");
+	}
+}
+
+constexpr void Parser::checkSpecifierCharType(const Specifier& specifier)
+{
+	checkSpecifierIntegralType(specifier);
+
+	//   Valid:  fill + align, width
+	// Invalid: sign, alternativeForm, zeroPadding, precision
+	if (specifier.type == PresentationType::None
+	    || specifier.type == PresentationType::Character) {
+		VERIFY(specifier.sign == Builder::Sign::None, "invalid specifier option");
+		VERIFY(specifier.alternativeForm == false, "invalid specifier option");
+		VERIFY(specifier.zeroPadding == false, "invalid specifier option");
+	}
+	// Precision checked in Integral
+}
+
+constexpr void Parser::checkSpecifierCStringType(const Specifier& specifier)
+{
+	switch (specifier.type) {
+	case PresentationType::None:
+	case PresentationType::String:
+	case PresentationType::Pointer:
+		break;
+	default:
+		VERIFY(false, "invalid type specifier");
+	}
+
+	//   Valid:  fill + align, width
+	// Invalid: sign, alternativeForm, zeroPadding, precision
+	VERIFY(specifier.sign == Builder::Sign::None, "invalid specifier option");
+	VERIFY(specifier.alternativeForm == false, "invalid specifier option");
+	VERIFY(specifier.zeroPadding == false, "invalid specifier option");
+	VERIFY(specifier.precision == -1, "invalid specifier option");
+}
+
+constexpr void Parser::checkSpecifierStringType(const Specifier& specifier)
+{
+	checkSpecifierCStringType(specifier);
+	VERIFY(specifier.type != PresentationType::Pointer, "invalid type specifier");
+}
+
+constexpr void Parser::checkSpecifierPointerType(const Specifier& specifier)
+{
+	checkSpecifierCStringType(specifier);
+	VERIFY(specifier.type != PresentationType::String, "invalid type specifier");
+}
+
+constexpr void Parser::checkSpecifierContainerType(const Specifier& specifier)
+{
+	switch (specifier.type) {
+	case PresentationType::None:
+	case PresentationType::Container:
+		break;
+	default:
+		VERIFY(false, "invalid type specifier");
+	}
+
+	//   Valid: fill + align, alternativeForm, width
+	// Invalid: sign, zeroPadding, precision
+	VERIFY(specifier.sign == Builder::Sign::None, "invalid specifier option");
+	VERIFY(specifier.zeroPadding == false, "invalid specifier option");
+	VERIFY(specifier.precision == -1, "invalid specifier option");
+}
+
+constexpr void Parser::checkSpecifierType(const Specifier& specifier, ParameterType type)
+{
+	switch (type) {
+	case ParameterType::Integral:
+		checkSpecifierIntegralType(specifier);
+		break;
+	case ParameterType::FloatingPoint:
+		checkSpecifierFloatingPointType(specifier);
+		break;
+	case ParameterType::Char:
+		checkSpecifierCharType(specifier);
+		break;
+	case ParameterType::CString:
+		checkSpecifierCStringType(specifier);
+		break;
+	case ParameterType::String:
+		checkSpecifierStringType(specifier);
+		break;
+	case ParameterType::Pointer:
+		checkSpecifierPointerType(specifier);
+		break;
+	case ParameterType::Container:
+		checkSpecifierContainerType(specifier);
+		break;
+	default:
+		VERIFY_NOT_REACHED();
+	}
+}
+
+} // namespace Util::Format

src/util/format/parser.h

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <optional>
+#include <string_view>
+
+#include "util/genericlexer.h"
+
+namespace Util::Format {
+
+class Builder;
+struct Specifier;
+
+class Parser final : public GenericLexer {
+public:
+	enum class ArgumentIndexingMode {
+		Automatic, // {} ,{}
+		Manual,    // {0},{1}
+	};
+
+	enum class ParameterType {
+		Integral,
+		FloatingPoint,
+		Char,
+		CString,
+		String,
+		Pointer,
+		Container,
+	};
+
+	Parser(std::string_view format, size_t parameterCount);
+	virtual ~Parser();
+
+	void checkFormatParameterConsistency();
+	size_t stringToNumber(std::string_view value);
+
+	std::string_view consumeLiteral();
+	std::optional<size_t> consumeIndex();
+
+	void parseSpecifier(Specifier& specifier, ParameterType type);
+	constexpr void checkSpecifierIntegralType(const Specifier& specifier);
+	constexpr void checkSpecifierFloatingPointType(const Specifier& specifier);
+	constexpr void checkSpecifierCharType(const Specifier& specifier);
+	constexpr void checkSpecifierCStringType(const Specifier& specifier);
+	constexpr void checkSpecifierStringType(const Specifier& specifier);
+	constexpr void checkSpecifierPointerType(const Specifier& specifier);
+	constexpr void checkSpecifierContainerType(const Specifier& specifier);
+	constexpr void checkSpecifierType(const Specifier& specifier, ParameterType type);
+
+private:
+	ArgumentIndexingMode m_mode { ArgumentIndexingMode::Automatic };
+	size_t m_parameterCount { 0 };
+};
+
+} // namespace Util::Format

src/util/format/print.cpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdio>  // FILE, fputs, stdout, stderr
+#include <iomanip> // setprecision
+#include <ios>     // defaultfloat, fixed
+#include <sstream> // stringstream
+#include <string>
+#include <string_view>
+
+#include "util/format/print.h"
+
+namespace Util::Format {
+
+void variadicPrint(FILE* file, std::string_view format, TypeErasedParameters& parameters)
+{
+	std::stringstream stream;
+	variadicFormat(stream, format, parameters);
+
+	std::string string = stream.str();
+	fputs(string.c_str(), file);
+}
+
+// -----------------------------------------
+
+PrintOperatorStyle::PrintOperatorStyle(FILE* file)
+	: m_file(file)
+	, m_stream()
+	, m_builder(m_stream)
+{
+}
+
+PrintOperatorStyle::~PrintOperatorStyle()
+{
+	std::string string = m_stream.str();
+	fputs(string.c_str(), m_file);
+}
+
+PrintOperatorStyle print()
+{
+	return PrintOperatorStyle(stdout);
+}
+
+PrintOperatorStyle print(FILE* file)
+{
+	return PrintOperatorStyle(file);
+}
+
+} // namespace Util::Format

src/util/format/print.h

@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstdint> // uint8_t
+#include <cstdio>  // FILE, stdout
+#include <sstream> // stringstream
+#include <string_view>
+
+#include "util/format/format.h"
+#include "util/timer.h"
+
+namespace Util::Format {
+
+void variadicPrint(FILE* file, std::string_view format, TypeErasedParameters& parameters);
+
+template<size_t N, typename... Parameters>
+void print(const char (&format)[N], const Parameters&... parameters)
+{
+	VariadicParameters variadicParameters { parameters... };
+	variadicPrint(stdout, { format, N - 1 }, variadicParameters);
+}
+
+template<size_t N, typename... Parameters>
+void print(FILE* file, const char (&format)[N], const Parameters&... parameters)
+{
+	VariadicParameters variadicParameters { parameters... };
+	variadicPrint(file, { format, N - 1 }, variadicParameters);
+}
+
+// -----------------------------------------
+
+class PrintOperatorStyle {
+public:
+	PrintOperatorStyle(FILE* file);
+	virtual ~PrintOperatorStyle();
+
+	Builder& builder() { return m_builder; }
+
+private:
+	FILE* m_file;
+
+	std::stringstream m_stream;
+	Builder m_builder;
+};
+
+template<typename T>
+const PrintOperatorStyle& operator<<(const PrintOperatorStyle& printOperatorStyle, const T& value)
+{
+	_format(const_cast<PrintOperatorStyle&>(printOperatorStyle).builder(), value);
+	return printOperatorStyle;
+}
+
+PrintOperatorStyle print();
+PrintOperatorStyle print(FILE* file);
+
+// -----------------------------------------
+
+} // namespace Util::Format
+
+namespace Util {
+
+using Util::Format::print;
+
+} // namespace Util

src/util/genericlexer.cpp

@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // max, min
+
+#include "util/genericlexer.h"
+#include "util/meta/assert.h"
+
+namespace Util {
+
+GenericLexer::GenericLexer(std::string_view input)
+	: m_input(input)
+{
+}
+
+GenericLexer::~GenericLexer()
+{
+}
+
+// -----------------------------------------
+
+size_t GenericLexer::tell() const
+{
+	return m_index;
+}
+
+size_t GenericLexer::tellRemaining() const
+{
+	return m_input.length() - m_index;
+}
+
+bool GenericLexer::isEOF() const
+{
+	return m_index >= m_input.length();
+}
+
+char GenericLexer::peek(size_t offset) const
+{
+	return (m_index + offset < m_input.length()) ? m_input[m_index + offset] : '\0';
+}
+
+void GenericLexer::ignore(size_t count)
+{
+	m_index += std::min(count, m_input.length() - m_index);
+}
+
+void GenericLexer::retreat(size_t count)
+{
+	m_index -= std::min(count, m_index);
+}
+
+char GenericLexer::consume()
+{
+	VERIFY(!isEOF());
+	return m_input[m_index++];
+}
+
+bool GenericLexer::consumeSpecific(const char& character)
+{
+	if (peek() != character) {
+		return false;
+	}
+
+	ignore();
+	return true;
+}
+
+} // namespace Util

src/util/genericlexer.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <string_view>
+
+namespace Util {
+
+class GenericLexer {
+public:
+	GenericLexer(std::string_view input);
+	virtual ~GenericLexer();
+
+	// Position
+
+	size_t tell() const;
+	size_t tellRemaining() const;
+	bool isEOF() const;
+
+	// Access
+
+	char peek(size_t offset = 0) const;
+
+	// Modifiers
+
+	void ignore(size_t count = 1);
+	void retreat(size_t count = 1);
+	char consume();
+	bool consumeSpecific(const char& character);
+
+protected:
+	size_t m_index { 0 };
+	std::string_view m_input;
+};
+
+} // namespace Util

src/util/json/array.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "util/json/array.h"
+#include "util/json/value.h"
+
+namespace Util::JSON {
+
+void Array::emplace_back(Value element)
+{
+	m_elements.emplace_back(std::move(element));
+}
+
+Value& Array::operator[](size_t index)
+{
+	if (index + 1 > m_elements.size()) {
+		m_elements.resize(index + 1);
+	}
+
+	return m_elements[index];
+}
+
+} // namespace Util::JSON

src/util/json/array.h

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <utility> // move
+#include <vector>
+
+#include "util/json/parser.h"
+
+namespace Util::JSON {
+
+class Value;
+
+class Array {
+public:
+	Array() {}
+	virtual ~Array() {}
+
+	Array(const std::vector<Value>& elements)
+		: m_elements(elements)
+	{}
+
+	Array(const Array& other)
+		: m_elements(other.m_elements)
+	{
+	}
+
+	// Capacity
+
+	bool empty() const { return m_elements.empty(); }
+	size_t size() const { return m_elements.size(); }
+	void reserve(size_t size) { m_elements.reserve(size); }
+
+	// Element access
+
+	Value& operator[](size_t index);
+
+	Value& at(size_t index) { return m_elements.at(index); }
+	const Value& at(size_t index) const { return m_elements.at(index); }
+
+	const std::vector<Value>& elements() const { return m_elements; }
+
+	// Modifiers
+
+	void clear() { m_elements.clear(); }
+	void emplace_back(Value element);
+
+private:
+	std::vector<Value> m_elements;
+};
+
+} // namespace Util::JSON

src/util/json/fromjson.h

@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <algorithm> // transform
+#include <cstddef>   // nullptr_t
+#include <map>
+#include <string>
+#include <unordered_map>
+#include <utility> // forward
+#include <vector>
+
+#include "util/json/array.h"
+#include "util/json/object.h"
+#include "util/meta/assert.h"
+#include "util/meta/odr.h"
+
+namespace Util::JSON {
+
+namespace Detail {
+
+// Required for containers with Json::Value type
+template<typename Json>
+void fromJson(const Json& json, Json& value)
+{
+	value = json;
+}
+
+template<typename Json>
+void fromJson(const Json& json, std::nullptr_t& null)
+{
+	VERIFY(json.type() == Json::Type::Null);
+	null = nullptr;
+}
+
+template<typename Json>
+void fromJson(const Json& json, bool& boolean)
+{
+	VERIFY(json.type() == Json::Type::Bool);
+	boolean = json.asBool();
+}
+
+template<typename Json>
+void fromJson(const Json& json, int& number)
+{
+	VERIFY(json.type() == Json::Type::Number);
+	number = (int)json.asDouble();
+}
+
+template<typename Json>
+void fromJson(const Json& json, double& number)
+{
+	VERIFY(json.type() == Json::Type::Number);
+	number = json.asDouble();
+}
+
+template<typename Json>
+void fromJson(const Json& json, std::string& string)
+{
+	VERIFY(json.type() == Json::Type::String);
+	string = json.asString();
+}
+
+template<typename Json, typename T>
+void fromJson(const Json& json, std::vector<T>& array)
+{
+	VERIFY(json.type() == Json::Type::Array);
+	array.resize(json.size());
+	std::transform(
+		json.asArray().elements().begin(),
+		json.asArray().elements().end(),
+		array.begin(),
+		[](const Json& json) {
+			return json.template get<T>(); // (missing-dependent-template-keyword)
+		});
+}
+
+template<typename Json, typename T>
+void fromJson(const Json& json, std::map<std::string, T>& object)
+{
+	VERIFY(json.type() == Json::Type::Object);
+	object.clear();
+	for (const auto& [name, value] : json.asObject().members()) {
+		object.emplace(name, value.template get<T>());
+	}
+}
+
+template<typename Json, typename T>
+void fromJson(const Json& json, std::unordered_map<std::string, T>& object)
+{
+	VERIFY(json.type() == Json::Type::Object);
+	object.clear();
+	for (const auto& [name, value] : json.asObject().members()) {
+		object.emplace(name, value.template get<T>());
+	}
+}
+
+struct fromJsonFunction {
+	template<typename Json, typename T>
+	auto operator()(const Json& json, T&& value) const
+	{
+		return fromJson(json, std::forward<T>(value));
+	}
+};
+
+} // namespace Detail
+
+// Anonymous namespace prevents multiple definition of the reference
+namespace {
+// Function object
+constexpr const auto& fromJson = Util::Detail::staticConst<Detail::fromJsonFunction>; // NOLINT(misc-definitions-in-headers,clang-diagnostic-unused-variable)
+} // namespace
+
+} // namespace Util::JSON
+
+// Customization Points
+// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
+
+// Json::fromJson is a function object, the type of which is
+// Json::Detail::fromJsonFunction. In the Json::Detail namespace are the
+// fromJson free functions. The function call operator of fromJsonFunction makes
+// an unqualified call to fromJson which, since it shares the Detail namespace
+// with the fromJson free functions, will consider those in addition to any
+// overloads that are found by argument-dependent lookup.
+
+// Variable templates are linked externally, therefor every translation unit
+// will see the same address for Detail::staticConst<Detail::fromJsonFunction>.
+// Since Json::fromJson is a reference to the variable template, it too will
+// have the same address in all translation units.

src/util/json/job.cpp

@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // count
+#include <sstream>   // istringstream
+#include <string>    // getline
+
+#include "util/json/job.h"
+#include "util/json/lexer.h"
+#include "util/json/parser.h"
+#include "util/json/value.h"
+
+namespace Util::JSON {
+
+Job::Job(std::string_view input)
+	: m_input(input)
+{
+	// FIXME: Make this work for all newline types: \n, \r, \r\n
+	m_lineNumbersWidth = std::count(m_input.begin(), m_input.end(), '\n');
+	m_lineNumbersWidth += m_input.back() == '\n' ? 0 : 1;
+	m_lineNumbersWidth = std::to_string(m_lineNumbersWidth).length();
+}
+
+Job::~Job()
+{
+}
+
+// ------------------------------------------
+
+Value Job::fire()
+{
+	Lexer lexer(this);
+	lexer.analyze();
+
+	if (!m_success) {
+		return nullptr;
+	}
+
+	Parser parser(this);
+	Value value = parser.parse();
+
+	if (!m_success) {
+		return nullptr;
+	}
+
+	return value;
+}
+
+void Job::printErrorLine(Token token, const char* message)
+{
+	m_success = false;
+
+	// Error message
+	std::string errorFormat = "\033[;1m" // Bold
+							  "JSON:%zu:%zu: "
+							  "\033[31;1m" // Bold red
+							  "error: "
+							  "\033[0m" // Reset
+							  "%s"
+							  "\n";
+	fprintf(stderr,
+	        errorFormat.c_str(),
+	        token.line + 1,
+	        token.column + 1,
+	        message);
+
+	// Get the JSON line that caused the error
+	std::istringstream input(m_input.data());
+	std::string line;
+	for (size_t i = 0; std::getline(input, line); ++i) {
+		if (i == token.line) {
+			break;
+		}
+	}
+	// Replace tab indentation with spaces
+	size_t oldLineLength = line.length();
+	size_t tabs = line.find_first_not_of('\t');
+	if (tabs > 0 && tabs < line.size()) {
+		line = std::string(tabs * 4, ' ') + line.substr(tabs);
+	}
+	token.column += line.length() - oldLineLength;
+
+	// JSON line
+	std::string lineFormat = " %"
+	                         + std::to_string(m_lineNumbersWidth)
+	                         + "zu | "
+	                           "%s"
+	                           "\033[31;1m" // Bold red
+	                           "%s"
+	                           "\033[0m" // Reset
+	                           "\n";
+	fprintf(stderr,
+	        lineFormat.c_str(),
+	        token.line + 1,
+	        line.substr(0, token.column).c_str(),
+	        line.substr(token.column).c_str());
+
+	// Arrow pointer
+	std::string arrowFormat = " %s | "
+							  "\033[31;1m" // Bold red
+							  "%s^%s"
+							  "\033[0m" // Reset
+							  "\n";
+	fprintf(stderr,
+	        arrowFormat.c_str(),
+	        std::string(m_lineNumbersWidth, ' ').c_str(),
+	        std::string(token.column, ' ').c_str(),
+	        std::string(line.length() - token.column, '~').c_str());
+}
+
+} // namespace Util::JSON

src/util/json/job.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <string_view>
+#include <vector>
+
+#include "util/json/lexer.h"
+
+namespace Util::JSON {
+
+class Value;
+
+class Job {
+public:
+	Job(std::string_view input);
+	virtual ~Job();
+
+	Value fire();
+
+	void printErrorLine(Token token, const char* message);
+
+	bool success() const { return m_success; }
+	std::string_view input() const { return m_input; }
+	std::vector<Token>* tokens() { return &m_tokens; }
+
+private:
+	bool m_success { true };
+
+	std::string_view m_input;
+	size_t m_lineNumbersWidth { 0 };
+
+	std::vector<Token> m_tokens;
+};
+
+} // namespace Util::JSON

src/util/json/json.h

@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include "util/json/value.h"
+
+namespace Util {
+
+using Json = Util::JSON::Value;
+
+} // namespace Util

src/util/json/lexer.cpp

@@ -0,0 +1,217 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstddef>
+#include <string>
+
+#include "util/json/job.h"
+#include "util/json/lexer.h"
+
+namespace Util::JSON {
+
+Lexer::Lexer(Job* job)
+	: GenericLexer(job->input())
+	, m_job(job)
+	, m_tokens(job->tokens())
+{
+}
+
+Lexer::~Lexer()
+{
+}
+
+// -----------------------------------------
+
+void Lexer::analyze()
+{
+	while (m_index < m_input.length()) {
+		switch (peek()) {
+		case '{':
+			m_tokens->push_back({ Token::Type::BraceOpen, m_line, m_column, "{" });
+			break;
+		case '}':
+			m_tokens->push_back({ Token::Type::BraceClose, m_line, m_column, "}" });
+			break;
+		case '[':
+			m_tokens->push_back({ Token::Type::BracketOpen, m_line, m_column, "[" });
+			break;
+		case ']':
+			m_tokens->push_back({ Token::Type::BracketClose, m_line, m_column, "]" });
+			break;
+		case ':':
+			m_tokens->push_back({ Token::Type::Colon, m_line, m_column, ":" });
+			break;
+		case ',':
+			m_tokens->push_back({ Token::Type::Comma, m_line, m_column, "," });
+			break;
+		case '"':
+			if (!consumeString()) {
+				return;
+			}
+			break;
+		case '-':
+		case '0':
+		case '1':
+		case '2':
+		case '3':
+		case '4':
+		case '5':
+		case '6':
+		case '7':
+		case '8':
+		case '9':
+			if (!consumeNumber()) {
+				return;
+			}
+			break;
+		case 'a':
+		case 'b':
+		case 'c':
+		case 'd':
+		case 'e':
+		case 'f':
+		case 'g':
+		case 'h':
+		case 'i':
+		case 'j':
+		case 'k':
+		case 'l':
+		case 'm':
+		case 'n':
+		case 'o':
+		case 'p':
+		case 'q':
+		case 'r':
+		case 's':
+		case 't':
+		case 'u':
+		case 'v':
+		case 'w':
+		case 'x':
+		case 'y':
+		case 'z':
+			if (!consumeLiteral()) {
+				return;
+			}
+			break;
+		case ' ':
+		case '\t':
+			break;
+		case '\r':
+			if (peek(1) == '\n') { // CRLF \r\n
+				break;
+			}
+			m_column = -1;
+			m_line++;
+			break;
+		case '\n':
+			m_column = -1;
+			m_line++;
+			break;
+		default:
+			// Error!
+			m_tokens->push_back({ Token::Type::None, m_line, m_column, std::string(1, peek()) });
+			m_job->printErrorLine(m_tokens->back(),
+			                      (std::string() + "unexpected character '" + peek() + "'").c_str());
+			return;
+			break;
+		}
+
+		ignore();
+		m_column++;
+	}
+}
+
+// -----------------------------------------
+
+bool Lexer::consumeString()
+{
+	size_t column = m_column;
+	std::string symbol = "";
+
+	bool escape = false;
+	char character = consume();
+	for (;;) {
+		character = peek();
+
+		if (!escape && character == '\\') {
+			symbol += '\\';
+			ignore();
+			escape = true;
+			continue;
+		}
+
+		if (!escape
+		    && (character == '"'
+		        || character == '\r'
+		        || character == '\n'
+		        || character == '\0')) {
+			break;
+		}
+
+		symbol += character;
+		ignore();
+
+		if (escape) {
+			escape = false;
+		}
+	}
+
+	m_tokens->push_back({ Token::Type::String, m_line, column, symbol });
+
+	if (character != '"') {
+		m_job->printErrorLine(m_job->tokens()->back(), "strings should be wrapped in double quotes");
+		return false;
+	}
+
+	return true;
+}
+
+bool Lexer::consumeNumberOrLiteral(Token::Type type)
+{
+	size_t index = m_index;
+	size_t column = m_column;
+
+	for (char character;;) {
+		character = peek();
+
+		if (character == '{'
+		    || character == '}'
+		    || character == '['
+		    || character == ']'
+		    || character == ':'
+		    || character == ','
+		    || character == '"'
+		    || character == ' '
+		    || character == '\t'
+		    || character == '\r'
+		    || character == '\n'
+		    || character == '\0') {
+			break;
+		}
+
+		ignore();
+	}
+
+	m_tokens->push_back({ type, m_line, column,
+	                      std::string(m_input.substr(index, m_index - index)) });
+
+	retreat();
+
+	return true;
+}
+
+bool Lexer::consumeNumber()
+{
+	return consumeNumberOrLiteral(Token::Type::Number);
+}
+
+bool Lexer::consumeLiteral()
+{
+	return consumeNumberOrLiteral(Token::Type::Literal);
+}
+
+} // namespace Util::JSON

src/util/json/lexer.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+// The JavaScript Object Notation (JSON) Data Interchange Format
+// https://www.rfc-editor.org/rfc/pdfrfc/rfc8259.txt.pdf
+
+#include <cstddef> // size_t
+#include <cstdint> // uint8_t
+#include <string>
+#include <vector>
+
+#include "util/genericlexer.h"
+
+namespace Util::JSON {
+
+class Job;
+
+struct Token {
+	enum class Type : uint8_t {
+		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 final : public Util::GenericLexer {
+public:
+	Lexer(Job* job);
+	virtual ~Lexer();
+
+	void analyze();
+
+private:
+	bool consumeString();
+	bool consumeNumberOrLiteral(Token::Type type);
+	bool consumeNumber();
+	bool consumeLiteral();
+
+	Job* m_job { nullptr };
+
+	size_t m_column { 0 };
+	size_t m_line { 0 };
+
+	std::vector<Token>* m_tokens { nullptr };
+};
+
+} // namespace Util::JSON

src/util/json/object.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "util/json/object.h"
+#include "util/json/value.h"
+
+namespace Util::JSON {
+
+void Object::emplace(const std::string& name, Value value)
+{
+	m_members.emplace(name, std::move(value));
+}
+
+Value& Object::operator[](const std::string& name)
+{
+	if (m_members.find(name) == m_members.end()) {
+		emplace(name, {});
+	}
+
+	return m_members.at(name);
+}
+
+} // namespace Util::JSON

src/util/json/object.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <map>
+#include <string>
+#include <utility> // move
+
+#include "util/json/parser.h"
+
+namespace Util::JSON {
+
+class Value;
+
+class Object {
+public:
+	Object() {}
+	virtual ~Object() {}
+
+	Object(const Object& other)
+		: m_members(other.m_members)
+	{
+	}
+
+	// Capacity
+
+	bool empty() const { return m_members.empty(); }
+	size_t size() const { return m_members.size(); }
+
+	// Member access
+
+	Value& operator[](const std::string& name);
+
+	Value& at(const std::string& name) { return m_members.at(name); }
+	const Value& at(const std::string& name) const { return m_members.at(name); }
+
+	const std::map<std::string, Value>& members() const { return m_members; }
+
+	// Modifiers
+
+	void clear() { m_members.clear(); }
+	void emplace(const std::string& name, Value value);
+
+private:
+	std::map<std::string, Value> m_members;
+};
+
+} // namespace Util::JSON

src/util/json/parser.cpp

@@ -0,0 +1,497 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // count
+#include <cstddef>   // size_t
+#include <cstdint>   // uint8_t
+#include <cstdio>    // printf
+#include <map>
+#include <string> // stod
+
+#include "util/json/array.h"
+#include "util/json/job.h"
+#include "util/json/lexer.h"
+#include "util/json/object.h"
+#include "util/json/parser.h"
+#include "util/json/value.h"
+#include "util/meta/assert.h"
+
+namespace Util::JSON {
+
+Parser::Parser(Job* job)
+	: m_job(job)
+	, m_tokens(m_job->tokens())
+{
+}
+
+Parser::~Parser()
+{
+}
+
+// -----------------------------------------
+
+Value Parser::parse()
+{
+	Value result;
+
+	if (m_tokens->size() == 0) {
+		m_job->printErrorLine({}, "expecting token, not 'EOF'");
+		return result;
+	}
+
+	Token token = peek();
+	switch (token.type) {
+	case Token::Type::Literal:
+		result = consumeLiteral();
+		break;
+	case Token::Type::Number:
+		result = consumeNumber();
+		break;
+	case Token::Type::String:
+		result = consumeString();
+		break;
+	case Token::Type::BracketOpen:
+		result = consumeArray();
+		break;
+	case Token::Type::BraceOpen:
+		result = consumeObject();
+		break;
+	case Token::Type::BracketClose:
+		m_job->printErrorLine(token, "expecting value, not ']'");
+		m_index++;
+		break;
+	case Token::Type::BraceClose:
+		m_job->printErrorLine(token, "expecting string, not '}'");
+		m_index++;
+		break;
+	default:
+		m_job->printErrorLine(token, "multiple root elements");
+		m_index++;
+		break;
+	}
+
+	if (!isEOF()) {
+		m_job->printErrorLine(peek(), "multiple root elements");
+	}
+
+	return result;
+}
+
+// -----------------------------------------
+
+bool Parser::isEOF()
+{
+	return m_index >= m_tokens->size();
+}
+
+Token Parser::peek()
+{
+	VERIFY(!isEOF());
+	return (*m_tokens)[m_index];
+}
+
+Token Parser::consume()
+{
+	VERIFY(!isEOF());
+	return (*m_tokens)[m_index++];
+}
+
+void Parser::ignoreUntil(Token::Type type)
+{
+	while (!isEOF() && peek().type != type) {
+		++m_index;
+	}
+}
+
+Value Parser::consumeLiteral()
+{
+	Token token = consume();
+
+	if (token.symbol == "null") {
+		return nullptr;
+	}
+	else if (token.symbol == "true") {
+		return true;
+	}
+	else if (token.symbol == "false") {
+		return false;
+	}
+
+	m_job->printErrorLine(token, "invalid literal");
+	return nullptr;
+}
+
+Value Parser::consumeNumber()
+{
+	Token token = consume();
+
+	auto reportError = [this](Token token, const std::string& message) -> void {
+		m_job->printErrorLine(token, message.c_str());
+	};
+
+	// Validation
+	// number = [ minus ] int [ frac ] [ exp ]
+
+	size_t minusPrefix = token.symbol[0] == '-' ? 1 : 0;
+
+	// Leading 0s
+	if (token.symbol[minusPrefix] == '0'
+	    && token.symbol[minusPrefix + 1] > '0' && token.symbol[minusPrefix + 1] < '9') {
+		reportError(token, "invalid leading zero");
+		return nullptr;
+	}
+
+	enum class State : uint8_t {
+		Int,
+		Fraction,
+		Exponent
+	};
+
+	State state = State::Int;
+
+#define CHECK_IF_VALID_NUMBER                                                                  \
+	if (character < 48 || character > 57) {                                                    \
+		reportError(token, std::string() + "invalid number, unexpected '" + character + '\''); \
+		return nullptr;                                                                        \
+	}
+
+	size_t fractionPosition = 0;
+	size_t exponentPosition = 0;
+	size_t length = token.symbol.length();
+	for (size_t i = 0; i < length; ++i) {
+		char character = token.symbol[i];
+
+		// Int -> Fraction
+		if (character == '.' && state == State::Int) {
+			state = State::Fraction;
+			fractionPosition = i;
+			continue;
+		}
+		// Int/Fraction -> Exponent
+		else if ((character == 'e' || character == 'E') && state != State::Exponent) {
+			state = State::Exponent;
+			exponentPosition = i;
+			continue;
+		}
+
+		if (state == State::Int) {
+			if (character == '-') {
+				if (i == length - 1) {
+					reportError(token, "expected number after minus");
+					return nullptr;
+				}
+				if (i != 0) {
+					reportError(token, "invalid minus");
+					return nullptr;
+				}
+			}
+			else {
+				CHECK_IF_VALID_NUMBER;
+			}
+		}
+		else if (state == State::Fraction) {
+			CHECK_IF_VALID_NUMBER;
+		}
+		else if (state == State::Exponent) {
+			if (character == '-' || character == '+') {
+				if (i == length - 1) {
+					reportError(token, "expected number after plus/minus");
+					return nullptr;
+				}
+				if (i > exponentPosition + 1) {
+					reportError(token, "invalid plus/minus");
+					return nullptr;
+				}
+			}
+			else {
+				CHECK_IF_VALID_NUMBER;
+			}
+		}
+	}
+
+	if (fractionPosition != 0 || exponentPosition != 0) {
+		if (fractionPosition == exponentPosition - 1) {
+			reportError(token, "invalid exponent sign, expected number");
+			return nullptr;
+		}
+
+		if (fractionPosition == length - 1 || exponentPosition == length - 1) {
+			reportError(token, "invalid number");
+			return nullptr;
+		}
+	}
+
+	return std::stod(token.symbol);
+}
+
+Value Parser::consumeString()
+{
+	Token token = consume();
+
+	auto reportError = [this](Token token, const std::string& message) -> void {
+		m_job->printErrorLine(token, message.c_str());
+	};
+
+	// FIXME: support \u Unicode character escape sequence
+	auto getPrintableString = [](char character) -> std::string {
+		if (character == '"' || character == '\\' || character == '/'
+		    || (character >= 0 && character <= 31)) {
+			switch (character) {
+			case '"':
+				return "\\\"";
+				break;
+			case '\\':
+				return "\\\\";
+				break;
+			case '/':
+				return "/";
+				break;
+			case '\b':
+				return "\\b";
+				break;
+			case '\f':
+				return "\\f";
+				break;
+			case '\n':
+				return "\\n";
+				break;
+			case '\r':
+				return "\\r";
+				break;
+			case '\t':
+				return "\\t";
+				break;
+			default:
+				char buffer[7];
+				sprintf(buffer, "\\u%0.4X", character);
+				return std::string(buffer);
+				break;
+			}
+		}
+
+		return std::string() + character;
+	};
+
+	std::string string;
+
+	bool escape = false;
+	for (char character : token.symbol) {
+		if (!escape) {
+			if (character == '\\') {
+				escape = true;
+				continue;
+			}
+
+			if (character == '"' || (character >= 0 && character <= 31)) {
+				reportError(token, "invalid string, unescaped character found");
+				return nullptr;
+			}
+		}
+
+		string += getPrintableString(character);
+
+		if (escape) {
+			escape = false;
+		}
+	}
+
+	return string;
+}
+
+Value Parser::consumeArray()
+{
+	m_index++;
+
+	auto reportError = [this](Token token, const std::string& message) -> void {
+		m_job->printErrorLine(token, message.c_str());
+
+		// After an error, try to find the closing bracket
+		ignoreUntil(Token::Type::BracketClose);
+		m_index++;
+	};
+
+	Value array = Value::Type::Array;
+	Token token;
+	for (;;) {
+		// EOF
+		if (isEOF()) {
+			reportError(m_tokens->at(m_index - 1), "expecting closing ']' at end");
+			break;
+		}
+
+		token = peek();
+		if (token.type == Token::Type::Literal) {
+			array.emplace_back(consumeLiteral());
+		}
+		else if (token.type == Token::Type::Number) {
+			array.emplace_back(consumeNumber());
+		}
+		else if (token.type == Token::Type::String) {
+			array.emplace_back(consumeString());
+		}
+		else if (token.type == Token::Type::BracketOpen) {
+			array.emplace_back(consumeArray());
+		}
+		else if (token.type == Token::Type::BraceOpen) {
+			array.emplace_back(consumeObject());
+		}
+		else if (token.type == Token::Type::BracketClose) {
+			// Trailing comma
+			if (array.m_value.array->size() > 0) {
+				reportError(m_tokens->at(m_index - 1), "invalid comma, expecting ']'");
+				break;
+			}
+		}
+		else {
+			reportError(token, "expecting value or ']', not '" + token.symbol + "'");
+			break;
+		}
+
+		// EOF
+		if (isEOF()) {
+			reportError(token, "expecting closing ']' at end");
+			break;
+		}
+
+		// Find , or ]
+		token = consume();
+		if (token.type == Token::Type::Comma) {
+			continue;
+		}
+		else if (token.type == Token::Type::BracketClose) {
+			break;
+		}
+		else {
+			reportError(m_tokens->at(m_index - 1), "expecting comma or ']', not '" + token.symbol + "'");
+			break;
+		}
+	}
+
+	return array;
+}
+
+Value Parser::consumeObject()
+{
+	m_index++;
+
+	auto reportError = [this](Token token, const std::string& message) -> void {
+		m_job->printErrorLine(token, message.c_str());
+
+		// After an error, try to find the closing brace
+		ignoreUntil(Token::Type::BraceClose);
+		m_index++;
+	};
+
+	Value object = Value::Type::Object;
+	Token token;
+	std::string name;
+	std::map<std::string, uint8_t> unique;
+	for (;;) {
+		// EOF
+		if (isEOF()) {
+			reportError(m_tokens->at(m_index - 1), "expecting closing '}' at end");
+			break;
+		}
+
+		token = consume();
+		if (token.type == Token::Type::BraceClose) {
+			// Trailing comma
+			if (object.m_value.object->size() > 0) {
+				reportError(m_tokens->at(m_index - 1), "invalid comma, expecting '}'");
+			}
+			// Empty object
+			break;
+		}
+		if (token.type != Token::Type::String) {
+			reportError(token, "expecting string or '}', not '" + token.symbol + "'");
+			break;
+		}
+
+		// Find member name
+		m_index--;
+		Value tmpName = consumeString();
+		if (tmpName.m_type != Value::Type::String) {
+			ignoreUntil(Token::Type::BraceClose);
+			m_index++;
+			break;
+		}
+
+		// Check if name exists in hashmap
+		name = *tmpName.m_value.string;
+		if (unique.find(name) != unique.end()) {
+			reportError(token, "duplicate name '" + token.symbol + "', names should be unique");
+			break;
+		}
+		// Add name to hashmap
+		unique.insert({ name, 0 });
+
+		// EOF
+		if (isEOF()) {
+			reportError(token, "expecting colon, not 'EOF'");
+			reportError(token, "expecting closing '}' at end");
+			break;
+		}
+
+		// Find :
+		token = consume();
+		if (token.type != Token::Type::Colon) {
+			reportError(token, "expecting colon, not '" + token.symbol + "'");
+			break;
+		}
+
+		// EOF
+		if (isEOF()) {
+			reportError(token, "expecting value, not 'EOF'");
+			reportError(token, "expecting closing '}' at end");
+			break;
+		}
+
+		// Add member (name:value pair) to object
+		token = peek();
+		if (token.type == Token::Type::Literal) {
+			object.emplace(name, consumeLiteral());
+		}
+		else if (token.type == Token::Type::Number) {
+			object.emplace(name, consumeNumber());
+		}
+		else if (token.type == Token::Type::String) {
+			object.emplace(name, consumeString());
+		}
+		else if (token.type == Token::Type::BracketOpen) {
+			object.emplace(name, consumeArray());
+		}
+		else if (token.type == Token::Type::BraceOpen) {
+			object.emplace(name, consumeObject());
+		}
+		else {
+			reportError(token, "expecting value, not '" + token.symbol + "'");
+			break;
+		}
+
+		// EOF
+		if (isEOF()) {
+			reportError(token, "expecting closing '}' at end");
+			break;
+		}
+
+		// Find , or }
+		token = consume();
+		if (token.type == Token::Type::Comma) {
+			continue;
+		}
+		else if (token.type == Token::Type::BraceClose) {
+			break;
+		}
+		else {
+			reportError(token, "expecting comma or '}', not '" + token.symbol + "'");
+			break;
+		}
+	}
+
+	return object;
+}
+
+} // namespace Util::JSON

src/util/json/parser.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <vector>
+
+#include "util/json/lexer.h"
+
+namespace Util::JSON {
+
+class Job;
+class Value;
+
+class Parser {
+public:
+	Parser(Job* job);
+	virtual ~Parser();
+
+	Value parse();
+
+private:
+	bool isEOF();
+	Token peek();
+	Token consume();
+	void ignoreUntil(Token::Type type);
+
+	Value consumeLiteral();
+	Value consumeNumber();
+	Value consumeString();
+	Value consumeArray();
+	Value consumeObject();
+
+	Job* m_job { nullptr };
+
+	size_t m_index { 0 };
+
+	std::vector<Token>* m_tokens { nullptr };
+};
+
+} // namespace Util::JSON

src/util/json/serializer.cpp

@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <cstdint>  // uint32_t
+#include <iterator> // next
+#include <sstream>  // ostringstream
+#include <string>
+
+#include "util/json/array.h"
+#include "util/json/lexer.h"
+#include "util/json/object.h"
+#include "util/json/serializer.h"
+
+namespace Util::JSON {
+
+Serializer::Serializer(const uint32_t indent, const char indentCharacter)
+	: m_indent(indent)
+	, m_indentCharacter(indentCharacter)
+	, m_compact(indent == 0)
+{
+}
+
+Serializer::~Serializer()
+{
+}
+
+// ------------------------------------------
+
+std::string Serializer::dump(const Value& value)
+{
+	dumpHelper(value);
+	return m_output;
+}
+
+// ------------------------------------------
+
+void Serializer::dumpHelper(const Value& value, const uint32_t indentLevel)
+{
+	switch (value.m_type) {
+	case Value::Type::Null:
+		m_output += "null";
+		break;
+	case Value::Type::Bool:
+		m_output += value.m_value.boolean ? "true" : "false";
+		break;
+	case Value::Type::Number: {
+		std::ostringstream os;
+		os << value.m_value.number;
+		m_output += os.str();
+		break;
+	}
+	case Value::Type::String:
+		m_output += "\"" + *value.m_value.string + "\"";
+		break;
+	case Value::Type::Array:
+		dumpArray(value, indentLevel);
+		break;
+	case Value::Type::Object:
+		dumpObject(value, indentLevel);
+		break;
+	default:
+		break;
+	}
+}
+
+void Serializer::dumpArray(const Value& value, const uint32_t indentLevel)
+{
+	m_output += '[';
+	if (!m_compact) {
+		m_output += '\n';
+	}
+
+	// Empty Array early return
+	if (value.m_value.array->empty()) {
+		m_output += ']';
+		return;
+	}
+
+	size_t i = 0;
+	auto it = value.m_value.array->elements().cbegin();
+	if (!m_indent) {
+		for (; i < value.m_value.array->size() - 1; ++i, ++it) {
+			dumpHelper(*it, indentLevel + 1);
+			m_output += ',';
+		}
+		dumpHelper(*it, indentLevel + 1);
+	}
+	else {
+		std::string indentation = std::string(m_indent * (indentLevel + 1), m_indentCharacter);
+
+		for (; i < value.m_value.array->size() - 1; ++i, ++it) {
+			m_output += indentation;
+			dumpHelper(*it, indentLevel + 1);
+			m_output += ",\n";
+		}
+		m_output += indentation;
+		dumpHelper(*it, indentLevel + 1);
+		m_output += '\n';
+
+		// Append indentation
+		m_output += std::string(m_indent * indentLevel, m_indentCharacter);
+	}
+
+	m_output += "]";
+}
+
+void Serializer::dumpObject(const Value& value, const uint32_t indentLevel)
+{
+	m_output += '{';
+	if (!m_compact) {
+		m_output += '\n';
+	}
+
+	// Empty Object early return
+	if (value.m_value.object->empty()) {
+		m_output += '}';
+		return;
+	}
+
+	size_t i = 0;
+	auto it = value.m_value.object->members().cbegin();
+	if (!m_indent) {
+		for (; i < value.m_value.object->size() - 1; ++i, ++it) {
+			m_output += '"' + it->first + "\":";
+			dumpHelper(it->second, indentLevel + 1);
+			m_output += ',';
+		}
+		m_output += '"' + it->first + "\":";
+		dumpHelper(it->second, indentLevel + 1);
+	}
+	else {
+		std::string indentation = std::string(m_indent * (indentLevel + 1), m_indentCharacter);
+
+		for (; i < value.m_value.object->size() - 1; ++i, ++it) {
+			m_output += indentation;
+			m_output += '"' + it->first + "\": ";
+			dumpHelper(it->second, indentLevel + 1);
+			m_output += ",\n";
+		}
+		m_output += indentation;
+		m_output += '"' + it->first + "\": ";
+		dumpHelper(it->second, indentLevel + 1);
+		m_output += '\n';
+
+		// Append indentation
+		m_output += std::string(m_indent * indentLevel, m_indentCharacter);
+	}
+
+	m_output += '}';
+}
+
+} // namespace Util::JSON

src/util/json/serializer.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstdint> // uint32_t
+#include <string>
+
+#include "util/json/value.h"
+
+namespace Util::JSON {
+
+class Serializer {
+public:
+	Serializer(const uint32_t indent = 0, const char indentCharacter = ' ');
+	virtual ~Serializer();
+
+	std::string dump(const Value& value);
+
+private:
+	void dumpHelper(const Value& value, const uint32_t indentLevel = 0);
+	void dumpArray(const Value& value, const uint32_t indentLevel = 0);
+	void dumpObject(const Value& value, const uint32_t indentLevel = 0);
+
+	std::string m_output;
+
+	uint32_t m_indent { 0 };
+	char m_indentCharacter { ' ' };
+	bool m_compact { true };
+};
+
+} // namespace Util::JSON

src/util/json/tojson.h

@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cassert> // assert
+#include <cstddef> // nullptr_t
+#include <map>
+#include <string>
+#include <unordered_map>
+#include <utility> // forward
+
+#include "util/json/array.h"
+#include "util/json/object.h"
+#include "util/meta/odr.h"
+
+namespace Util::JSON {
+
+namespace Detail {
+
+struct jsonConstructor {
+	template<typename Json>
+	static void construct(Json& json, bool boolean)
+	{
+		json.destroy();
+		json.m_type = Json::Type::Bool;
+		json.m_value.boolean = boolean;
+	}
+
+	template<typename Json>
+	static void construct(Json& json, int number)
+	{
+		json.destroy();
+		json.m_type = Json::Type::Number;
+		json.m_value.number = (double)number;
+	}
+
+	template<typename Json>
+	static void construct(Json& json, double number)
+	{
+		json.destroy();
+		json.m_type = Json::Type::Number;
+		json.m_value.number = number;
+	}
+
+	template<typename Json>
+	static void construct(Json& json, const char* string)
+	{
+		json.destroy();
+		json.m_type = Json::Type::String;
+		json.m_value.string = new std::string(string);
+	}
+
+	template<typename Json>
+	static void construct(Json& json, const std::string& string)
+	{
+		json.destroy();
+		json.m_type = Json::Type::String;
+		json.m_value.string = new std::string(string);
+	}
+
+	template<typename Json>
+	static void construct(Json& json, const Array& array)
+	{
+		json.destroy();
+		json.m_type = Json::Type::Array;
+		json.m_value.array = new Array(array);
+	}
+
+	template<typename Json, typename T>
+	static void construct(Json& json, const std::vector<T>& array)
+	{
+		json.destroy();
+		json.m_type = Json::Type::Array;
+		json.m_value.array = new Array;
+		json.m_value.array->reserve(array.size());
+		for (const T& value : array) {
+			json.m_value.array->emplace_back(value);
+		}
+	}
+
+	template<typename Json>
+	static void construct(Json& json, const Object& object)
+	{
+		json.destroy();
+		json.m_type = Json::Type::Object;
+		json.m_value.object = new Object(object);
+	}
+
+	template<typename Json, typename T>
+	static void construct(Json& json, const std::map<std::string, T>& object)
+	{
+		json.destroy();
+		json.m_type = Json::Type::Object;
+		json.m_value.object = new Object;
+		for (const auto& [name, value] : object) {
+			json.m_value.object->emplace(name, value);
+		}
+	}
+
+	template<typename Json, typename T>
+	static void construct(Json& json, const std::unordered_map<std::string, T>& object)
+	{
+		json.destroy();
+		json.m_type = Json::Type::Object;
+		json.m_value.object = new Object;
+		for (const auto& [name, value] : object) {
+			json.m_value.object->emplace(name, value);
+		}
+	}
+};
+
+template<typename Json, typename T>
+void toJson(Json& json, const T& value)
+{
+	jsonConstructor::construct(json, value);
+}
+
+struct toJsonFunction {
+	template<typename Json, typename T>
+	auto operator()(Json& json, T&& value) const
+	{
+		return toJson(json, std::forward<T>(value));
+	}
+};
+
+} // namespace Detail
+
+// Anonymous namespace prevents multiple definition of the reference
+namespace {
+// Function object
+constexpr const auto& toJson = Util::Detail::staticConst<Detail::toJsonFunction>; // NOLINT(misc-definitions-in-headers,clang-diagnostic-unused-variable)
+} // namespace
+
+} // namespace Util::JSON
+
+// Customization Points
+// https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
+
+// Json::toJson is a function object, the type of which is
+// Json::Detail::toJsonFunction. In the Json::Detail namespace are the toJson
+// free functions. The function call operator of toJsonFunction makes an
+// unqualified call to toJson which, since it shares the Detail namespace with
+// the toJson free functions, will consider those in addition to any overloads
+// that are found by argument-dependent lookup.
+
+// Variable templates are linked externally, therefor every translation unit
+// will see the same address for Detail::staticConst<Detail::toJsonFunction>.
+// Since Json::toJson is a reference to the variable template, it too will have
+// the same address in all translation units.

src/util/json/value.cpp

@@ -0,0 +1,340 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <algorithm> // all_of
+#include <cstdint>   // uint32_t
+#include <fstream>   // >>
+#include <iostream>  // istream, ostream
+#include <string>
+#include <utility> // move, swap
+
+#include "util/format/builder.h"
+#include "util/json/array.h"
+#include "util/json/job.h"
+#include "util/json/object.h"
+#include "util/json/serializer.h"
+#include "util/json/value.h"
+#include "util/meta/assert.h"
+
+namespace Util::JSON {
+
+Value::Value(std::nullptr_t)
+	: Value(Type::Null)
+{
+}
+
+Value::Value(Type type)
+	: m_type(type)
+{
+	switch (m_type) {
+	case Type::Bool:
+		m_value.boolean = false;
+		break;
+	case Type::Number:
+		m_value.number = 0.0;
+		break;
+	case Type::String:
+		m_value.string = new std::string;
+		break;
+	case Type::Array:
+		m_value.array = new Array;
+		break;
+	case Type::Object:
+		m_value.object = new Object;
+		break;
+	case Type::Null:
+	default:
+		break;
+	}
+}
+
+Value::Value(const std::initializer_list<Value>& values)
+{
+	bool isObject = std::all_of(values.begin(), values.end(), [](const Value& value) {
+		return value.type() == Type::Array
+		       && value.size() == 2
+		       && value[0].m_type == Type::String;
+	});
+
+	if (!isObject) {
+		m_type = Type::Array;
+		m_value.array = new Array(values);
+	}
+	else {
+		m_type = Type::Object;
+		m_value.object = new Object;
+
+		for (auto& value : values) {
+			m_value.object->emplace(std::move(*value[0].m_value.string),
+			                        std::move(value[1]));
+		}
+	}
+}
+
+// Copy constructor
+Value::Value(const Value& other)
+	: m_type(other.m_type)
+{
+	switch (m_type) {
+	case Type::Bool:
+		m_value.boolean = other.m_value.boolean;
+		break;
+	case Type::Number:
+		m_value.number = other.m_value.number;
+		break;
+	case Type::String:
+		m_value.string = new std::string(*other.m_value.string);
+		break;
+	case Type::Array:
+		m_value.array = new Array(*other.m_value.array);
+		break;
+	case Type::Object:
+		m_value.object = new Object(*other.m_value.object);
+		break;
+	case Type::Null:
+	default:
+		break;
+	}
+}
+
+// Move constructor
+Value::Value(Value&& other) noexcept
+	: Value(Type::Null) // Initialize via default construction
+{
+	// Allow std::swap as a fallback on ADL failure
+	using std::swap;
+	// Unqualified call to swap, allow ADL to operate and find best match
+	swap(*this, other);
+}
+
+// Copy assignment
+// Move assignment
+Value& Value::operator=(Value other)
+{
+	// Allow std::swap as a fallback on ADL failure
+	using std::swap;
+	// Unqualified call to swap, allow ADL to operate and find best match
+	swap(*this, other);
+
+	return *this;
+}
+
+void swap(Value& left, Value& right) noexcept
+{
+	std::swap(left.m_type, right.m_type);
+	std::swap(left.m_value, right.m_value);
+}
+
+// ------------------------------------------
+
+void Value::clear()
+{
+	switch (m_type) {
+	case Type::Bool:
+		m_value.boolean = false;
+		break;
+	case Type::Number:
+		m_value.number = 0.0;
+		break;
+	case Type::String:
+		m_value.string->clear();
+		break;
+	case Type::Array:
+		m_value.array->clear();
+		break;
+	case Type::Object:
+		m_value.object->clear();
+		break;
+	case Type::Null:
+	default:
+		break;
+	}
+}
+
+Value Value::parse(std::string_view input)
+{
+	return Job(input).fire();
+}
+
+Value Value::parse(std::ifstream& file)
+{
+	Value value;
+	file >> value;
+	return value;
+}
+
+std::string Value::dump(const uint32_t indent, const char indentCharacter) const
+{
+	Serializer serializer(indent, indentCharacter);
+	return serializer.dump(*this);
+}
+
+void Value::emplace_back(Value value)
+{
+	// Implicitly convert null to an array
+	if (m_type == Type::Null) {
+		m_type = Type::Array;
+		m_value.array = new Array;
+	}
+
+	VERIFY(m_type == Type::Array);
+	m_value.array->emplace_back(value);
+}
+
+void Value::emplace(const std::string& key, Value value)
+{
+	// Implicitly convert null to an object
+	if (m_type == Type::Null) {
+		m_type = Type::Object;
+		m_value.object = new Object;
+	}
+
+	VERIFY(m_type == Type::Object);
+	m_value.object->emplace(key, value);
+}
+
+bool Value::exists(size_t index) const
+{
+	return index < size();
+}
+
+bool Value::exists(const std::string& key) const
+{
+	VERIFY(m_type == Type::Object);
+	return m_value.object->members().find(key) != m_value.object->members().end();
+}
+
+// ------------------------------------------
+
+Value& Value::operator[](size_t index)
+{
+	// Implicitly convert null to an array
+	if (m_type == Type::Null) {
+		m_type = Type::Array;
+		m_value.array = new Array;
+	}
+
+	VERIFY(m_type == Type::Array);
+	return (*m_value.array)[index];
+}
+
+Value& Value::operator[](const std::string& key)
+{
+	// Implicitly convert null to an object
+	if (m_type == Type::Null) {
+		m_type = Type::Object;
+		m_value.object = new Object;
+	}
+
+	VERIFY(m_type == Type::Object);
+	return (*m_value.object)[key];
+}
+
+const Value& Value::operator[](size_t index) const
+{
+	VERIFY(m_type == Type::Array);
+	return (*m_value.array)[index];
+}
+
+const Value& Value::operator[](const std::string& key) const
+{
+	VERIFY(m_type == Type::Object);
+	return (*m_value.object)[key];
+}
+
+Value& Value::at(size_t index)
+{
+	VERIFY(m_type == Type::Array);
+	return m_value.array->at(index);
+}
+
+Value& Value::at(const std::string& key)
+{
+	VERIFY(m_type == Type::Object);
+	return m_value.object->at(key);
+}
+
+const Value& Value::at(size_t index) const
+{
+	VERIFY(m_type == Type::Array);
+	return m_value.array->at(index);
+}
+
+const Value& Value::at(const std::string& key) const
+{
+	VERIFY(m_type == Type::Object);
+	return m_value.object->at(key);
+}
+
+// ------------------------------------------
+
+size_t Value::size() const
+{
+	switch (m_type) {
+	case Type::Null:
+		return 0;
+	case Type::Array:
+		return m_value.array->size();
+	case Type::Object:
+		return m_value.object->size();
+	case Type::Bool:
+	case Type::Number:
+	case Type::String:
+	default:
+		return 1;
+	}
+}
+
+// ------------------------------------------
+
+void Value::destroy()
+{
+	switch (m_type) {
+	case Type::String:
+		delete m_value.string;
+		break;
+	case Type::Array:
+		delete m_value.array;
+		break;
+	case Type::Object:
+		delete m_value.object;
+		break;
+	case Type::Null:
+	case Type::Bool:
+	case Type::Number:
+	default:
+		break;
+	}
+}
+
+// ------------------------------------------
+
+std::istream& operator>>(std::istream& input, Value& value)
+{
+	std::string inputString;
+
+	char buffer[4096];
+	while (input.read(buffer, sizeof(buffer))) {
+		inputString.append(buffer, sizeof(buffer));
+	}
+	inputString.append(buffer, input.gcount());
+
+	value = Job(inputString).fire();
+
+	return input;
+}
+
+std::ostream& operator<<(std::ostream& output, const Value& value)
+{
+	return output << value.dump(4);
+}
+
+void format(Util::Format::Builder& builder, const Value& value)
+{
+	builder.putString(value.dump(4));
+}
+
+} // namespace Util::JSON

src/util/json/value.h

@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // nullptr_t, size_t
+#include <cstdint> // uint8_t, uint32_t
+#include <initializer_list>
+#include <iostream> // istream, ostream
+#include <string>
+#include <utility> // forward
+
+#include "util/format/builder.h"
+#include "util/json/fromjson.h"
+#include "util/json/tojson.h"
+
+namespace Util::JSON {
+
+class Array;
+class Object;
+
+class Value {
+private:
+	friend Detail::jsonConstructor;
+	friend class Parser;
+	friend class Serializer;
+
+public:
+	enum class Type : uint8_t {
+		Null,   // null       (case sensitive!)
+		Bool,   // true/false (case sensitive!)
+		Number, // 123
+		String, // ""
+		Array,  // []
+		Object, // {}
+	};
+
+	// --------------------------------------
+
+	// Constructors
+	Value(std::nullptr_t = nullptr);
+	Value(Type type);
+	Value(const std::initializer_list<Value>& values);
+	template<typename T>
+	Value(T value)
+	{
+		toJson(*this, std::forward<T>(value));
+	}
+
+	// Rule of Five:
+	// Copy constructor
+	Value(const Value& other);
+	// Move constructor
+	Value(Value&& other) noexcept;
+	// Copy assignment
+	// Move assignment
+	Value& operator=(Value other);
+	// Destructor
+	virtual ~Value() { destroy(); }
+
+	friend void swap(Value& left, Value& right) noexcept;
+
+	// --------------------------------------
+
+	static Value parse(std::string_view input);
+	static Value parse(std::ifstream& file);
+	std::string dump(const uint32_t indent = 0, const char indentCharacter = ' ') const;
+
+	void clear();
+
+	void emplace_back(Value value);
+	void emplace(const std::string& key, Value value);
+
+	bool exists(size_t index) const;
+	bool exists(const std::string& key) const;
+
+	// --------------------------------------
+
+	// Array index operator
+	Value& operator[](size_t index);
+	Value& operator[](const std::string& key);
+	const Value& operator[](size_t index) const;
+	const Value& operator[](const std::string& key) const;
+
+	Value& at(size_t index);
+	Value& at(const std::string& key);
+	const Value& at(size_t index) const;
+	const Value& at(const std::string& key) const;
+
+	// --------------------------------------
+
+	template<typename T>
+	T get() const
+	{
+		T type;
+		fromJson(*this, type);
+		return type;
+	}
+
+	template<typename T>
+	void getTo(T& type) const
+	{
+		fromJson(*this, type);
+	}
+
+	// --------------------------------------
+
+	Type type() const { return m_type; }
+	size_t size() const;
+
+	bool asBool() const { return m_value.boolean; }
+	double asDouble() const { return m_value.number; }
+	const std::string& asString() const { return *m_value.string; }
+	const Array& asArray() const { return *m_value.array; }
+	const Object& asObject() const { return *m_value.object; }
+
+private:
+	void destroy();
+
+	Type m_type { Type::Null };
+
+	union {
+		bool boolean;
+		double number;
+		std::string* string;
+		Array* array;
+		Object* object;
+	} m_value {};
+};
+
+std::istream& operator>>(std::istream& input, Value& value);
+std::ostream& operator<<(std::ostream& output, const Value& value);
+
+void format(Util::Format::Builder& builder, const Value& value);
+
+} // namespace Util::JSON
+
+/**
+ * User-defined string literal
+ *
+ * Example usage: auto json = "[ 3.14, true, null ]"_json;
+ */
+// inline Util::JSON::Value operator"" _json(const char* input, size_t length)
+// {
+// 	return Util::JSON::Value::parse(std::string(input, length));
+// }
+
+// TODO:
+// - find
+// - custom iterator
+//   - begin
+//   - end
+// v parse function that accepts ifstream > redirect to operator>>
+// - dump(-1), 0 inserts only newlines, -1 is full compact(?)
+// v add timer pause and unpause functions
+// v std::prev -> std::next in serializer
+// v serializer: output as member, does this speed it up?
+// - add Badge pattern, ex: Serializer constructor isnt needed publically
+// v Rename namespace Json -> Util::Json, create easy include json.h
+
+// - look into this for correctness
+//     https://www.json.org/json-en.html

src/util/meta/assert.h

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstddef> // size_t
+#include <cstdint> // uint32_t
+#include <cstring> // strlen
+#include <fstream> // ifstream
+#include <string>
+#include <string_view>
+
+#include "util/format/format.h"
+#include "util/meta/compiler.h"
+
+#define CRASH() asm volatile("int $0x03");
+
+#ifndef NDEBUG
+	#define VERIFY(expr, ...) (static_cast<bool>(expr) ? (void)0 : Util::__assertion_failed(#expr, __FILE__, __LINE__, FUNCTION_MACRO __VA_OPT__(, ) __VA_ARGS__))
+	#define VERIFY_NOT_REACHED() VERIFY(false)
+#else
+	#define VERIFY(expr, ...) (static_cast<bool>(expr) ? (void)0 : CRASH()
+	#define VERIFY_NOT_REACHED() CRASH()
+#endif
+
+#ifndef NDEBUG
+namespace Util {
+
+template<typename... Parameters>
+inline void __assertion_failed(const char* assertion, const char* file, uint32_t line, const char* function, const Parameters&... parameters)
+{
+	// Get the line that caused the error
+	std::ifstream source(file);
+	std::string content;
+	if (source.is_open()) {
+		for (uint32_t i = 0; std::getline(source, content); ++i) {
+			if (i == line - 1) {
+				break;
+			}
+		}
+	}
+	// Replace tab indentation with spaces
+	size_t tabs = content.find_first_not_of('\t');
+	if (tabs > 0 && tabs < content.size()) {
+		content = std::string(tabs * 4, ' ') + content.substr(tabs);
+	}
+
+	// Find the assertion in the line
+	size_t column = content.find(assertion);
+	size_t assertionLength = strlen(assertion);
+	if (column == std::string::npos) {
+		column = content.find_first_not_of(' ');
+		assertionLength = content.length() - column;
+	}
+
+	// Error message
+	fprintf(stderr,
+	        "\033[;1m%s:%u:%zu "
+	        "\033[31;1merror: "
+	        "\033[0massertion failed",
+	        file, line, column + 1);
+	if constexpr (sizeof...(Parameters) > 0) {
+		fprintf(stderr, ": ");
+		// Cant use the formatting library to print asserts caused by the formatting library
+		std::string_view functionString = function;
+		if (functionString.find("Util::Format::") != std::string_view::npos
+		    && functionString.find("Util::GenericLexer::") != std::string_view::npos) {
+			std::string message;
+			formatTo(message, parameters...);
+			fprintf(stderr, "%s", message.c_str());
+		}
+		else {
+			fprintf(stderr, parameters...);
+		}
+	}
+
+	// Code line
+	fprintf(stderr, "\n %u | %s\033[31;1m%s\033[0m%s\n", line,
+	        content.substr(0, column).c_str(),                 // Whitespace at front
+	        content.substr(column, assertionLength).c_str(),   // Error portion
+	        content.substr(column + assertionLength).c_str()); // Rest of the line
+
+	// Arrow pointer
+	fprintf(stderr, " %s | %s\033[31;1m^%s\033[0m\n",
+	        std::string(std::to_string(line).length(), ' ').c_str(), // Line number spacing
+	        std::string(column, ' ').c_str(),                        // Content spacing
+	        std::string(assertionLength - 1, '~').c_str());          // Arrow pointer
+
+	CRASH();
+}
+
+} // namespace Util
+#endif

src/util/meta/compiler.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+// Compiler
+#if defined(__clang__)
+	#define GCC
+#elif defined(__GNUG__) || (defined(__GNUC__) && defined(__cplusplus))
+	#define GCC
+#elif defined(__INTEL_COMPILER) // Supports some GCC extensions
+	#define GCC
+#elif defined(_MSC_VER)
+	#define MSVC
+#endif
+
+// Non-standard function macro
+#ifdef GCC
+	#define FUNCTION_MACRO __PRETTY_FUNCTION__ // GCC extension
+#elif MSVC
+	#define FUNCTION_MACRO __FUNCSIG__
+#else
+	#define FUNCTION_MACRO __func__ // C99
+#endif

src/util/meta/concepts.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <type_traits> // is_integral_v, floating_point_v
+
+namespace Util::Concepts {
+
+template<class T>
+concept Integral = std::is_integral_v<T>;
+
+template<typename T>
+concept FloatingPoint = std::is_floating_point_v<T>;
+
+} // namespace Util::Concepts
+
+using Util::Concepts::FloatingPoint;
+using Util::Concepts::Integral;

src/util/meta/odr.h

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+namespace Util {
+
+namespace Detail {
+
+// Avoid ODR (One Definition Rule) violations,
+// variable templates are required to have external linkage
+template<typename T>
+constexpr T staticConst {};
+
+} // namespace Detail
+
+} // namespace Util

src/util/shell.cpp

@@ -0,0 +1,53 @@
+#include <cstdio> // pclose, perror, popen
+#include <string>
+#include <string_view>
+
+#include "util/shell.h"
+
+namespace Util {
+
+Shell::Shell()
+{
+}
+
+Shell::Shell(const std::string& output, int status)
+	: m_output(output)
+	, m_status(status)
+{
+}
+
+Shell Shell::operator()(const char* command)
+{
+	FILE* shell = popen(command, "r");
+	if (!shell) {
+		perror("\033[31;1mError:\033[0m popen");
+		return { "", -1 };
+	}
+
+	std::string output;
+
+	constexpr int bufferSize = 4096;
+	char buffer[bufferSize];
+	while (fgets(buffer, sizeof(buffer), shell)) {
+		output.append(buffer);
+	}
+
+	int status = pclose(shell);
+	if (status < 0) {
+		perror("\033[31;1mError:\033[0m pclose");
+	}
+
+	return { output, status };
+}
+
+Shell Shell::operator()(std::string command)
+{
+	return operator()(command.c_str());
+}
+
+Shell Shell::operator()(std::string_view command)
+{
+	return operator()(command.data());
+}
+
+} // namespace Util

src/util/shell.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <string>
+#include <string_view>
+
+namespace Util {
+
+class Shell {
+public:
+	Shell();
+	virtual ~Shell() {}
+
+	Shell operator()(const char* command);
+	Shell operator()(std::string command);
+	Shell operator()(std::string_view command);
+
+	std::string output() const { return m_output; }
+	int status() const { return m_status; }
+
+private:
+	Shell(const std::string& output, int status);
+
+	std::string m_output;
+	int m_status { 0 };
+};
+
+} // namespace Util

src/util/singleton.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cassert>
+
+namespace Util {
+
+template<typename T>
+class Singleton {
+public:
+	static inline T& the()
+	{
+		if (s_instance == nullptr) {
+			s_instance = new T { s {} };
+		}
+
+		return *s_instance;
+	}
+
+	static inline void destroy()
+	{
+		if (s_instance) {
+			delete s_instance;
+		}
+
+		s_instance = nullptr;
+	}
+
+	// Remove copy constructor and copy assignment operator
+	Singleton(const Singleton&) = delete;
+	Singleton& operator=(const Singleton&) = delete;
+	Singleton(Singleton&&) = delete;
+	Singleton& operator=(Singleton&&) = delete;
+
+protected:
+	Singleton() {}
+
+	// Constructor token
+	struct s {};
+
+private:
+	static T* s_instance;
+};
+
+template<typename T>
+T* Singleton<T>::s_instance = nullptr;
+
+} // namespace Util

src/util/system.cpp

@@ -0,0 +1,328 @@
+#include <cerrno>     // errno, EAGAIN, EINTR
+#include <cstddef>    // size_t
+#include <cstdio>     // perror, ssize_t
+#include <cstdlib>    // exit, WEXITSTATUS
+#include <cstring>    // strcpy, strtok
+#include <functional> // function
+#include <sstream>    // istringstream
+#include <string>
+#include <string_view>
+#include <sys/wait.h> // waitpid
+#include <unistd.h>   // close, dup2, execvp, fork, pipe, read
+#include <vector>
+
+#include "util/system.h"
+
+namespace Util {
+
+System::System()
+{
+}
+
+System::System(const std::vector<std::string>& arguments)
+	: m_arguments(arguments)
+{
+}
+
+System System::operator()()
+{
+	return exec();
+}
+
+System System::operator()(const char* command)
+{
+	return operator()(std::string { command });
+}
+
+System System::operator()(std::string command)
+{
+	std::vector<std::string> arguments;
+
+	size_t index = 0;
+	while (index != std::string::npos) {
+		index = command.find_first_of(" ");
+		arguments.push_back(command.substr(0, index));
+		command = command.substr(index + 1);
+	}
+
+	return { arguments };
+}
+
+System System::operator()(std::string_view command)
+{
+	return operator()(std::string { command });
+}
+
+System System::operator()(const std::vector<const char*>& arguments)
+{
+	std::vector<std::string> stringArguments(arguments.size(), "");
+	for (size_t i = 0; i < arguments.size(); ++i) {
+		stringArguments[i] = arguments[i];
+	}
+
+	return { stringArguments };
+}
+
+System System::operator()(const std::vector<std::string>& arguments)
+{
+	return { arguments };
+}
+
+System System::operator()(const std::vector<std::string_view>& arguments)
+{
+	std::vector<std::string> stringArguments(arguments.size(), "");
+	for (size_t i = 0; i < arguments.size(); ++i) {
+		stringArguments[i] = arguments[i];
+	}
+
+	return { stringArguments };
+}
+
+// Shell equivalent ;
+System System::operator+(System rhs)
+{
+	auto lhs = *this;
+
+	lhs.exec();
+	rhs.m_output.append(lhs.m_output);
+	rhs.m_error.append(lhs.m_error);
+	rhs.exec();
+
+	return rhs;
+}
+
+System System::operator|(System rhs)
+{
+	auto lhs = *this;
+
+	lhs.exec();
+	rhs.exec(lhs.m_output);
+
+	return rhs;
+}
+
+System System::operator&&(System rhs)
+{
+	auto lhs = *this;
+
+	lhs.exec();
+	if (lhs.m_status > 0) {
+		return lhs;
+	}
+
+	rhs.m_output.append(lhs.m_output);
+	rhs.m_error.append(lhs.m_error);
+	rhs.exec();
+
+	return rhs;
+}
+
+System System::operator||(System rhs)
+{
+	auto lhs = *this;
+
+	lhs.exec();
+	if (lhs.m_status == 0) {
+		return lhs;
+	}
+
+	rhs.m_output.append(lhs.m_output);
+	rhs.m_error.append(lhs.m_error);
+	rhs.exec();
+
+	return rhs;
+}
+
+// cut -f -d
+System& System::cut(uint32_t field, char delimiter)
+{
+	exec();
+
+	return apply([&field, &delimiter](std::vector<std::string>& lines) {
+		for (auto& line : lines) {
+			size_t count = 1;
+			size_t index = 0;
+			while (index != std::string::npos) {
+				if (count == field) {
+					line = line.substr(0, line.find_first_of(delimiter));
+					break;
+				}
+
+				index = line.find_first_of(delimiter);
+				line = line.substr(index + 1);
+				count++;
+			}
+		}
+	});
+}
+
+System& System::sort(bool unique)
+{
+	exec();
+
+	return apply([&unique](std::vector<std::string>& lines) {
+		std::sort(lines.begin(), lines.end());
+
+		if (unique) {
+			auto last = std::unique(lines.begin(), lines.end());
+			lines.erase(last, lines.end());
+		}
+	});
+}
+
+// tail -n
+System& System::tail(int32_t number, bool starting)
+{
+	exec();
+
+	return apply([&number, &starting](std::vector<std::string>& lines) {
+		number = abs(number);
+		if (!starting) {
+			lines.erase(lines.begin(), lines.end() - number);
+		}
+		else {
+			lines.erase(lines.begin(), lines.begin() + number - 1);
+		}
+	});
+}
+
+System& System::apply(LineCallback callback)
+{
+	exec();
+
+	std::vector<std::string> lines;
+
+	auto stream = std::istringstream(m_output);
+	std::string line;
+	while (std::getline(stream, line)) {
+		lines.push_back(line);
+	}
+
+	callback(lines);
+
+	m_output.clear();
+	for (size_t i = 0; i < lines.size(); ++i) {
+		m_output.append(lines.at(i) + '\n');
+	}
+
+	return *this;
+}
+
+void System::print(const std::vector<std::string>& arguments)
+{
+	if (!arguments.size()) {
+		return;
+	}
+
+	printf("----------\n");
+	printf("size:    %zu\n", arguments.size());
+	printf("command: ");
+	for (size_t i = 0; i < arguments.size(); ++i) {
+		printf("%s ", arguments.at(i).c_str());
+	}
+	printf("\n");
+	printf("----------\n");
+}
+
+// -----------------------------------------
+
+System System::exec(std::string input)
+{
+	if (m_arguments.empty()) {
+		return *this;
+	}
+
+	int stdinFd[2];
+	int stdoutFd[2];
+	int stderrFd[2];
+	if (pipe(stdinFd) < 0) {
+		perror("\033[31;1mError:\033[0m pipe");
+	}
+	if (pipe(stdoutFd) < 0) {
+		perror("\033[31;1mError:\033[0m pipe");
+	}
+	if (pipe(stderrFd) < 0) {
+		perror("\033[31;1mError:\033[0m pipe");
+	}
+
+	pid_t pid = fork();
+	switch (pid) {
+	// Failed
+	case -1:
+		perror("\033[31;1mError:\033[0m fork");
+		break;
+	// Child
+	case 0: {
+		close(stdinFd[WriteFileDescriptor]);
+		dup2(stdinFd[ReadFileDescriptor], fileno(stdin));
+		close(stdinFd[ReadFileDescriptor]);
+
+		close(stdoutFd[ReadFileDescriptor]);
+		dup2(stdoutFd[WriteFileDescriptor], fileno(stdout));
+		close(stdoutFd[WriteFileDescriptor]);
+
+		close(stderrFd[ReadFileDescriptor]);
+		dup2(stderrFd[WriteFileDescriptor], fileno(stderr));
+		close(stderrFd[WriteFileDescriptor]);
+
+		std::vector<char*> charArguments(m_arguments.size() + 1, 0);
+		for (size_t i = 0; i < m_arguments.size(); ++i) {
+			charArguments[i] = const_cast<char*>(m_arguments[i].c_str());
+		}
+
+		execvp(charArguments[0], &charArguments[0]);
+		exit(0);
+	}
+	// Parent
+	default:
+		m_arguments.clear();
+		break;
+	}
+
+	close(stdinFd[ReadFileDescriptor]);
+	if (!input.empty()) {
+		write(stdinFd[WriteFileDescriptor], input.c_str(), input.size());
+	}
+	close(stdinFd[WriteFileDescriptor]);
+
+	readFromFileDescriptor(stdoutFd, m_output);
+	readFromFileDescriptor(stderrFd, m_error);
+
+	int result;
+	do {
+		result = waitpid(pid, &m_status, 0);
+	} while (result == -1 && errno == EINTR);
+	m_status = WEXITSTATUS(m_status);
+
+	return *this;
+}
+
+void System::readFromFileDescriptor(int fileDescriptor[2], std::string& output)
+{
+	close(fileDescriptor[WriteFileDescriptor]);
+
+	constexpr int bufferSize = 4096;
+	char buffer[bufferSize];
+
+	for (;;) {
+		const ssize_t result = read(fileDescriptor[ReadFileDescriptor], buffer, bufferSize);
+		if (result > 0) {
+			output.append(buffer, result);
+		}
+		// EOF
+		if (result == 0) {
+			break;
+		}
+		// Error
+		else if (result == -1) {
+			if (errno != EAGAIN && errno != EINTR) {
+				perror("\033[31;1mError:\033[0m read");
+				break;
+			}
+		}
+	}
+
+	close(fileDescriptor[ReadFileDescriptor]);
+}
+
+} // namespace Util

src/util/system.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <cstdint>    // int32_t, uint32_t
+#include <functional> // function
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace Util {
+
+using LineCallback = std::function<void(std::vector<std::string>&)>;
+
+class System {
+public:
+	System();
+	virtual ~System() {}
+
+	enum FileDescriptor {
+		ReadFileDescriptor,
+		WriteFileDescriptor,
+	};
+
+	System operator()();
+	System operator()(const char* command);
+	System operator()(std::string command);
+	System operator()(std::string_view command);
+	System operator()(const std::vector<const char*>& arguments);
+	System operator()(const std::vector<std::string>& arguments);
+	System operator()(const std::vector<std::string_view>& arguments);
+
+	// Operator order
+	// + -> | -> && -> ||
+	System operator+(System rhs);
+	System operator|(System rhs);
+	System operator&&(System rhs);
+	System operator||(System rhs);
+
+	System& cut(uint32_t field, char delimiter = '\t');
+	System& sort(bool unique = false);
+	System& tail(int32_t number, bool starting = false);
+	System& apply(LineCallback callback);
+
+	void print(const std::vector<std::string>& arguments);
+
+	const std::vector<std::string>& arguments() const { return m_arguments; }
+	std::string output() const { return m_output; }
+	std::string error() const { return m_error; }
+	int status() const { return m_status; }
+
+private:
+	System(const std::vector<std::string>& arguments);
+
+	System exec(std::string input = "");
+	void readFromFileDescriptor(int fileDescriptor[2], std::string& output);
+
+	std::vector<std::string> m_arguments;
+	std::string m_output;
+	std::string m_error;
+	int m_status { 0 };
+};
+
+} // namespace Util

src/util/timer.cpp

@@ -0,0 +1,131 @@
+#include <chrono>  // high_resolution_clock, seconds, milliseconds, microseconds, nanoseconds
+#include <cstdint> // uint64_t
+#include <cstdio>  // printf
+
+#include "util/timer.h"
+
+namespace Util {
+
+Timer::Timer()
+	: m_running(true)
+	, m_accumulated(TimePoint::min())
+	, m_start(now())
+{
+}
+
+Timer::Timer(const TimePoint& timePoint)
+	: m_running(true)
+	, m_accumulated(TimePoint::min())
+	, m_start(timePoint)
+{
+}
+
+// -----------------------------------------
+
+Timer Timer::operator-(const Timer& timer)
+{
+	return Timer(TimePoint { m_start - timer.start() });
+}
+
+TimePoint Timer::now()
+{
+	return std::chrono::high_resolution_clock::now();
+}
+
+void Timer::pause()
+{
+	if (!m_running) {
+		return;
+	}
+
+	m_accumulated += now() - m_start;
+	m_running = false;
+}
+
+void Timer::resume()
+{
+	if (m_running) {
+		return;
+	}
+
+	m_running = true;
+	m_start = now();
+}
+
+template<typename To, typename From>
+To Timer::to(From from)
+{
+	return std::chrono::duration_cast<To>(from);
+}
+
+uint64_t Timer::toSeconds()
+{
+	return to<std::chrono::seconds>(m_start.time_since_epoch()).count();
+}
+
+uint64_t Timer::toMilliseconds()
+{
+	return to<std::chrono::milliseconds>(m_start.time_since_epoch()).count();
+}
+
+uint64_t Timer::toMicroseconds()
+{
+	return to<std::chrono::microseconds>(m_start.time_since_epoch()).count();
+}
+
+uint64_t Timer::toNanoseconds()
+{
+	return to<std::chrono::nanoseconds>(m_start.time_since_epoch()).count();
+}
+
+template<typename T>
+uint64_t Timer::elapsed()
+{
+	uint64_t elapsed = 0;
+
+	if (m_running) {
+		elapsed += std::chrono::duration_cast<T>(now() - m_start).count();
+	}
+
+	elapsed += std::chrono::duration_cast<T>(m_accumulated - TimePoint::min()).count();
+
+	return elapsed;
+}
+
+uint64_t Timer::elapsedSeconds()
+{
+	return elapsed<std::chrono::seconds>();
+}
+
+uint64_t Timer::elapsedMilliseconds()
+{
+	return elapsed<std::chrono::milliseconds>();
+}
+
+uint64_t Timer::elapsedMicroseconds()
+{
+	return elapsed<std::chrono::microseconds>();
+}
+
+uint64_t Timer::elapsedNanoseconds()
+{
+	return elapsed<std::chrono::nanoseconds>();
+}
+
+void Timer::fancyPrint(uint64_t nanoseconds)
+{
+	if (nanoseconds > 999999999) {
+		printf("%.3fs", nanoseconds / 1000000000.0);
+	}
+	else if (nanoseconds > 999999) {
+		printf("%.0fms", nanoseconds / 1000000.0);
+	}
+	else if (nanoseconds > 999) {
+		printf("%.0fμs", nanoseconds / 1000.0);
+	}
+	else {
+		printf("%luns", nanoseconds);
+	}
+}
+
+} // namespace Util

src/util/timer.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2022 Riyyi
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <chrono>  // high_resolution_clock
+#include <cstdint> // uint64_t
+
+namespace Util {
+
+using TimePoint = std::chrono::high_resolution_clock::time_point;
+
+class Timer {
+public:
+	Timer();
+	Timer(const TimePoint& timePoint);
+
+	Timer operator-(const Timer& timer);
+
+	static TimePoint now();
+	void pause();
+	void resume();
+
+	template<typename To, typename From>
+	To to(From from);
+	uint64_t toSeconds();
+	uint64_t toMilliseconds();
+	uint64_t toMicroseconds();
+	uint64_t toNanoseconds();
+
+	template<typename T>
+	uint64_t elapsed();
+	uint64_t elapsedSeconds();
+	uint64_t elapsedMilliseconds();
+	uint64_t elapsedMicroseconds();
+	uint64_t elapsedNanoseconds();
+
+	static void fancyPrint(uint64_t nanoseconds);
+
+	const TimePoint& start() const { return m_start; }
+
+private:
+	bool m_running { true };
+	TimePoint m_accumulated;
+	TimePoint m_start;
+};
+
+} // namespace Util