1 files changed, 138 insertions, 0 deletions
diff --git a/meshmc/launcher/java/JavaVersion.cpp b/meshmc/launcher/java/JavaVersion.cpp
new file mode 100644
index 0000000000..fe6fd21be8
--- /dev/null
+++ b/meshmc/launcher/java/JavaVersion.cpp
@@ -0,0 +1,138 @@
+/* SPDX-FileCopyrightText: 2026 Project Tick
+ * SPDX-FileContributor: Project Tick
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   MeshMC - A Custom Launcher for Minecraft
+ *   Copyright (C) 2026 Project Tick
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "JavaVersion.h"
+#include <MMCStrings.h>
+
+#include <QRegularExpression>
+#include <QString>
+
+JavaVersion& JavaVersion::operator=(const QString& javaVersionString)
+{
+	m_string = javaVersionString;
+
+	auto getCapturedInteger = [](const QRegularExpressionMatch& match,
+								 const QString& what) -> int {
+		auto str = match.captured(what);
+		if (str.isEmpty()) {
+			return 0;
+		}
+		return str.toInt();
+	};
+
+	QRegularExpression pattern;
+	if (javaVersionString.startsWith("1.")) {
+		pattern = QRegularExpression(
+			"1[.](?<major>[0-9]+)([.](?<minor>[0-9]+))?(_(?<security>[0-9]+)?)?"
+			"(-(?<prerelease>[a-zA-Z0-9]+))?");
+	} else {
+		pattern = QRegularExpression(
+			"(?<major>[0-9]+)([.](?<minor>[0-9]+))?([.](?<security>[0-9]+))?(-("
+			"?<prerelease>[a-zA-Z0-9]+))?");
+	}
+
+	auto match = pattern.match(m_string);
+	m_parseable = match.hasMatch();
+	m_major = getCapturedInteger(match, "major");
+	m_minor = getCapturedInteger(match, "minor");
+	m_security = getCapturedInteger(match, "security");
+	m_prerelease = match.captured("prerelease");
+	return *this;
+}
+
+JavaVersion::JavaVersion(const QString& rhs)
+{
+	operator=(rhs);
+}
+
+QString JavaVersion::toString() const
+{
+	return m_string;
+}
+
+bool JavaVersion::requiresPermGen() const
+{
+	if (m_parseable) {
+		return m_major < 8;
+	}
+	return true;
+}
+
+bool JavaVersion::operator<(const JavaVersion& rhs) const
+{
+	if (m_parseable && rhs.m_parseable) {
+		auto major = m_major;
+		auto rmajor = rhs.m_major;
+
+		// HACK: discourage using java 9
+		if (major > 8)
+			major = -major;
+		if (rmajor > 8)
+			rmajor = -rmajor;
+
+		if (major < rmajor)
+			return true;
+		if (major > rmajor)
+			return false;
+		if (m_minor < rhs.m_minor)
+			return true;
+		if (m_minor > rhs.m_minor)
+			return false;
+		if (m_security < rhs.m_security)
+			return true;
+		if (m_security > rhs.m_security)
+			return false;
+
+		// everything else being equal, consider prerelease status
+		bool thisPre = !m_prerelease.isEmpty();
+		bool rhsPre = !rhs.m_prerelease.isEmpty();
+		if (thisPre && !rhsPre) {
+			// this is a prerelease and the other one isn't -> lesser
+			return true;
+		} else if (!thisPre && rhsPre) {
+			// this isn't a prerelease and the other one is -> greater
+			return false;
+		} else if (thisPre && rhsPre) {
+			// both are prereleases - use natural compare...
+			return Strings::naturalCompare(m_prerelease, rhs.m_prerelease,
+										   Qt::CaseSensitive) < 0;
+		}
+		// neither is prerelease, so they are the same -> this cannot be less
+		// than rhs
+		return false;
+	} else
+		return Strings::naturalCompare(m_string, rhs.m_string,
+									   Qt::CaseSensitive) < 0;
+}
+
+bool JavaVersion::operator==(const JavaVersion& rhs) const
+{
+	if (m_parseable && rhs.m_parseable) {
+		return m_major == rhs.m_major && m_minor == rhs.m_minor &&
+			   m_security == rhs.m_security && m_prerelease == rhs.m_prerelease;
+	}
+	return m_string == rhs.m_string;
+}
+
+bool JavaVersion::operator>(const JavaVersion& rhs) const
+{
+	return (!operator<(rhs)) && (!operator==(rhs));
+}