Merge pull request 'add tinyv1/2 parsers + writers, add mapping merging + flattening, fix bugs' (#3) from owlsys/tiny-mappings into main

Reviewed-on: #3
Reviewed-by: ender <ender@noreply.localhost>
Reviewed-by: Ecorous <ecorous@outlook.com>

build.gradle.kts

@@ -8,14 +8,14 @@ plugins {
 }
 
 group = "dev.frogmc"
-version = "0.0.1-alpha.5"
+version = "0.0.1-alpha.6"
 
 repositories {
     mavenCentral()
 }
 
 dependencies {
-    implementation("com.electronwill.night-config:json:3.7.3")
+    implementation("com.electronwill.night-config:json:3.8.0")
     implementation("org.ow2.asm:asm:9.7")
     implementation("org.ow2.asm:asm-commons:9.7")
 }

src/main/java/dev/frogmc/thyroxine/Thyroxine.java

@@ -10,12 +10,11 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
 import dev.frogmc.thyroxine.api.ParameterClassRemapper;
-import dev.frogmc.thyroxine.parser.ProguardParser;
+import dev.frogmc.thyroxine.api.data.MappingBundle;
 import dev.frogmc.thyroxine.provider.MojmapProvider;
 import dev.frogmc.thyroxine.provider.ParchmentProvider;
 import dev.frogmc.thyroxine.api.Mapper;
 import dev.frogmc.thyroxine.api.data.MappingData;
-import dev.frogmc.thyroxine.api.data.Parchment;
 import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.ClassWriter;
@@ -25,22 +24,33 @@ import org.objectweb.asm.commons.ClassRemapper;
 public class Thyroxine {
 
 	public static void run(String minecraftVersion, Path inputJar, Path outputJar, boolean skipMetaInf, boolean renameParameters) throws IOException, InterruptedException {
-		MappingData data = ProguardParser.read(MojmapProvider.get(minecraftVersion,
+		MappingBundle data = MojmapProvider.get(minecraftVersion,
-			outputJar.resolveSibling("client-" + minecraftVersion + ".txt")).orElseThrow()).reverse();
+			outputJar.resolveSibling("client-" + minecraftVersion + ".txt")).orElseThrow().reverse();
 
-		Parchment paramMappings = null;
+		MappingBundle parchment = null;
 		if (renameParameters) {
-			paramMappings = ParchmentProvider.getParchment(minecraftVersion, outputJar.getParent());
+			parchment = ParchmentProvider.getParchment(minecraftVersion, outputJar.getParent());
 		}
 
-		remap(data, inputJar, outputJar, skipMetaInf, renameParameters, paramMappings);
+		MappingBundle result;
+		if (parchment != null) {
+			result = MappingBundle.merge(data, parchment);
+		} else {
+			result = data;
 		}
 
-	public static void remap(MappingData data, Path inputJar, Path outputJar, boolean skipMetaInf, Parchment paramMappings) throws IOException, InterruptedException {
+		remap(result, inputJar, outputJar, skipMetaInf, renameParameters, "official", "named");
-		remap(data, inputJar, outputJar, skipMetaInf, true, paramMappings);
 	}
 
-	public static void remap(MappingData data, Path inputJar, Path outputJar, boolean skipMetaInf, boolean renameParameters, Parchment paramMappings) throws IOException, InterruptedException {
+	public static void remap(MappingData data, Path inputJar, Path outputJar, boolean skipMetaInf) throws IOException, InterruptedException {
+		remap(data, inputJar, outputJar, skipMetaInf, true);
+	}
+
+	public static void remap(MappingBundle bundle, Path inputJar, Path outputJar, boolean skipMetaInf, boolean renameParameters, String srcNamespace, String dstNamespace) throws IOException, InterruptedException {
+		remap(bundle.forNamespaces(srcNamespace, dstNamespace), inputJar, outputJar, skipMetaInf, renameParameters);
+	}
+
+	public static void remap(MappingData data, Path inputJar, Path outputJar, boolean skipMetaInf, boolean renameParameters) throws IOException, InterruptedException {
 		Files.deleteIfExists(outputJar);
 
 		System.out.println("Remapping...");
@@ -81,7 +91,7 @@ public class Thyroxine {
 								ClassVisitor remapper = new ClassRemapper(writer, mapper);
 								ClassVisitor visitor;
 								if (renameParameters) {
-									visitor = new ParameterClassRemapper(remapper, mapper, paramMappings);
+									visitor = new ParameterClassRemapper(remapper, mapper, data);
 								} else {
 									visitor = remapper;
 								}

src/main/java/dev/frogmc/thyroxine/api/Mapper.java

@@ -60,4 +60,9 @@ public class Mapper extends Remapper {
 
 		return null;
 	}
+
+	@Override
+	public String mapMethodDesc(String methodDescriptor) {
+		return super.mapMethodDesc(methodDescriptor);
+	}
 }

src/main/java/dev/frogmc/thyroxine/api/ParameterClassRemapper.java

@@ -1,6 +1,10 @@
 package dev.frogmc.thyroxine.api;
 
-import dev.frogmc.thyroxine.api.data.Parchment;
+import java.util.Collections;
+import java.util.Map;
+
+import dev.frogmc.thyroxine.api.data.MappingData;
+import dev.frogmc.thyroxine.api.data.Member;
 import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
@@ -8,11 +12,11 @@ import org.objectweb.asm.commons.ClassRemapper;
 import org.objectweb.asm.commons.Remapper;
 
 public class ParameterClassRemapper extends ClassRemapper {
-	private final Parchment parchment;
+	private final MappingData data;
 
-	public ParameterClassRemapper(ClassVisitor classVisitor, Remapper remapper, Parchment parchment) {
+	public ParameterClassRemapper(ClassVisitor classVisitor, Remapper remapper, MappingData data) {
 		super(Opcodes.ASM9, classVisitor, remapper);
-		this.parchment = parchment;
+		this.data = data;
 	}
 
 	@Override
@@ -21,9 +25,8 @@ public class ParameterClassRemapper extends ClassRemapper {
 		MethodVisitor methodVisitor = cv.visitMethod(access, remapper.mapMethodName(className, name, descriptor), remappedDescriptor,
 			remapper.mapSignature(signature, false), exceptions == null ? null : remapper.mapTypes(exceptions));
 
-		Parchment.Method method = parchment != null ? parchment.getClass(remapper.map(className)).flatMap(c -> c.getMethod(remapper.mapMethodName(className, name, descriptor), remapper.mapMethodDesc(descriptor)))
+		Member member = new Member(remapper.map(className), remapper.mapMethodName(className, name, descriptor), remappedDescriptor);
-				.orElse(null) : null;
+		Map<Integer, String> parameters = data != null ? data.parameters().getOrDefault(member, Collections.emptyMap()) : Collections.emptyMap();
-		return methodVisitor == null ? null : new ParameterMethodRemapper(methodVisitor, remapper, method);
+		return methodVisitor == null ? null : new ParameterMethodRemapper(methodVisitor, remapper, parameters);
-
 	}
 }

src/main/java/dev/frogmc/thyroxine/api/ParameterMethodRemapper.java

@@ -1,11 +1,7 @@
 package dev.frogmc.thyroxine.api;
 
-import java.util.HashSet;
+import java.util.*;
-import java.util.Locale;
-import java.util.Optional;
-import java.util.Set;
 
-import dev.frogmc.thyroxine.api.data.Parchment;
 import org.objectweb.asm.Label;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
@@ -14,20 +10,19 @@ import org.objectweb.asm.commons.MethodRemapper;
 import org.objectweb.asm.commons.Remapper;
 
 public class ParameterMethodRemapper extends MethodRemapper {
-	private final Parchment.Method parchment;
+	private final Map<Integer, String> parameters;
 	private final Set<String> usedLocalNames = new HashSet<>();
 
-	public ParameterMethodRemapper(MethodVisitor methodVisitor, Remapper remapper, Parchment.Method parchment) {
+	public ParameterMethodRemapper(MethodVisitor methodVisitor, Remapper remapper, Map<Integer, String> parameters) {
 		super(Opcodes.ASM9, methodVisitor, remapper);
-		this.parchment = parchment;
+		this.parameters = parameters;
 	}
 
 	@Override
 	public void visitLocalVariable(String name, String descriptor, String signature, Label start, Label end, int index) {
 		if (!name.equals("this")) {
-			if (parchment != null) {
+			if (parameters.containsKey(index)) {
-				Optional<Parchment.Parameter> parameter = parchment.getParameter(index);
+				name = parameters.get(index);
-				name = parameter.map(Parchment.Parameter::name).orElseGet(() -> getNewName(descriptor, signature));
 			} else {
 				name = getNewName(descriptor, signature);
 			}

src/main/java/dev/frogmc/thyroxine/api/data/DocumentationData.java

@@ -0,0 +1,123 @@
+package dev.frogmc.thyroxine.api.data;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public record DocumentationData(String namespace, List<Package> packages, List<Class> classes) {
+
+	public DocumentationData(String namespace) {
+		this(namespace, new ArrayList<>(), new ArrayList<>());
+	}
+
+	public DocumentationData insert(DocumentationData other) {
+		other.classes().forEach(c -> {
+			Optional<Class> opt = getClass(c.name);
+			if (opt.isPresent()) {
+				opt.get().merge(c);
+			} else {
+				classes.add(c);
+			}
+		});
+
+		other.packages().forEach(p -> {
+			Optional<Package> opt = getPackage(p.name);
+			if (opt.isPresent()) {
+				opt.get().merge(p);
+			} else {
+				packages.add(p);
+			}
+		});
+
+		return this;
+	}
+
+	public Optional<Class> getClass(String name) {
+		if (classes == null){
+			return Optional.empty();
+		}
+		return classes.stream().filter(c -> c.name().equals(name)).findFirst();
+	}
+
+	public Optional<Package> getPackage(String name) {
+		if (packages == null){
+			return Optional.empty();
+		}
+		return packages().stream().filter(p -> p.name().equals(name)).findFirst();
+	}
+
+	public record Package(String name, List<String> javadoc) {
+
+		public void merge(Package other) {
+			if (other.javadoc() != null && !String.join("\n", other.javadoc()).equals(String.join("\n", javadoc()))) {
+				javadoc().addAll(other.javadoc());
+			}
+		}
+	}
+
+	public record Class(String name, List<String> javadoc, List<Field> fields, List<Method> methods) {
+		public Optional<Field> getField(String name, String descriptor) {
+			if (fields == null){
+				return Optional.empty();
+			}
+			return fields.stream()
+					.filter(f -> f.name.equals(name) &&
+								 f.descriptor.equals(descriptor))
+					.findFirst();
+		}
+
+		public Optional<Method> getMethod(String name, String descriptor) {
+			if (methods == null){
+				return Optional.empty();
+			}
+			return methods.stream()
+					.filter(method -> method.name.equals(name) &&
+									  method.descriptor.equals(descriptor))
+					.findFirst();
+		}
+
+		public void merge(Class other) {
+			if (other.javadoc() != null && !String.join("\n", other.javadoc()).equals(String.join("\n", javadoc()))) {
+				if (!other.javadoc().isEmpty()) {
+					javadoc().addAll(other.javadoc());
+				}
+			}
+
+			other.fields.forEach(f -> {
+				Optional<Field> opt = getField(f.name, f.descriptor);
+				if (opt.isPresent()) {
+					opt.get().merge(f);
+				} else {
+					fields.add(f);
+				}
+			});
+
+			other.methods.forEach(m -> {
+				Optional<Method> opt = getMethod(m.name, m.descriptor);
+				if (opt.isPresent()) {
+					opt.get().merge(m);
+				} else {
+					methods.add(m);
+				}
+			});
+
+		}
+	}
+
+	public record Field(String name, String descriptor, List<String> javadoc) {
+		public void merge(Field other) {
+			if (other.javadoc() != null && !String.join("\n", other.javadoc()).equals(String.join("\n", javadoc()))) {
+				javadoc().addAll(other.javadoc());
+			}
+		}
+	}
+
+	public record Method(String name, String descriptor, List<String> javadoc) {
+		public void merge(Method other) {
+			if (other.javadoc() != null && !String.join("\n", other.javadoc()).equals(String.join("\n", javadoc()))) {
+				javadoc().addAll(other.javadoc());
+			}
+		}
+	}
+}
+

src/main/java/dev/frogmc/thyroxine/api/data/MappingBundle.java

@@ -0,0 +1,350 @@
+package dev.frogmc.thyroxine.api.data;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+import dev.frogmc.thyroxine.api.Mapper;
+
+public record MappingBundle(List<MappingData> data, List<DocumentationData> documentation) {
+
+	public MappingBundle() {
+		this((MappingData) null);
+	}
+
+	public MappingBundle(MappingData data) {
+		this(data, null);
+	}
+
+	public MappingBundle(DocumentationData data) {
+		this(null, data);
+	}
+
+	public MappingBundle(MappingData data, DocumentationData documentation) {
+		this(list(data), list(documentation));
+	}
+
+	private static <T> List<T> list(T element) { // create a mutable list populated with a single element
+		List<T> list = new ArrayList<>();
+		if (element != null) {
+			list.add(element);
+		}
+		return list;
+	}
+
+	public static MappingBundle merge(MappingBundle... bundles) {
+		List<MappingData> mergedData = new ArrayList<>();
+		List<DocumentationData> mergedDocs = new ArrayList<>();
+
+		for (MappingBundle bundle : bundles) {
+			mergedData.addAll(bundle.data());
+			mergedDocs.addAll(bundle.documentation());
+		}
+
+		return new MappingBundle(mergedData, mergedDocs);
+	}
+
+	public MappingBundle insert(MappingData data) {
+		this.data.add(data);
+		return this;
+	}
+
+	public MappingBundle insert(DocumentationData data) {
+		for (DocumentationData d : documentation) {
+			if (d.namespace().equals(data.namespace())) {
+				d.insert(data);
+				return this;
+			}
+		}
+
+		documentation.add(data);
+		return this;
+	}
+
+	public List<String> srcNamespaces() {
+		return data.stream().map(MappingData::srcNamespace).toList();
+	}
+
+	public List<String> dstNamespaces() {
+		return data.stream().map(MappingData::dstNamespace).toList();
+	}
+
+	public MappingData forNamespaces(String src, String dst) {
+		return flattenInternal(src, dst, false);
+	}
+
+	public MappingData forNamespaces(String src, String dst, boolean allowIncomplete) {
+		return flattenInternal(src, dst, allowIncomplete);
+	}
+
+	public MappingBundle flatten(String src, String dst) {
+		return flatten(src, dst, false);
+	}
+
+	public MappingBundle flatten(String src, String dst, boolean allowIncomplete) {
+		MappingData data = flattenInternal(src, dst, allowIncomplete);
+		return new MappingBundle(data, get(data.dstNamespace()));
+	}
+
+	public DocumentationData docsForNamespace(String ns) {
+		DocumentationData result = new DocumentationData(ns);
+		for (DocumentationData d : documentation) {
+			if (d.namespace().equals(ns)) {
+				result.insert(d);
+			} else {
+				Mapper mappings = new Mapper(forNamespaces(d.namespace(), ns, false), a -> Collections.emptyList());
+				DocumentationData remapped = new DocumentationData(ns);
+				// TODO is there something we can do about the packages...? (don't think so)
+				d.classes().forEach(c -> {
+					String name = mappings.map(c.name());
+					List<DocumentationData.Method> methods = c.methods().stream().map(m ->
+						new DocumentationData.Method(mappings.mapMethodName(c.name(), m.name(), m.descriptor()),
+							mappings.mapMethodDesc(m.descriptor()), m.javadoc())).toList();
+					List<DocumentationData.Field> fields = c.fields().stream().map(f ->
+						new DocumentationData.Field(mappings.mapFieldName(c.name(), f.name(), f.descriptor()),
+							mappings.mapDesc(f.descriptor()), f.javadoc())).collect(Collectors.toCollection(ArrayList::new));
+					remapped.classes().add(new DocumentationData.Class(name, c.javadoc(), fields, methods));
+				});
+				result.insert(remapped);
+			}
+		}
+		return result;
+	}
+
+	public MappingBundle flatten() {
+		return flatten(false);
+	}
+
+	public MappingBundle flatten(boolean allowIncomplete) {
+		MappingData data = flattenData(allowIncomplete);
+		return new MappingBundle(data, get(data.dstNamespace()));
+	}
+
+	public MappingData flattenData(boolean allowIncomplete) {
+		Set<String> overlayNs = new HashSet<>();
+		for (MappingData d : data()) {
+			if (d.srcNamespace().equals(d.dstNamespace())) {
+				overlayNs.add(d.srcNamespace());
+			}
+		}
+		List<String> srcNs = srcNamespaces();
+		List<String> dstNs = dstNamespaces();
+		List<String> srcNsCandidates = srcNs.stream().distinct().filter(s -> !dstNs.contains(s) && !overlayNs.contains(s)).toList();
+		List<String> dstNsCandidates = dstNs.stream().distinct().filter(s -> !srcNs.contains(s) || overlayNs.contains(s)).toList();
+		if (srcNsCandidates.size() > 1) {
+			throw new IllegalStateException("Not a linear graph, cannot flatten! Got possible roots: " + String.join(", ", srcNsCandidates));
+		} else if (srcNsCandidates.isEmpty()) {
+			throw new IllegalStateException("Not a linear graph, cannot flatten! Got no possible roots! SrcNamespaces: " + String.join(", ", srcNs) + " Overlays: " + String.join(", ", overlayNs));
+		}
+		if (dstNsCandidates.size() > 1) {
+			throw new IllegalStateException("Not a linear graph, cannot flatten! Got possible ends: " + String.join(", ", dstNsCandidates));
+		} else if (dstNsCandidates.isEmpty()) {
+			throw new IllegalStateException("Not a linear graph, cannot flatten! Got no possible roots! DstNamespaces: " + String.join(", ", dstNs));
+		}
+		String srcRoot = srcNsCandidates.getFirst();
+		String dstRoot = dstNsCandidates.getFirst();
+		return flattenInternal(srcRoot, dstRoot, allowIncomplete);
+	}
+
+	private MappingData flattenInternal(String srcRoot, String dstRoot, boolean allowIncomplete) {
+		Deque<MappingData> path = computePath(srcRoot, dstRoot).reversed();
+
+		MappingData result = new MappingData(srcRoot, dstRoot);
+
+		MappingData first = path.pop();
+
+		Map<String, Map<String, Mapper>> mappers = new HashMap<>();
+		Mapper start = mappers.computeIfAbsent(first.srcNamespace(),
+			a -> new HashMap<>()).computeIfAbsent(first.dstNamespace(),
+			a -> new Mapper(first, b -> Collections.emptyList()));
+
+		first.classes().forEach((s, s2) -> {
+			String res = s2;
+			for (MappingData d : path) {
+				String w = res;
+				res = d.classes().get(res);
+				if (res == null) {
+					if (!allowIncomplete) {
+						/*
+						 * The mapping set is incomplete at this point.
+						 * We're using the last available value to prevent incompleteness
+						 * in the resulting set.
+						 */
+						res = w;
+					}
+					break;
+				}
+			}
+			if (res != null) {
+				result.classes().put(s, res);
+			}
+		});
+
+		first.methods().forEach((member, s) -> {
+			String res = s;
+			String owner = start.map(member.owner());
+			String desc = start.mapMethodDesc(member.descriptor());
+			for (MappingData d : path) {
+				Mapper mapper = mappers.computeIfAbsent(d.srcNamespace(),
+					a -> new HashMap<>()).computeIfAbsent(d.dstNamespace(),
+					a -> new Mapper(d, b -> Collections.emptyList()));
+				String w = res;
+				res = d.methods().get(new Member(owner, res, desc));
+				owner = mapper.map(owner);
+				desc = mapper.mapMethodDesc(desc);
+				if (res == null) {
+					if (!allowIncomplete) {
+						/*
+						 * The mapping set is incomplete at this point.
+						 * We're using the last available value to prevent incompleteness
+						 * in the resulting set.
+						 */
+						res = w;
+					}
+					break;
+				}
+			}
+			if (res != null) {
+				result.methods().put(member, res);
+			}
+		});
+
+		first.fields().forEach((member, s) -> {
+			String res = s;
+			String owner = start.map(member.owner());
+			String desc = start.mapDesc(member.descriptor());
+			for (MappingData d : path) {
+				Mapper mapper = mappers.computeIfAbsent(d.srcNamespace(),
+					a -> new HashMap<>()).computeIfAbsent(d.dstNamespace(),
+					a -> new Mapper(d, b -> Collections.emptyList()));
+				String w = res;
+				res = d.fields().get(new Member(owner, res, desc));
+				owner = mapper.map(owner);
+				desc = mapper.mapDesc(desc);
+				if (res == null) {
+					if (!allowIncomplete) {
+						/*
+						 * The mapping set is incomplete at this point.
+						 * We're using the last available value to prevent incompleteness
+						 * in the resulting set.
+						 */
+						res = w;
+					}
+					break;
+				}
+			}
+			if (res != null) {
+				result.fields().put(member, res);
+			}
+		});
+
+		{
+			List<MappingData> all = new ArrayList<>(path);
+			all.addFirst(first);
+			Map<Member, Map<Integer, String>> queue = new HashMap<>();
+			for (MappingData d : all) {
+				queue.putAll(d.parameters());
+				Mapper mapper = mappers.computeIfAbsent(d.srcNamespace(),
+					a -> new HashMap<>()).computeIfAbsent(d.dstNamespace(),
+					a -> new Mapper(d, b -> Collections.emptyList()));
+				Map<Member, Map<Integer, String>> map = new HashMap<>(queue);
+				queue.clear();
+				map.forEach((member, param) -> queue.put(new Member(mapper.map(member.owner()),
+						mapper.mapMethodName(member.owner(), member.name(), member.descriptor()),
+						mapper.mapMethodDesc(member.descriptor())),
+					param));
+			}
+			result.parameters().putAll(queue);
+		}
+
+		return result;
+	}
+
+	private Deque<MappingData> computePath(String srcRoot, String dstRoot) {
+
+		Deque<MappingData> path = new ArrayDeque<>();
+		List<MappingData> available = new ArrayList<>(data);
+		for (MappingData d : data) {
+			if (d.srcNamespace().equals(srcRoot)) {
+				path.push(d);
+				available.remove(d);
+				break;
+			} else if (d.dstNamespace().equals(srcRoot)) {
+				path.push(d.reverse());
+				available.remove(d);
+				break;
+			}
+		}
+
+		while (!path.getFirst().dstNamespace().equals(dstRoot)) {
+			MappingData last = path.getFirst();
+
+			String needed = last.dstNamespace();
+			for (MappingData d : new ArrayList<>(available)) {
+				if (d.srcNamespace().equals(needed)) {
+					available.remove(d);
+					path.push(d);
+				} else if (d.dstNamespace().equals(needed)) {
+					available.remove(d);
+					path.push(d.reverse());
+				}
+			}
+		}
+
+		for (MappingData d : available) {
+			if (d.srcNamespace().equals(d.dstNamespace()) && d.srcNamespace().equals(dstRoot)) {
+				path.push(d);
+			}
+		}
+
+		return path;
+	}
+
+	public MappingBundle insert(MappingData data, DocumentationData documentation) {
+		return insert(data).insert(documentation);
+	}
+
+	public MappingBundle insert(MappingBundle other) {
+		return insert(other.data, other.documentation);
+	}
+
+	public MappingBundle insert(List<MappingData> data, List<DocumentationData> documentation) {
+		data.forEach(this::insert);
+		documentation.forEach(this::insert);
+		return this;
+	}
+
+	public DocumentationData get(String namespace) {
+		DocumentationData result = null;
+		for (DocumentationData d : documentation) {
+			if (d.namespace().equals(namespace)) {
+				if (result == null) {
+					result = new DocumentationData(namespace);
+				}
+				result.insert(d);
+			}
+		}
+		return result;
+	}
+
+	public MappingData getWithSrcNamespace(String namespace) {
+		return data.stream().filter(d -> d.srcNamespace().equals(namespace)).findFirst().orElse(null);
+	}
+
+	public MappingData getWithDstNamespace(String namespace) {
+		return data.stream().filter(d -> d.dstNamespace().equals(namespace)).findFirst().orElse(null);
+	}
+
+	public MappingBundle reverse() {
+		MappingBundle reversed = new MappingBundle();
+		for (MappingData d : data) {
+			reversed.data().addFirst(d.reverse());
+		}
+
+		reversed.documentation.addAll(documentation);
+		return reversed;
+	}
+
+	public MappingData flattenData() {
+		return flattenData(false);
+	}
+}

src/main/java/dev/frogmc/thyroxine/api/data/MappingData.java

@@ -1,21 +1,23 @@
 package dev.frogmc.thyroxine.api.data;
 
-import org.objectweb.asm.Type;
-
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 
-public record MappingData(Map<String, String> classes, Map<Member, String> methods, Map<Member, String> fields) {
+import org.objectweb.asm.Type;
 
-    public MappingData() {
+public record MappingData(String srcNamespace, String dstNamespace, Map<String, String> classes, Map<Member, String> methods,
-        this(new HashMap<>(), new HashMap<>(), new HashMap<>());
+						  Map<Member, String> fields, Map<Member, Map<Integer, String>> parameters) {
+
+	public MappingData(String srcNs, String dstNs) {
+		this(srcNs, dstNs, new HashMap<>(), new HashMap<>(), new HashMap<>(), new HashMap<>());
 	}
 
 	public MappingData reverse() {
 		Map<String, String> classesReversed = new HashMap<>();
 		Map<Member, String> methodsReversed = new HashMap<>();
 		Map<Member, String> fieldsReversed = new HashMap<>();
+		Map<Member, Map<Integer, String>> parametersReversed = new HashMap<>();
 
 		for (Map.Entry<String, String> clazz : classes.entrySet())
 			classesReversed.put(clazz.getValue(), clazz.getKey());
@@ -42,7 +44,15 @@ public record MappingData(Map<String, String> classes, Map<Member, String> metho
 			);
 		}
 
-        return new MappingData(classesReversed, methodsReversed, fieldsReversed);
+		for (Map.Entry<Member, Map<Integer, String>> param : parameters.entrySet()) {
+			parametersReversed.put(new Member(
+				classes.getOrDefault(param.getKey().owner(), param.getKey().owner()),
+				fields.getOrDefault(param.getKey(), param.getKey().name()),
+				remapType(Type.getType(param.getKey().descriptor())).getDescriptor()
+			), param.getValue());
+		}
+
+		return new MappingData(dstNamespace, srcNamespace, classesReversed, methodsReversed, fieldsReversed, parametersReversed);
 	}
 
 	private Type remapType(Type type) {

src/main/java/dev/frogmc/thyroxine/api/data/Parchment.java

@@ -1,63 +0,0 @@
-package dev.frogmc.thyroxine.api.data;
-
-import java.util.List;
-import java.util.Optional;
-
-public record Parchment(String version, List<Package> packages, List<Class> classes) {
-	public Optional<Class> getClass(String name) {
-		if (classes == null){
-			return Optional.empty();
-		}
-		return classes.stream().filter(c -> c.name().equals(name)).findFirst();
-	}
-
-	public Optional<Package> getPackage(String name) {
-		if (packages == null){
-			return Optional.empty();
-		}
-		return packages().stream().filter(p -> p.name().equals(name)).findFirst();
-	}
-
-	public record Package(String name, List<String> javadoc) {
-	}
-
-	public record Class(String name, List<String> javadoc, List<Field> fields, List<Method> methods) {
-		public Optional<Field> getField(String name, String descriptor) {
-			if (fields == null){
-				return Optional.empty();
-			}
-			return fields.stream()
-					.filter(f -> f.name.equals(name) &&
-								 f.descriptor.equals(descriptor))
-					.findFirst();
-		}
-
-		public Optional<Method> getMethod(String name, String descriptor) {
-			if (methods == null){
-				return Optional.empty();
-			}
-			return methods.stream()
-					.filter(method -> method.name.equals(name) &&
-									  method.descriptor.equals(descriptor))
-					.findFirst();
-		}
-	}
-
-	public record Field(String name, String descriptor, List<String> javadoc) {
-	}
-
-	public record Method(String name, String descriptor, List<String> javadoc, List<Parameter> parameters) {
-		public Optional<Parameter> getParameter(int index) {
-			if (parameters == null){
-				return Optional.empty();
-			}
-			return parameters.stream()
-					.filter(f -> f.index == index)
-					.findFirst();
-		}
-	}
-
-	public record Parameter(int index, String name) {
-	}
-}
-

src/main/java/dev/frogmc/thyroxine/parser/ProguardParser.java

@@ -8,7 +8,7 @@ public class ProguardParser {
 	public static MappingData read(String mappings) {
 		String[] lines = mappings.split("\n");
 
-		MappingData data = new MappingData();
+		MappingData data = new MappingData("named", "official");
 		String currentClass = null;
 		for (String line : lines) {
 			if (line.contains("#")) {

src/main/java/dev/frogmc/thyroxine/parser/tiny/TinyV1Parser.java

@@ -0,0 +1,82 @@
+package dev.frogmc.thyroxine.parser.tiny;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import dev.frogmc.thyroxine.api.data.MappingBundle;
+import dev.frogmc.thyroxine.api.data.MappingData;
+import dev.frogmc.thyroxine.api.data.Member;
+
+public class TinyV1Parser {
+
+	private static final Pattern HEADER = Pattern.compile("v(?<majorVer>[12]+)\\s\\w*\\s?(?<srcns>\\S+)\\s(?<dstns>\\S+)");
+
+	public static MappingBundle parse(String mappings) {
+		String[] lines = mappings.split("\n");
+		int length = lines.length;
+
+		Matcher header = HEADER.matcher(lines[0]);
+		if (!header.matches()) {
+			throw new IllegalStateException("Not a valid tiny file");
+		}
+
+		MappingData data = new MappingData(header.group("srcns"), header.group("dstns"));
+		//DocumentationData documentation = new DocumentationData();
+		for (int i = 1; i < length; i++) {
+			String[] line = lines[i].split("\\s");
+
+			String type = line[0];
+
+			if ("CLASS".equals(type)) {
+				data.classes().put(line[1], line[2]);
+				//documentation.classes().add(new DocumentationData.Class(line[1], new ArrayList<>(0), new ArrayList<>(), new ArrayList<>()));
+				continue;
+			}
+
+
+			if ("FIELD".equals(type)) {
+				String desc = line[2];
+				String obf = line[line.length - 2]; // aaa these files can contain more than two namespaces, we *should* be fine by just using the last two
+				String deobf = line[line.length - 1];
+				data.fields().put(new Member(line[1], obf, desc), deobf);
+				//documentation.getClass(line[1]).ifPresent(c -> c.fields().add(new DocumentationData.Field(obf, desc, new ArrayList<>())));
+				//continue;
+			} else if ("METHOD".equals(type)) {
+				String desc = line[2];
+				String obf = line[line.length - 2]; // aaa these files can contain more than two namespaces, we *should* be fine by just using the last two
+				String deobf = line[line.length - 1];
+
+				data.methods().put(new Member(line[1], obf, desc), deobf);
+				//documentation.getClass(line[1]).ifPresent(c -> c.methods().add(new DocumentationData.Method(obf, desc, new ArrayList<>(), new ArrayList<>())));
+				//continue;
+			}
+			// TODO Observe if there are any tinyv1 files with javadocs and/or parameter mappings
+			/* else if ("c".equals(type)) {
+				currentC.javadoc().addAll(Arrays.asList(line[2].split("\n")));
+				continue;
+			}
+
+
+			if (currentF == null && currentM == null) {
+				throw new IllegalStateException("Field javadoc/Method parameter mapping/javadoc specified before a declaration");
+			}
+
+
+			if (currentM != null) {
+				if ("p".equals(type)) {
+					currentM.parameters().add(new DocumentationData.Parameter(Integer.parseInt(line[3]), line[5]));
+				} else if ("c".equals(type)) {
+					currentM.javadoc().addAll(Arrays.asList(line[2].split("\n")));
+				}
+			} else {
+				if ("c".equals(type)) {
+					currentF.javadoc().addAll(Arrays.asList(line[2].split("\n")));
+				}
+			}*/
+
+
+		}
+
+		return new MappingBundle(data);
+	}
+}

src/main/java/dev/frogmc/thyroxine/parser/tiny/TinyV2Parser.java

@@ -0,0 +1,135 @@
+package dev.frogmc.thyroxine.parser.tiny;
+
+import java.util.*;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import dev.frogmc.thyroxine.api.Mapper;
+import dev.frogmc.thyroxine.api.data.DocumentationData;
+import dev.frogmc.thyroxine.api.data.MappingBundle;
+import dev.frogmc.thyroxine.api.data.MappingData;
+import dev.frogmc.thyroxine.api.data.Member;
+
+public class TinyV2Parser {
+
+	private static final Pattern HEADER = Pattern.compile("tiny\t(?<majorVer>\\d+)\t(?<minorVer>\\d+)\t(?<namespaces>(?:\t?[^\t]+){2,})");
+
+	public static MappingBundle parse(String mappings) {
+		String[] lines = mappings.split("\n");
+		int length = lines.length;
+
+		Matcher header = HEADER.matcher(lines[0]);
+		if (!header.matches()) {
+			throw new IllegalStateException("Not a valid tiny file! (header: "+lines[0]+")");
+		}
+
+		List<String> namespaces = Arrays.asList(header.group("namespaces").split("\t"));
+		int count = namespaces.size();
+		MappingBundle bundle = new MappingBundle();
+		List<Mapper> mappers = new ArrayList<>();
+
+		for (int ns = 1;ns<count;ns++) {
+			String srcNs = namespaces.get(ns-1);
+			String dstNs = namespaces.get(ns);
+
+			MappingData data = new MappingData(srcNs, dstNs);
+			String currentClass = null;
+			DocumentationData.Class currentC = null;
+			DocumentationData.Method currentM = null;
+			DocumentationData.Field currentF = null;
+			DocumentationData documentation = new DocumentationData(dstNs);
+			for (int i = 1; i < length; i++) {
+				String[] line = lines[i].split("\t");
+
+				if ("c".equals(line[0])) {
+					if (1+ns >= line.length) {
+						do {
+							i++;
+						} while (lines[i].startsWith("\t"));
+						continue;
+					}
+					currentClass = line[ns];
+					data.classes().put(currentClass, line[1+ns]);
+					documentation.classes().add(currentC = new DocumentationData.Class(line[1+ns], new ArrayList<>(0), new ArrayList<>(), new ArrayList<>()));
+					currentM = null;
+					currentF = null;
+					continue;
+				}
+
+				if (currentClass == null) {
+					throw new IllegalStateException("Member mapping specified before a class");
+				}
+
+				{
+					String type = line[1];
+					if ("f".equals(type)) {
+						if (3+ns >= line.length) {
+							continue;
+						}
+						String desc = line[2];
+						String obf = line[2+ns];
+						String deobf = line[3+ns];
+
+						if (ns > 1) {
+							for (Mapper mapper : mappers) {
+								desc = mapper.mapDesc(desc);
+							}
+						}
+
+						data.fields().put(new Member(currentClass, obf, desc), deobf);
+						currentC.fields().add(currentF = new DocumentationData.Field(deobf, desc, new ArrayList<>()));
+						continue;
+					} else if ("m".equals(type)) {
+						if (3+ns >= line.length) {
+							continue;
+						}
+						String desc = line[2];
+						String obf = line[2+ns];
+						String deobf = line[3+ns];
+
+						if (ns > 1) {
+							for (Mapper mapper : mappers) {
+								desc = mapper.mapMethodDesc(desc);
+							}
+						}
+
+						data.methods().put(new Member(currentClass, obf, desc), deobf);
+						currentC.methods().add(currentM = new DocumentationData.Method(deobf, desc, new ArrayList<>()));
+						continue;
+					} else if ("c".equals(type)) {
+						currentC.javadoc().addAll(Arrays.asList(line[2].split("\n")));
+						continue;
+					}
+				}
+
+				if (currentF == null && currentM == null) {
+					continue;
+				}
+
+				{
+					String type = line[2];
+					if (currentM != null) {
+						if ("p".equals(type)) {
+							if (4+ns >= line.length) {
+								continue;
+							}
+							data.parameters().computeIfAbsent(new Member(currentClass, currentM.name(), currentM.descriptor()), a -> new HashMap<>())
+									.put(Integer.parseInt(line[3]), line[4+ns]);
+						} else if ("c".equals(type)) {
+							currentM.javadoc().addAll(Arrays.asList(line[3].split("\n")));
+						}
+					} else {
+						if ("c".equals(type)) {
+							currentF.javadoc().addAll(Arrays.asList(line[3].split("\n")));
+						}
+					}
+				}
+			}
+			mappers.add(new Mapper(data, s -> Collections.emptyList()));
+			bundle.insert(data, documentation);
+
+		}
+
+		return bundle;
+	}
+}

src/main/java/dev/frogmc/thyroxine/provider/MojmapProvider.java

@@ -3,6 +3,8 @@ package dev.frogmc.thyroxine.provider;
 import com.electronwill.nightconfig.core.UnmodifiableConfig;
 import dev.frogmc.thyroxine.Constants;
 import dev.frogmc.thyroxine.HttpHelper;
+import dev.frogmc.thyroxine.api.data.MappingBundle;
+import dev.frogmc.thyroxine.parser.ProguardParser;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
@@ -14,8 +16,12 @@ import java.util.Optional;
 
 public class MojmapProvider {
 
+	public static Optional<MappingBundle> get(String gameVersion, Path cacheFile) {
+		return getMappings(gameVersion, cacheFile).map(ProguardParser::read).map(MappingBundle::new);
+	}
+
     @SuppressWarnings("unchecked")
-	public static Optional<String> get(String gameVersion, Path cacheFile) {
+	private static Optional<String> getMappings(String gameVersion, Path cacheFile) {
         if (Files.exists(cacheFile)){
 			try {
 				return Optional.of(Files.readString(cacheFile, StandardCharsets.UTF_8));

src/main/java/dev/frogmc/thyroxine/provider/ParchmentProvider.java

@@ -18,7 +18,10 @@ import java.util.*;
 
 import com.electronwill.nightconfig.core.UnmodifiableConfig;
 import dev.frogmc.thyroxine.Constants;
-import dev.frogmc.thyroxine.api.data.Parchment;
+import dev.frogmc.thyroxine.api.data.DocumentationData;
+import dev.frogmc.thyroxine.api.data.MappingBundle;
+import dev.frogmc.thyroxine.api.data.MappingData;
+import dev.frogmc.thyroxine.api.data.Member;
 import org.w3c.dom.Document;
 import org.xml.sax.SAXException;
 
@@ -42,15 +45,15 @@ public class ParchmentProvider {
 		}
 	}
 
-	public static Parchment getParchment(String gameVersion, Path cacheDir) throws IOException {
+	public static MappingBundle getParchment(String gameVersion, Path cacheDir) throws IOException {
 		return getParchment(gameVersion, findParchmentVersion(gameVersion), cacheDir);
 	}
 
-	public static Parchment getParchment(String gameVersion, String parchmentVer, Path cacheDir) throws IOException {
+	public static MappingBundle getParchment(String gameVersion, String parchmentVer, Path cacheDir) throws IOException {
 		return getParchment(gameVersion, parchmentVer, cacheDir, false);
 	}
 
-	public static Parchment getParchment(String gameVersion, String parchmentVer, Path cacheDir, boolean forceDownload) throws IOException {
+	public static MappingBundle getParchment(String gameVersion, String parchmentVer, Path cacheDir, boolean forceDownload) throws IOException {
 		long time = System.currentTimeMillis();
 		System.out.println("Loading Parchment mappings..");
 		var cachePath = cacheDir.resolve("parchment-" + gameVersion + "-" + parchmentVer + ".zip");
@@ -79,29 +82,52 @@ public class ParchmentProvider {
 				throw new IOException(e);
 			}
 		}
-		Parchment parchment;
+		MappingBundle parchment = new MappingBundle();
+		MappingData parameters = new MappingData("named", "named");
 		try (FileSystem fs = FileSystems.newFileSystem(cachePath)) {
 			var mappings = Files.readString(fs.getPath("parchment.json"));
 			UnmodifiableConfig c = Constants.JSON_PARSER.parse(mappings);
-			String version = c.get("version");
+			// String version = c.get("version"); // currently unused
-			List<Parchment.Package> packages = c.get("packages");
+			List<UnmodifiableConfig> packagesList = Objects.requireNonNullElse(c.get("packages"), Collections.emptyList());
-			List<Parchment.Class> classes = new ArrayList<>();
+			List<DocumentationData.Package> packages = new ArrayList<>();
+			packagesList.forEach(config ->
+				packages.add(new DocumentationData.Package(config.get("name"), new ArrayList<>(Objects.requireNonNullElse(c.get("javadoc"),
+				Collections.emptyList())))));
+
+			List<DocumentationData.Class> classes = new ArrayList<>();
 			List<UnmodifiableConfig> classesList = Objects.requireNonNullElse(c.get("classes"), Collections.emptyList());
 			classesList.forEach(config -> {
-				List<Parchment.Method> methods = new ArrayList<>();
+				List<DocumentationData.Method> methods = new ArrayList<>();
-				List<Parchment.Field> fields = new ArrayList<>();
+				List<DocumentationData.Field> fields = new ArrayList<>();
 
 				List<UnmodifiableConfig> methodsList = Objects.requireNonNullElse(config.get("methods"), Collections.emptyList());
 				methodsList.forEach(uc -> {
-					List<Parchment.Parameter> parameters = new ArrayList<>();
+					List<String> javadoc = uc.get("javadoc");
 					List<UnmodifiableConfig> parametersList = Objects.requireNonNullElse(uc.get("parameters"), Collections.emptyList());
-					parametersList.forEach(puC -> parameters.add(new Parchment.Parameter(puC.get("index"), puC.get("name"))));
+					for (UnmodifiableConfig puC : parametersList) {
-					methods.add(new Parchment.Method(uc.get("name"), uc.get("descriptor"), uc.get("javadoc"), parameters));
+						parameters.parameters().computeIfAbsent(new Member(config.get("name"), uc.get("name"), uc.get("descriptor")),
+							a -> new HashMap<>()).put(puC.get("index"), puC.get("name"));
+						String doc = puC.get("javadoc");
+						if (doc != null) {
+							if (javadoc == null) {
+								javadoc = new ArrayList<>();
+							}
+							javadoc.add("@parameter " + puC.get("name") + " " + doc);
+						}
+					}
+					methods.add(new DocumentationData.Method(uc.get("name"), uc.get("descriptor"), Objects.requireNonNullElse(javadoc, new ArrayList<>())));
 				});
 
-				classes.add(new Parchment.Class(config.get("name"), config.get("javadoc"), fields, methods));
+				List<UnmodifiableConfig> fieldsList = Objects.requireNonNullElse(config.get("fields"), Collections.emptyList());
+				fieldsList.forEach(uc -> {
+					List<String> javadoc = new ArrayList<>(uc.get("javadoc"));
+					fields.add(new DocumentationData.Field(uc.get("name"), uc.get("descriptor"), javadoc));
 				});
-			parchment = new Parchment(version, packages, classes);
+
+				classes.add(new DocumentationData.Class(config.get("name"), new ArrayList<>(Objects.requireNonNullElse(config.get("javadoc"),
+					Collections.emptyList())), fields, methods));
+			});
+			parchment.insert(parameters, new DocumentationData("named", packages, classes));
 		}
 
 		System.out.printf("Finished loading (%.2fs)\n", (System.currentTimeMillis() - time) / 1000F);

src/main/java/dev/frogmc/thyroxine/writer/ProguardWriter.java

@@ -0,0 +1,51 @@
+package dev.frogmc.thyroxine.writer;
+
+import java.io.PrintWriter;
+import java.io.Writer;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import dev.frogmc.thyroxine.api.data.MappingBundle;
+import dev.frogmc.thyroxine.api.data.MappingData;
+import dev.frogmc.thyroxine.api.data.Member;
+import org.objectweb.asm.Type;
+
+public class ProguardWriter {
+
+	/**
+	 * WARNING: This format should probably not be used.
+	 * <strong>The Proguard format does not support parameter mappings or javadocs.
+	 * This means that this process is likely to be lossy!</strong>
+	 *
+	 * @param bundle the data
+	 * @param writer a writer for the mappings to be written to
+	 */
+	public static void write(MappingBundle bundle, Writer writer) {
+		MappingData data = bundle.flattenData(); // we can only have 2 namespaces.
+		Map<String, Map<Member, String>> methods = new HashMap<>();
+		Map<String, Map<Member, String>> fields = new HashMap<>();
+
+		data.methods().forEach((member, s) -> methods.computeIfAbsent(member.owner(), a -> new HashMap<>()).put(member, s));
+		data.fields().forEach((member, s) -> fields.computeIfAbsent(member.owner(), a -> new HashMap<>()).put(member, s));
+
+		PrintWriter print = new PrintWriter(writer, true);
+		print.println("# Generated by FrogMC/Thyroxine.");
+		print.println("# src-ns: " + data.srcNamespace() + " dst-ns: " + data.dstNamespace());
+
+		data.classes().keySet().stream().sorted().toList().forEach(s -> {
+			String s2 = data.classes().get(s);
+			print.println(s.replace("/", ".") + " -> " + s2.replace("/", "."));
+			fields.getOrDefault(s, Collections.emptyMap()).forEach((member, s1) ->
+				print.println("    " + Type.getType(member.descriptor()).getClassName() +
+							  " " + member.name() + " -> " + s1));
+			methods.getOrDefault(s, Collections.emptyMap()).forEach((member, s1) -> {
+				Type type = Type.getMethodType(member.descriptor());
+				print.println("    ::" + type.getReturnType().getClassName() + " " +
+							  member.name() + "(" + String.join(",", Arrays.stream(type.getArgumentTypes())
+					.map(Type::getClassName).toList()) + ") -> " + s1);
+			});
+		});
+	}
+}

src/main/java/dev/frogmc/thyroxine/writer/tiny/TinyV1Writer.java

@@ -0,0 +1,34 @@
+package dev.frogmc.thyroxine.writer.tiny;
+
+import java.io.PrintWriter;
+import java.io.Writer;
+
+import dev.frogmc.thyroxine.api.data.MappingBundle;
+import dev.frogmc.thyroxine.api.data.MappingData;
+
+public class TinyV1Writer {
+
+	/**
+	 * WARNING: This format should probably not be used.
+	 * <strong>Tiny V1 does not support parameter mappings or javadocs.
+	 * This means that this process is likely to be lossy!</strong>
+	 *
+	 * @param bundle the data
+	 * @param writer a writer for the mappings to be written to
+	 */
+	public static void write(MappingBundle bundle, Writer writer) {
+		MappingData data;
+		if (bundle.srcNamespaces().size() > 1 || bundle.dstNamespaces().size() > 1) {
+			data = bundle.flattenData(); // we can only have 2 namespaces.
+		} else {
+			data = bundle.data().getFirst();
+		}
+
+		PrintWriter print = new PrintWriter(writer, true);
+		print.println("v1\t" + data.srcNamespace() + "\t" + data.dstNamespace());
+
+		data.classes().forEach((s, s2) -> print.println("CLASS\t" + s + "\t" + s2));
+		data.fields().forEach((member, s) -> print.println("FIELD\t" + member.owner() + "\t" + member.descriptor() + "\t" + member.name() + "\t" + s));
+		data.methods().forEach((member, s) -> print.println("METHOD\t" + member.owner() + "\t" + member.descriptor() + "\t" + member.name() + "\t" + s));
+	}
+}

src/main/java/dev/frogmc/thyroxine/writer/tiny/TinyV2Writer.java

@@ -0,0 +1,188 @@
+package dev.frogmc.thyroxine.writer.tiny;
+
+import java.io.*;
+import java.util.*;
+import java.util.stream.Collectors;
+
+import dev.frogmc.thyroxine.api.Mapper;
+import dev.frogmc.thyroxine.api.data.DocumentationData;
+import dev.frogmc.thyroxine.api.data.MappingBundle;
+import dev.frogmc.thyroxine.api.data.MappingData;
+import dev.frogmc.thyroxine.api.data.Member;
+
+public class TinyV2Writer {
+
+	public static void write(MappingBundle bundle, Writer writer) {
+
+		Set<String> overlayNs = new HashSet<>();
+		for (MappingData d : bundle.data()) {
+			if (d.srcNamespace().equals(d.dstNamespace())) {
+				overlayNs.add(d.srcNamespace());
+			}
+		}
+		List<String> srcNs = bundle.srcNamespaces();
+		List<String> dstNs = bundle.dstNamespaces();
+		List<String> srcNamespaces = srcNs.stream().distinct().filter(s -> !dstNs.contains(s) && !overlayNs.contains(s)).toList();
+		if (srcNamespaces.size() > 1) {
+			throw new IllegalStateException("Mapping Data cannot be reduced to a single source namespace, " +
+											"please use .flatten(...) to obtain a mappings set with defined namespaces");
+		}
+		String srcNamespace = srcNamespaces.getFirst();
+
+		Map<String, Map<Integer, String>> classes = new HashMap<>();
+		Map<String, Map<Member, Map<Integer, String>>> methods = new HashMap<>();
+		Map<String, Map<Member, Map<Integer, String>>> fields = new HashMap<>();
+		Map<Member, Map<Integer, Map<Integer, String>>> parameters = new HashMap<>();
+		Map<String, String> javadocs = new HashMap<>();
+
+		List<Mapper> reverseMappers = new ArrayList<>();
+
+		String src = srcNamespace;
+
+		MappingData data = bundle.getWithSrcNamespace(src);
+		DocumentationData docs;
+		int indent = 0;
+		while (data != null) {
+			reverseMappers.addFirst(new Mapper(data.reverse(), s -> Collections.emptyList()));
+			docs = bundle.get(data.dstNamespace());
+			Map<String, DocumentationData.Class> docsClasses = null;
+			Mapper selfMap = new Mapper(data, s -> Collections.emptyList());
+			if (docs != null) {
+				docsClasses = docs.classes().stream().collect(Collectors.toMap(DocumentationData.Class::name, c -> c));
+			}
+			for (Map.Entry<String, String> e : data.classes().entrySet()) {
+				String k = e.getKey();
+				String s2 = e.getValue();
+				String root = k;
+				for (Mapper mapper : reverseMappers) {
+					root = mapper.map(root);
+				}
+				classes.computeIfAbsent(root, a -> new HashMap<>()).put(indent, s2);
+				if (docs != null) {
+					DocumentationData.Class c = docsClasses.get(k);
+					if (c != null) {
+						if (c.javadoc() != null && !c.javadoc().isEmpty()) {
+							javadocs.put(root, String.join("\\n", c.javadoc()));
+						}
+					}
+				}
+			}
+			for (Map.Entry<Member, String> entry : data.methods().entrySet()) {
+				Member key = entry.getKey();
+				String value = entry.getValue();
+				Member root = key;
+				for (Mapper mapper : reverseMappers) {
+					root = new Member(mapper.map(root.owner()),
+						mapper.mapMethodName(root.owner(), root.name(), root.descriptor()),
+						mapper.mapMethodDesc(root.descriptor()));
+				}
+				methods.computeIfAbsent(root.owner(), a -> new HashMap<>()).computeIfAbsent(root, a -> new HashMap<>()).put(indent, value);
+				if (docs != null) {
+					Member rt = root;
+					DocumentationData.Class c = docsClasses.get(data.classes().get(key.owner()));
+					if (c != null) {
+						c.getMethod(data.methods().get(key), selfMap.mapMethodDesc(key.descriptor()))
+							.ifPresent(m -> {
+								if (m.javadoc() != null && !m.javadoc().isEmpty()) {
+									javadocs.put(rt.owner() + rt.descriptor() + rt.name(), String.join("\\n", m.javadoc()));
+								}
+							});
+					}
+				}
+			}
+			for (Map.Entry<Member, String> entry : data.fields().entrySet()) {
+				Member member = entry.getKey();
+				String value = entry.getValue();
+				Member root = member;
+				for (Mapper mapper : reverseMappers) {
+					root = new Member(mapper.map(root.owner()),
+						mapper.mapFieldName(root.owner(), root.name(), root.descriptor()),
+						mapper.mapDesc(root.descriptor()));
+				}
+				fields.computeIfAbsent(root.owner(), a -> new HashMap<>()).computeIfAbsent(root, a -> new HashMap<>()).put(indent, value);
+				if (docs != null) {
+					String id = root.owner() + root.descriptor() + root.name();
+					DocumentationData.Class c = docsClasses.get(data.classes().get(member.owner()));
+					if (c != null) {
+						c.getField(data.fields().get(member), selfMap.mapDesc(member.descriptor()))
+							.ifPresent(f -> {
+								if (f.javadoc() != null && !f.javadoc().isEmpty()) {
+									javadocs.put(id, String.join("\\n", f.javadoc()));
+								}
+							});
+					}
+				}
+			}
+			for (Map.Entry<Member, Map<Integer, String>> entry : data.parameters().entrySet()) {
+				Member member = entry.getKey();
+				Map<Integer, String> integerStringMap = entry.getValue();
+				Member root = member;
+				for (Mapper mapper : reverseMappers) {
+					root = new Member(mapper.map(root.owner()),
+						mapper.mapFieldName(root.owner(), root.name(), root.descriptor()),
+						mapper.mapDesc(root.descriptor()));
+				}
+				Map<Integer, Map<Integer, String>> map = parameters.computeIfAbsent(root, a -> new HashMap<>());
+				for (Map.Entry<Integer, String> e : integerStringMap.entrySet()) {
+					Integer integer = e.getKey();
+					String s = e.getValue();
+					map.computeIfAbsent(integer, a -> new HashMap<>()).put(indent, s);
+				}
+			}
+			indent++;
+			src = data.dstNamespace();
+			data = bundle.getWithSrcNamespace(src);
+		}
+		PrintWriter print = new PrintWriter(writer, true);
+		print.println("tiny\t2\t0\t" + srcNamespace + "\t" + String.join("\t", dstNs));
+
+		classes.keySet().stream().sorted().forEach(s -> {
+			Map<Integer, String> strings = classes.get(s);
+			print.println("c\t" + s + "\t" + printWithIndent(strings));
+			if (javadocs.containsKey(s)) {
+				print.println("\tc\t" + javadocs.get(s));
+			}
+			Map<Member, Map<Integer, String>> fmap = fields.getOrDefault(s, Collections.emptyMap());
+			fmap.keySet().stream().sorted(Comparator.comparing(Member::name)).forEach(m -> {
+				Map<Integer, String> map = fmap.get(m);
+				print.println("\tf\t" + m.descriptor() + "\t" + m.name() + "\t" + printWithIndent(map));
+				String id = m.owner() + m.descriptor() + m.name();
+				if (javadocs.containsKey(id)) {
+					print.println("\t\tc\t" + javadocs.get(id));
+				}
+			});
+			Map<Member, Map<Integer, String>> mmap = methods.getOrDefault(s, Collections.emptyMap());
+			mmap.keySet().stream().sorted(Comparator.comparing(Member::name)).forEach(m -> {
+				Map<Integer, String> map = mmap.get(m);
+				print.println("\tm\t" + m.descriptor() + "\t" + m.name() + "\t" + printWithIndent(map));
+				String id = m.owner() + m.descriptor() + m.name();
+				if (javadocs.containsKey(id) && !javadocs.get(id).isEmpty()) {
+					print.println("\t\tc\t" + javadocs.get(id));
+				}
+				if (parameters.containsKey(m)) {
+					parameters.get(m).forEach((integer, ps) -> {
+						if (ps.values().stream().anyMatch(pname -> !pname.isEmpty())) {
+							print.println("\t\tp\t" + integer + "\t\t" + printWithIndent(ps));
+						}
+					});
+				}
+			});
+		});
+	}
+
+	private static String printWithIndent(Map<Integer, String> map) {
+		int max = map.keySet().stream().max(Comparator.comparingInt(i -> i)).orElse(0);
+		StringBuilder builder = new StringBuilder();
+		for (int current = 0; current <= max; current++) {
+			if (current > 0) {
+				builder.append("\t");
+			}
+			builder.append(map.getOrDefault(current, ""));
+		}
+		String line = builder.toString();
+		while (line.endsWith("\t")) {
+			line = line.substring(0, line.length()-1);
+		}
+		return line;
+	}
+}