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Merged
octylFractal merged 1 commit into from
Feb 23, 2026
Merged

Replace simple state records with enums #17

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32 changes: 18 additions & 14 deletions format-snbt/src/main/java/org/enginehub/linbus/format/snbt/impl/LinSnbtWriter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -41,10 +41,17 @@ private sealed interface WriteState {
record List(int remainingValues) implements WriteState {
}

record Compound(boolean hasPrevious) implements WriteState {
enum Compound implements WriteState {
DEFAULT,
/**
* Indicates that an entry was just finished, so when a new name is encountered, a comma should be emitted
* first.
*/
HAS_PREVIOUS_ENTRY,
}

record WritingArray() implements WriteState {
enum WritingArray implements WriteState {
INSTANCE
}
}

Expand Down Expand Up @@ -72,13 +79,14 @@ public void write(Appendable output, LinStream tokens) throws IOException {
}
switch (token) {
case LinToken.Name(String name, Optional<LinTagId> id) -> {
if (!(state instanceof WriteState.Compound compound)) {
if (!(state instanceof WriteState.Compound)) {
throw new NbtWriteException("Names can only appear inside compounds");
}
if (compound.hasPrevious) {
if (state == WriteState.Compound.HAS_PREVIOUS_ENTRY) {
output.append(',');
// Kill the previous flag
replaceLast(new WriteState.Compound(false));
stateStack.removeLast();
stateStack.addLast(WriteState.Compound.DEFAULT);
}
output.append(Elusion.escapeIfNeeded(name)).append(':');
}
Expand All @@ -87,7 +95,7 @@ public void write(Appendable output, LinStream tokens) throws IOException {
if (state instanceof WriteState.WritingArray) {
output.append(',');
} else {
stateStack.addLast(new WriteState.WritingArray());
stateStack.addLast(WriteState.WritingArray.INSTANCE);
}
while (buffer.hasRemaining()) {
output.append(String.valueOf(buffer.get())).append('B');
Expand All @@ -112,7 +120,7 @@ public void write(Appendable output, LinStream tokens) throws IOException {
case LinToken.CompoundStart compoundStart -> {
output.append('{');

stateStack.addLast(new WriteState.Compound(false));
stateStack.addLast(WriteState.Compound.DEFAULT);
}
case LinToken.CompoundEnd compoundEnd -> {
output.append('}');
Expand All @@ -135,7 +143,7 @@ public void write(Appendable output, LinStream tokens) throws IOException {
if (state instanceof WriteState.WritingArray) {
output.append(',');
} else {
stateStack.addLast(new WriteState.WritingArray());
stateStack.addLast(WriteState.WritingArray.INSTANCE);
}
while (buffer.hasRemaining()) {
output.append(String.valueOf(buffer.get()));
Expand Down Expand Up @@ -173,7 +181,7 @@ public void write(Appendable output, LinStream tokens) throws IOException {
if (state instanceof WriteState.WritingArray) {
output.append(',');
} else {
stateStack.addLast(new WriteState.WritingArray());
stateStack.addLast(WriteState.WritingArray.INSTANCE);
}
while (buffer.hasRemaining()) {
output.append(String.valueOf(buffer.get())).append('L');
Expand Down Expand Up @@ -221,13 +229,9 @@ private void handleValueEnd(Appendable output) throws IOException {
output.append(',');
}
}
case WriteState.Compound compound -> stateStack.addLast(new WriteState.Compound(true));
case WriteState.Compound compound -> stateStack.addLast(WriteState.Compound.HAS_PREVIOUS_ENTRY);
default -> throw new NbtWriteException("Unexpected state: " + state);
}
}

private void replaceLast(WriteState state) {
stateStack.removeLast();
stateStack.addLast(state);
}
}
56 changes: 32 additions & 24 deletions format-snbt/src/main/java/org/enginehub/linbus/format/snbt/impl/reader/LinSnbtReader.java
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,8 @@ private sealed interface State {
* The cursor should either point to a comma or a closing brace.
* </p>
*/
record InCompound() implements State {
enum InCompound implements State {
INSTANCE
}

/**
Expand All @@ -60,7 +61,8 @@ record InCompound() implements State {
* After this, the cursor will be one character after the colon.
* </p>
*/
record CompoundEntryName() implements State {
enum CompoundEntryName implements State {
INSTANCE
}

/**
Expand All @@ -70,7 +72,8 @@ record CompoundEntryName() implements State {
* The cursor should either point to a comma or a closing bracket.
* </p>
*/
record InList() implements State {
enum InList implements State {
INSTANCE
}

/**
Expand All @@ -80,7 +83,8 @@ record InList() implements State {
* The cursor should always point to the start of a value.
* </p>
*/
record InByteArray() implements State {
enum InByteArray implements State {
INSTANCE
}

/**
Expand All @@ -90,7 +94,8 @@ record InByteArray() implements State {
* The cursor should always point to the start of a value.
* </p>
*/
record InIntArray() implements State {
enum InIntArray implements State {
INSTANCE
}

/**
Expand All @@ -100,14 +105,17 @@ record InIntArray() implements State {
* The cursor should always point to the start of a value.
* </p>
*/
record InLongArray() implements State {
enum InLongArray implements State {
INSTANCE
}

/**
* We need to read a value. Usually, we'll just return the value, and not push a new state, unless we need to
* read a complex value such as a compound or list.
*/
record ReadValue(boolean mustBeCompound) implements State {
enum ReadValue implements State {
ANY,
COMPOUND_ONLY,
}
}

Expand Down Expand Up @@ -135,7 +143,7 @@ record ReadValue(boolean mustBeCompound) implements State {
*/
public LinSnbtReader(Iterator<? extends SnbtTokenWithMetadata> input) {
this.input = input;
this.stateStack = new ArrayDeque<>(List.of(new State.ReadValue(true)));
this.stateStack = new ArrayDeque<>(List.of(State.ReadValue.COMPOUND_ONLY));
this.tokenQueue = new ArrayDeque<>();
this.readAgainStack = new ArrayDeque<>();
}
Expand Down Expand Up @@ -182,7 +190,7 @@ private NbtParseException unexpectedTokenSpecificError(SnbtToken token, String e

private void fillTokenStack(State state) {
switch (state) {
case State.ReadValue(boolean mustBeCompound) -> readValue(mustBeCompound);
case State.ReadValue readValue -> readValue(readValue);
case State.InCompound inCompound -> advanceCompound();
case State.CompoundEntryName compoundEntryName -> readName();
case State.InList inList -> advanceList();
Expand Down Expand Up @@ -211,18 +219,18 @@ private void fillTokenStack(State state) {
}
}

private void readValue(boolean mustBeCompound) {
private void readValue(State.ReadValue readValue) {
// Remove the ReadValue
stateStack.removeLast();
var token = read().token();
if (token instanceof SnbtToken.CompoundStart) {
stateStack.addLast(new State.InCompound());
stateStack.addLast(new State.CompoundEntryName());
stateStack.addLast(State.InCompound.INSTANCE);
stateStack.addLast(State.CompoundEntryName.INSTANCE);
tokenQueue.addLast(new LinToken.CompoundStart());
return;
}

if (mustBeCompound) {
if (readValue == State.ReadValue.COMPOUND_ONLY) {
throw unexpectedTokenSpecificError(token, SnbtToken.CompoundStart.INSTANCE.toString());
}

Expand All @@ -243,7 +251,7 @@ private void advanceCompound() {
stateStack.removeLast();
tokenQueue.addLast(new LinToken.CompoundEnd());
}
case SnbtToken.Separator separator -> stateStack.addLast(new State.CompoundEntryName());
case SnbtToken.Separator separator -> stateStack.addLast(State.CompoundEntryName.INSTANCE);
default -> throw unexpectedTokenError(token);
}
}
Expand All @@ -259,7 +267,7 @@ private void readName() {
if (!(token instanceof SnbtToken.EntrySeparator)) {
throw unexpectedTokenSpecificError(token, SnbtToken.EntrySeparator.INSTANCE.toString());
}
stateStack.addLast(new State.ReadValue(false));
stateStack.addLast(State.ReadValue.ANY);
tokenQueue.addLast(new LinToken.Name(text.content()));
}

Expand All @@ -270,7 +278,7 @@ private void advanceList() {
stateStack.removeLast();
tokenQueue.addLast(new LinToken.ListEnd());
}
case SnbtToken.Separator separator -> stateStack.addLast(new State.ReadValue(false));
case SnbtToken.Separator separator -> stateStack.addLast(State.ReadValue.ANY);
default -> throw unexpectedTokenError(token);
}
}
Expand Down Expand Up @@ -324,23 +332,23 @@ private <T extends Buffer, L extends LinToken> void advanceArray(
private void prepareListLike() {
int initialCharIndex = charIndex;
var typing = read();
if (typing.token() instanceof SnbtToken.Text text && !text.quoted() && text.content().length() == 1) {
if (typing.token() instanceof SnbtToken.Text(boolean quoted, String content) && !quoted && content.length() == 1) {
var separatorCheck = read();
if (separatorCheck.token() instanceof SnbtToken.ListTypeSeparator) {
switch (text.content().charAt(0)) {
switch (content.charAt(0)) {
case 'B' -> {
stateStack.addLast(new State.InByteArray());
stateStack.addLast(State.InByteArray.INSTANCE);
tokenQueue.addLast(new LinToken.ByteArrayStart());
}
case 'I' -> {
stateStack.addLast(new State.InIntArray());
stateStack.addLast(State.InIntArray.INSTANCE);
tokenQueue.addLast(new LinToken.IntArrayStart());
}
case 'L' -> {
stateStack.addLast(new State.InLongArray());
stateStack.addLast(State.InLongArray.INSTANCE);
tokenQueue.addLast(new LinToken.LongArrayStart());
}
default -> throw new NbtParseException(errorPrefix() + "Invalid array type: " + text.content());
default -> throw new NbtParseException(errorPrefix() + "Invalid array type: " + content);
}
return;
}
Expand All @@ -349,8 +357,8 @@ private void prepareListLike() {
readAgainStack.addFirst(typing);
charIndex = initialCharIndex;

stateStack.addLast(new State.InList());
stateStack.addLast(new State.ReadValue(false));
stateStack.addLast(State.InList.INSTANCE);
stateStack.addLast(State.ReadValue.ANY);
tokenQueue.addLast(new LinToken.ListStart());
}

Expand Down
19 changes: 11 additions & 8 deletions stream/src/main/java/org/enginehub/linbus/stream/impl/LinNbtReader.java
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Original file line number Diff line number Diff line change
Expand Up @@ -114,19 +114,22 @@ private sealed interface State {
/**
* We need to initialize and return the root name.
*/
record Initial() implements State {
enum Initial implements State {
INSTANCE
}

/**
* We need to return {@link LinToken.CompoundStart}.
*/
record CompoundStart() implements State {
enum CompoundStart implements State {
INSTANCE
}

/**
* We need to give the name of the next entry. We'll load the ID here too.
*/
record CompoundEntryName() implements State {
enum CompoundEntryName implements State {
INSTANCE
}

/**
Expand Down Expand Up @@ -247,7 +250,7 @@ public String decode() throws CharacterCodingException {
*/
public LinNbtReader(DataInput input, LinReadOptions options) {
this.input = input;
this.stateStack = new ArrayDeque<>(List.of(new State.Initial()));
this.stateStack = new ArrayDeque<>(List.of(State.Initial.INSTANCE));
// We only need to check strings if we're allowing normal UTF-8 encoding.
this.stringEncoding = options.allowNormalUtf8Encoding()
? StringEncoding.UNKNOWN : StringEncoding.MODIFIED_UTF_8;
Expand All @@ -262,11 +265,11 @@ public LinNbtReader(DataInput input, LinReadOptions options) {
if (input.readUnsignedByte() != LinTagId.COMPOUND.id()) {
throw new NbtParseException("NBT stream does not start with a compound tag");
}
stateStack.addLast(new State.CompoundStart());
stateStack.addLast(State.CompoundStart.INSTANCE);
yield new LinToken.Name(readUtf(), LinTagId.COMPOUND);
}
case State.CompoundStart compoundStart -> {
stateStack.addLast(new State.CompoundEntryName());
stateStack.addLast(State.CompoundEntryName.INSTANCE);
yield new LinToken.CompoundStart();
}
case State.CompoundEntryName compoundEntryName -> {
Expand All @@ -276,7 +279,7 @@ public LinNbtReader(DataInput input, LinReadOptions options) {
}

// After we read the value, we'll be back at reading the name.
stateStack.addLast(new State.CompoundEntryName());
stateStack.addLast(State.CompoundEntryName.INSTANCE);
stateStack.addLast(new State.ReadValue(id));
yield new LinToken.Name(readUtf(), id);
}
Expand Down Expand Up @@ -345,7 +348,7 @@ private LinToken handleReadValue(LinTagId id) throws IOException {
yield new LinToken.ListStart(size, elementId);
}
case COMPOUND -> {
stateStack.addLast(new State.CompoundEntryName());
stateStack.addLast(State.CompoundEntryName.INSTANCE);
yield new LinToken.CompoundStart();
}
case INT_ARRAY -> {
Expand Down
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