Version 2.1.0

Author: Synt4xErr0r4

README.md

@@ -10,9 +10,9 @@ This is a reference implementation, capable of parsing JSON5 data according to t
 
 ## Getting started
 
-In order to use the code, you can either [download the jar](https://github.com/Synt4xErr0r4/json5/releases/download/2.0.0/json5-2.0.0.jar), or use the Maven dependency:
+In order to use the code, you can either [download the jar](https://github.com/Synt4xErr0r4/json5/releases/download/2.1.0/json5-2.1.0.jar), or use the Maven dependency:
 
-*Note:* Starting with version 2.0.0, the Maven dependency is now also available from [Maven Central](https://central.sonatype.com/artifact/at.syntaxerror/json5/2.0.0).
+*Note:* Starting with version 2.0.0, the Maven dependency is now also available from [Maven Central](https://central.sonatype.com/artifact/at.syntaxerror/json5/2.1.0).
 
 ```xml
 <!-- Repository -->
@@ -27,7 +27,7 @@ In order to use the code, you can either [download the jar](https://github.com/S
 <dependency>
   <groupId>at.syntaxerror</groupId>
   <artifactId>json5</artifactId>
-  <version>2.0.0</version>
+  <version>2.1.0</version>
 </dependency>
 ```
 
@@ -259,6 +259,14 @@ When the behavior is `DUPLICATE`, the snippet above is effectively equal to the
 
 Note regarding digit separators: Digit separators may neither occur next to each other, nor at the beginning nor the end of a literal. They can also be used within binary/octal/hexadecimal and hexadecimal floating-point literals.
 
+### v2.1.0
+
+- `JSONObject`s now store entries in the order they were added ([#7](https://github.com/Synt4xErr0r4/json5/issues/7))
+- added option `allowTrailingData` (*Parser-only*, default `false`):
+  - if `true`, trailing data after a JSON object or array (e.g. `abc` in `{ }abc`) will be ignored
+  - otherwise, an exception will be thrown
+- various small improvements ([#7](https://github.com/Synt4xErr0r4/json5/issues/7), [#8](https://github.com/Synt4xErr0r4/json5/issues/8), [#9](https://github.com/Synt4xErr0r4/json5/issues/9))
+
 ## Documentation
 
 The JavaDoc for the latest version can be found [here](https://javadoc.syntaxerror.at/json5/latest).

pom.xml

@@ -4,7 +4,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>at.syntaxerror</groupId>
 	<artifactId>json5</artifactId>
-	<version>2.0.0</version>
+	<version>2.1.0</version>
 	<packaging>jar</packaging>
 
 	<name>JSON5 for Java</name>

src/main/java/at/syntaxerror/json5/JSONArray.java

@@ -82,6 +82,9 @@ public JSONArray(JSONParser parser) {
 			case 0:
 				throw parser.syntaxError("A JSONArray must end with ']'");
 			case ']':
+				if(parser.root && !parser.options.isAllowTrailingData() && parser.nextClean() != 0) {
+					throw parser.syntaxError("Trailing data after JSONArray");
+				}
 				return;
 			default:
 				parser.back();
@@ -97,7 +100,7 @@ public JSONArray(JSONParser parser) {
 				return;
 
 			if(c != ',')
-				throw parser.syntaxError("Expected ',' or ']' after value, got '" + c + "' instead");
+				throw parser.syntaxError("Expected ',' or ']' after value, got " + JSONParser.charToString(c) + " instead");
 		}
 	}
 

src/main/java/at/syntaxerror/json5/JSONObject.java

@@ -27,9 +27,9 @@
 import java.math.BigInteger;
 import java.time.DateTimeException;
 import java.time.Instant;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
@@ -56,7 +56,7 @@ public class JSONObject implements Iterable<Map.Entry<String, Object>> {
 	 * Constructs a new JSONObject
 	 */
 	public JSONObject() {
-		values = new HashMap<>();
+		values = new LinkedHashMap<>();
 	}
 
 	/**
@@ -93,6 +93,9 @@ public JSONObject(JSONParser parser) {
 			case 0:
 				throw parser.syntaxError("A JSONObject must end with '}'");
 			case '}':
+				if(parser.root && !parser.options.isAllowTrailingData() && parser.nextClean() != 0) {
+					throw parser.syntaxError("Trailing data after JSONObject");
+				}
 				return;
 			default:
 				parser.back();
@@ -107,7 +110,7 @@ public JSONObject(JSONParser parser) {
 			c = parser.nextClean();
 
 			if(c != ':')
-				throw parser.syntaxError("Expected ':' after a key, got '" + c + "' instead");
+				throw parser.syntaxError("Expected ':' after a key, got " + JSONParser.charToString(c) + " instead");
 
 			Object value = parser.nextValue();
 
@@ -136,7 +139,7 @@ public JSONObject(JSONParser parser) {
 				return;
 
 			if(c != ',')
-				throw parser.syntaxError("Expected ',' or '}' after value, got '" + c + "' instead");
+				throw parser.syntaxError("Expected ',' or '}' after value, got " + JSONParser.charToString(c) + " instead");
 		}
 	}
 
@@ -188,7 +191,7 @@ else if(value instanceof JSONObject)
 	 * @return a map of the entries of this object
 	 */
 	public Map<String, Object> toMap() {
-		Map<String, Object> map = new HashMap<>();
+		Map<String, Object> map = new LinkedHashMap<>();
 
 		for(Entry<String, Object> entry : this) {
 			Object value = entry.getValue();

src/main/java/at/syntaxerror/json5/JSONOptions.java

@@ -259,6 +259,30 @@ public class JSONOptions {
 	@Builder.Default
 	DuplicateBehavior duplicateBehaviour = DuplicateBehavior.UNIQUE;
 
+	/**
+	 * Specifies whether trailing data should be allowed.<br>
+	 * If {@code false}, parsing the following will produce an error
+	 * due to the trailing {@code abc}:
+	 * 
+	 * <pre><code>{ }abc</code></pre>
+	 * 
+	 * If {@code true}, however, this will be interpreted as an empty
+	 * {@link JSONObject} and any trailing will be ignored.
+	 * <p>
+	 * Whitespace never counts as trailing data.
+	 * <p>
+	 * Default: {@code false}
+	 * <p>
+	 * <i>This is a {@link JSONParser Parser}-only option</i>
+	 * 
+	 * @param allowTrailingData a boolean
+	 * 
+	 * @return whether trailing data should be allowed
+	 * @since 2.1.0
+	 */
+	@Builder.Default
+	boolean allowTrailingData = false;
+	
 	/**
 	 * An enum containing all supported behaviors for duplicate keys
 	 * 

src/main/java/at/syntaxerror/json5/JSONParser.java

@@ -41,6 +41,9 @@ public class JSONParser {
 
 	private final Reader reader;
 	protected final JSONOptions options;
+	
+	/** whether we're currently parsing the root object/array */
+	protected boolean root = true;
 
 	/** whether the end of the file has been reached */
 	private boolean eof;
@@ -273,7 +276,7 @@ private void nextSingleLineComment() {
 	public char nextClean() {
 		while(true) {
 			if(!more())
-				throw syntaxError("Unexpected end of data");
+				return 0;
 
 			char n = next();
 
@@ -302,11 +305,11 @@ private String nextCleanTo(String delimiters) {
 		StringBuilder result = new StringBuilder();
 
 		while(true) {
-			if(!more())
-				throw syntaxError("Unexpected end of data");
-			
 			char n = nextClean();
 
+			if(n == 0)
+				return null;
+			
 			if(delimiters.indexOf(n) > -1 || isWhitespace(n)) {
 				back();
 				break;
@@ -372,7 +375,7 @@ private String nextString(char quote) {
 
 		while(true) {
 			if(!more())
-				throw syntaxError("Unexpected end of data");
+				throw syntaxError("Expected '" + quote + "' to close string, got EOF instead");
 
 			prev = n;
 			n = next();
@@ -397,6 +400,9 @@ private String nextString(char quote) {
 				}
 
 				else switch(n) {
+				case 0:
+					throw syntaxError("Expected escape sequence in string, got EOF instead");
+				
 				case '\'':
 				case '"':
 				case '\\':
@@ -436,6 +442,10 @@ else switch(n) {
 
 					for(int i = 0; i < 2; ++i) {
 						n = next();
+						
+						if(n == 0)
+							throw syntaxError("Expected hexadecimal digit for hexadecimal escape sequence in string, got EOF instead");
+						
 						value += n;
 
 						int hex = dehex(n);
@@ -519,23 +529,26 @@ public String nextMemberName() {
 		char prev;
 		char n = next();
 
+		if(n == 0)
+			throw syntaxError("Expected key, got EOF instead");
+		
 		if(n == '"' || n == '\'')
 			return nextString(n);
 
 		back();
 		n = 0;
 
-		while(true) {
-			if(!more())
-				throw syntaxError("Unexpected end of data");
-
+		do {
 			boolean part = result.length() > 0;
 
 			prev = n;
 			n = next();
 
 			if(n == '\\') { // unicode escape sequence
 				n = next();
+
+				if(n == 0)
+					throw syntaxError("Expected escape sequence in key, got EOF instead");
 
 				if(n != 'u' && n != 'U')
 					throw syntaxError("Illegal escape sequence '\\" + n + "' in key");
@@ -560,10 +573,10 @@ else if(!isMemberNameChar(n, part)) {
 			checkSurrogate(prev, n);
 
 			result.append(n);
-		}
+		} while(more());
 
 		if(result.length() == 0)
-			throw syntaxError("Empty key");
+			throw syntaxError("Expected key");
 
 		return result.toString();
 	}
@@ -572,27 +585,37 @@ else if(!isMemberNameChar(n, part)) {
 	 * Reads a value from the source according to the
 	 * <a href="https://spec.json5.org/#prod-JSON5Value">JSON5 Specification</a>
 	 * 
-	 * @return an member name
+	 * @return a value
 	 */
 	public Object nextValue() {
 		char n = nextClean();
+		boolean wasRoot = root;
 
-		switch(n) {
-		case '"':
-		case '\'':
-			return nextString(n);
-		case '{':
-			back();
-			return new JSONObject(this);
-		case '[':
-			back();
-			return new JSONArray(this);
+		try {
+			switch(n) {
+			case '"':
+			case '\'':
+				return nextString(n);
+			case '{':
+				back();
+				root = false;
+				return new JSONObject(this);
+			case '[':
+				back();
+				root = false;
+				return new JSONArray(this);
+			}
+		} finally {
+			root = wasRoot;
 		}
 
 		back();
 
 		String string = nextCleanTo(",]}");
 
+		if(string == null)
+			throw syntaxError("Expected value, got EOF instead");
+		
 		if(string.equals("null"))
 			return null;
 
@@ -636,17 +659,15 @@ else if(leading == '-') {
 				if((leading >= '0' && leading <= '9') || leading == '.') {
 					Number num = parseNumber(leading, rest);
 
-					if(num != null) {
-						if(sign < 0) {
-							if(num instanceof BigInteger)
-								return ((BigInteger) num).negate();
-
-							if(num instanceof BigDecimal)
-								return ((BigDecimal) num).negate();
-						}
+					if(sign < 0) {
+						if(num instanceof BigInteger)
+							return ((BigInteger) num).negate();
 
-						return num;
+						if(num instanceof BigDecimal)
+							return ((BigDecimal) num).negate();
 					}
+
+					return num;
 				}
 			}
 		}
@@ -1023,5 +1044,38 @@ private static boolean ishex(char c) {
 			|| (c >= 'a' && c <= 'f')
 			|| (c >= 'A' && c <= 'F');
 	}
+
+	/**
+	 * Converts a character into a string representation:
+	 * 
+	 * <ul>
+	 * <li>if {@code c == 0}, {@code "EOF"} is returned</li>
+	 * <li>if {@code c} fulfills one of the following conditions, {@code "'x'"}
+	 *   is returned, where {@code x} is the value returned by {@link Character#toString(char)}:
+	 *   <ul>
+	 *   <li>if {@code c} is an extended ASCII character ({@code U+0001-U+00FF}),
+	 *       except {@link Character#isISOControl(char) control characters}</li>
+	 *   <li>if {@code c} is a {@link Character#isLetter(char) Unicode letter}</li>
+	 *   <li>if {@code c} is a {@link Character#isDigit(char) Unicode digit}</li>
+	 *   </ul>
+	 * </li>
+	 * <li>otherwise, {@code "U+XXXX"} is returned, where {@code XXXX} is the uppercase
+	 *     hexadecimal representation of {@code c}'s Unicode codepoint, padded with zeros
+	 *     ({@code 0}) to a length of 4 characters</li>
+	 * </ul>
+	 * 
+	 * @param c the character
+	 * @return the string representation
+	 * @since 2.1.0
+	 */
+	protected static String charToString(char c) {
+		if(c == 0)
+			return "EOF";
+		
+		if((c <= 0xFF && !Character.isISOControl(c)) || Character.isLetterOrDigit(c))
+			return "'" + c + "'";
+		
+		return String.format("U+%04X", (int) c);
+	}
 
 }

src/main/java/at/syntaxerror/json5/JSONStringify.java

@@ -288,7 +288,9 @@ private static String quote(String string, JSONOptions options) {
 
 		quoted.append(qt);
 
-		for(char c : string.toCharArray()) {
+		for(int i = 0, n = string.length(); i < n; ++i) {
+			char c = string.charAt(i);
+			
 			if(c == qt) {
 				quoted.append('\\');
 				quoted.append(c);