How to use

HjsonParser

in

org.hjson

/**
 * Reads a Hjson value from the given reader.
 * <p>
 * Characters are read in chunks and buffered internally, therefore wrapping an existing reader in
 * an additional <code>BufferedReader</code> does <strong>not</strong> improve reading
 * performance.
 * </p>
 *
 * @param reader the reader to read the Hjson value from
 * @return the Hjson value that has been read
 * @throws IOException if an I/O error occurs in the reader
 * @throws ParseException if the input is not valid Hjson
 */
public static JsonValue readHjson(Reader reader) throws IOException {
 return new HjsonParser(reader, null).parse();
}

JsonValue parse() throws IOException {
 // Braces for the root object are optional
 read();
 skipWhiteSpace();
 if (legacyRoot) {
  switch (current) {
   case '[':
   case '{':
    return checkTrailing(readValue());
   default:
    try {
     // assume we have a root object without braces
     return checkTrailing(readObject(true));
    } catch (Exception exception) {
     // test if we are dealing with a single JSON value instead (true/false/null/num/"")
     reset();
     read();
     skipWhiteSpace();
     try { return checkTrailing(readValue()); }
     catch (Exception exception2) { }
     throw exception; // throw original error
    }
  }
 } else {
  return checkTrailing(readValue());
 }
}

private String readStringInternal(boolean allowML) throws IOException {
 // callees make sure that (current=='"' || current=='\'')
 int exitCh = current;
 read();
 startCapture();
 while (current!=exitCh) {
  if (current=='\\') readEscape();
  else if (current<0x20) throw expected("valid string character");
  else read();
 }
 String string=endCapture();
 read();
 if (allowML && exitCh=='\'' && current=='\'' && string.length()==0) {
  // ''' indicates a multiline string
  read();
  return readMlString();
 } else return string;
}

JsonValue checkTrailing(JsonValue v) throws ParseException, IOException {
 skipWhiteSpace();
 if (!isEndOfText()) throw error("Extra characters in input: "+current);
 return v;
}

private ParseException expected(String expected) {
 if (isEndOfText()) {
  return error("Unexpected end of input");
 }
 return error("Expected "+expected);
}

private void skipIndent(int indent) throws IOException {
 while (indent-->0) {
  if (isWhiteSpace(current) && current!='\n') read();
  else break;
 }
}

private JsonObject readObject(boolean objectWithoutBraces) throws IOException {
 if (!objectWithoutBraces) read();
 JsonObject object=new JsonObject();
 skipWhiteSpace();
 while (true) {
  if (objectWithoutBraces) {
   if (isEndOfText()) break;
  } else {
   if (isEndOfText()) throw error("End of input while parsing an object (did you forget a closing '}'?)");
   if (readIf('}')) break;
  }
  String name=readName();
  skipWhiteSpace();
  if (!readIf(':')) {
   throw expected("':'");
  }
  skipWhiteSpace();
  object.add(name, readValue());
  skipWhiteSpace();
  if (readIf(',')) skipWhiteSpace(); // , is optional
 }
 return object;
}

private JsonArray readArray() throws IOException {
 read();
 JsonArray array=new JsonArray();
 skipWhiteSpace();
 if (readIf(']')) {
  return array;
 }
 while (true) {
  skipWhiteSpace();
  array.add(readValue());
  skipWhiteSpace();
  if (readIf(',')) skipWhiteSpace(); // , is optional
  if (readIf(']')) break;
  else if (isEndOfText()) throw error("End of input while parsing an array (did you forget a closing ']'?)");
 }
 return array;
}

private void skipWhiteSpace() throws IOException {
 while (!isEndOfText()) {
  while (isWhiteSpace()) read();
  if (current=='#' || current=='/' && peek()=='/') {
   do {
    read();
   } while (current>=0 && current!='\n');
  }
  else if (current=='/' && peek()=='*') {
   read();
   do {
    read();
   } while (current>=0 && !(current=='*' && peek()=='/'));
   read(); read();
  }
  else break;
 }
}

private String readName() throws IOException {
 if (current=='"' || current=='\'') return readStringInternal(false);
 StringBuilder name=new StringBuilder();
 int space=-1, start=index;
 while (true) {
  if (current==':') {
   if (name.length()==0) throw error("Found ':' but no key name (for an empty key name use quotes)");
   else if (space>=0 && space!=name.length()) { index=start+space; throw error("Found whitespace in your key name (use quotes to include)"); }
   return name.toString();
  } else if (isWhiteSpace(current)) {
   if (space<0) space=name.length();
  } else if (current<' ') {
   throw error("Name is not closed");
  } else if (JsonValue.isPunctuatorChar(current)) {
   throw error("Found '" + (char)current + "' where a key name was expected (check your syntax or use quotes if the key name includes {}[],: or whitespace)");
  } else name.append((char)current);
  read();
 }
}

int first=current;
if (JsonValue.isPunctuatorChar(first))
 throw error("Found a punctuator character '" + (char)first + "' when expecting a quoteless string (check your syntax)");
value.append((char)current);
for (;;) {
 read();
 boolean isEol=current<0 || current=='\r' || current=='\n';
 if (isEol || current==',' ||
  current=='}' || current==']' ||
  current=='#' ||
  current=='/' && (peek()=='/' || peek()=='*')
  ) {
  switch (first) {
   default:
    if (first=='-' || first>='0' && first<='9') {
     JsonValue n=tryParseNumber(value, false);
     if (n!=null) return n;

 if (isWhiteSpace(current) && current!='\n') read();
 else break;
if (current=='\n') { read(); skipIndent(indent); }
 if (current<0) throw error("Bad multiline string");
 else if (current=='\'') {
  triple++;
  read();
  if (triple==3) {
   if (sb.charAt(sb.length()-1)=='\n') sb.deleteCharAt(sb.length()-1);
  read();
  skipIndent(indent);
  read();

private void readEscape() throws IOException {
 pauseCapture();
 read();
 switch(current) {
  case '"':
   char[] hexChars=new char[4];
   for (int i=0; i<4; i++) {
    read();
    if (!isHexDigit()) {
     throw expected("hexadecimal digit");
   break;
  default:
   throw expected("valid escape sequence");
 read();

if (!isDigit(first)) return null;
if (first=='0' && idx<len && isDigit(value.charAt(idx)))
 return null; // leading zero is not allowed
while (idx<len && isDigit(value.charAt(idx))) idx++;
 if (idx>=len || !isDigit(value.charAt(idx++))) return null;
 while (idx<len && isDigit(value.charAt(idx))) idx++;
 if (idx<len && (value.charAt(idx)=='+' || value.charAt(idx)=='-')) idx++;
 if (idx>=len || !isDigit(value.charAt(idx++))) return null;
 while (idx<len && isDigit(value.charAt(idx))) idx++;
while (idx<len && isWhiteSpace(value.charAt(idx))) idx++;

HjsonParser.isWhiteSpace(left) || HjsonParser.isWhiteSpace(right) ||
left=='"' ||
left=='\'' ||
left=='/' && (left1=='*' || left1=='/') ||
JsonValue.isPunctuatorChar(left) ||
HjsonParser.tryParseNumber(value, true)!=null ||
startsWithKeyword(value)) {
for(char ch : valuec) {
 if (needsEscapeML(ch)) { noEscapeML=false; break; }
 else if (!HjsonParser.isWhiteSpace(ch)) allWhite=false;

private boolean isWhiteSpace() {
 return isWhiteSpace((char)current);
}

private ParseException error(String message) {
 int column=index-lineOffset;
 int offset=isEndOfText()?index:index-1;
 return new ParseException(message, offset, line, column-1);
}

private JsonObject readObject(boolean objectWithoutBraces) throws IOException {
 if (!objectWithoutBraces) read();
 JsonObject object=new JsonObject();
 skipWhiteSpace();
 while (true) {
  if (objectWithoutBraces) {
   if (isEndOfText()) break;
  } else {
   if (isEndOfText()) throw error("End of input while parsing an object (did you forget a closing '}'?)");
   if (readIf('}')) break;
  }
  String name=readName();
  skipWhiteSpace();
  if (!readIf(':')) {
   throw expected("':'");
  }
  skipWhiteSpace();
  object.add(name, readValue());
  skipWhiteSpace();
  if (readIf(',')) skipWhiteSpace(); // , is optional
 }
 return object;
}

private JsonArray readArray() throws IOException {
 read();
 JsonArray array=new JsonArray();
 skipWhiteSpace();
 if (readIf(']')) {
  return array;
 }
 while (true) {
  skipWhiteSpace();
  array.add(readValue());
  skipWhiteSpace();
  if (readIf(',')) skipWhiteSpace(); // , is optional
  if (readIf(']')) break;
  else if (isEndOfText()) throw error("End of input while parsing an array (did you forget a closing ']'?)");
 }
 return array;
}

private void skipWhiteSpace() throws IOException {
 while (!isEndOfText()) {
  while (isWhiteSpace()) read();
  if (current=='#' || current=='/' && peek()=='/') {
   do {
    read();
   } while (current>=0 && current!='\n');
  }
  else if (current=='/' && peek()=='*') {
   read();
   do {
    read();
   } while (current>=0 && !(current=='*' && peek()=='/'));
   read(); read();
  }
  else break;
 }
}