private String parseString()

in juneau-core/juneau-marshall/src/main/java/org/apache/juneau/json/JsonParserSession.java [727:805]
76 lines of code
30 McCabe index (conditional complexity)

	private String parseString(ParserReader r) throws IOException, ParseException {
		r.mark();
		int qc = r.read();		// The quote character being used (" or ')
		if (qc != '"' && isStrict()) {
			String msg = (
				qc == '\''
				? "Invalid quote character \"{0}\" being used."
				: "Did not find quote character marking beginning of string.  Character=\"{0}\""
			);
			throw new ParseException(this, msg, (char)qc);
		}
		final boolean isQuoted = (qc == '\'' || qc == '"');
		String s = null;
		boolean isInEscape = false;
		int c = 0;
		while (c != -1) {
			c = r.read();
			// Strict syntax requires that all control characters be escaped.
			if (isStrict() && c <= 0x1F)
				throw new ParseException(this, "Unescaped control character encountered: ''0x{0}''", String.format("%04X", c));
			if (isInEscape) {
				switch (c) {
					case 'n': r.replace('\n'); break;
					case 'r': r.replace('\r'); break;
					case 't': r.replace('\t'); break;
					case 'f': r.replace('\f'); break;
					case 'b': r.replace('\b'); break;
					case '\\': r.replace('\\'); break;
					case '/': r.replace('/'); break;
					case '\'': r.replace('\''); break;
					case '"': r.replace('"'); break;
					case 'u': {
						String n = r.read(4);
						try {
							r.replace(Integer.parseInt(n, 16), 6);
						} catch (NumberFormatException e) {
							throw new ParseException(this, "Invalid Unicode escape sequence in string.");
						}
						break;
					}
					default:
						throw new ParseException(this, "Invalid escape sequence in string.");
				}
				isInEscape = false;
			} else {
				if (c == '\\') {
					isInEscape = true;
					r.delete();
				} else if (isQuoted) {
					if (c == qc) {
						s = r.getMarked(1, -1);
						break;
					}
				} else {
					if (c == ',' || c == '}' || c == ']' || isWhitespace(c)) {
						s = r.getMarked(0, -1);
						r.unread();
						break;
					} else if (c == -1) {
						s = r.getMarked(0, 0);
						break;
					}
				}
			}
		}
		if (s == null)
			throw new ParseException(this, "Could not find expected end character ''{0}''.", (char)qc);

		// Look for concatenated string (i.e. whitespace followed by +).
		skipCommentsAndSpace(r);
		if (r.peek() == '+') {
			if (isStrict())
				throw new ParseException(this, "String concatenation detected.");
			r.read();	// Skip past '+'
			skipCommentsAndSpace(r);
			s += parseString(r);
		}
		return trim(s); // End of input reached.
	}