private void readString()

in johnzon-core/src/main/java/org/apache/johnzon/core/JsonStreamParserImpl.java [626:707]
45 lines of code
18 McCabe index (conditional complexity)

    private void readString() {

        do {
            char n = readNextChar();
            //when first called n its first char after the starting quote
            //after that its the next character after the while loop below

            if (n == QUOTE_CHAR) {
                endOfValueInBuffer = startOfValueInBuffer = bufferPos; //->"" case
                return;
            } else if (n == EOL) {
                throw uexc("Unexpected linebreak");

            } else if (/* n >= '\u0000' && */ n <= '\u001F') {
                throw uexc("Unescaped control character");

            } else if (n == ESCAPE_CHAR) {

                n = readNextChar();

                //  \ u XXXX -> unicode char
                if (n == 'u') {
                    n = parseUnicodeHexChars();
                    appendToCopyBuffer(n);

                    // \\ -> \
                } else if (n == ESCAPE_CHAR) {
                    appendToCopyBuffer(n);

                    //another escape chars, for example \t
                } else {
                    appendToCopyBuffer(Strings.asEscapedChar(n));
                }

            } else {

                startOfValueInBuffer = bufferPos;
                endOfValueInBuffer = -1;

                while ((n = readNextChar()) > '\u001F' && n != ESCAPE_CHAR && n != EOL && n != QUOTE_CHAR) {
                    //read fast
                }

                endOfValueInBuffer = bufferPos;

                if (n == QUOTE_CHAR) {

                    if (fallBackCopyBufferLength > 0) {
                        copyCurrentValue();
                    } else {
                        if ((endOfValueInBuffer - startOfValueInBuffer) > maxValueLength) {
                            throw tmc();
                        }

                    }

                    return;
                } else if (n == EOL) {
                    throw uexc("Unexpected linebreak");

                } else if (n >= '\u0000' && n <= '\u001F') {
                    throw uexc("Unescaped control character");
                }

                copyCurrentValue();

                //current n is one of < '\u001F' -OR- ESCAPE_CHAR -OR- EOL -OR- QUOTE

                unreadChar(); //unread one char

            }
        } while (true);

        // before this do while(true) it was:
        //
        //recurse until string is terminated by a non escaped quote
        //readString();
        //
        //
        // but recursive = can't read big strings

    }