private static List parseArgumentsWindows()

in com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/DebugUtility.java [685:776]
80 lines of code
23 McCabe index (conditional complexity)

    private static List<String> parseArgumentsWindows(String args) {
        // see http://msdn.microsoft.com/en-us/library/a1y7w461.aspx
        List<String> result = new ArrayList<>();
        final int DEFAULT = 0;
        final int ARG = 1;
        final int IN_DOUBLE_QUOTE = 2;

        int state = DEFAULT;
        int backslashes = 0;
        StringBuilder buf = new StringBuilder();
        int len = args.length();
        for (int i = 0; i < len; i++) {
            char ch = args.charAt(i);
            if (ch == '\\') {
                backslashes++;
                continue;
            } else if (backslashes != 0) {
                if (ch == '"') {
                    for (; backslashes >= 2; backslashes -= 2) {
                        buf.append('\\');
                    }
                    if (backslashes == 1) {
                        if (state == DEFAULT) {
                            state = ARG;
                        }
                        buf.append('"');
                        backslashes = 0;
                        continue;
                    } // else fall through to switch
                } else {
                    // false alarm, treat passed backslashes literally...
                    if (state == DEFAULT) {
                        state = ARG;
                    }
                    for (; backslashes > 0; backslashes--) {
                        buf.append('\\');
                    }
                    // fall through to switch
                }
            }
            if (Character.isWhitespace(ch)) {
                if (state == DEFAULT) {
                    // skip
                    continue;
                } else if (state == ARG) {
                    state = DEFAULT;
                    result.add(buf.toString());
                    buf.setLength(0);
                    continue;
                }
            }
            switch (state) {
                case DEFAULT:
                case ARG:
                    if (ch == '"') {
                        state = IN_DOUBLE_QUOTE;
                    } else {
                        state = ARG;
                        buf.append(ch);
                    }
                    break;

                case IN_DOUBLE_QUOTE:
                    if (ch == '"') {
                        if (i + 1 < len && args.charAt(i + 1) == '"') {
                            /* Undocumented feature in Windows:
                             * Two consecutive double quotes inside a double-quoted argument are interpreted as
                             * a single double quote.
                             */
                            buf.append('"');
                            i++;
                        } else if (buf.length() == 0) {
                            // empty string on Windows platform. Account for bug in constructor of JDK's java.lang.ProcessImpl.
                            result.add("\"\""); //$NON-NLS-1$
                            state = DEFAULT;
                        } else {
                            state = ARG;
                        }
                    } else {
                        buf.append(ch);
                    }
                    break;

                default:
                    throw new IllegalStateException();
            }
        }
        if (buf.length() > 0 || state != DEFAULT) {
            result.add(buf.toString());
        }
        return result;
    }