private void processDirStream()

in poi/src/main/java/org/apache/poi/poifs/macros/VBAMacroReader.java [483:606]
111 lines of code
26 McCabe index (conditional complexity)

    private void processDirStream(Entry dir, ModuleMap modules) throws IOException {
        DocumentNode dirDocumentNode = (DocumentNode)dir;
        DIR_STATE dirState = DIR_STATE.INFORMATION_RECORD;
        try (DocumentInputStream dis = new DocumentInputStream(dirDocumentNode)) {
            String streamName = null;
            int recordId = 0;

            try (RLEDecompressingInputStream in = new RLEDecompressingInputStream(dis)) {
                while (true) {
                    recordId = in.readShort();
                    if (recordId == -1) {
                        break;
                    }
                    RecordType type = RecordType.lookup(recordId);

                    if (type.equals(RecordType.EOF) || type.equals(RecordType.DIR_STREAM_TERMINATOR)) {
                        break;
                    }
                    switch (type) {
                        case PROJECT_VERSION:
                            trySkip(in, RecordType.PROJECT_VERSION.getConstantLength());
                            break;
                        case PROJECT_CODEPAGE:
                            in.readInt();//record size must == 4
                            int codepage = in.readShort();
                            modules.charset = Charset.forName(CodePageUtil.codepageToEncoding(codepage, true));
                            break;
                        case MODULE_STREAM_NAME:
                            ASCIIUnicodeStringPair pair = readStringPair(in, modules.charset, STREAMNAME_RESERVED);
                            streamName = pair.getAscii();
                            break;
                        case PROJECT_DOC_STRING:
                            readStringPair(in, modules.charset, DOC_STRING_RESERVED);
                            break;
                        case PROJECT_HELP_FILE_PATH:
                            readStringPair(in, modules.charset, HELP_FILE_PATH_RESERVED);
                            break;
                        case PROJECT_CONSTANTS:
                            readStringPair(in, modules.charset, PROJECT_CONSTANTS_RESERVED);
                            break;
                        case REFERENCE_NAME:
                            if (dirState.equals(DIR_STATE.INFORMATION_RECORD)) {
                                dirState = DIR_STATE.REFERENCES_RECORD;
                            }
                            ASCIIUnicodeStringPair stringPair = readStringPair(in,
                                    modules.charset, REFERENCE_NAME_RESERVED, false);
                            if (stringPair.getPushbackRecordId() == -1) {
                                break;
                            }
                            //Special handling for when there's only an ascii string and a REFERENCED_REGISTERED
                            //record that follows.
                            //See https://github.com/decalage2/oletools/blob/master/oletools/olevba.py#L1516
                            //and https://github.com/decalage2/oletools/pull/135 from (@c1fe)
                            if (stringPair.getPushbackRecordId() != RecordType.REFERENCE_REGISTERED.id) {
                                throw new IllegalArgumentException("Unexpected reserved character. "+
                                        "Expected "+Integer.toHexString(REFERENCE_NAME_RESERVED)
                                        + " or "+Integer.toHexString(RecordType.REFERENCE_REGISTERED.id)+
                                        " not: "+Integer.toHexString(stringPair.getPushbackRecordId()));
                            }
                            //fall through!
                        case REFERENCE_REGISTERED:
                            //REFERENCE_REGISTERED must come immediately after
                            //REFERENCE_NAME to allow for fall through in special case of bug 62625
                            int recLength = in.readInt();
                            trySkip(in, recLength);
                            break;
                        case MODULE_DOC_STRING:
                            int modDocStringLength = in.readInt();
                            readString(in, modDocStringLength, modules.charset);
                            int modDocStringReserved = in.readShort();
                            if (modDocStringReserved != MODULE_DOCSTRING_RESERVED) {
                                throw new IOException("Expected x003C after stream name before Unicode stream name, but found: " +
                                        Integer.toHexString(modDocStringReserved));
                            }
                            int unicodeModDocStringLength = in.readInt();
                            readUnicodeString(in, unicodeModDocStringLength);
                            // do something with this at some point
                            break;
                        case MODULE_OFFSET:
                            int modOffsetSz = in.readInt();
                            //should be 4
                            readModuleMetadataFromDirStream(in, streamName, modules);
                            break;
                        case PROJECT_MODULES:
                            dirState = DIR_STATE.MODULES_RECORD;
                            in.readInt();//size must == 2
                            in.readShort();//number of modules
                            break;
                        case REFERENCE_CONTROL_A:
                            int szTwiddled = in.readInt();
                            trySkip(in, szTwiddled);
                            int nextRecord = in.readShort();
                            //reference name is optional!
                            if (nextRecord == RecordType.REFERENCE_NAME.id) {
                                readStringPair(in, modules.charset, REFERENCE_NAME_RESERVED);
                                nextRecord = in.readShort();
                            }
                            if (nextRecord != 0x30) {
                                throw new IOException("Expected 0x30 as Reserved3 in a ReferenceControl record");
                            }
                            int szExtended = in.readInt();
                            trySkip(in, szExtended);
                            break;
                        case MODULE_TERMINATOR:
                            int endOfModulesReserved = in.readInt();
                            //must be 0;
                            break;
                        default:
                            if (type.getConstantLength() > -1) {
                                trySkip(in, type.getConstantLength());
                            } else {
                                int recordLength = in.readInt();
                                trySkip(in, recordLength);
                            }
                            break;
                    }
                }
            } catch (final IOException e) {
                throw new IOException(
                        "Error occurred while reading macros at section id "
                                + recordId + " (" + HexDump.shortToHex(recordId) + ")", e);
            }
        }
    }