private void readFrame()

in src/main/java/com/aliyun/oss/model/SelectInputStream.java [99:178]
73 lines of code
17 McCabe index (conditional complexity)

    private void readFrame() throws IOException {
        while (currentFrameOffset >= currentFramePayloadLength && !finished) {
            if (!firstReadFrame) {
                internalRead(currentFramePayloadChecksumBytes, 0, 4);
                validateCheckSum(currentFramePayloadChecksumBytes, crc32);
            }
            firstReadFrame = false;
            //advance to next frame
            internalRead(currentFrameTypeBytes, 0, 4);
            //first byte is version byte
            if (currentFrameTypeBytes[0] != SELECT_VERSION) {
                throw new SelectObjectException(SelectObjectException.INVALID_SELECT_VERSION, "Invalid select version found " + currentFrameTypeBytes[0] + ", expect: " + SELECT_VERSION, requestId);
            }
            internalRead(currentFramePayloadLengthBytes, 0, 4);
            internalRead(currentFrameHeaderChecksumBytes, 0, 4);
            internalRead(scannedDataBytes, 0, 8);
            if (payloadCrcEnabled) {
                crc32.update(scannedDataBytes);
            }

            currentFrameTypeBytes[0] = 0;
            int type = ByteBuffer.wrap(currentFrameTypeBytes).getInt();
            switch (type) {
                case DATA_FRAME_MAGIC:
                    currentFramePayloadLength = ByteBuffer.wrap(currentFramePayloadLengthBytes).getInt() - 8;
                    currentFrameOffset = 0;
                    break;
                case CONTINUOUS_FRAME_MAGIC:
                    //just break, continue
                    break;
                case END_FRAME_MAGIC:
                    currentFramePayloadLength = ByteBuffer.wrap(currentFramePayloadLengthBytes).getInt() - 8;
                    byte[] totalScannedDataSizeBytes = new byte[8];
                    internalRead(totalScannedDataSizeBytes, 0, 8);
                    byte[] statusBytes = new byte[4];
                    internalRead(statusBytes, 0, 4);
                    if (payloadCrcEnabled) {
                        crc32.update(totalScannedDataSizeBytes);
                        crc32.update(statusBytes);
                    }
                    int status = ByteBuffer.wrap(statusBytes).getInt();
                    int errorMessageSize = (int)(currentFramePayloadLength - 12);
                    String error = "";
                    if (errorMessageSize > 0) {
                        byte[] errorMessageBytes = new byte[errorMessageSize];
                        internalRead(errorMessageBytes, 0, errorMessageSize);
                        error = new String(errorMessageBytes);
                        if (payloadCrcEnabled) {
                            crc32.update(errorMessageBytes);
                        }
                    }
                    finished = true;
                    currentFramePayloadLength = currentFrameOffset;
                    internalRead(currentFramePayloadChecksumBytes, 0, 4);

                    validateCheckSum(currentFramePayloadChecksumBytes, crc32);
                    if (status / 100 != 2) {
                        if (error.contains(".")) {
                            throw new SelectObjectException(error.split("\\.")[0], error.substring(error.indexOf(".") + 1), requestId);
                        } else {
                            // forward compatbility consideration
                            throw new SelectObjectException(error, error, requestId);
                        }
                    }
                    break;
                default:
                    throw new SelectObjectException(SelectObjectException.INVALID_SELECT_FRAME, "Unsupported frame type " + type + " found", requestId);
            }
            //notify select progress
            ProgressEventType eventType = ProgressEventType.SELECT_SCAN_EVENT;
            if (finished) {
                eventType = ProgressEventType.SELECT_COMPLETED_EVENT;
            }
            long scannedDataSize = ByteBuffer.wrap(scannedDataBytes).getLong();
            if (scannedDataSize >= nextNotificationScannedSize || finished) {
                publishSelectProgress(selectProgressListener, eventType, scannedDataSize);
                nextNotificationScannedSize += DEFAULT_NOTIFICATION_THRESHOLD;
            }
        }
    }