Source code for blue_st_sdk.features.feature_audio_scene_classification

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# COPYRIGHT(c) 2018 STMicroelectronics                                         #
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# IMPORT

from enum import Enum

from blue_st_sdk.feature import Feature
from blue_st_sdk.feature import Sample
from blue_st_sdk.feature import ExtractedData
from blue_st_sdk.features.field import Field
from blue_st_sdk.features.field import FieldType
from blue_st_sdk.utils.number_conversion import NumberConversion
from blue_st_sdk.utils.blue_st_exceptions import BlueSTInvalidDataException
from blue_st_sdk.utils.python_utils import lock


# CLASSES

class SceneType(Enum):
    """Type of scene."""

    UNKNOWN = -1
    INDOOR = 0
    OUTDOOR = 1
    IN_VEHICLE = 2
    ERROR = 3


class FeatureAudioSceneClassification(Feature):
    """The feature handles the type of scene that can be detected by a device.

    Data is one byte long and has no decimal digits.
    """

    FEATURE_NAME = "Audio Scene Classification"
    FEATURE_UNIT = None
    FEATURE_DATA_NAME = "SceneType"
    DATA_MAX = 3
    DATA_MIN = 0
    FEATURE_FIELDS = Field(
        FEATURE_DATA_NAME,
        FEATURE_UNIT,
        FieldType.UInt8,
        DATA_MAX,
        DATA_MIN)
    DATA_LENGTH_BYTES = 1

    def __init__(self, node):
        """Constructor.

        Args:
            node (:class:`blue_st_sdk.node.Node`): Node that will send data to
                this feature.
        """
        super(FeatureAudioSceneClassification, self).__init__(
            self.FEATURE_NAME, node, [self.FEATURE_FIELDS])

    def extract_data(self, timestamp, data, offset):
        """Extract the data from the feature's raw data.
        
        Args:
            timestamp (int): Data's timestamp.
            data (str): The data read from the feature.
            offset (int): Offset where to start reading data.
        
        Returns:
            :class:`blue_st_sdk.feature.ExtractedData`: Container of the number
            of bytes read and the extracted data.

        Raises:
            :exc:`blue_st_sdk.utils.blue_st_exceptions.BlueSTInvalidDataException`
                if the data array has not enough data to read.
        """
        if len(data) - offset < self.DATA_LENGTH_BYTES:
            raise BlueSTInvalidDataException(
                'There is no %d byte available to read.' \
                % (self.DATA_LENGTH_BYTES))
        sample = Sample(
            [NumberConversion.byte_to_uint8(data, offset)],
            self.get_fields_description(),
            timestamp)
        return ExtractedData(sample, self.DATA_LENGTH_BYTES)

    @classmethod
    def get_scene(self, sample):
        """Getting the scene from a sample.

        Args:
            sample (:class:`blue_st_sdk.feature.Sample`): Sample data.

        Returns:
            :class:`SceneType`: The type of the scene if the sample is valid,
            "SceneType.ERROR" otherwise.
        """
        if sample is not None:
            if sample._data:
                if sample._data[0] is not None:
                    return SceneType(sample._data[0])
        return SceneType.ERROR

    def __str__(self):
        """Get a string representing the last sample.

        Return:
            str: A string representing the last sample.
        """
        with lock(self):
            sample = self._last_sample

        if sample is None:
            return self._name + ': Unknown'
        if not sample._data:
            return self._name + ': Unknown'

        if len(sample._data) == 1:
            result = '%s(%d): Scene is \"%s\"' \
                % (self._name,
                   sample._timestamp,
                   str(self.get_scene(sample))
                   )
        return result