Swift Wrapper

---

The Pryonlite Swift wrapper provides a Swift interface around the PryonLite library's C APIs.

Files required for integration

The following files need to be added to the target iOS App's workspace.

BridgingHeader.h

Imports the pryonlite C header files and provides a bridging interface needed by the Swift wrapper.

PryonWrapper.swift

Provides the Swift interface for iOS Apps to use the pryonlite library.

PryonWrapper APIs:

/// Initializer method of the PronLite wrapper class.
/// Configures and sets up the PryonLite Wake Word detector.
///
/// - Parameters:
///   - detectThreshold: wake word detection threshold in the range [1-1000],
///                      1 = lowest threshold, most detections, 1000 = highest threshold, fewer restrictive.
///   - modelFile: Wake Word model file.
///   - modelDir: Directory of the wake word model file, optional, default is nil
///   - internalConfigReserved: Reserved config pointer, optional, default is nil.
///   - useVad: Use Pryonlite's Voice Activity Detector, optional, default is 0.
///   - lowLatency: enable Low latency mode. Only valid for type 'U' models.
///                 Results in ~200ms lower detection latency, at the cost of less accurate ww end indexes reported in
///                 the detection callback.
///
init(detectThreshold: Int32, modelFile: NSString, modelDir:String? = nil, internalConfigReserved: UnsafeMutableRawPointer? = nil,
         useVad: Int32? = 0, lowLatency: Int32? = 0)


/// Push audio samples for PryonLite's processing.
///
/// - Parameters:
///   - samples: Pointer to Int16 array of the input audio samples.
///   - sampleCount: Number of samples in the samples array. This should be equal to 160.
/// - Returns: PryonLiteError code, nominally PRYON_LITE_ERROR_OK.
///            Refer to pryon_lite_error.h for the list of error values.
///
pushSamples(samples: UnsafeMutablePointer<Int16>, sampleCount: Int32) ->PryonLiteError

/// Enable or disable one or all wakeword keywords
/// - Parameters:
///   - keyword: Pointer to C CHAR array type for keyword to enable or disable; ex. "ALEXA".
///     Pass keyword "ALL" to enable or disable all keywords.
///   - enable: (Int32): Integer 0: disable keyword, 1 enable keyword.
///
wakewordEnableKeyword(keyword: UnsafeMutablePointer<CChar>, enable: Int32) -> PryonLiteStatus

/// Destory the PryonLite Wrapper Instance.
///
/// - Returns: PryonLiteError code, nominally PRYON_LITE_ERROR_OK.
///            Refer to pryon_lite_error.h for the list of error values.
///
destroy() ->PryonLiteError

Usage

The iOS App can invoke the pryonlite library in it's various stages as follows:

• Initialization stage to configure and initialize the pryonlite library.

      var pryonWrapper: PryonWrapper
  
      let detectionThreshold = 500
      let useVad = 0
      let lowLatency = 0
      modelFilePath = "D.en-US.alexa"
      modelDir = "models/common"
  
      pryonWrapper = PryonWrapper(detectThreshold: detectionThreshold, modelFile: modelFilePath, modelDir: modelDir,
                                  internalConfigReserved: nil, useVad: useVad, lowLatency: lowLatency)
  

• Audio processing loop to push the audio samples to processing.

      let pryonliteStatusCode = pryonWrapper.pushSamples(samples: &samplesArray, sampleCount: Int32(samplesArray.count))
      if (pryonliteStatusCode.publicCode != Int32(PRYON_LITE_ERROR_OK.rawValue)) {
          print("""
                Error pushing Samples with index \(readSampleIndex)
                Public Error Code: \(pryonliteStatusCode.publicCode) Internal Error Code: \(pryonliteStatusCode.internalCode)
                """ , to:&LogFileOutput)
      }
  

• Teardown stage of the application to destory the pryonlite instance.

      // Flush the decoder
      let pryonliteStatusCode = pryonWrapper.destroy()
      if (pryonliteStatusCode.publicCode != Int32(PRYON_LITE_ERROR_OK.rawValue)) {
          print("""
                Error flushing decoder.
                Public Error Code: \(pryonliteStatusCode.publicCode) Internal Error Code: \(pryonliteStatusCode.internalCode)
                """ , to:&LogFileOutput)
      }