Add jni interface and kotlin API examples for TTS. (#381)

kotlin-api-examples/Tts.kt

@@ -0,0 +1,112 @@
+// Copyright (c)  2023  Xiaomi Corporation
+package com.k2fsa.sherpa.onnx
+
+import android.content.res.AssetManager
+
+data class OfflineTtsVitsModelConfig(
+    var model: String,
+    var lexicon: String,
+    var tokens: String,
+    var noiseScale: Float = 0.667f,
+    var noiseScaleW: Float = 0.8f,
+    var lengthScale: Float = 1.0f,
+)
+
+data class OfflineTtsModelConfig(
+    var vits: OfflineTtsVitsModelConfig,
+    var numThreads: Int = 1,
+    var debug: Boolean = false,
+    var provider: String = "cpu",
+)
+
+data class OfflineTtsConfig(
+    var model: OfflineTtsModelConfig,
+)
+
+class GeneratedAudio(
+    val samples : FloatArray,
+    val sampleRate: Int,
+) {
+    fun save(filename: String) = saveImpl(filename=filename, samples=samples, sampleRate=sampleRate)
+
+    private external fun saveImpl(
+        filename: String,
+        samples: FloatArray,
+        sampleRate: Int
+    ): Boolean
+}
+
+class OfflineTts(
+    assetManager: AssetManager? = null,
+    var config: OfflineTtsConfig,
+) {
+    private var ptr: Long
+
+    init {
+        if (assetManager != null) {
+            ptr = new(assetManager, config)
+        } else {
+            ptr = newFromFile(config)
+        }
+    }
+
+    fun generate(
+        text: String,
+        sid: Int = 0,
+        speed: Float = 1.0f
+    ): GeneratedAudio {
+      var objArray = generateImpl(ptr, text=text, sid=sid, speed=speed)
+      return GeneratedAudio(samples=objArray[0] as FloatArray,
+                            sampleRate=objArray[1] as Int)
+    }
+
+    fun allocate(assetManager: AssetManager? = null) {
+      if (ptr == 0L) {
+        if (assetManager != null) {
+          ptr = new(assetManager, config)
+        } else {
+          ptr = newFromFile(config)
+        }
+      }
+    }
+
+    fun free() {
+      if (ptr != 0L) {
+        delete(ptr)
+        ptr = 0
+      }
+    }
+
+    protected fun finalize() {
+        delete(ptr)
+    }
+
+    private external fun new(
+        assetManager: AssetManager,
+        config: OfflineTtsConfig,
+    ): Long
+
+    private external fun newFromFile(
+        config: OfflineTtsConfig,
+    ): Long
+
+    private external fun delete(ptr: Long)
+
+    // The returned array has two entries:
+    //  - the first entry is an 1-D float array containing audio samples.
+    //    Each sample is normalized to the range [-1, 1]
+    //  - the second entry is the sample rate
+    external fun generateImpl(
+        ptr: Long,
+        text: String,
+        sid: Int = 0,
+        speed: Float = 1.0f
+    ): Array<Any>
+
+    companion object {
+        init {
+            System.loadLibrary("sherpa-onnx-jni")
+        }
+    }
+
+}