Add examples for Kotlin API (#124)

kotlin-api-examples/Main.kt

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+package com.k2fsa.sherpa.onnx
+
+import android.content.res.AssetManager
+
+fun main() {
+    var featConfig = FeatureConfig(
+        sampleRate = 16000,
+        featureDim = 80,
+    )
+
+    // please refer to
+    // https://k2-fsa.github.io/sherpa/onnx/pretrained_models/index.html
+    // to dowload pre-trained models
+    var modelConfig = OnlineTransducerModelConfig(
+        encoder = "./sherpa-onnx-streaming-zipformer-en-2023-02-21/encoder-epoch-99-avg-1.onnx",
+        decoder = "./sherpa-onnx-streaming-zipformer-en-2023-02-21/decoder-epoch-99-avg-1.onnx",
+        joiner = "./sherpa-onnx-streaming-zipformer-en-2023-02-21/joiner-epoch-99-avg-1.onnx",
+        tokens = "./sherpa-onnx-streaming-zipformer-en-2023-02-21/tokens.txt",
+        numThreads = 1,
+        debug = false,
+    )
+
+    var endpointConfig = EndpointConfig()
+
+    var config = OnlineRecognizerConfig(
+        modelConfig = modelConfig,
+        featConfig = featConfig,
+        endpointConfig = endpointConfig,
+        enableEndpoint = true,
+        decodingMethod = "greedy_search",
+        maxActivePaths = 4,
+    )
+
+    var model = SherpaOnnx(
+        config = config,
+    )
+
+    var objArray = WaveReader.readWaveFromFile(
+        filename = "./sherpa-onnx-streaming-zipformer-en-2023-02-21/test_wavs/0.wav",
+    )
+    var samples : FloatArray = objArray[0] as FloatArray
+    var sampleRate : Int = objArray[1] as Int
+
+    model.acceptWaveform(samples, sampleRate=sampleRate)
+    while (model.isReady()) {
+      model.decode()
+    }
+
+    var tailPaddings = FloatArray((sampleRate * 0.5).toInt()) // 0.5 seconds
+    model.acceptWaveform(tailPaddings, sampleRate=sampleRate)
+    model.inputFinished()
+    while (model.isReady()) {
+      model.decode()
+    }
+
+    println("results: ${model.text}")
+}

kotlin-api-examples/SherpaOnnx.kt

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+../android/SherpaOnnx/app/src/main/java/com/k2fsa/sherpa/onnx/SherpaOnnx.kt

kotlin-api-examples/WaveReader.kt

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+../android/SherpaOnnx/app/src/main/java/com/k2fsa/sherpa/onnx/WaveReader.kt

kotlin-api-examples/faked-asset-manager.kt

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+package android.content.res
+
+class AssetManager {}

kotlin-api-examples/run.sh

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+#!/usr/bin/env bash
+#
+# This scripts shows how to build JNI libs for sherpa-onnx
+# Note: This scripts runs only on Linux and macOS, though sherpa-onnx
+# supports building JNI libs for Windows.
+
+set -e
+
+cd ..
+mkdir -p build
+cd build
+
+cmake \
+  -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+  -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+  -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+  -DBUILD_SHARED_LIBS=ON \
+  -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+  -DSHERPA_ONNX_ENABLE_JNI=ON \
+  ..
+
+make -j4
+ls -lh lib
+
+export LD_LIBRARY_PATH=$PWD/build/lib:$LD_LIBRARY_PATH
+
+cd ../kotlin-api-examples
+
+if [ ! -f ./sherpa-onnx-streaming-zipformer-en-2023-02-21/tokens.txt ]; then
+  git lfs install
+  git clone https://huggingface.co/csukuangfj/sherpa-onnx-streaming-zipformer-en-2023-02-21
+fi
+
+kotlinc-jvm -include-runtime -d main.jar Main.kt WaveReader.kt SherpaOnnx.kt faked-asset-manager.kt
+
+ls -lh main.jar
+
+java -Djava.library.path=../build/lib -jar main.jar