Build a vfpv4 library for armeabi-v7a and do runtime detection to select the right library

examples/whisper.android/app/src/main/java/com/whispercppdemo/whisper/LibWhisper.kt

@@ -1,8 +1,13 @@
 package com.whispercppdemo.whisper
 
+import android.os.Build
+import android.util.Log
 import kotlinx.coroutines.*
+import java.io.File
 import java.util.concurrent.Executors
 
+private const val LOG_TAG = "LibWhisper"
+
 class WhisperContext private constructor(private var ptr: Long) {
     // Meet Whisper C++ constraint: Don't access from more than one thread at a time.
     private val scope: CoroutineScope = CoroutineScope(
@@ -47,7 +52,27 @@ class WhisperContext private constructor(private var ptr: Long) {
 private class WhisperLib {
     companion object {
         init {
-            System.loadLibrary("whisper")
+            Log.d(LOG_TAG, "Primary ABI: ${Build.SUPPORTED_ABIS[0]}")
+            var loadVfpv4 = false
+            if (isArmEabiV7a()) {
+                // armeabi-v7a needs runtime detection support
+                val cpuInfo = cpuInfo()
+                cpuInfo?.let {
+                    Log.d(LOG_TAG, "CPU info: $cpuInfo")
+                    if (cpuInfo.contains("vfpv4")) {
+                        Log.d(LOG_TAG, "CPU supports vfpv4")
+                        loadVfpv4 = true
+                    }
+                }
+            }
+
+            if (loadVfpv4) {
+                Log.d(LOG_TAG, "Loading libwhisper_vfpv4.so")
+                System.loadLibrary("whisper_vfpv4")
+            } else {
+                Log.d(LOG_TAG, "Loading libwhisper.so")
+                System.loadLibrary("whisper")
+            }
         }
 
         // JNI methods
@@ -59,3 +84,17 @@ private class WhisperLib {
     }
 }
 
+private fun isArmEabiV7a(): Boolean {
+    return Build.SUPPORTED_ABIS[0].equals("armeabi-v7a")
+}
+
+private fun cpuInfo(): String? {
+    return try {
+        File("/proc/cpuinfo").inputStream().bufferedReader().use {
+            it.readText()
+        }
+    } catch (e: Exception) {
+        Log.w(LOG_TAG, "Couldn't read /proc/cpuinfo", e)
+        null
+    }
+}