Android: Use SparseArrayCompat for better performance and lower memor…

…y usage Before: 64,136 bytes After: 8,072 bytes See woltapp/blurhash#108
mrousavy · Feb 19, 2021 · 5b279e6 · 5b279e6
1 parent 51437e3
commit 5b279e6
Showing 1 changed file with 7 additions and 6 deletions.
diff --git a/android/src/main/java/com/mrousavy/blurhash/BlurhashDecoder.kt b/android/src/main/java/com/mrousavy/blurhash/BlurhashDecoder.kt
@@ -2,6 +2,7 @@ package com.mrousavy.blurhash
 
 import android.graphics.Bitmap
 import android.graphics.Color
+import androidx.collection.SparseArrayCompat
 import com.mrousavy.blurhash.Utils.linearToSrgb
 import com.mrousavy.blurhash.Utils.signedPow2
 import com.mrousavy.blurhash.Utils.srgbToLinear
@@ -14,8 +15,8 @@ object BlurHashDecoder {
     // cache Math.cos() calculations to improve performance.
     // The number of calculations can be huge for many bitmaps: width * height * numCompX * numCompY * 2 * nBitmaps
     // the cache is enabled by default, it is recommended to disable it only when just a few images are displayed
-    private val cacheCosinesX = HashMap<Int, DoubleArray>()
-    private val cacheCosinesY = HashMap<Int, DoubleArray>()
+    private val cacheCosinesX = SparseArrayCompat<DoubleArray>()
+    private val cacheCosinesY = SparseArrayCompat<DoubleArray>()
 
     /**
      * Clear calculations stored in memory cache.
@@ -114,21 +115,21 @@ object BlurHashDecoder {
     private fun getArrayForCosinesY(calculate: Boolean, height: Int, numCompY: Int) = when {
         calculate -> {
             DoubleArray(height * numCompY).also {
-                cacheCosinesY[height * numCompY] = it
+                cacheCosinesY.put(height * numCompY, it)
             }
         }
         else -> {
-            cacheCosinesY[height * numCompY]!!
+            cacheCosinesY.get(height * numCompY)!!
         }
     }
 
     private fun getArrayForCosinesX(calculate: Boolean, width: Int, numCompX: Int) = when {
         calculate -> {
             DoubleArray(width * numCompX).also {
-                cacheCosinesX[width * numCompX] = it
+                cacheCosinesX.put(width * numCompX, it)
             }
         }
-        else -> cacheCosinesX[width * numCompX]!!
+        else -> cacheCosinesX.get(width * numCompX)!!
     }
 
     private fun DoubleArray.getCos(