use long instead of BigInteger (#50)

Co-authored-by: Bohdan Akimenko <bohdan.akimenko@kevychsolutions.com>
growthbook · May 7, 2024 · d2d88cc · d2d88cc
1 parent 9513f72
commit d2d88cc
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Showing 2 changed files with 19 additions and 19 deletions.
diff --git a/lib/src/main/java/growthbook/sdk/java/GrowthBookUtils.java b/lib/src/main/java/growthbook/sdk/java/GrowthBookUtils.java
@@ -42,22 +42,22 @@ class GrowthBookUtils {
     }
 
     private static Float hashV1(String stringValue, String seed) {
-        BigInteger bigInt = MathUtils.fnv1a_32((stringValue + seed).getBytes());
-        BigInteger thousand = new BigInteger("1000");
-        BigInteger remainder = bigInt.remainder(thousand);
+        long hashValue = MathUtils.fnv1a_32((stringValue + seed).getBytes());
+        long thousand = 1000;
+        long remainder = hashValue % thousand;
 
-        float remainderAsFloat = Float.parseFloat(remainder.toString());
+        float remainderAsFloat = Float.parseFloat(String.valueOf(remainder));
         return remainderAsFloat / 1000f;
     }
 
     private static Float hashV2(String stringValue, String seed) {
-        BigInteger first = MathUtils.fnv1a_32((seed + stringValue).getBytes());
-        BigInteger second = MathUtils.fnv1a_32(first.toString().getBytes());
+        long first = MathUtils.fnv1a_32((seed + stringValue).getBytes());
+        long second = MathUtils.fnv1a_32(String.valueOf(first).getBytes());
 
-        BigInteger tenThousand = new BigInteger("10000");
-        BigInteger remainder = second.remainder(tenThousand);
+        long tenThousand = 10000;
+        long remainder = second % tenThousand;
 
-        float remainderAsFloat = Float.parseFloat(remainder.toString());
+        float remainderAsFloat = Float.parseFloat(String.valueOf(remainder));
         return remainderAsFloat / 10000f;
     }
 

diff --git a/lib/src/main/java/growthbook/sdk/java/MathUtils.java b/lib/src/main/java/growthbook/sdk/java/MathUtils.java
@@ -1,26 +1,26 @@
 package growthbook.sdk.java;
 
-import java.math.BigInteger;
 import java.util.List;
 
 class MathUtils {
-    private static final BigInteger INIT32 = new BigInteger("811c9dc5", 16);
-    private static final BigInteger PRIME32 = new BigInteger("01000193", 16);
-    private static final BigInteger MOD32 = new BigInteger("2").pow(32);
+    private static final long INIT32 = 0x811c9dc5L;
+    private static final long PRIME32 = 0x01000193L;
+    private static final long MOD32 = 1L << 32;
 
     /**
      * Fowler-Noll-Vo algorithm
-     * fnv32a returns an integer, so we convert that to a float using a modulus
+     * fnv32a returns an long, so we convert that to a float using a modulus
      *
      * @param data byte list
-     * @return BigInteger
+     * @return long
      */
-    public static BigInteger fnv1a_32(byte[] data) {
-        BigInteger hash = INIT32;
+    public static long fnv1a_32(byte[] data) {
+        long hash = INIT32;
 
         for (byte b : data) {
-            hash = hash.xor(BigInteger.valueOf((int) b & 0xff));
-            hash = hash.multiply(PRIME32).mod(MOD32);
+            hash ^= (b & 0xff);
+            hash *= PRIME32;
+            hash %= MOD32;
         }
 
         return hash;