22: Add method decodeCumulativeInterestSnapshot

src/main/tjava/com/r35157/libs/jupiter/perps/impl/anchoridl/AnchorIdlJupiterPerpsPositionDecoder.tjava

@@ -62,8 +62,6 @@ class AnchorIdlJupiterPerpsPositionDecoder {
                 CUMULATIVE_INTEREST_SNAPSHOT_OFFSET
         );
 
-        System.out.println("cumulativeInterestSnapshot = " + cumulativeInterestSnapshot);
-
         JupiterPerpsPosition pos = new JupiterPerpsPosition(
                 positionAccount,
                 entryPrice,
@@ -76,6 +74,22 @@ class AnchorIdlJupiterPerpsPositionDecoder {
         return pos;
     }
 
+    BigInteger decodeCumulativeInterestSnapshot(SolanaAccountInfo accountInfo) {
+        byte[] data = Base64.getDecoder().decode(accountInfo.dataBase64());
+
+        if (data.length < CUMULATIVE_INTEREST_SNAPSHOT_OFFSET + U128_LENGTH) {
+            throw new IllegalArgumentException(
+                    "Jupiter Perps position account data is too short: " + data.length
+            );
+        }
+
+        BigInteger value = readU128(
+                data,
+                CUMULATIVE_INTEREST_SNAPSHOT_OFFSET
+        );
+        return value;
+    }
+
     ΩSolanaAddressΩ decodeCustodyAccount(SolanaAccountInfo accountInfo) {
         byte[] data = Base64.getDecoder().decode(accountInfo.dataBase64());