Merge pull request #383 from tim-hoffman/PR_ArrayCopyPerformance

Replace array copy loops with System.arraycopy
jboss-javassist · May 12, 2022 · df3f4b7 · df3f4b7
2 parents c00688b + aeee909
commit df3f4b7
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Showing 2 changed files with 10 additions and 5 deletions.
diff --git a/src/main/javassist/bytecode/StackMapTable.java b/src/main/javassist/bytecode/StackMapTable.java
@@ -912,9 +912,15 @@ else if (offsetDelta < 64 && current != entry) {
         static byte[] insertGap(byte[] info, int where, int gap) {
             int len = info.length;
             byte[] newinfo = new byte[len + gap];
-            for (int i = 0; i < len; i++)
-                newinfo[i + (i < where ? 0 : gap)] = info[i];
-
+            if (where <= 0) {
+                System.arraycopy(info, 0, newinfo, gap, len);
+            } else if (where >= len) {
+                System.arraycopy(info, 0, newinfo, 0, len);
+            } else {
+                assert (where > 0 && where < len);
+                System.arraycopy(info, 0, newinfo, 0, where);
+                System.arraycopy(info, where, newinfo, where + gap, len - where);
+            }
             return newinfo;
         }
 

diff --git a/src/main/javassist/bytecode/stackmap/MapMaker.java b/src/main/javassist/bytecode/stackmap/MapMaker.java
@@ -309,8 +309,7 @@ protected static int recordTypeData(int n, TypeData[] srcTypes, TypeData[] destT
     }
 
     protected static void copyTypeData(int n, TypeData[] srcTypes, TypeData[] destTypes) {
-        for (int i = 0; i < n; i++)
-            destTypes[i] = srcTypes[i];
+        System.arraycopy(srcTypes, 0, destTypes, 0, n);
     }
 
     private static TypeData validateTypeData(TypeData[] data, int length, int index) {