Promote float varargs to double

CHANGES.md

@@ -40,6 +40,7 @@ Bug Fixes
 * [#536](https://github.com/java-native-access/jna/pull/536): Fixed bug in determining the Library and options associated with types defined outside of a Library - [@twall](https://github.com/twall).
 * [#531](https://github.com/java-native-access/jna/pull/531): Ensure direct-mapped callbacks use the right calling convention - [@twall](https://github.com/twall).
 * [#566](https://github.com/java-native-access/jna/pull/566): Fix return type of Native#loadLibrary to match unconstrained generic [@lgoldstein](https://github.com/lgoldstein)
+* [#584](https://github.com/java-native-access/jna/pull/584): Promote float varargs to double - [@marco2357](https://github.com/marco2357).
 
 Release 4.2.1
 =============

native/testlib.c

@@ -872,6 +872,10 @@ addInt32VarArgs(const char *fmt, ...) {
     case 'c':
       sum += (int) va_arg(ap, int);
       break;
+    case 'f': // float (promoted to ‘double’ when passed through ‘...’)
+    case 'F': // double
+      sum += va_arg(ap, double);
+      break;
     default:
       break;
     }

src/com/sun/jna/Function.java

@@ -726,6 +726,12 @@ static Object[] concatenateVarArgs(Object[] inArgs) {
             Class<?> argType = lastArg != null ? lastArg.getClass() : null;
             if (argType != null && argType.isArray()) {
                 Object[] varArgs = (Object[])lastArg;
+                // Promote float varargs to double (https://github.com/java-native-access/jna/issues/463).
+                for (int i=0; i < varArgs.length; i++) {
+                    if (varArgs[i] instanceof Float) {
+                        varArgs[i] = (double)(Float)varArgs[i];
+                    }
+                }
                 Object[] fullArgs = new Object[inArgs.length+varArgs.length];
                 System.arraycopy(inArgs, 0, fullArgs, 0, inArgs.length-1);
                 System.arraycopy(varArgs, 0, fullArgs, inArgs.length-1, varArgs.length);

test/com/sun/jna/VarArgsTest.java

@@ -60,6 +60,18 @@ public void testLongVarArgs() {
         assertEquals("VarArgs not added correctly", arg1 + arg2,
                      lib.addInt32VarArgs("ll", Long.valueOf(arg1), Long.valueOf(arg2)));
     }
+    public void testFloatVarArgs() {
+        float arg1 = 1;
+        float arg2 = 2;
+        assertEquals("VarArgs not added correctly", (int)arg1 + (int)arg2,
+                     lib.addInt32VarArgs("ff", Float.valueOf(arg1), Float.valueOf(arg2)));
+    }
+    public void testDoubleVarArgs() {
+        double arg1 = 1;
+        double arg2 = 2;
+        assertEquals("VarArgs not added correctly", (int)arg1 + (int)arg2,
+                     lib.addInt32VarArgs("FF", Double.valueOf(arg1), Double.valueOf(arg2)));
+    }
     public void testStringVarArgs() {
         Object[] args = new Object[] { "Test" };
         assertEquals("Did not return correct string", args[0],