Merge pull request #299 from charleskorn/unterminated-string-ref

Fix issue where string references aren't always completed with a null terminator.
jnr · Mar 3, 2022 · 46661c2 · 46661c2
2 parents 9d89e0a + 152a430
commit 46661c2
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Showing 3 changed files with 43 additions and 2 deletions.
diff --git a/src/main/java/jnr/ffi/Struct.java b/src/main/java/jnr/ffi/Struct.java
@@ -2469,8 +2469,9 @@ public final java.lang.String get() {
 
         public final void set(java.lang.String value) {
             if (value != null) {
-                valueHolder = getRuntime().getMemoryManager().allocateDirect(value.length() * 4);
-                valueHolder.putString(0, value, value.length() * 4, charset);
+                int maxBytes = (value.length() * 4) + 1; // Additional byte required for trailing null termination.
+                valueHolder = getRuntime().getMemoryManager().allocateDirect(maxBytes);
+                valueHolder.putString(0, value, maxBytes, charset);
                 getMemory().putPointer(offset(), valueHolder);
 
             } else {

diff --git a/src/test/java/jnr/ffi/struct/AsciiStringFieldTest.java b/src/test/java/jnr/ffi/struct/AsciiStringFieldTest.java
@@ -101,4 +101,24 @@ public StructWithStringByRef() {
 
         assertEquals(testValue, struct.stringValue.get());
     }
+
+    public static final class StructWithConsecutiveStringsByRef extends Struct {
+        private final AsciiStringRef firstValue = new AsciiStringRef();
+        private final AsciiStringRef secondValue = new AsciiStringRef();
+
+        public StructWithConsecutiveStringsByRef() {
+            super(runtime);
+        }
+    }
+
+    @Test public void testStructWithConsecutiveStringsByRef() {
+        final String testValue = "some test string";
+        final StructWithConsecutiveStringsByRef struct = new StructWithConsecutiveStringsByRef();
+
+        struct.firstValue.set("");
+        struct.secondValue.set(testValue);
+
+        assertEquals("", struct.firstValue.get());
+        assertEquals(testValue, struct.secondValue.get());
+    }
 }
diff --git a/src/test/java/jnr/ffi/struct/UTF8StringFieldTest.java b/src/test/java/jnr/ffi/struct/UTF8StringFieldTest.java
@@ -122,4 +122,24 @@ public StructWithStringByRef() {
 
         assertEquals(testValue, struct.stringValue.get());
     }
+
+    public static final class StructWithConsecutiveStringsByRef extends Struct {
+        private final UTF8StringRef firstValue = new UTF8StringRef();
+        private final UTF8StringRef secondValue = new UTF8StringRef();
+
+        public StructWithConsecutiveStringsByRef() {
+            super(runtime);
+        }
+    }
+
+    @Test public void testStructWithConsecutiveStringsByRef() {
+        final String testValue = "some test string";
+        final StructWithConsecutiveStringsByRef struct = new StructWithConsecutiveStringsByRef();
+
+        struct.firstValue.set("");
+        struct.secondValue.set(testValue);
+
+        assertEquals("", struct.firstValue.get());
+        assertEquals(testValue, struct.secondValue.get());
+    }
 }