CFStringRef#stringValue buffer needs space for 4 UTF8 bytes (#1345)

java-native-access · Apr 25, 2021 · 402d4c5 · 402d4c5
1 parent 5ac6161
commit 402d4c5
Show file tree

Hide file tree

Showing 3 changed files with 13 additions and 12 deletions.
diff --git a/CHANGES.md b/CHANGES.md
@@ -14,7 +14,7 @@ Features
 
 Bug Fixes
 ---------
-* [#1343](https://github.com/java-native-access/jna/issues/1343): `c.s.j.p.mac.CoreFoundation.CFStringRef#stringValue` buffer needs space for null byte - [@dbwiddis](https://github.com/dbwiddis).
+* [#1343](https://github.com/java-native-access/jna/issues/1343), [#1345](https://github.com/java-native-access/jna/issues/1345): `c.s.j.p.mac.CoreFoundation.CFStringRef#stringValue` buffer needs space for 4 UTF8 bytes plus a null byte - [@dbwiddis](https://github.com/dbwiddis).
 
 Release 5.8.0
 =============

diff --git a/contrib/platform/src/com/sun/jna/platform/mac/CoreFoundation.java b/contrib/platform/src/com/sun/jna/platform/mac/CoreFoundation.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019 Daniel Widdis
+ * Copyright (c) 2019, 2021 Daniel Widdis
  *
  * The contents of this file is dual-licensed under 2
  * alternative Open Source/Free licenses: LGPL 2.1 or later and
@@ -488,18 +488,19 @@ public static CFStringRef createCFString(String s) {
          */
         public String stringValue() {
             // Get number of characters
-            CFIndex length = INSTANCE.CFStringGetLength(this);
-            if (length.longValue() == 0) {
+            long length = INSTANCE.CFStringGetLength(this).longValue();
+            if (length == 0) {
                 return "";
             }
             // Calculate maximum possible size in UTF8 bytes
-            CFIndex maxSize = INSTANCE.CFStringGetMaximumSizeForEncoding(length, kCFStringEncodingUTF8);
-            if (maxSize.intValue() == kCFNotFound) {
+            // the CFStringGetMaximumSizeForEncoding function incorrectly returns 3 bytes
+            // per character so we'll use 4 bytes plus a null byte
+            if (length > (Long.MAX_VALUE - 1) / 4) {
                 throw new StringIndexOutOfBoundsException("CFString maximum number of bytes exceeds LONG_MAX.");
             }
-            // Increment size by 1 for a null byte
-            maxSize.setValue(maxSize.longValue() + 1);
-            Memory buf = new Memory(maxSize.longValue());
+            long bufSize = 4 * length + 1;
+            CFIndex maxSize = new CFIndex(bufSize);
+            Memory buf = new Memory(bufSize);
             if (0 != INSTANCE.CFStringGetCString(this, buf, maxSize, kCFStringEncodingUTF8)) {
                 return buf.getString(0, "UTF8");
             }

diff --git a/contrib/platform/test/com/sun/jna/platform/mac/CoreFoundationTest.java b/contrib/platform/test/com/sun/jna/platform/mac/CoreFoundationTest.java
@@ -63,9 +63,9 @@ public class CoreFoundationTest {
 
     @Test
     public void testCFStringRef() throws UnsupportedEncodingException {
-        // Create a unicode string of a single 3-byte character
-        byte[] alaf = { (byte) 0xe0, (byte) 0xa0, (byte) 0x80 };
-        String utf8Str = new String(alaf, StandardCharsets.UTF_8);
+        // Create a unicode string of a single 4-byte character
+        byte[] smileEmoji = { (byte) 0xF0, (byte) 0x9F, (byte) 0x98, (byte) 0x83 };
+        String utf8Str = new String(smileEmoji, StandardCharsets.UTF_8);
         CFStringRef cfStr = CFStringRef.createCFString(utf8Str);
         assertEquals(utf8Str.length(), CF.CFStringGetLength(cfStr).intValue());
         assertEquals(utf8Str, cfStr.stringValue());