utf-16/32 support for getCharSequence()

Author: demon36

src/main/java/jnr/ffi/util/BufferUtil.java

@@ -64,7 +64,8 @@ public static CharSequence getCharSequence(ByteBuffer buf, Charset charset) {
         final ByteBuffer buffer = buf.slice();
         // Find the NUL terminator and limit to that, so the
         // StringBuffer/StringBuilder does not have superfluous NUL chars
-        int end = indexOf(buffer, (byte) 0);
+        final byte[] nullCharBytes = new String("\0").getBytes(charset);
+        int end = indexOf(buffer, nullCharBytes);
         if (end < 0) {
             end = buffer.limit();
         }
@@ -141,6 +142,38 @@ public static int indexOf(ByteBuffer buf, byte value) {
         return -1;
     }
 
+    public static int indexOf(ByteBuffer buf, byte[] value) {
+        byte[] array = null;
+        int matchingBytesCount = 0;
+        int i;
+        int limit;
+        if (buf.hasArray()) {
+            i = 0;
+            array = buf.array();
+            limit = array.length;
+        } else {
+            i = buf.position();
+            limit = buf.limit();
+        }
+
+        while(i < limit){
+            byte it = buf.hasArray() ? array[i] : buf.get(i);
+            if(it == value[matchingBytesCount]){
+                matchingBytesCount++;
+                i++;
+            } else {
+                matchingBytesCount = 0;
+                i += value.length - (i%value.length);//jump to start of next character
+                continue;
+            }
+
+            if(matchingBytesCount == value.length){
+                return  i;
+            }
+        }
+        return -1;
+    }
+
     public static int indexOf(ByteBuffer buf, int offset, byte value) {
         if (buf.hasArray()) {
             byte[] array = buf.array();