Merge pull request #5 from psm14/feature/thread_safety

Make Utf8Utils thread-safe

dexlib/src/main/java/org/jf/dexlib/Util/ByteArrayInput.java

@@ -40,6 +40,9 @@ public class ByteArrayInput
     /** >= 0; current read cursor */
     private int cursor;
 
+    /* buffer for reading UTF-8 strings */
+    private char[] buffer = null;
+
     /**
      * Constructs an instance with the given data
      *
@@ -291,7 +294,11 @@ public class ByteArrayInput
         //skip the terminating null
         cursor++;
 
-        return Utf8Utils.utf8BytesToString(data, startPosition, byteCount);
+        if (buffer == null || buffer.length < byteCount) {
+            buffer = new char[byteCount];
+        }
+
+        return Utf8Utils.utf8BytesToString(buffer, data, startPosition, byteCount);
     }
 
     /** {@inheritDoc} */

dexlib/src/main/java/org/jf/dexlib/Util/Utf8Utils.java

@@ -68,23 +68,16 @@ public final class Utf8Utils {
         return result;
     }
 
-    private static char[] tempBuffer = null;
-
     /**
      * Converts an array of UTF-8 bytes into a string.
      *
-     * This method uses a global buffer to avoid having to allocate one every time, so it is *not* thread-safe
+     * @param buffer a buffer to hold the chars as they are read.  Make sure the length of the array is at least 'length'
-     *
      * @param bytes non-null; the bytes to convert
      * @param start the start index of the utf8 string to convert
      * @param length the length of the utf8 string to convert, not including any null-terminator that might be present
      * @return non-null; the converted string
      */
-    public static String utf8BytesToString(byte[] bytes, int start, int length) {
+    public static String utf8BytesToString(char[] buffer, byte[] bytes, int start, int length) {
-        if (tempBuffer == null || tempBuffer.length < length) {
-            tempBuffer = new char[length];
-        }
-        char[] chars = tempBuffer;
         int outAt = 0;
 
         for (int at = start; length > 0; /*at*/) {
@@ -157,11 +150,11 @@ public final class Utf8Utils {
                     return throwBadUtf8(v0, at);
                 }
             }
-            chars[outAt] = out;
+            buffer[outAt] = out;
             outAt++;
         }
 
-        return new String(chars, 0, outAt);
+        return new String(buffer, 0, outAt);
     }
 
     /**