Internal refactoring

No need to separately track "first bytes" length in an instance variable

Author: garydgregory

src/main/java/org/apache/commons/io/input/BOMInputStream.java

@@ -229,7 +229,6 @@ public static Builder builder() {
 
     private ByteOrderMark byteOrderMark;
     private int fbIndex;
-    private int fbLength;
     private int[] firstBytes;
     private final boolean include;
     private boolean markedAtStart;
@@ -458,26 +457,27 @@ public int read(final byte[] buf, int off, int len) throws IOException {
     }
 
     private ByteOrderMark readBom() throws IOException {
-        fbLength = 0;
+        int fbLength = 0;
         // BOMs are sorted from longest to shortest
         final int maxBomSize = bomList.get(0).length();
-        firstBytes = new int[maxBomSize];
+        final int[] tmp = new int[maxBomSize];
         // Read first maxBomSize bytes
-        for (int i = 0; i < firstBytes.length; i++) {
-            firstBytes[i] = in.read();
-            afterRead(firstBytes[i]);
+        for (int i = 0; i < tmp.length; i++) {
+            tmp[i] = in.read();
+            afterRead(tmp[i]);
             fbLength++;
-            if (firstBytes[i] < 0) {
+            if (tmp[i] < 0) {
                 break;
             }
         }
+        firstBytes = Arrays.copyOf(tmp, fbLength);
         // match BOM in firstBytes
         final ByteOrderMark bom = find();
         if (bom != null && !include) {
             if (bom.length() < firstBytes.length) {
                 fbIndex = bom.length();
             } else {
-                fbLength = 0;
+                firstBytes = new int[0];
             }
         }
         return bom;
@@ -494,7 +494,7 @@ private ByteOrderMark readBom() throws IOException {
      */
     private int readFirstBytes() throws IOException {
         getBOM();
-        return fbIndex < fbLength ? firstBytes[fbIndex++] : EOF;
+        return fbIndex < firstBytes.length ? firstBytes[fbIndex++] : EOF;
     }
 
     /**