Refactor magic number into constant.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/io/trunk@1586307 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

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

@@ -85,6 +85,7 @@
  * @since 2.0
  */
 public class BOMInputStream extends ProxyInputStream {
+    private static final int EOF = -1;
     private final boolean include;
     /**
      * BOMs are sorted from longest to shortest.
@@ -140,7 +141,7 @@ public int compare(final ByteOrderMark bom1, final ByteOrderMark bom2) {
             final int len1 = bom1.length();
             final int len2 = bom2.length();
             if (len1 > len2) {
-                return -1;
+                return EOF;
             }
             if (len2 > len1) {
                 return 1;
@@ -260,7 +261,7 @@ public String getBOMCharsetName() throws IOException {
      */
     private int readFirstBytes() throws IOException {
         getBOM();
-        return fbIndex < fbLength ? firstBytes[fbIndex++] : -1;
+        return fbIndex < fbLength ? firstBytes[fbIndex++] : EOF;
     }
 
     /**
@@ -340,7 +341,7 @@ public int read(final byte[] buf, int off, int len) throws IOException {
             }
         }
         final int secondCount = in.read(buf, off, len);
-        return secondCount < 0 ? firstCount > 0 ? firstCount : -1 : firstCount + secondCount;
+        return secondCount < 0 ? firstCount > 0 ? firstCount : EOF : firstCount + secondCount;
     }
 
     /**