[CODEC-168] Reported by Daniel Cassidy: Add DigestUtils.updateDigest(MessageDigest, InputStream). No need for additional tests as the method is used by Codec itself.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/codec/trunk@1462710 13f79535-47bb-0310-9956-ffa450edef68

Author: garydgregory

src/changes/changes.xml

@@ -48,6 +48,7 @@ The <action> type attribute can be add,update,fix,remove.
     </release>
     -->
     <release version="1.8" date="TBA" description="Feature and fix release.">
+      <action dev="ggregory" type="add" issue="CODEC-168" due-to="Daniel Cassidy">Add DigestUtils.updateDigest(MessageDigest, InputStream).</action>   
       <action dev="julius" type="add" issue="CODEC-167">Add JUnit to test our decode with pad character in the middle.</action> 
       <action dev="ggregory" type="add" issue="CODEC-161" due-to="crice">Add Match Rating Approach (MRA) phonetic algorithm encoder.</action>   
       <action dev="ggregory" type="fix" issue="CODEC-163" due-to="leo141">ColognePhonetic encoder unnecessarily creates many char arrays on every loop run.</action>   

src/main/java/org/apache/commons/codec/digest/DigestUtils.java

@@ -46,15 +46,7 @@ public class DigestUtils {
      *             On error reading from the stream
      */
     private static byte[] digest(final MessageDigest digest, final InputStream data) throws IOException {
-        final byte[] buffer = new byte[STREAM_BUFFER_LENGTH];
-        int read = data.read(buffer, 0, STREAM_BUFFER_LENGTH);
-
-        while (read > -1) {
-            digest.update(buffer, 0, read);
-            read = data.read(buffer, 0, STREAM_BUFFER_LENGTH);
-        }
-
-        return digest.digest();
+        return updateDigest(digest, data).digest();
     }
 
     /**
@@ -784,6 +776,30 @@ public static MessageDigest updateDigest(final MessageDigest messageDigest, fina
         return messageDigest;
     }
 
+    /**
+     * Reads through an InputStream and updates the digest for the data
+     *
+     * @param digest
+     *            The MessageDigest to use (e.g. MD5)
+     * @param data
+     *            Data to digest
+     * @return MD5 digest
+     * @throws IOException
+     *             On error reading from the stream
+     * @since 1.8             
+     */
+    public static MessageDigest updateDigest(final MessageDigest digest, final InputStream data) throws IOException {
+        final byte[] buffer = new byte[STREAM_BUFFER_LENGTH];
+        int read = data.read(buffer, 0, STREAM_BUFFER_LENGTH);
+
+        while (read > -1) {
+            digest.update(buffer, 0, read);
+            read = data.read(buffer, 0, STREAM_BUFFER_LENGTH);
+        }
+
+        return digest;
+    }
+
     /**
      * Updates the given {@link MessageDigest}.
      *