moved checkSumTest.file, checksum.java, and checksumTest.java to dependency-check-utils

Former-commit-id: 0c05e466b5fe071ca55552660d471431572c0558

dependency-check-utils/src/main/java/org/owasp/dependencycheck/utils/Checksum.java

@@ -0,0 +1,117 @@
+package org.owasp.dependencycheck.utils;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Includes methods to generate the MD5 and SHA1 checksum.
+ *
+ * This code was copied from Real's How To. It has been slightly modified.
+ *
+ * Written and compiled by Réal Gagnon ©1998-2012
+ *
+ * @author Real's How To: http://www.rgagnon.com/javadetails/java-0416.html
+ *
+ */
+public final class Checksum {
+    
+    /**
+     * The logger.
+     */
+    private static final Logger LOGGER = Logger.getLogger(Checksum.class.getName());
+    /**
+     * Private constructor for a utility class.
+     */
+    private Checksum() {
+    }
+
+    /**
+     * <p>Creates the cryptographic checksum of a given file using the specified
+     * algorithm.</p> <p>This algorithm was copied and heavily modified from
+     * Real's How To: http://www.rgagnon.com/javadetails/java-0416.html</p>
+     *
+     * @param algorithm the algorithm to use to calculate the checksum
+     * @param file the file to calculate the checksum for
+     * @return the checksum
+     * @throws IOException when the file does not exist
+     * @throws NoSuchAlgorithmException when an algorithm is specified that does
+     * not exist
+     */
+    public static byte[] getChecksum(String algorithm, File file) throws NoSuchAlgorithmException, IOException {
+        InputStream fis = null;
+        byte[] buffer = new byte[1024];
+        MessageDigest complete = MessageDigest.getInstance(algorithm);
+        int numRead;
+        try {
+            fis = new FileInputStream(file);
+            do {
+                numRead = fis.read(buffer);
+                if (numRead > 0) {
+                    complete.update(buffer, 0, numRead);
+                }
+            } while (numRead != -1);
+        } finally {
+            if (fis != null) {
+                try {
+                    fis.close();
+                } catch (IOException ex) {
+                    LOGGER.log(Level.FINEST, "Error closing file '" + file.getName() + "'.", ex);
+                }
+            }
+        }
+        return complete.digest();
+    }
+
+    /**
+     * Calculates the MD5 checksum of a specified file.
+     *
+     * @param file the file to generate the MD5 checksum
+     * @return the hex representation of the MD5 hash
+     * @throws IOException when the file passed in does not exist
+     * @throws NoSuchAlgorithmException when the MD5 algorithm is not available
+     */
+    public static String getMD5Checksum(File file) throws IOException, NoSuchAlgorithmException {
+        byte[] b = getChecksum("MD5", file);
+        return getHex(b);
+    }
+
+    /**
+     * Calculates the SHA1 checksum of a specified file.
+     *
+     * @param file the file to generate the MD5 checksum
+     * @return the hex representation of the SHA1 hash
+     * @throws IOException when the file passed in does not exist
+     * @throws NoSuchAlgorithmException when the SHA1 algorithm is not available
+     */
+    public static String getSHA1Checksum(File file) throws IOException, NoSuchAlgorithmException {
+        byte[] b = getChecksum("SHA1", file);
+        return getHex(b);
+    }
+    private static final String HEXES = "0123456789ABCDEF";
+
+    /**
+     * <p>Converts a byte array into a hex string.</p>
+     *
+     * <p>This method was copied from <a
+     * href="http://www.rgagnon.com/javadetails/java-0596.html">http://www.rgagnon.com/javadetails/java-0596.html</a></p>
+     *
+     * @param raw a byte array
+     * @return the hex representation of the byte array
+     */
+    public static String getHex(byte[] raw) {
+        if (raw == null) {
+            return null;
+        }
+        final StringBuilder hex = new StringBuilder(2 * raw.length);
+        for (final byte b : raw) {
+            hex.append(HEXES.charAt((b & 0xF0) >> 4)).append(HEXES.charAt((b & 0x0F)));
+        }
+        return hex.toString();
+    }
+}