#2 - Added test to test the cypto library

src/main/java/net/locusworks/crypto/utils/HashUtils.java

@@ -0,0 +1,188 @@
+package net.locusworks.crypto.utils;
+
+import java.io.BufferedInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.MessageDigest;
+
+/**
+ * Wrapper class that leverages java's MessageDigest to hash files
+ * @author Isaac Parenteau
+ *
+ */
+public class HashUtils {
+  
+  private static final Charset UTF_8 = StandardCharsets.UTF_8;
+
+  /**
+   * Used to build output as Hex
+   */
+  private static final char[] DIGITS_LOWER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
+
+  /**
+   * Used to build output as Hex
+   */
+  private static final char[] DIGITS_UPPER = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
+  
+  /**
+   * Size of the streaming buffer
+   */
+  public static final Integer STREAM_BUFFER_LENGTH = 1024;
+
+  /**
+   * Hash a string literal
+   * @param hashType Hash types supported by MessageDigest (i.e MD5, SHA-1, SHA-512)
+   * @param data String to hash
+   * @return hash value of the string literal
+   */
+  public static String hash(String hashType, String data) {
+    return hash(hashType, data, true);
+  }
+  
+  /**
+   * Hash a string literal
+   * @param hashType Hash types supported by MessageDigest (i.e MD5, SHA-1, SHA-512)
+   * @param data String to hash
+   * @param toLower True to output the hash in lower case. False to output in upper case
+   * @return hash value of the string literal
+   */
+  public static String hash(String hashType, String data, boolean toLower) {
+    byte[] stringData = data.getBytes(UTF_8);
+    return hash(hashType, stringData, toLower);
+  }
+  
+  @Deprecated
+  public static String hash(String hashType, File data) {
+    return hash(hashType, data.toPath());
+  }
+
+  /**
+   * Hash a file
+   * @param hashType Hash types supported by MessageDigest (i.e MD5, SHA-1, SHA-512)
+   * @param data File to hash
+   * @return hash value of the file
+   */
+  public static String hash(String hashType, Path data) {
+    return hash(hashType, data, true);
+  }
+  
+  @Deprecated
+  public static String hash(String hashType, File data, boolean toLower) {
+    return hash(hashType, data.toPath(), toLower);
+  }
+
+  /**
+   * Hash a file
+   * @param hashType Hash types supported by MessageDigest (i.e MD5, SHA-1, SHA-512)
+   * @param data File to hash
+   * @param toLower True to output the hash in lower case. False to output in upper case
+   * @return hash value of the file
+   */
+  public static String hash(String hashType, Path data, boolean toLower) {
+    try (InputStream stream = Files.newInputStream(data)) {
+      return hash(stream, hashType, toLower);
+    } catch (IOException ex) {
+      throw new IllegalArgumentException(ex.getMessage());
+    }
+  }
+  
+  /**
+   * Hash a byte array
+   * @param hashType Hash types supported by MessageDigest (i.e MD5, SHA-1, SHA-512)
+   * @param data data to hash
+   * @return hash value of the data
+   */
+  public static String hash(String hashType, byte[] data) {
+    return hash(hashType, data, true);
+  }
+  
+  /**
+   * Hash a byte array
+   * @param hashType Hash types supported by MessageDigest (i.e MD5, SHA-1, SHA-512)
+   * @param data data to hash
+   * @param toLower True to output the hash in lower case. False to output in upper case
+   * @return hash value of the data
+   */
+  public static String hash(String hashType, byte[] data, boolean toLower) {
+    return hash(new BufferedInputStream(new ByteArrayInputStream(data)), hashType, toLower);
+  }
+  
+  /**
+   * Hash an input stream
+   * @param stream Stream with the data to hash
+   * @param hashType Hash types supported by MessageDigest (i.e MD5, SHA-1, SHA-512)
+   * @return Hash value of the input stream
+   */
+  public static String hash(InputStream stream, String hashType) {
+    return hash(stream, hashType, true);
+  }
+  
+  /**
+   * Hash an input stream
+   * @param stream Stream with the data to hash
+   * @param hashType Hash types supported by MessageDigest (i.e MD5, SHA-1, SHA-512)
+   * @param toLower True to output the hash in lower case. False to output in upper case
+   * @return Hash value of the input stream
+   */
+  public static String hash(InputStream stream, String hashType, boolean toLower) {
+    MessageDigest digest = null;
+    try(InputStream is = stream) {
+      digest = MessageDigest.getInstance(hashType);
+      
+      byte[] buffer = new byte[STREAM_BUFFER_LENGTH];
+      int read = is.read(buffer, 0, STREAM_BUFFER_LENGTH);
+
+      while (read > -1) {
+          digest.update(buffer, 0, read);
+          read = is.read(buffer, 0, STREAM_BUFFER_LENGTH);
+      }
+      
+      return encodeHexString(digest.digest(), toLower);
+    } catch (Exception ex) {
+      throw new IllegalArgumentException(ex.getMessage());
+    } 
+  }
+
+  /**
+   * Encode the hash data back to a string
+   * @param data Data to encode
+   * @param toLower output to lower case
+   * @return
+   */
+  private static String encodeHexString(byte[] data, boolean toLower) {
+    return new String(encodeHex(data, toLower));
+  }
+
+  /**
+   * Encode the hash data to a character array
+   * @param data Data to encode
+   * @param toLower output to lower case
+   * @return
+   */
+  private static char[] encodeHex(byte[] data, boolean toLower) {
+    return encodeHex(data, toLower ? DIGITS_LOWER : DIGITS_UPPER);
+  }
+
+  /**
+   * Encode the hex to a character array
+   * @param data Data to encode
+   * @param toDigits digits to use
+   * @return
+   */
+  private static char[] encodeHex(byte[] data, char[] toDigits) {
+    int l = data.length;
+    char[] out = new char[l << 1];
+    // two characters form the hex value.
+    for (int i = 0, j = 0; i < l; i++) {
+      out[j++] = toDigits[(0xF0 & data[i]) >>> 4];
+      out[j++] = toDigits[0x0F & data[i]];
+    }
+    return out;
+  }
+}