Removing reverted changes from RemoteStoreUtils

Signed-off-by: Shourya Dutta Biswas <114977491+shourya035@users.noreply.github.com>

server/src/main/java/org/opensearch/index/remote/RemoteStoreUtils.java

@@ -20,7 +20,6 @@
 import java.util.Base64;
 import java.util.HashMap;
 import java.util.List;
-import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.function.Function;
@@ -33,16 +32,10 @@
 public class RemoteStoreUtils {
     public static final int LONG_MAX_LENGTH = String.valueOf(Long.MAX_VALUE).length();
 
-    /**
-     * URL safe base 64 character set. This must not be changed as this is used in deriving the base64 equivalent of binary.
-     */
-    static final char[] URL_BASE64_CHARSET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_".toCharArray();
-
     /**
      * This method subtracts given numbers from Long.MAX_VALUE and returns a string representation of the result.
      * The resultant string is guaranteed to be of the same length that of Long.MAX_VALUE. If shorter, we add left padding
      * of 0s to the string.
-     *
      * @param num number to get the inverted long string for
      * @return String value of Long.MAX_VALUE - num
      */
@@ -59,7 +52,6 @@ public static String invertLong(long num) {
 
     /**
      * This method converts the given string into long and subtracts it from Long.MAX_VALUE
-     *
      * @param str long in string format to be inverted
      * @return long value of the invert result
      */
@@ -73,7 +65,6 @@ public static long invertLong(String str) {
 
     /**
      * Extracts the segment name from the provided segment file name
-     *
      * @param filename Segment file name to parse
      * @return Name of the segment that the segment file belongs to
      */
@@ -94,9 +85,10 @@ public static String getSegmentName(String filename) {
     }
 
     /**
+     *
      * @param mdFiles List of segment/translog metadata files
-     * @param fn      Function to extract PrimaryTerm_Generation and Node Id from metadata file name .
-     *                fn returns null if node id is not part of the file name
+     * @param fn Function to extract PrimaryTerm_Generation and Node Id from metadata file name .
+     *          fn returns null if node id is not part of the file name
      */
     public static void verifyNoMultipleWriters(List<String> mdFiles, Function<String, Tuple<String, String>> fn) {
         Map<String, String> nodesByPrimaryTermAndGen = new HashMap<>();
@@ -131,28 +123,6 @@ static String longToUrlBase64(long value) {
         return base64Str.substring(0, base64Str.length() - 1);
     }
 
-    static long urlBase64ToLong(String base64Str) {
-        byte[] hashBytes = Base64.getUrlDecoder().decode(base64Str);
-        return ByteBuffer.wrap(hashBytes).getLong();
-    }
-
-    /**
-     * Converts an input hash which occupies 64 bits of memory into a composite encoded string. The string will have 2 parts -
-     * 1. Base 64 string and 2. Binary String. We will use the first 6 bits for creating the base 64 string.
-     * For the second part, the rest of the bits (of length {@code len}-6) will be used as is in string form.
-     */
-    static String longToCompositeBase64AndBinaryEncoding(long value, int len) {
-        if (len < 7 || len > 64) {
-            throw new IllegalArgumentException("In longToCompositeBase64AndBinaryEncoding, len must be between 7 and 64 (both inclusive)");
-        }
-        String binaryEncoding = String.format(Locale.ROOT, "%64s", Long.toBinaryString(value)).replace(' ', '0');
-        String base64Part = binaryEncoding.substring(0, 6);
-        String binaryPart = binaryEncoding.substring(6, len);
-        int base64DecimalValue = Integer.valueOf(base64Part, 2);
-        assert base64DecimalValue >= 0 && base64DecimalValue < 64;
-        return URL_BASE64_CHARSET[base64DecimalValue] + binaryPart;
-    }
-
     /**
      * Returns <code>true</code> iff current cluster settings have:
      * <br>