src/java.base/share/classes/java/util/Base64.java

*** 29,38 ****
--- 29,39 ----
  import java.io.InputStream;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.nio.ByteBuffer;
  import java.nio.charset.StandardCharsets;
+ import jdk.internal.HotSpotIntrinsicCandidate;
  
  /**
   * This class consists exclusively of static methods for obtaining
   * encoders and decoders for the Base64 encoding scheme. The
   * implementation of this class supports the following types of Base64
*** 388,416 ****
              if (!doPadding)
                  return this;
              return new Encoder(isURL, newline, linemax, false);
          }
  
          private int encode0(byte[] src, int off, int end, byte[] dst) {
              char[] base64 = isURL ? toBase64URL : toBase64;
              int sp = off;
              int slen = (end - off) / 3 * 3;
              int sl = off + slen;
              if (linemax > 0 && slen  > linemax / 4 * 3)
                  slen = linemax / 4 * 3;
              int dp = 0;
              while (sp < sl) {
                  int sl0 = Math.min(sp + slen, sl);
!                 for (int sp0 = sp, dp0 = dp ; sp0 < sl0; ) {
!                     int bits = (src[sp0++] & 0xff) << 16 |
!                                (src[sp0++] & 0xff) <<  8 |
!                                (src[sp0++] & 0xff);
!                     dst[dp0++] = (byte)base64[(bits >>> 18) & 0x3f];
!                     dst[dp0++] = (byte)base64[(bits >>> 12) & 0x3f];
!                     dst[dp0++] = (byte)base64[(bits >>> 6)  & 0x3f];
!                     dst[dp0++] = (byte)base64[bits & 0x3f];
!                 }
                  int dlen = (sl0 - sp) / 3 * 4;
                  dp += dlen;
                  sp = sl0;
                  if (dlen == linemax && sp < end) {
                      for (byte b : newline){
--- 389,423 ----
              if (!doPadding)
                  return this;
              return new Encoder(isURL, newline, linemax, false);
          }
  
+         @HotSpotIntrinsicCandidate
+         private void encodeBlock(byte[] src, int sp, int sl, byte[] dst, int dp, boolean isURL) {
+             char[] base64 = isURL ? toBase64URL : toBase64;
+             for (int sp0 = sp, dp0 = dp ; sp0 < sl; ) {
+                 int bits = (src[sp0++] & 0xff) << 16 |
+                            (src[sp0++] & 0xff) <<  8 |
+                            (src[sp0++] & 0xff);
+                 dst[dp0++] = (byte)base64[(bits >>> 18) & 0x3f];
+                 dst[dp0++] = (byte)base64[(bits >>> 12) & 0x3f];
+                 dst[dp0++] = (byte)base64[(bits >>> 6)  & 0x3f];
+                 dst[dp0++] = (byte)base64[bits & 0x3f];
+             }
+         }
+ 
          private int encode0(byte[] src, int off, int end, byte[] dst) {
              char[] base64 = isURL ? toBase64URL : toBase64;
              int sp = off;
              int slen = (end - off) / 3 * 3;
              int sl = off + slen;
              if (linemax > 0 && slen  > linemax / 4 * 3)
                  slen = linemax / 4 * 3;
              int dp = 0;
              while (sp < sl) {
                  int sl0 = Math.min(sp + slen, sl);
!                 encodeBlock(src, sp, sl0, dst, dp, isURL);
                  int dlen = (sl0 - sp) / 3 * 4;
                  dp += dlen;
                  sp = sl0;
                  if (dlen == linemax && sp < end) {
                      for (byte b : newline){