8315968: Move java.util.Digits to jdk.internal.util and refactor to reduce duplication

Reviewed-by: rriggs, liach, redestad

src/java.base/share/classes/java/lang/StringLatin1.java

@@ -33,6 +33,7 @@ import java.util.function.IntConsumer;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 import jdk.internal.util.ArraysSupport;
+import jdk.internal.util.DecimalDigits;
 import jdk.internal.util.ByteArrayLittleEndian;
 import jdk.internal.vm.annotation.IntrinsicCandidate;
 import jdk.internal.vm.annotation.Stable;
@@ -43,41 +44,6 @@ import static java.lang.String.checkIndex;
 import static java.lang.String.checkOffset;
 
 final class StringLatin1 {
-
-    /**
-     * Each element of the array represents the packaging of two ascii characters based on little endian:<p>
-     * <pre>
-     *      00 -> '0' | ('0' << 8) -> 0x3030
-     *      01 -> '1' | ('0' << 8) -> 0x3130
-     *      02 -> '2' | ('0' << 8) -> 0x3230
-     *
-     *     ...
-     *
-     *      10 -> '0' | ('1' << 8) -> 0x3031
-     *      11 -> '1' | ('1' << 8) -> 0x3131
-     *      12 -> '2' | ('1' << 8) -> 0x3231
-     *
-     *     ...
-     *
-     *      97 -> '7' | ('9' << 8) -> 0x3739
-     *      98 -> '8' | ('9' << 8) -> 0x3839
-     *      99 -> '9' | ('9' << 8) -> 0x3939
-     * </pre>
-     */
-    @Stable
-    static final short[] PACKED_DIGITS = new short[] {
-            0x3030, 0x3130, 0x3230, 0x3330, 0x3430, 0x3530, 0x3630, 0x3730, 0x3830, 0x3930,
-            0x3031, 0x3131, 0x3231, 0x3331, 0x3431, 0x3531, 0x3631, 0x3731, 0x3831, 0x3931,
-            0x3032, 0x3132, 0x3232, 0x3332, 0x3432, 0x3532, 0x3632, 0x3732, 0x3832, 0x3932,
-            0x3033, 0x3133, 0x3233, 0x3333, 0x3433, 0x3533, 0x3633, 0x3733, 0x3833, 0x3933,
-            0x3034, 0x3134, 0x3234, 0x3334, 0x3434, 0x3534, 0x3634, 0x3734, 0x3834, 0x3934,
-            0x3035, 0x3135, 0x3235, 0x3335, 0x3435, 0x3535, 0x3635, 0x3735, 0x3835, 0x3935,
-            0x3036, 0x3136, 0x3236, 0x3336, 0x3436, 0x3536, 0x3636, 0x3736, 0x3836, 0x3936,
-            0x3037, 0x3137, 0x3237, 0x3337, 0x3437, 0x3537, 0x3637, 0x3737, 0x3837, 0x3937,
-            0x3038, 0x3138, 0x3238, 0x3338, 0x3438, 0x3538, 0x3638, 0x3738, 0x3838, 0x3938,
-            0x3039, 0x3139, 0x3239, 0x3339, 0x3439, 0x3539, 0x3639, 0x3739, 0x3839, 0x3939
-    };
-
     public static char charAt(byte[] value, int index) {
         checkIndex(index, value.length);
         return (char)(value[index] & 0xff);
@@ -148,13 +114,13 @@ final class StringLatin1 {
             r = (q * 100) - i;
             i = q;
             charPos -= 2;
-            ByteArrayLittleEndian.setShort(buf, charPos, PACKED_DIGITS[r]);
+            ByteArrayLittleEndian.setShort(buf, charPos, DecimalDigits.digitPair(r));
         }
 
         // We know there are at most two digits left at this point.
         if (i < -9) {
             charPos -= 2;
-            ByteArrayLittleEndian.setShort(buf, charPos, PACKED_DIGITS[-i]);
+            ByteArrayLittleEndian.setShort(buf, charPos, DecimalDigits.digitPair(-i));
         } else {
             buf[--charPos] = (byte)('0' - i);
         }
@@ -196,7 +162,7 @@ final class StringLatin1 {
         while (i <= Integer.MIN_VALUE) {
             q = i / 100;
             charPos -= 2;
-            ByteArrayLittleEndian.setShort(buf, charPos, PACKED_DIGITS[(int)((q * 100) - i)]);
+            ByteArrayLittleEndian.setShort(buf, charPos, DecimalDigits.digitPair((int)((q * 100) - i)));
             i = q;
         }
 
@@ -206,14 +172,14 @@ final class StringLatin1 {
         while (i2 <= -100) {
             q2 = i2 / 100;
             charPos -= 2;
-            ByteArrayLittleEndian.setShort(buf, charPos, PACKED_DIGITS[(q2 * 100) - i2]);
+            ByteArrayLittleEndian.setShort(buf, charPos, DecimalDigits.digitPair((q2 * 100) - i2));
             i2 = q2;
         }
 
         // We know there are at most two digits left at this point.
         if (i2 < -9) {
             charPos -= 2;
-            ByteArrayLittleEndian.setShort(buf, charPos, PACKED_DIGITS[-i2]);
+            ByteArrayLittleEndian.setShort(buf, charPos, DecimalDigits.digitPair(-i2));
         } else {
             buf[--charPos] = (byte)('0' - i2);
         }

src/java.base/share/classes/java/lang/StringUTF16.java

@@ -33,6 +33,7 @@ import java.util.function.IntConsumer;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 import jdk.internal.util.ArraysSupport;
+import jdk.internal.util.DecimalDigits;
 import jdk.internal.vm.annotation.DontInline;
 import jdk.internal.vm.annotation.ForceInline;
 import jdk.internal.vm.annotation.IntrinsicCandidate;
@@ -1612,7 +1613,7 @@ final class StringUTF16 {
     }
 
     private static void putPair(byte[] buf, int charPos, int v) {
-        int packed = (int) StringLatin1.PACKED_DIGITS[v];
+        int packed = (int) DecimalDigits.digitPair(v);
         putChar(buf, charPos, packed & 0xFF);
         putChar(buf, charPos + 1, packed >> 8);
     }

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

@@ -36,6 +36,9 @@ import java.util.Formatter.FormatSpecifier;
 import jdk.internal.access.JavaLangAccess;
 import jdk.internal.access.SharedSecrets;
 import jdk.internal.util.FormatConcatItem;
+import jdk.internal.util.DecimalDigits;
+import jdk.internal.util.HexDigits;
+import jdk.internal.util.OctalDigits;
 
 import static java.lang.invoke.MethodType.methodType;
 

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

@@ -32,6 +32,7 @@ import java.security.*;
 import jdk.internal.access.JavaLangAccess;
 import jdk.internal.access.SharedSecrets;
 import jdk.internal.util.ByteArray;
+import jdk.internal.util.HexDigits;
 
 /**
  * A class that represents an immutable universally unique identifier (UUID).

src/java.base/share/classes/jdk/internal/util/DecimalDigits.java

@@ -23,7 +23,7 @@
  * questions.
  */
 
-package java.util;
+package jdk.internal.util;
 
 import java.lang.invoke.MethodHandle;
 
@@ -34,29 +34,46 @@ import jdk.internal.vm.annotation.Stable;
  *
  * @since 21
  */
-final class DecimalDigits implements Digits {
+public final class DecimalDigits implements Digits {
+
+    /**
+     * Each element of the array represents the packaging of two ascii characters based on little endian:<p>
+     * <pre>
+     *      00 -> '0' | ('0' << 8) -> 0x3030
+     *      01 -> '1' | ('0' << 8) -> 0x3130
+     *      02 -> '2' | ('0' << 8) -> 0x3230
+     *
+     *     ...
+     *
+     *      10 -> '0' | ('1' << 8) -> 0x3031
+     *      11 -> '1' | ('1' << 8) -> 0x3131
+     *      12 -> '2' | ('1' << 8) -> 0x3231
+     *
+     *     ...
+     *
+     *      97 -> '7' | ('9' << 8) -> 0x3739
+     *      98 -> '8' | ('9' << 8) -> 0x3839
+     *      99 -> '9' | ('9' << 8) -> 0x3939
+     * </pre>
+     */
     @Stable
-    private static final short[] DIGITS;
+    private static final short[] DIGITS = new short[] {
+            0x3030, 0x3130, 0x3230, 0x3330, 0x3430, 0x3530, 0x3630, 0x3730, 0x3830, 0x3930,
+            0x3031, 0x3131, 0x3231, 0x3331, 0x3431, 0x3531, 0x3631, 0x3731, 0x3831, 0x3931,
+            0x3032, 0x3132, 0x3232, 0x3332, 0x3432, 0x3532, 0x3632, 0x3732, 0x3832, 0x3932,
+            0x3033, 0x3133, 0x3233, 0x3333, 0x3433, 0x3533, 0x3633, 0x3733, 0x3833, 0x3933,
+            0x3034, 0x3134, 0x3234, 0x3334, 0x3434, 0x3534, 0x3634, 0x3734, 0x3834, 0x3934,
+            0x3035, 0x3135, 0x3235, 0x3335, 0x3435, 0x3535, 0x3635, 0x3735, 0x3835, 0x3935,
+            0x3036, 0x3136, 0x3236, 0x3336, 0x3436, 0x3536, 0x3636, 0x3736, 0x3836, 0x3936,
+            0x3037, 0x3137, 0x3237, 0x3337, 0x3437, 0x3537, 0x3637, 0x3737, 0x3837, 0x3937,
+            0x3038, 0x3138, 0x3238, 0x3338, 0x3438, 0x3538, 0x3638, 0x3738, 0x3838, 0x3938,
+            0x3039, 0x3139, 0x3239, 0x3339, 0x3439, 0x3539, 0x3639, 0x3739, 0x3839, 0x3939
+    };
 
     /**
      * Singleton instance of DecimalDigits.
      */
-    static final Digits INSTANCE = new DecimalDigits();
+    public static final Digits INSTANCE = new DecimalDigits();
-
-    static {
-        short[] digits = new short[10 * 10];
-
-        for (int i = 0; i < 10; i++) {
-            short hi = (short) ((i + '0') << 8);
-
-            for (int j = 0; j < 10; j++) {
-                short lo = (short) (j + '0');
-                digits[i * 10 + j] = (short) (hi | lo);
-            }
-        }
-
-        DIGITS = digits;
-    }
 
     /**
      * Constructor.
@@ -80,8 +97,8 @@ final class DecimalDigits implements Digits {
             value = q;
             int digits = DIGITS[r];
 
-            putCharMH.invokeExact(buffer, --index, digits & 0xFF);
             putCharMH.invokeExact(buffer, --index, digits >> 8);
+            putCharMH.invokeExact(buffer, --index, digits & 0xFF);
         }
 
         int iq, ivalue = (int)value;
@@ -90,8 +107,8 @@ final class DecimalDigits implements Digits {
             r = (iq * 100) - ivalue;
             ivalue = iq;
             int digits = DIGITS[r];
-            putCharMH.invokeExact(buffer, --index, digits & 0xFF);
             putCharMH.invokeExact(buffer, --index, digits >> 8);
+            putCharMH.invokeExact(buffer, --index, digits & 0xFF);
         }
 
         if (ivalue < 0) {
@@ -99,10 +116,10 @@ final class DecimalDigits implements Digits {
         }
 
         int digits = DIGITS[ivalue];
-        putCharMH.invokeExact(buffer, --index, digits & 0xFF);
+        putCharMH.invokeExact(buffer, --index, digits >> 8);
 
         if (9 < ivalue) {
-            putCharMH.invokeExact(buffer, --index, digits >> 8);
+            putCharMH.invokeExact(buffer, --index, digits & 0xFF);
         }
 
         if (negative) {
@@ -131,4 +148,13 @@ final class DecimalDigits implements Digits {
 
         return 19 + sign;
     }
+
+    /**
+     * For values from 0 to 99 return a short encoding a pair of ASCII-encoded digit characters in little-endian
+     * @param i value to convert
+     * @return a short encoding a pair of ASCII-encoded digit characters
+     */
+    public static short digitPair(int i) {
+        return DIGITS[i];
+    }
 }

src/java.base/share/classes/jdk/internal/util/Digits.java

@@ -23,7 +23,7 @@
  * questions.
  */
 
-package java.util;
+package jdk.internal.util;
 
 import java.lang.invoke.MethodHandle;
 
@@ -33,7 +33,7 @@ import java.lang.invoke.MethodHandle;
  *
  * @since 21
  */
-sealed interface Digits permits DecimalDigits, HexDigits, OctalDigits {
+public sealed interface Digits permits DecimalDigits, HexDigits, OctalDigits {
     /**
      * Insert digits for long value in buffer from high index to low index.
      *

src/java.base/share/classes/jdk/internal/util/HexDigits.java

@@ -23,7 +23,7 @@
  * questions.
  */
 
-package java.util;
+package jdk.internal.util;
 
 import java.lang.invoke.MethodHandle;
 
@@ -34,7 +34,7 @@ import jdk.internal.vm.annotation.Stable;
  *
  * @since 21
  */
-final class HexDigits implements Digits {
+public final class HexDigits implements Digits {
     /**
      * Each element of the array represents the ascii encoded
      * hex relative to its index, for example:<p>
@@ -79,7 +79,7 @@ final class HexDigits implements Digits {
     /**
      * Singleton instance of HexDigits.
      */
-    static final Digits INSTANCE = new HexDigits();
+    public static final Digits INSTANCE = new HexDigits();
 
     static {
         short[] digits = new short[16 * 16];
@@ -105,14 +105,14 @@ final class HexDigits implements Digits {
     /**
      * Combine two hex shorts into one int based on big endian
      */
-    static int digit(int b0, int b1) {
+    public static int digit(int b0, int b1) {
         return (DIGITS[b0 & 0xff] << 16) | DIGITS[b1 & 0xff];
     }
 
     /**
      * Combine four hex shorts into one long based on big endian
      */
-    static long digit(int b0, int b1, int b2, int b3) {
+    public static long digit(int b0, int b1, int b2, int b3) {
         return (((long) DIGITS[b0 & 0xff]) << 48)
                 | (((long) DIGITS[b1 & 0xff]) << 32)
                 | (DIGITS[b2 & 0xff] << 16)

src/java.base/share/classes/jdk/internal/util/OctalDigits.java

@@ -23,7 +23,7 @@
  * questions.
  */
 
-package java.util;
+package jdk.internal.util;
 
 import java.lang.invoke.MethodHandle;
 
@@ -34,23 +34,23 @@ import jdk.internal.vm.annotation.Stable;
  *
  * @since 21
  */
-final class OctalDigits implements Digits {
+public final class OctalDigits implements Digits {
     @Stable
     private static final short[] DIGITS;
 
     /**
      * Singleton instance of OctalDigits.
      */
-    static final Digits INSTANCE = new OctalDigits();
+    public static final Digits INSTANCE = new OctalDigits();
 
     static {
         short[] digits = new short[8 * 8];
 
         for (int i = 0; i < 8; i++) {
-            short hi = (short) ((i + '0') << 8);
+            short lo = (short) (i + '0');
 
             for (int j = 0; j < 8; j++) {
-                short lo = (short) (j + '0');
+                short hi = (short) ((j + '0') << 8);
                 digits[(i << 3) + j] = (short) (hi | lo);
             }
         }
@@ -70,15 +70,15 @@ final class OctalDigits implements Digits {
         while ((value & ~0x3F) != 0) {
             int digits = DIGITS[(int) (value & 0x3F)];
             value >>>= 6;
-            putCharMH.invokeExact(buffer, --index, digits & 0xFF);
             putCharMH.invokeExact(buffer, --index, digits >> 8);
+            putCharMH.invokeExact(buffer, --index, digits & 0xFF);
         }
 
         int digits = DIGITS[(int) (value & 0x3F)];
-        putCharMH.invokeExact(buffer, --index, digits & 0xFF);
+        putCharMH.invokeExact(buffer, --index, digits >> 8);
 
         if (7 < value) {
-            putCharMH.invokeExact(buffer, --index, digits >> 8);
+            putCharMH.invokeExact(buffer, --index, digits & 0xFF);
         }
 
         return index;