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8370503: Use String.newStringWithLatin1Bytes to simplify Integer/Long toString method #27929

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8370503: Use String.newStringWithLatin1Bytes to simplify Integer/Long toString method #27929

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cf7b33a
Simplify toString() implementations in Integer and Long classes\n\nRe…
wenshao Oct 22, 2025
9818de0
clean up, from @rgiulietti
wenshao Oct 23, 2025
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44 changes: 6 additions & 38 deletions src/java.base/share/classes/java/lang/Integer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -363,15 +363,9 @@ private static String toUnsignedString0(int val, int shift) {
// assert shift > 0 && shift <=5 : "Illegal shift value";
int mag = Integer.SIZE - Integer.numberOfLeadingZeros(val);
int chars = Math.max(((mag + (shift - 1)) / shift), 1);
if (COMPACT_STRINGS) {
byte[] buf = new byte[chars];
formatUnsignedInt(val, shift, buf, chars);
return new String(buf, LATIN1);
} else {
byte[] buf = new byte[chars * 2];
formatUnsignedIntUTF16(val, shift, buf, chars);
return new String(buf, UTF16);
}
byte[] buf = new byte[chars];
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Should the array size be chars*2 in when compact strings is not in use?

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There is no need to handle the case where COMPACT_STRING false is used, as it is inflate in java.lang.String#newStringWithLatin1Bytes.

formatUnsignedInt(val, shift, buf, chars);
return String.newStringWithLatin1Bytes(buf);
}

/**
Expand All @@ -394,26 +388,6 @@ private static void formatUnsignedInt(int val, int shift, byte[] buf, int len) {
} while (charPos > 0);
}

/**
* Format an {@code int} (treated as unsigned) into a byte buffer (UTF16 version). If
* {@code len} exceeds the formatted ASCII representation of {@code val},
* {@code buf} will be padded with leading zeroes.
*
* @param val the unsigned int to format
* @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
* @param buf the byte buffer to write to
* @param len the number of characters to write
*/
private static void formatUnsignedIntUTF16(int val, int shift, byte[] buf, int len) {
int charPos = len;
int radix = 1 << shift;
int mask = radix - 1;
do {
StringUTF16.putChar(buf, --charPos, Integer.digits[val & mask]);
val >>>= shift;
} while (charPos > 0);
}

/**
* Returns a {@code String} object representing the
* specified integer. The argument is converted to signed decimal
Expand All @@ -427,15 +401,9 @@ private static void formatUnsignedIntUTF16(int val, int shift, byte[] buf, int l
@IntrinsicCandidate
public static String toString(int i) {
int size = DecimalDigits.stringSize(i);
if (COMPACT_STRINGS) {
byte[] buf = new byte[size];
DecimalDigits.uncheckedGetCharsLatin1(i, size, buf);
return new String(buf, LATIN1);
} else {
byte[] buf = new byte[size * 2];
DecimalDigits.uncheckedGetCharsUTF16(i, size, buf);
return new String(buf, UTF16);
}
byte[] buf = new byte[size];
DecimalDigits.uncheckedGetCharsLatin1(i, size, buf);
return String.newStringWithLatin1Bytes(buf);
}

/**
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45 changes: 6 additions & 39 deletions src/java.base/share/classes/java/lang/Long.java
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Original file line number Diff line number Diff line change
Expand Up @@ -391,15 +391,9 @@ static String toUnsignedString0(long val, int shift) {
// assert shift > 0 && shift <=5 : "Illegal shift value";
int mag = Long.SIZE - Long.numberOfLeadingZeros(val);
int chars = Math.max(((mag + (shift - 1)) / shift), 1);
if (COMPACT_STRINGS) {
byte[] buf = new byte[chars];
formatUnsignedLong0(val, shift, buf, 0, chars);
return new String(buf, LATIN1);
} else {
byte[] buf = new byte[chars * 2];
formatUnsignedLong0UTF16(val, shift, buf, 0, chars);
return new String(buf, UTF16);
}
byte[] buf = new byte[chars];
formatUnsignedLong0(val, shift, buf, 0, chars);
return String.newStringWithLatin1Bytes(buf);
}

/**
Expand All @@ -423,27 +417,6 @@ private static void formatUnsignedLong0(long val, int shift, byte[] buf, int off
} while (charPos > offset);
}

/**
* Format a long (treated as unsigned) into a byte buffer (UTF16 version). If
* {@code len} exceeds the formatted ASCII representation of {@code val},
* {@code buf} will be padded with leading zeroes.
*
* @param val the unsigned long to format
* @param shift the log2 of the base to format in (4 for hex, 3 for octal, 1 for binary)
* @param buf the byte buffer to write to
* @param offset the offset in the destination buffer to start at
* @param len the number of characters to write
*/
private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, int offset, int len) {
int charPos = offset + len;
int radix = 1 << shift;
int mask = radix - 1;
do {
StringUTF16.putChar(buf, --charPos, Integer.digits[((int) val) & mask]);
val >>>= shift;
} while (charPos > offset);
}

/**
* Returns a {@code String} object representing the specified
* {@code long}. The argument is converted to signed decimal
Expand All @@ -456,15 +429,9 @@ private static void formatUnsignedLong0UTF16(long val, int shift, byte[] buf, in
*/
public static String toString(long i) {
int size = DecimalDigits.stringSize(i);
if (COMPACT_STRINGS) {
byte[] buf = new byte[size];
DecimalDigits.uncheckedGetCharsLatin1(i, size, buf);
return new String(buf, LATIN1);
} else {
byte[] buf = new byte[size * 2];
DecimalDigits.uncheckedGetCharsUTF16(i, size, buf);
return new String(buf, UTF16);
}
byte[] buf = new byte[size];
DecimalDigits.uncheckedGetCharsLatin1(i, size, buf);
return String.newStringWithLatin1Bytes(buf);
}

/**
Expand Down