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Add default implementation on codePointCount in CharSequence

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This commit is contained in:
Tatsunori Uchino 2025-07-26 19:05:05 +09:00
parent 1e7da59d46
commit 4811c9df90
1 changed files with 25 additions and 0 deletions
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25
src/java.base/share/classes/java/lang/CharSequence.java
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@ -253,6 +253,31 @@ public interface CharSequence {
false);
}
/**
* Returns the number of Unicode code points in
* this sequence. Unpaired surrogates count
* as one code point each.
*
* @return the number of Unicode code points in this sequence
* @since 26
*/
public default int codePointCount() {
final int length = length();
int n = length;
final int lastIndex = length - 1;
// i < lastIndex works properly even for an empty sequence
// thank to the fact that the length/index type in Java is signed
for (int i = 0; i < lastIndex;) {
if (Character.isHighSurrogate(charAt(i++)) && Character.isLowSurrogate(charAt(i))) {
n--;
i++;
}
}
return n;
}
/**
* Compares two {@code CharSequence} instances lexicographically. Returns a
* negative value, zero, or a positive value if the first sequence is lexicographically