archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-08-27 14:54:52 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

8222955: Optimize String.replace(CharSequence, CharSequence) for common cases

Browse source 
Reviewed-by: redestad, tvaleev
This commit is contained in:
Ivan Gerasimov 2019-05-06 18:07:55 -07:00
parent 0c6f7e5516
commit 4f02d011b0
5 changed files with 408 additions and 34 deletions
Download patch file Download diff file Expand all files Collapse all files

57
src/java.base/share/classes/java/lang/String.java
View file

@ -75,7 +75,7 @@ import static java.util.function.Predicate.not;
* System.out.println("abc");
* String cde = "cde";
* System.out.println("abc" + cde);
* String c = "abc".substring(2,3);
* String c = "abc".substring(2, 3);
* String d = cde.substring(1, 2);
* </pre></blockquote>
* <p>
@ -2160,27 +2160,48 @@ public final class String
* @since 1.5
*/
public String replace(CharSequence target, CharSequence replacement) {
String tgtStr = target.toString();
String trgtStr = target.toString();
String replStr = replacement.toString();
int j = indexOf(tgtStr);
if (j < 0) {
return this;
}
int tgtLen = tgtStr.length();
int tgtLen1 = Math.max(tgtLen, 1);
int thisLen = length();
int trgtLen = trgtStr.length();
int replLen = replStr.length();
int newLenHint = thisLen - tgtLen + replStr.length();
if (newLenHint < 0) {
throw new OutOfMemoryError();
if (trgtLen > 0) {
if (trgtLen == 1 && replLen == 1) {
return replace(trgtStr.charAt(0), replStr.charAt(0));
}
boolean thisIsLatin1 = this.isLatin1();
boolean trgtIsLatin1 = trgtStr.isLatin1();
boolean replIsLatin1 = replStr.isLatin1();
String ret = (thisIsLatin1 && trgtIsLatin1 && replIsLatin1)
? StringLatin1.replace(value, thisLen,
trgtStr.value, trgtLen,
replStr.value, replLen)
: StringUTF16.replace(value, thisLen, thisIsLatin1,
trgtStr.value, trgtLen, trgtIsLatin1,
replStr.value, replLen, replIsLatin1);
if (ret != null) {
return ret;
}
return this;
} else { // trgtLen == 0
int resultLen;
try {
resultLen = Math.addExact(thisLen, Math.multiplyExact(
Math.addExact(thisLen, 1), replLen));
} catch (ArithmeticException ignored) {
throw new OutOfMemoryError();
}
StringBuilder sb = new StringBuilder(resultLen);
sb.append(replStr);
for (int i = 0; i < thisLen; ++i) {
sb.append(charAt(i)).append(replStr);
}
return sb.toString();
}
StringBuilder sb = new StringBuilder(newLenHint);
int i = 0;
do {
sb.append(this, i, j).append(replStr);
i = j + tgtLen;
} while (j < thisLen && (j = indexOf(tgtStr, j + tgtLen1)) > 0);
return sb.append(this, i, thisLen).toString();
}
/**