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use long for string equals (#613)

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use more generic hashcode
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John Ziamos 2024-01-28 16:03:42 +00:00 committed by GitHub
parent 8ef22ab1bd
commit 97334e8621
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GPG Key ID: B5690EEEBB952194
1 changed files with 11 additions and 8 deletions
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src/main/java/dev/morling/onebrc/CalculateAverage_iziamos.java
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@ -185,7 +185,7 @@ public class CalculateAverage_iziamos {
byte b = UNSAFE.getByte(pointer); byte b = UNSAFE.getByte(pointer);
for (; b != ';'; ++strLen, b = UNSAFE.getByte(pointer + strLen)) { for (; b != ';'; ++strLen, b = UNSAFE.getByte(pointer + strLen)) {
hash += b << strLen; hash = 31 * hash + b;
} }
pointer += strLen + 1; pointer += strLen + 1;
@ -351,22 +351,25 @@ public class CalculateAverage_iziamos {
} }
} }
private static boolean stringEquals(final long thisNameAddress, final int thisStringLength, final long otherNameAddress, final long otherNameLength) { private static boolean stringEquals(final long thisNameAddress,
final int thisStringLength,
final long otherNameAddress,
final long otherNameLength) {
if (thisStringLength != otherNameLength) { if (thisStringLength != otherNameLength) {
return false; return false;
} }
int i = 0; int i = 0;
for (; i < thisStringLength - 3; i += 4) { for (; i < thisStringLength - 7; i += 8) {
if (UNSAFE.getInt(thisNameAddress + i) != UNSAFE.getInt(otherNameAddress + i)) { if (UNSAFE.getLong(thisNameAddress + i) != UNSAFE.getLong(otherNameAddress + i)) {
return false; return false;
} }
} }
final int remainingToCheck = thisStringLength - i; final long remainingToCheck = thisStringLength - i;
final int finalBytesMask = ((1 << remainingToCheck * 8)) - 1; final long finalBytesMask = ((1L << remainingToCheck * 8)) - 1;
final int thisLastWord = UNSAFE.getInt(thisNameAddress + i); final long thisLastWord = UNSAFE.getLong(thisNameAddress + i);
final int otherLastWord = UNSAFE.getInt(otherNameAddress + i); final long otherLastWord = UNSAFE.getLong(otherNameAddress + i);
return 0 == ((thisLastWord ^ otherLastWord) & finalBytesMask); return 0 == ((thisLastWord ^ otherLastWord) & finalBytesMask);
} }