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Slice improvements and optimizations #188

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Merged
dain merged 8 commits into from
Mar 6, 2026
Merged

Slice improvements and optimizations #188

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c4fbeaa
Add Slice.equals accepting other byte array
wendigo Mar 6, 2026
39f29d2
Fix incorrect Slice.clear implementation
wendigo Mar 6, 2026
7097318
Use unchecked operations in DynamicSliceOutput
wendigo Mar 6, 2026
8d8f57c
Vectorize indexOfByte
wendigo Mar 6, 2026
42fa599
Check checkFromIndexSize only once per setCodePointAt call
wendigo Mar 6, 2026
0c44731
Add Slice.lastIndexOf method
wendigo Mar 6, 2026
772b266
Drop unnecessary range checks performed by Arrays
wendigo Mar 6, 2026
a419bd7
Use faster indexOfByte to speed up indexOfBruteForce
wendigo Mar 6, 2026
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29 changes: 21 additions & 8 deletions src/main/java/io/airlift/slice/Slice.java
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Original file line number Diff line number Diff line change
Expand Up @@ -199,7 +199,8 @@ public void clear()

public void clear(int offset, int length)
{
Arrays.fill(base, baseOffset, baseOffset + size, (byte) 0);
checkFromIndexSize(offset, length, size);
Arrays.fill(base, baseOffset + offset, baseOffset + offset + length, (byte) 0);
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}

/**
Expand Down Expand Up @@ -1150,7 +1151,7 @@ public int indexOf(Slice pattern, int offset)
}

// Try fast match of head and the rest
if (value == head && equalsUnchecked(index, pattern, 0, pattern.length())) {
if (value == head && equalsUnchecked(index, pattern.byteArray(), pattern.byteArrayOffset(), pattern.length())) {
return index;
}

Expand Down Expand Up @@ -1182,7 +1183,7 @@ int indexOfBruteForce(Slice pattern, int offset)
break;
}

if (equalsUnchecked(index, pattern, 0, pattern.length())) {
if (equalsUnchecked(index, pattern.byteArray(), pattern.byteArrayOffset(), pattern.length())) {
return index;
}

Expand Down Expand Up @@ -1248,7 +1249,7 @@ public boolean equals(Object o)
return false;
}

return equalsUnchecked(0, that, 0, length());
return equalsUnchecked(0, that.byteArray(), that.byteArrayOffset(), length());
}

/**
Expand Down Expand Up @@ -1293,18 +1294,30 @@ public boolean equals(int offset, int length, Slice that, int otherOffset, int o
checkFromIndexSize(offset, length, length());
checkFromIndexSize(otherOffset, otherLength, that.length());

return equalsUnchecked(offset, that.byteArray(), that.byteArrayOffset() + otherOffset, length);
}

public boolean equals(int offset, int length, byte[] that, int otherOffset, int otherLength)
{
if (length != otherLength) {
return false;
}

checkFromIndexSize(offset, length, length());
checkFromIndexSize(otherOffset, otherLength, that.length);
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Outdated

return equalsUnchecked(offset, that, otherOffset, length);
}

boolean equalsUnchecked(int offset, Slice that, int otherOffset, int length)
boolean equalsUnchecked(int offset, byte[] that, int otherOffset, int length)
{
return Arrays.equals(
base,
baseOffset + offset,
baseOffset + offset + length,
that.base,
that.baseOffset + otherOffset,
that.baseOffset + otherOffset + length);
that,
otherOffset,
otherOffset + length);
}

/**
Expand Down
2 changes: 1 addition & 1 deletion src/test/java/io/airlift/slice/BenchmarkSlice.java
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,7 @@ public Object compareTo(BenchmarkData data)
@Benchmark
public Object equalsUnchecked(BenchmarkData data)
{
return data.slice1.equalsUnchecked(0, data.slice2, 0, data.slice1.length());
return data.slice1.equalsUnchecked(0, data.slice2.byteArray(), data.slice2.byteArrayOffset(), data.slice1.length());
}

@Benchmark
Expand Down
15 changes: 15 additions & 0 deletions src/test/java/io/airlift/slice/TestSlice.java
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Original file line number Diff line number Diff line change
Expand Up @@ -163,6 +163,7 @@ private static void assertSlicesEquals(Slice slice, Slice other)
assertThat(slice.compareTo(0, size, other, 0, size)).isEqualTo(0);
for (int i = 0; i < slice.length(); i++) {
assertThat(slice.equals(i, size - i, other, i, size - i)).isTrue();
assertThat(slice.equals(i, size - i, other.byteArray(), other.byteArrayOffset() + i, size - i)).isTrue();
assertThat(slice.hashCode(i, size - i)).isEqualTo(other.hashCode(i, size - i));
assertThat(slice.compareTo(i, size - i, other, i, size - i)).isEqualTo(0);
}
Expand Down Expand Up @@ -664,6 +665,20 @@ public void testBytesSlice()
}
}

@Test
public void testClear()
{
byte[] bytes = new byte[] {0, 1, 2, 3, 4, 5, 6, 7, 8};

Slice slice = Slices.wrappedBuffer(bytes);

assertThat(slice.getByte(1)).isEqualTo((byte) 1);
assertThat(slice.getByte(2)).isEqualTo((byte) 2);
slice.clear(1, 1);
assertThat(slice.getByte(1)).isEqualTo((byte) 0);
assertThat(slice.getByte(2)).isEqualTo((byte) 2);
}

private void assertBytesSlice(Slice slice, int index)
{
// fill slice with FF
Expand Down