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LUCENE-10125: Another idea of DirectWriter

This commit is contained in:
Uwe Schindler 2021-09-30 00:03:51 +02:00
parent 88b264a368
commit 12ad4bbf75
1 changed files with 23 additions and 16 deletions
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31
lucene/core/src/java/org/apache/lucene/util/packed/DirectWriter.java
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@ -98,21 +98,32 @@ public final class DirectWriter {
off = 0;
}
@FunctionalInterface
private interface Setter {
void set(byte[] b, int o, long v);
}
private static final Setter LONG_SETTER = BitUtil.VH_LE_LONG::set,
INT_SETTER = (b, o, v) -> BitUtil.VH_LE_INT.set(b, o, (int) v),
SHORT_SETTER = (b, o, v) -> BitUtil.VH_LE_SHORT.set(b, o, (short) v),
BYTE_SETTER = (b, o, v) -> b[o] = (byte) v;
private static void encode(long[] nextValues, int upTo, byte[] nextBlocks, int bitsPerValue) {
if ((bitsPerValue & 7) == 0) {
// bitsPerValue is a multiple of 8: 8, 16, 24, 32, 30, 48, 56, 64
final int bytesPerValue = bitsPerValue / Byte.SIZE;
for (int i = 0, o = 0; i < upTo; ++i, o += bytesPerValue) {
final long l = nextValues[i];
final Setter setter;
if (bitsPerValue > Integer.SIZE) {
BitUtil.VH_LE_LONG.set(nextBlocks, o, l);
setter = LONG_SETTER;
} else if (bitsPerValue > Short.SIZE) {
BitUtil.VH_LE_INT.set(nextBlocks, o, (int) l);
setter = INT_SETTER;
} else if (bitsPerValue > Byte.SIZE) {
BitUtil.VH_LE_SHORT.set(nextBlocks, o, (short) l);
setter = SHORT_SETTER;
} else {
nextBlocks[o] = (byte) l;
setter = BYTE_SETTER;
}
for (int i = 0, o = 0; i < upTo; ++i, o += bytesPerValue) {
setter.set(nextBlocks, o, nextValues[i]);
}
} else if (bitsPerValue < 8) {
// bitsPerValue is 1, 2 or 4
@ -128,15 +139,11 @@ public final class DirectWriter {
// bitsPerValue is 12, 20 or 28
// Write values 2 by 2
final int numBytesFor2Values = bitsPerValue * 2 / Byte.SIZE;
final Setter setter = (bitsPerValue <= Integer.SIZE / 2) ? INT_SETTER : LONG_SETTER;
for (int i = 0, o = 0; i < upTo; i += 2, o += numBytesFor2Values) {
final long l1 = nextValues[i];
final long l2 = nextValues[i + 1];
final long merged = l1 | (l2 << bitsPerValue);
if (bitsPerValue <= Integer.SIZE / 2) {
BitUtil.VH_LE_INT.set(nextBlocks, o, (int) merged);
} else {
BitUtil.VH_LE_LONG.set(nextBlocks, o, merged);
}
setter.set(nextBlocks, o, l1 | (l2 << bitsPerValue));
}
}
}