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LUCENE-1470: Remove the recursion from splitRange and implement with loop

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git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@745533 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Uwe Schindler 2009-02-18 15:08:02 +00:00
parent cd89bc9de3
commit 03db7c81c1
1 changed files with 24 additions and 29 deletions
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53
contrib/queries/src/java/org/apache/lucene/search/trie/TrieUtils.java
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@ -395,10 +395,7 @@ public final class TrieUtils {
) {
if (precisionStep<1 || precisionStep>64)
throw new IllegalArgumentException("precisionStep may only be 1..64");
splitRange(
builder, 64, precisionStep, minBound, maxBound,
0 /* start with no shift */
);
splitRange(builder, 64, precisionStep, minBound, maxBound);
}
/**
@ -414,42 +411,40 @@ public final class TrieUtils {
) {
if (precisionStep<1 || precisionStep>32)
throw new IllegalArgumentException("precisionStep may only be 1..32");
splitRange(
builder, 32, precisionStep, (long)minBound, (long)maxBound,
0 /* start with no shift */
);
splitRange(builder, 32, precisionStep, (long)minBound, (long)maxBound);
}
/** This helper does the splitting for both 32 and 64 bit. */
private static void splitRange(
final Object builder, final int valSize,
final int precisionStep, final long minBound, final long maxBound,
final int shift
final int precisionStep, long minBound, long maxBound
) {
// calculate new bounds for inner precision
final long diff = 1L << (shift+precisionStep),
mask = ((1L<<precisionStep) - 1L) << shift;
final boolean
hasLower = (minBound & mask) != 0L,
hasUpper = (maxBound & mask) != mask;
final long
nextMinBound = (hasLower ? (minBound + diff) : minBound) & ~mask,
nextMaxBound = (hasUpper ? (maxBound - diff) : maxBound) & ~mask;
for (int shift=0;; shift+=precisionStep) {
// calculate new bounds for inner precision
final long diff = 1L << (shift+precisionStep),
mask = ((1L<<precisionStep) - 1L) << shift;
final boolean
hasLower = (minBound & mask) != 0L,
hasUpper = (maxBound & mask) != mask;
final long
nextMinBound = (hasLower ? (minBound + diff) : minBound) & ~mask,
nextMaxBound = (hasUpper ? (maxBound - diff) : maxBound) & ~mask;
if (shift+precisionStep>=valSize || nextMinBound>nextMaxBound) {
// We are in the lowest precision or the next precision is not available.
addRange(builder, valSize, precisionStep, minBound, maxBound, shift);
} else {
if (shift+precisionStep>=valSize || nextMinBound>nextMaxBound) {
// We are in the lowest precision or the next precision is not available.
addRange(builder, valSize, precisionStep, minBound, maxBound, shift);
// exit the split recursion loop
break;
}
if (hasLower)
addRange(builder, valSize, precisionStep, minBound, minBound | mask, shift);
if (hasUpper)
addRange(builder, valSize, precisionStep, maxBound & ~mask, maxBound, shift);
// recurse down to next precision
splitRange(
builder, valSize, precisionStep,
nextMinBound, nextMaxBound,
shift+precisionStep
);
// recurse to next precision
minBound = nextMinBound;
maxBound = nextMaxBound;
}
}