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ICU-11610 rename usearch hash() to hashFromCE32(), improve implementation

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X-SVN-Rev: 37477
This commit is contained in:
Markus Scherer 2015-05-29 21:51:00 +00:00
parent 2ad94b4e93
commit 7bd5656680
1 changed files with 22 additions and 18 deletions
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40
icu4c/source/i18n/usearch.cpp
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@ -1,6 +1,6 @@
/*
**********************************************************************
* Copyright (C) 2001-2014 IBM and others. All rights reserved.
* Copyright (C) 2001-2015 IBM and others. All rights reserved.
**********************************************************************
* Date Name Description
* 07/02/2001 synwee Creation.
@ -75,18 +75,22 @@ inline uint32_t getMask(UCollationStrength strength)
}
/**
* This is to squeeze the 21bit ces into a 256 table
* @param ce collation element
* @return collapsed version of the collation element
* @param ce 32-bit collation element
* @return hash code
*/
static
inline int hash(uint32_t ce)
inline int hashFromCE32(uint32_t ce)
{
// the old value UCOL_PRIMARYORDER(ce) % MAX_TABLE_SIZE_ does not work
// well with the new collation where most of the latin 1 characters
// are of the value xx000xxx. their hashes will most of the time be 0
// to be discussed on the hash algo.
return UCOL_PRIMARYORDER(ce) % MAX_TABLE_SIZE_;
int hc = (int)(
((((((ce >> 24) * 37) +
(ce >> 16)) * 37) +
(ce >> 8)) * 37) +
ce);
hc %= MAX_TABLE_SIZE_;
if (hc < 0) {
hc += MAX_TABLE_SIZE_;
}
return hc;
}
U_CDECL_BEGIN
@ -492,22 +496,22 @@ inline void setShiftTable(int16_t shift[], int16_t backshift[],
for (count = 0; count < cesize; count ++) {
// number of ces from right of array to the count
int temp = defaultforward - count - 1;
shift[hash(cetable[count])] = temp > 1 ? temp : 1;
shift[hashFromCE32(cetable[count])] = temp > 1 ? temp : 1;
}
shift[hash(cetable[cesize])] = 1;
shift[hashFromCE32(cetable[cesize])] = 1;
// for ignorables we just shift by one. see test examples.
shift[hash(0)] = 1;
shift[hashFromCE32(0)] = 1;
for (count = 0; count < MAX_TABLE_SIZE_; count ++) {
backshift[count] = defaultbackward;
}
for (count = cesize; count > 0; count --) {
// the original value count does not seem to work
backshift[hash(cetable[count])] = count > expansionsize ?
backshift[hashFromCE32(cetable[count])] = count > expansionsize ?
(int16_t)(count - expansionsize) : 1;
}
backshift[hash(cetable[0])] = 1;
backshift[hash(0)] = 1;
backshift[hashFromCE32(cetable[0])] = 1;
backshift[hashFromCE32(0)] = 1;
}
/**
@ -730,7 +734,7 @@ inline int32_t shiftForward(UStringSearch *strsrch,
{
UPattern *pattern = &(strsrch->pattern);
if (ce != UCOL_NULLORDER) {
int32_t shift = pattern->shift[hash(ce)];
int32_t shift = pattern->shift[hashFromCE32(ce)];
// this is to adjust for characters in the middle of the
// substring for matching that failed.
int32_t adjust = pattern->cesLength - patternceindex;
@ -1971,7 +1975,7 @@ inline int32_t reverseShift(UStringSearch *strsrch,
}
else {
if (ce != UCOL_NULLORDER) {
int32_t shift = strsrch->pattern.backShift[hash(ce)];
int32_t shift = strsrch->pattern.backShift[hashFromCE32(ce)];
// this is to adjust for characters in the middle of the substring
// for matching that failed.