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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /intl/icu/source/common/locdistance.h | |
parent | Initial commit. (diff) | |
download | firefox-esr-upstream.tar.xz firefox-esr-upstream.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'intl/icu/source/common/locdistance.h')
-rw-r--r-- | intl/icu/source/common/locdistance.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/intl/icu/source/common/locdistance.h b/intl/icu/source/common/locdistance.h new file mode 100644 index 0000000000..51b777e627 --- /dev/null +++ b/intl/icu/source/common/locdistance.h @@ -0,0 +1,151 @@ +// © 2019 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html + +// locdistance.h +// created: 2019may08 Markus W. Scherer + +#ifndef __LOCDISTANCE_H__ +#define __LOCDISTANCE_H__ + +#include "unicode/utypes.h" +#include "unicode/bytestrie.h" +#include "unicode/localematcher.h" +#include "unicode/locid.h" +#include "unicode/uobject.h" +#include "lsr.h" + +U_NAMESPACE_BEGIN + +struct LocaleDistanceData; + +/** + * Offline-built data for LocaleMatcher. + * Mostly but not only the data for mapping locales to their maximized forms. + */ +class LocaleDistance final : public UMemory { +public: + static const LocaleDistance *getSingleton(UErrorCode &errorCode); + + static int32_t shiftDistance(int32_t distance) { + return distance << DISTANCE_SHIFT; + } + + static int32_t getShiftedDistance(int32_t indexAndDistance) { + return indexAndDistance & DISTANCE_MASK; + } + + static double getDistanceDouble(int32_t indexAndDistance) { + double shiftedDistance = getShiftedDistance(indexAndDistance); + return shiftedDistance / (1 << DISTANCE_SHIFT); + } + + static int32_t getDistanceFloor(int32_t indexAndDistance) { + return (indexAndDistance & DISTANCE_MASK) >> DISTANCE_SHIFT; + } + + static int32_t getIndex(int32_t indexAndDistance) { + // assert indexAndDistance >= 0; + return indexAndDistance >> INDEX_SHIFT; + } + + /** + * Finds the supported LSR with the smallest distance from the desired one. + * Equivalent LSR subtags must be normalized into a canonical form. + * + * <p>Returns the index of the lowest-distance supported LSR in the high bits + * (negative if none has a distance below the threshold), + * and its distance (0..ABOVE_THRESHOLD) in the low bits. + */ + int32_t getBestIndexAndDistance(const LSR &desired, + const LSR **supportedLSRs, int32_t supportedLSRsLength, + int32_t shiftedThreshold, + ULocMatchFavorSubtag favorSubtag, + ULocMatchDirection direction) const; + + UBool isParadigmLSR(const LSR &lsr) const; + + int32_t getDefaultScriptDistance() const { + return defaultScriptDistance; + } + + int32_t getDefaultDemotionPerDesiredLocale() const { + return defaultDemotionPerDesiredLocale; + } + +private: + // The distance is shifted left to gain some fraction bits. + static constexpr int32_t DISTANCE_SHIFT = 3; + static constexpr int32_t DISTANCE_FRACTION_MASK = 7; + // 7 bits for 0..100 + static constexpr int32_t DISTANCE_INT_SHIFT = 7; + static constexpr int32_t INDEX_SHIFT = DISTANCE_INT_SHIFT + DISTANCE_SHIFT; + static constexpr int32_t DISTANCE_MASK = 0x3ff; + // tic constexpr int32_t MAX_INDEX = 0x1fffff; // avoids sign bit + static constexpr int32_t INDEX_NEG_1 = 0xfffffc00; + + LocaleDistance(const LocaleDistanceData &data, const XLikelySubtags &likely); + LocaleDistance(const LocaleDistance &other) = delete; + LocaleDistance &operator=(const LocaleDistance &other) = delete; + + static void initLocaleDistance(UErrorCode &errorCode); + + UBool isMatch(const LSR &desired, const LSR &supported, + int32_t shiftedThreshold, ULocMatchFavorSubtag favorSubtag) const { + const LSR *pSupp = &supported; + return getBestIndexAndDistance( + desired, &pSupp, 1, + shiftedThreshold, favorSubtag, ULOCMATCH_DIRECTION_WITH_ONE_WAY) >= 0; + } + + static int32_t getDesSuppScriptDistance(BytesTrie &iter, uint64_t startState, + const char *desired, const char *supported); + + static int32_t getRegionPartitionsDistance( + BytesTrie &iter, uint64_t startState, + const char *desiredPartitions, const char *supportedPartitions, + int32_t threshold); + + static int32_t getFallbackRegionDistance(BytesTrie &iter, uint64_t startState); + + static int32_t trieNext(BytesTrie &iter, const char *s, bool wantValue); + + const char *partitionsForRegion(const LSR &lsr) const { + // ill-formed region -> one non-matching string + int32_t pIndex = regionToPartitionsIndex[lsr.regionIndex]; + return partitionArrays[pIndex]; + } + + int32_t getDefaultRegionDistance() const { + return defaultRegionDistance; + } + + const XLikelySubtags &likelySubtags; + + // The trie maps each dlang+slang+dscript+sscript+dregion+sregion + // (encoded in ASCII with bit 7 set on the last character of each subtag) to a distance. + // There is also a trie value for each subsequence of whole subtags. + // One '*' is used for a (desired, supported) pair of "und", "Zzzz"/"", or "ZZ"/"". + BytesTrie trie; + + /** + * Maps each region to zero or more single-character partitions. + */ + const uint8_t *regionToPartitionsIndex; + const char **partitionArrays; + + /** + * Used to get the paradigm region for a cluster, if there is one. + */ + const LSR *paradigmLSRs; + int32_t paradigmLSRsLength; + + int32_t defaultLanguageDistance; + int32_t defaultScriptDistance; + int32_t defaultRegionDistance; + int32_t minRegionDistance; + int32_t defaultDemotionPerDesiredLocale; +}; + +U_NAMESPACE_END + +#endif // __LOCDISTANCE_H__ |