--- /dev/null
+// © 2019 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html#License
+
+// locdistance.cpp
+// created: 2019may08 Markus W. Scherer
+
+#include "unicode/utypes.h"
+#include "unicode/bytestrie.h"
+#include "unicode/localematcher.h"
+#include "unicode/locid.h"
+#include "unicode/uobject.h"
+#include "unicode/ures.h"
+#include "cstring.h"
+#include "locdistance.h"
+#include "loclikelysubtags.h"
+#include "uassert.h"
+#include "ucln_cmn.h"
+#include "uinvchar.h"
+#include "umutex.h"
+
+U_NAMESPACE_BEGIN
+
+namespace {
+
+/**
+ * Bit flag used on the last character of a subtag in the trie.
+ * Must be set consistently by the builder and the lookup code.
+ */
+constexpr int32_t END_OF_SUBTAG = 0x80;
+/** Distance value bit flag, set by the builder. */
+constexpr int32_t DISTANCE_SKIP_SCRIPT = 0x80;
+/** Distance value bit flag, set by trieNext(). */
+constexpr int32_t DISTANCE_IS_FINAL = 0x100;
+constexpr int32_t DISTANCE_IS_FINAL_OR_SKIP_SCRIPT = DISTANCE_IS_FINAL | DISTANCE_SKIP_SCRIPT;
+
+constexpr int32_t ABOVE_THRESHOLD = 100;
+
+// Indexes into array of distances.
+enum {
+ IX_DEF_LANG_DISTANCE,
+ IX_DEF_SCRIPT_DISTANCE,
+ IX_DEF_REGION_DISTANCE,
+ IX_MIN_REGION_DISTANCE,
+ IX_LIMIT
+};
+
+LocaleDistance *gLocaleDistance = nullptr;
+UInitOnce gInitOnce = U_INITONCE_INITIALIZER;
+
+UBool U_CALLCONV cleanup() {
+ delete gLocaleDistance;
+ gLocaleDistance = nullptr;
+ gInitOnce.reset();
+ return TRUE;
+}
+
+} // namespace
+
+void U_CALLCONV LocaleDistance::initLocaleDistance(UErrorCode &errorCode) {
+ // This function is invoked only via umtx_initOnce().
+ U_ASSERT(gLocaleDistance == nullptr);
+ const XLikelySubtags &likely = *XLikelySubtags::getSingleton(errorCode);
+ if (U_FAILURE(errorCode)) { return; }
+ const LocaleDistanceData &data = likely.getDistanceData();
+ if (data.distanceTrieBytes == nullptr ||
+ data.regionToPartitions == nullptr || data.partitions == nullptr ||
+ // ok if no paradigms
+ data.distances == nullptr) {
+ errorCode = U_MISSING_RESOURCE_ERROR;
+ return;
+ }
+ gLocaleDistance = new LocaleDistance(data);
+ if (gLocaleDistance == nullptr) {
+ errorCode = U_MEMORY_ALLOCATION_ERROR;
+ return;
+ }
+ ucln_common_registerCleanup(UCLN_COMMON_LOCALE_DISTANCE, cleanup);
+}
+
+const LocaleDistance *LocaleDistance::getSingleton(UErrorCode &errorCode) {
+ if (U_FAILURE(errorCode)) { return nullptr; }
+ umtx_initOnce(gInitOnce, &LocaleDistance::initLocaleDistance, errorCode);
+ return gLocaleDistance;
+}
+
+LocaleDistance::LocaleDistance(const LocaleDistanceData &data) :
+ trie(data.distanceTrieBytes),
+ regionToPartitionsIndex(data.regionToPartitions), partitionArrays(data.partitions),
+ paradigmLSRs(data.paradigms), paradigmLSRsLength(data.paradigmsLength),
+ defaultLanguageDistance(data.distances[IX_DEF_LANG_DISTANCE]),
+ defaultScriptDistance(data.distances[IX_DEF_SCRIPT_DISTANCE]),
+ defaultRegionDistance(data.distances[IX_DEF_REGION_DISTANCE]),
+ minRegionDistance(data.distances[IX_MIN_REGION_DISTANCE]) {
+ // For the default demotion value, use the
+ // default region distance between unrelated Englishes.
+ // Thus, unless demotion is turned off,
+ // a mere region difference for one desired locale
+ // is as good as a perfect match for the next following desired locale.
+ // As of CLDR 36, we have <languageMatch desired="en_*_*" supported="en_*_*" distance="5"/>.
+ LSR en("en", "Latn", "US");
+ LSR enGB("en", "Latn", "GB");
+ const LSR *p_enGB = &enGB;
+ defaultDemotionPerDesiredLocale = getBestIndexAndDistance(en, &p_enGB, 1,
+ 50, ULOCMATCH_FAVOR_LANGUAGE) & 0xff;
+}
+
+int32_t LocaleDistance::getBestIndexAndDistance(
+ const LSR &desired,
+ const LSR **supportedLSRs, int32_t supportedLSRsLength,
+ int32_t threshold, ULocMatchFavorSubtag favorSubtag) const {
+ BytesTrie iter(trie);
+ // Look up the desired language only once for all supported LSRs.
+ // Its "distance" is either a match point value of 0, or a non-match negative value.
+ // Note: The data builder verifies that there are no <*, supported> or <desired, *> rules.
+ int32_t desLangDistance = trieNext(iter, desired.language, false);
+ uint64_t desLangState = desLangDistance >= 0 && supportedLSRsLength > 1 ? iter.getState64() : 0;
+ // Index of the supported LSR with the lowest distance.
+ int32_t bestIndex = -1;
+ for (int32_t slIndex = 0; slIndex < supportedLSRsLength; ++slIndex) {
+ const LSR &supported = *supportedLSRs[slIndex];
+ bool star = false;
+ int32_t distance = desLangDistance;
+ if (distance >= 0) {
+ U_ASSERT((distance & DISTANCE_IS_FINAL) == 0);
+ if (slIndex != 0) {
+ iter.resetToState64(desLangState);
+ }
+ distance = trieNext(iter, supported.language, true);
+ }
+ // Note: The data builder verifies that there are no rules with "any" (*) language and
+ // real (non *) script or region subtags.
+ // This means that if the lookup for either language fails we can use
+ // the default distances without further lookups.
+ int32_t flags;
+ if (distance >= 0) {
+ flags = distance & DISTANCE_IS_FINAL_OR_SKIP_SCRIPT;
+ distance &= ~DISTANCE_IS_FINAL_OR_SKIP_SCRIPT;
+ } else { // <*, *>
+ if (uprv_strcmp(desired.language, supported.language) == 0) {
+ distance = 0;
+ } else {
+ distance = defaultLanguageDistance;
+ }
+ flags = 0;
+ star = true;
+ }
+ U_ASSERT(0 <= distance && distance <= 100);
+ // We implement "favor subtag" by reducing the language subtag distance
+ // (unscientifically reducing it to a quarter of the normal value),
+ // so that the script distance is relatively more important.
+ // For example, given a default language distance of 80, we reduce it to 20,
+ // which is below the default threshold of 50, which is the default script distance.
+ if (favorSubtag == ULOCMATCH_FAVOR_SCRIPT) {
+ distance >>= 2;
+ }
+ if (distance >= threshold) {
+ continue;
+ }
+
+ int32_t scriptDistance;
+ if (star || flags != 0) {
+ if (uprv_strcmp(desired.script, supported.script) == 0) {
+ scriptDistance = 0;
+ } else {
+ scriptDistance = defaultScriptDistance;
+ }
+ } else {
+ scriptDistance = getDesSuppScriptDistance(iter, iter.getState64(),
+ desired.script, supported.script);
+ flags = scriptDistance & DISTANCE_IS_FINAL;
+ scriptDistance &= ~DISTANCE_IS_FINAL;
+ }
+ distance += scriptDistance;
+ if (distance >= threshold) {
+ continue;
+ }
+
+ if (uprv_strcmp(desired.region, supported.region) == 0) {
+ // regionDistance = 0
+ } else if (star || (flags & DISTANCE_IS_FINAL) != 0) {
+ distance += defaultRegionDistance;
+ } else {
+ int32_t remainingThreshold = threshold - distance;
+ if (minRegionDistance >= remainingThreshold) {
+ continue;
+ }
+
+ // From here on we know the regions are not equal.
+ // Map each region to zero or more partitions. (zero = one non-matching string)
+ // (Each array of single-character partition strings is encoded as one string.)
+ // If either side has more than one, then we find the maximum distance.
+ // This could be optimized by adding some more structure, but probably not worth it.
+ distance += getRegionPartitionsDistance(
+ iter, iter.getState64(),
+ partitionsForRegion(desired),
+ partitionsForRegion(supported),
+ remainingThreshold);
+ }
+ if (distance < threshold) {
+ if (distance == 0) {
+ return slIndex << 8;
+ }
+ bestIndex = slIndex;
+ threshold = distance;
+ }
+ }
+ return bestIndex >= 0 ? (bestIndex << 8) | threshold : 0xffffff00 | ABOVE_THRESHOLD;
+}
+
+int32_t LocaleDistance::getDesSuppScriptDistance(
+ BytesTrie &iter, uint64_t startState, const char *desired, const char *supported) {
+ // Note: The data builder verifies that there are no <*, supported> or <desired, *> rules.
+ int32_t distance = trieNext(iter, desired, false);
+ if (distance >= 0) {
+ distance = trieNext(iter, supported, true);
+ }
+ if (distance < 0) {
+ UStringTrieResult result = iter.resetToState64(startState).next(u'*'); // <*, *>
+ U_ASSERT(USTRINGTRIE_HAS_VALUE(result));
+ if (uprv_strcmp(desired, supported) == 0) {
+ distance = 0; // same script
+ } else {
+ distance = iter.getValue();
+ U_ASSERT(distance >= 0);
+ }
+ if (result == USTRINGTRIE_FINAL_VALUE) {
+ distance |= DISTANCE_IS_FINAL;
+ }
+ }
+ return distance;
+}
+
+int32_t LocaleDistance::getRegionPartitionsDistance(
+ BytesTrie &iter, uint64_t startState,
+ const char *desiredPartitions, const char *supportedPartitions, int32_t threshold) {
+ char desired = *desiredPartitions++;
+ char supported = *supportedPartitions++;
+ U_ASSERT(desired != 0 && supported != 0);
+ // See if we have single desired/supported partitions, from NUL-terminated
+ // partition strings without explicit length.
+ bool suppLengthGt1 = *supportedPartitions != 0; // gt1: more than 1 character
+ // equivalent to: if (desLength == 1 && suppLength == 1)
+ if (*desiredPartitions == 0 && !suppLengthGt1) {
+ // Fastpath for single desired/supported partitions.
+ UStringTrieResult result = iter.next(uprv_invCharToAscii(desired) | END_OF_SUBTAG);
+ if (USTRINGTRIE_HAS_NEXT(result)) {
+ result = iter.next(uprv_invCharToAscii(supported) | END_OF_SUBTAG);
+ if (USTRINGTRIE_HAS_VALUE(result)) {
+ return iter.getValue();
+ }
+ }
+ return getFallbackRegionDistance(iter, startState);
+ }
+
+ const char *supportedStart = supportedPartitions - 1; // for restart of inner loop
+ int32_t regionDistance = 0;
+ // Fall back to * only once, not for each pair of partition strings.
+ bool star = false;
+ for (;;) {
+ // Look up each desired-partition string only once,
+ // not for each (desired, supported) pair.
+ UStringTrieResult result = iter.next(uprv_invCharToAscii(desired) | END_OF_SUBTAG);
+ if (USTRINGTRIE_HAS_NEXT(result)) {
+ uint64_t desState = suppLengthGt1 ? iter.getState64() : 0;
+ for (;;) {
+ result = iter.next(uprv_invCharToAscii(supported) | END_OF_SUBTAG);
+ int32_t d;
+ if (USTRINGTRIE_HAS_VALUE(result)) {
+ d = iter.getValue();
+ } else if (star) {
+ d = 0;
+ } else {
+ d = getFallbackRegionDistance(iter, startState);
+ star = true;
+ }
+ if (d >= threshold) {
+ return d;
+ } else if (regionDistance < d) {
+ regionDistance = d;
+ }
+ if ((supported = *supportedPartitions++) != 0) {
+ iter.resetToState64(desState);
+ } else {
+ break;
+ }
+ }
+ } else if (!star) {
+ int32_t d = getFallbackRegionDistance(iter, startState);
+ if (d >= threshold) {
+ return d;
+ } else if (regionDistance < d) {
+ regionDistance = d;
+ }
+ star = true;
+ }
+ if ((desired = *desiredPartitions++) != 0) {
+ iter.resetToState64(startState);
+ supportedPartitions = supportedStart;
+ supported = *supportedPartitions++;
+ } else {
+ break;
+ }
+ }
+ return regionDistance;
+}
+
+int32_t LocaleDistance::getFallbackRegionDistance(BytesTrie &iter, uint64_t startState) {
+#if U_DEBUG
+ UStringTrieResult result =
+#endif
+ iter.resetToState64(startState).next(u'*'); // <*, *>
+ U_ASSERT(USTRINGTRIE_HAS_VALUE(result));
+ int32_t distance = iter.getValue();
+ U_ASSERT(distance >= 0);
+ return distance;
+}
+
+int32_t LocaleDistance::trieNext(BytesTrie &iter, const char *s, bool wantValue) {
+ uint8_t c;
+ if ((c = *s) == 0) {
+ return -1; // no empty subtags in the distance data
+ }
+ for (;;) {
+ c = uprv_invCharToAscii(c);
+ // EBCDIC: If *s is not an invariant character,
+ // then c is now 0 and will simply not match anything, which is harmless.
+ uint8_t next = *++s;
+ if (next != 0) {
+ if (!USTRINGTRIE_HAS_NEXT(iter.next(c))) {
+ return -1;
+ }
+ } else {
+ // last character of this subtag
+ UStringTrieResult result = iter.next(c | END_OF_SUBTAG);
+ if (wantValue) {
+ if (USTRINGTRIE_HAS_VALUE(result)) {
+ int32_t value = iter.getValue();
+ if (result == USTRINGTRIE_FINAL_VALUE) {
+ value |= DISTANCE_IS_FINAL;
+ }
+ return value;
+ }
+ } else {
+ if (USTRINGTRIE_HAS_NEXT(result)) {
+ return 0;
+ }
+ }
+ return -1;
+ }
+ c = next;
+ }
+}
+
+UBool LocaleDistance::isParadigmLSR(const LSR &lsr) const {
+ // Linear search for a very short list (length 6 as of 2019).
+ // If there are many paradigm LSRs we should use a hash set.
+ U_ASSERT(paradigmLSRsLength <= 15);
+ for (int32_t i = 0; i < paradigmLSRsLength; ++i) {
+ if (lsr == paradigmLSRs[i]) { return true; }
+ }
+ return false;
+}
+
+U_NAMESPACE_END
projects / apple / icu.git / blobdiff