240 lines
7.7 KiB
C++
240 lines
7.7 KiB
C++
// © 2019 and later: Unicode, Inc. and others.
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// License & terms of use: http://www.unicode.org/copyright.html
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// localeprioritylist.cpp
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// created: 2019jul11 Markus W. Scherer
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#include "unicode/utypes.h"
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#include "unicode/localpointer.h"
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#include "unicode/locid.h"
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#include "unicode/stringpiece.h"
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#include "unicode/uobject.h"
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#include "charstr.h"
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#include "cmemory.h"
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#include "localeprioritylist.h"
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#include "uarrsort.h"
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#include "uassert.h"
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#include "uhash.h"
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U_NAMESPACE_BEGIN
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namespace {
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int32_t hashLocale(const UHashTok token) {
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const auto* locale = static_cast<const Locale*>(token.pointer);
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return locale->hashCode();
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}
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UBool compareLocales(const UHashTok t1, const UHashTok t2) {
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const auto* l1 = static_cast<const Locale*>(t1.pointer);
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const auto* l2 = static_cast<const Locale*>(t2.pointer);
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return *l1 == *l2;
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}
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constexpr int32_t WEIGHT_ONE = 1000;
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struct LocaleAndWeight {
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Locale *locale;
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int32_t weight; // 0..1000 = 0.0..1.0
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int32_t index; // force stable sort
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int32_t compare(const LocaleAndWeight &other) const {
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int32_t diff = other.weight - weight; // descending: other-this
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if (diff != 0) { return diff; }
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return index - other.index;
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}
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};
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int32_t U_CALLCONV
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compareLocaleAndWeight(const void * /*context*/, const void *left, const void *right) {
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return static_cast<const LocaleAndWeight *>(left)->
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compare(*static_cast<const LocaleAndWeight *>(right));
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}
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const char *skipSpaces(const char *p, const char *limit) {
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while (p < limit && *p == ' ') { ++p; }
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return p;
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}
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int32_t findTagLength(const char *p, const char *limit) {
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// Look for accept-language delimiters.
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// Leave other validation up to the Locale constructor.
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const char *q;
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for (q = p; q < limit; ++q) {
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char c = *q;
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if (c == ' ' || c == ',' || c == ';') { break; }
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}
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return static_cast<int32_t>(q - p);
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}
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/**
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* Parses and returns a qvalue weight in millis.
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* Advances p to after the parsed substring.
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* Returns a negative value if parsing fails.
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*/
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int32_t parseWeight(const char *&p, const char *limit) {
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p = skipSpaces(p, limit);
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char c;
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if (p == limit || ((c = *p) != '0' && c != '1')) { return -1; }
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int32_t weight = (c - '0') * 1000;
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if (++p == limit || *p != '.') { return weight; }
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int32_t multiplier = 100;
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while (++p != limit && '0' <= (c = *p) && c <= '9') {
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c -= '0';
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if (multiplier > 0) {
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weight += c * multiplier;
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multiplier /= 10;
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} else if (multiplier == 0) {
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// round up
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if (c >= 5) { ++weight; }
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multiplier = -1;
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} // else ignore further fraction digits
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}
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return weight <= WEIGHT_ONE ? weight : -1; // bad if > 1.0
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}
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} // namespace
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/**
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* Nothing but a wrapper over a MaybeStackArray of LocaleAndWeight.
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*
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* This wrapper exists (and is not in an anonymous namespace)
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* so that we can forward-declare it in the header file and
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* don't have to expose the MaybeStackArray specialization and
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* the LocaleAndWeight to code (like the test) that #includes localeprioritylist.h.
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* Also, otherwise we would have to do a platform-specific
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* template export declaration of some kind for the MaybeStackArray specialization
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* to be properly exported from the common DLL.
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*/
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struct LocaleAndWeightArray : public UMemory {
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MaybeStackArray<LocaleAndWeight, 20> array;
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};
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LocalePriorityList::LocalePriorityList(StringPiece s, UErrorCode &errorCode) {
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if (U_FAILURE(errorCode)) { return; }
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list = new LocaleAndWeightArray();
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if (list == nullptr) {
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errorCode = U_MEMORY_ALLOCATION_ERROR;
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return;
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}
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const char *p = s.data();
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const char *limit = p + s.length();
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while ((p = skipSpaces(p, limit)) != limit) {
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if (*p == ',') { // empty range field
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++p;
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continue;
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}
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int32_t tagLength = findTagLength(p, limit);
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if (tagLength == 0) {
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errorCode = U_ILLEGAL_ARGUMENT_ERROR;
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return;
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}
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CharString tag(p, tagLength, errorCode);
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if (U_FAILURE(errorCode)) { return; }
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Locale locale = Locale(tag.data());
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if (locale.isBogus()) {
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errorCode = U_ILLEGAL_ARGUMENT_ERROR;
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return;
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}
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int32_t weight = WEIGHT_ONE;
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if ((p = skipSpaces(p + tagLength, limit)) != limit && *p == ';') {
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if ((p = skipSpaces(p + 1, limit)) == limit || *p != 'q' ||
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(p = skipSpaces(p + 1, limit)) == limit || *p != '=' ||
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(++p, (weight = parseWeight(p, limit)) < 0)) {
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errorCode = U_ILLEGAL_ARGUMENT_ERROR;
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return;
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}
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p = skipSpaces(p, limit);
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}
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if (p != limit && *p != ',') { // trailing junk
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errorCode = U_ILLEGAL_ARGUMENT_ERROR;
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return;
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}
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add(locale, weight, errorCode);
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if (p == limit) { break; }
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++p;
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}
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sort(errorCode);
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}
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LocalePriorityList::~LocalePriorityList() {
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if (list != nullptr) {
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for (int32_t i = 0; i < listLength; ++i) {
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delete list->array[i].locale;
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}
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delete list;
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}
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uhash_close(map);
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}
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const Locale *LocalePriorityList::localeAt(int32_t i) const {
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return list->array[i].locale;
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}
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Locale *LocalePriorityList::orphanLocaleAt(int32_t i) {
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if (list == nullptr) { return nullptr; }
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LocaleAndWeight &lw = list->array[i];
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Locale *l = lw.locale;
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lw.locale = nullptr;
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return l;
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}
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bool LocalePriorityList::add(const Locale &locale, int32_t weight, UErrorCode &errorCode) {
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if (U_FAILURE(errorCode)) { return false; }
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if (map == nullptr) {
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if (weight <= 0) { return true; } // do not add q=0
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map = uhash_open(hashLocale, compareLocales, uhash_compareLong, &errorCode);
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if (U_FAILURE(errorCode)) { return false; }
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}
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LocalPointer<Locale> clone;
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UBool found = false;
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int32_t index = uhash_getiAndFound(map, &locale, &found);
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if (found) {
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// Duplicate: Remove the old item and append it anew.
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LocaleAndWeight &lw = list->array[index];
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clone.adoptInstead(lw.locale);
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lw.locale = nullptr;
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lw.weight = 0;
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++numRemoved;
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}
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if (weight <= 0) { // do not add q=0
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if (found) {
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// Not strictly necessary but cleaner.
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uhash_removei(map, &locale);
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}
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return true;
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}
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if (clone.isNull()) {
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clone.adoptInstead(locale.clone());
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if (clone.isNull() || (clone->isBogus() && !locale.isBogus())) {
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errorCode = U_MEMORY_ALLOCATION_ERROR;
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return false;
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}
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}
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if (listLength == list->array.getCapacity()) {
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int32_t newCapacity = listLength < 50 ? 100 : 4 * listLength;
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if (list->array.resize(newCapacity, listLength) == nullptr) {
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errorCode = U_MEMORY_ALLOCATION_ERROR;
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return false;
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}
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}
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uhash_putiAllowZero(map, clone.getAlias(), listLength, &errorCode);
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if (U_FAILURE(errorCode)) { return false; }
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LocaleAndWeight &lw = list->array[listLength];
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lw.locale = clone.orphan();
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lw.weight = weight;
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lw.index = listLength++;
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if (weight < WEIGHT_ONE) { hasWeights = true; }
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U_ASSERT(uhash_count(map) == getLength());
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return true;
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}
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void LocalePriorityList::sort(UErrorCode &errorCode) {
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// Sort by descending weights if there is a mix of weights.
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// The comparator forces a stable sort via the item index.
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if (U_FAILURE(errorCode) || getLength() <= 1 || !hasWeights) { return; }
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uprv_sortArray(list->array.getAlias(), listLength, sizeof(LocaleAndWeight),
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compareLocaleAndWeight, nullptr, false, &errorCode);
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}
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U_NAMESPACE_END
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