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// © 2019 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
// localeprioritylist.h
// created: 2019jul11 Markus W. Scherer
#ifndef __LOCALEPRIORITYLIST_H__
#define __LOCALEPRIORITYLIST_H__
#include "unicode/utypes.h"
#include "unicode/locid.h"
#include "unicode/stringpiece.h"
#include "unicode/uobject.h"
struct UHashtable;
U_NAMESPACE_BEGIN
struct LocaleAndWeightArray;
/**
* Parses a list of locales from an accept-language string.
* We are a bit more lenient than the spec:
* We accept extra whitespace in more places, empty range fields,
* and any number of qvalue fraction digits.
*
* https://tools.ietf.org/html/rfc2616#section-14.4
* 14.4 Accept-Language
*
* Accept-Language = "Accept-Language" ":"
* 1#( language-range [ ";" "q" "=" qvalue ] )
* language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" )
*
* Each language-range MAY be given an associated quality value which
* represents an estimate of the user's preference for the languages
* specified by that range. The quality value defaults to "q=1". For
* example,
*
* Accept-Language: da, en-gb;q=0.8, en;q=0.7
*
* https://tools.ietf.org/html/rfc2616#section-3.9
* 3.9 Quality Values
*
* HTTP content negotiation (section 12) uses short "floating point"
* numbers to indicate the relative importance ("weight") of various
* negotiable parameters. A weight is normalized to a real number in
* the range 0 through 1, where 0 is the minimum and 1 the maximum
* value. If a parameter has a quality value of 0, then content with
* this parameter is `not acceptable' for the client. HTTP/1.1
* applications MUST NOT generate more than three digits after the
* decimal point. User configuration of these values SHOULD also be
* limited in this fashion.
*
* qvalue = ( "0" [ "." 0*3DIGIT ] )
* | ( "1" [ "." 0*3("0") ] )
*/
class U_COMMON_API LocalePriorityList : public UMemory {
public:
class Iterator : public Locale::Iterator {
public:
UBool hasNext() const override { return count < length; }
const Locale &next() override {
for(;;) {
const Locale *locale = list.localeAt(index++);
if (locale != nullptr) {
++count;
return *locale;
}
}
}
private:
friend class LocalePriorityList;
Iterator(const LocalePriorityList &list) : list(list), length(list.getLength()) {}
const LocalePriorityList &list;
int32_t index = 0;
int32_t count = 0;
const int32_t length;
};
LocalePriorityList(StringPiece s, UErrorCode &errorCode);
~LocalePriorityList();
int32_t getLength() const { return listLength - numRemoved; }
int32_t getLengthIncludingRemoved() const { return listLength; }
Iterator iterator() const { return Iterator(*this); }
const Locale *localeAt(int32_t i) const;
Locale *orphanLocaleAt(int32_t i);
private:
LocalePriorityList(const LocalePriorityList &) = delete;
LocalePriorityList &operator=(const LocalePriorityList &) = delete;
bool add(const Locale &locale, int32_t weight, UErrorCode &errorCode);
void sort(UErrorCode &errorCode);
LocaleAndWeightArray *list = nullptr;
int32_t listLength = 0;
int32_t numRemoved = 0;
bool hasWeights = false; // other than 1.0
UHashtable *map = nullptr;
};
U_NAMESPACE_END
#endif // __LOCALEPRIORITYLIST_H__
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