added LanguageTag::getFallbackStrings()

Change-Id: Ia597cb184e0402e776cde50967541f008e22d4c9

i18npool/inc/i18npool/languagetag.hxx

@@ -16,6 +16,8 @@
 #include <i18npool/i18npooldllapi.h>
 #include <i18npool/lang.h>
 
+#include <vector>
+
 typedef struct _rtl_Locale rtl_Locale;  // as in rtl/locale.h
 
 
@@ -212,6 +214,25 @@ public:
      */
     LanguageTag &                   makeFallback();
 
+    /** Return a vector of fall-back strings.
+
+        In order:
+        full BCP 47 tag, same as getBcp47()
+        lll-Ssss-CC
+        lll-Ssss
+        lll-CC
+        lll
+
+        Only strings that differ from a higher order are included, for example
+        if there is no script the elements will be bcp47, lll-CC, lll; if the
+        bcp47 string is identical to lll-CC then only lll-CC, lll.
+
+        Note that lll is only ISO 639-1/2 alpha code and CC is only ISO 3166
+        alpha code. If the region can not be expressed as ISO 3166 then no -CC
+        tags are included.
+     */
+    ::std::vector< OUString >       getFallbackStrings() const;
+
     /* Test equality of two LangageTag. */
     bool    operator==( const LanguageTag & rLanguageTag ) const;
 

i18npool/source/languagetag/languagetag.cxx

@@ -1003,6 +1003,46 @@ LanguageTag & LanguageTag::makeFallback()
 }
 
 
+::std::vector< OUString > LanguageTag::getFallbackStrings() const
+{
+    ::std::vector< OUString > aVec;
+    OUString aLanguage( getLanguage());
+    OUString aCountry( getCountry());
+    if (isIsoLocale())
+    {
+        if (!aCountry.isEmpty())
+            aVec.push_back( aLanguage + "-" + aCountry);
+        aVec.push_back( aLanguage);
+        return aVec;
+    }
+    aVec.push_back( getBcp47());
+    OUString aTmp;
+    if (hasScript())
+    {
+        OUString aScript( getScript());
+        if (!aCountry.isEmpty())
+        {
+            aTmp = aLanguage + "-" + aScript + "-" + aCountry;
+            if (aTmp != aVec[0])
+                aVec.push_back( aTmp);
+        }
+        aTmp = aLanguage + "-" + aScript;
+        if (aTmp != aVec[0])
+            aVec.push_back( aTmp);
+    }
+    if (!aCountry.isEmpty())
+    {
+        aTmp = aLanguage + "-" + aCountry;
+        if (aTmp != aVec[0])
+            aVec.push_back( aTmp);
+    }
+    aTmp = aLanguage;
+    if (aTmp != aVec[0])
+        aVec.push_back( aTmp);
+    return aVec;
+}
+
+
 bool LanguageTag::operator==( const LanguageTag & rLanguageTag ) const
 {
     // Compare full language tag strings but SYSTEM unresolved.