add static LanguageTag::isValidBcp47()

Change-Id: I2c646b3e2f13a6fccc845ce8eb82fccee154f3c6

2 files changed, 56 insertions, 0 deletions

diff --git a/i18nlangtag/source/languagetag/languagetag.cxx b/i18nlangtag/source/languagetag/languagetag.cxx
index 33816b3c7e0f..8a96bde83f81 100644
--- a/i18nlangtag/source/languagetag/languagetag.cxx
+++ b/i18nlangtag/source/languagetag/languagetag.cxx
@@ -2685,4 +2685,44 @@ com::sun::star::lang::Locale LanguageTag::convertToLocaleWithFallback( const OUS
     return LanguageTag( rBcp47).makeFallback().getLocale( true);
 }
 
+
+// static
+bool LanguageTag::isValidBcp47( const OUString& rString, OUString* o_pCanonicalized )
+{
+    struct guard
+    {
+        lt_tag_t* mpLangtag;
+        guard()
+        {
+            theDataRef::get().incRef();
+            mpLangtag = lt_tag_new();
+        }
+        ~guard()
+        {
+            lt_tag_unref( mpLangtag);
+            theDataRef::get().decRef();
+        }
+    } aVar;
+
+    myLtError aError;
+
+    if (lt_tag_parse( aVar.mpLangtag, OUStringToOString( rString, RTL_TEXTENCODING_UTF8).getStr(), &aError.p))
+    {
+        char* pTag = lt_tag_canonicalize( aVar.mpLangtag, &aError.p);
+        SAL_WARN_IF( !pTag, "i18nlangtag", "LanguageTag:isValidBcp47: could not canonicalize '" << rString << "'");
+        if (pTag)
+        {
+            if (o_pCanonicalized)
+                *o_pCanonicalized = OUString::createFromAscii( pTag);
+            free( pTag);
+            return true;
+        }
+    }
+    else
+    {
+        SAL_INFO( "i18nlangtag", "LanguageTag:isValidBcp47: could not parse '" << rString << "'");
+    }
+    return false;
+}
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/include/i18nlangtag/languagetag.hxx b/include/i18nlangtag/languagetag.hxx
index dcb95c61d911..0e12235c34ba 100644
--- a/include/i18nlangtag/languagetag.hxx
+++ b/include/i18nlangtag/languagetag.hxx
@@ -228,6 +228,8 @@ public:
     /** If this is a valid BCP 47 language tag.
 
         Always resolves an empty tag to the system locale.
+
+        @seealso    static bool isValidBcp47(const OUString&)
      */
     bool                            isValidBcp47() const;
 
@@ -479,6 +481,20 @@ public:
      */
     static com::sun::star::lang::Locale convertToLocaleWithFallback( const OUString& rBcp47 );
 
+    /** If rString represents a valid BCP 47 language tag.
+
+        Never resolves an empty tag to the system locale, in fact an empty
+        string is invalid here. Does not create an instance to be registered
+        with a conversion to Locale or LanguageType.
+
+        @param  o_pCanonicalized
+                If given and rString is a valid BCP 47 language tag, the
+                canonicalized form is assigned, which may differ from the
+                original string even if that was a valid tag. If rString is not
+                a valid tag, nothing is assigned.
+     */
+    static bool         isValidBcp47( const OUString& rString, OUString* o_pCanonicalized = NULL );
+
     /** If nLang is a generated on-the-fly LangID */
     static bool         isOnTheFlyID( LanguageType nLang );