[fclang] Implement FcLangSetGetLangs() (#18846)

doc/fclangset.fncs

@@ -123,6 +123,14 @@ function returns FcLangDiffentTerritory. If <parameter>ls</parameter>
 has no matching language, this function returns FcLangDifferentLang.
 @@
 
+@RET@		FcStrSet *
+@FUNC@		FcLangSetGetLangs
+@TYPE1@		const FcLangSet *		@ARG1@		ls
+@PURPOSE@	get the list of languages in the langset
+@DESC@
+Returns a string set of all languages in <parameter>langset</parameter>.
+@@
+
 @RET@		FcStrSet *
 @FUNC@		FcGetLangs
 @TYPE1@		void

fontconfig/fontconfig.h

@@ -597,6 +597,9 @@ FcLangSetEqual (const FcLangSet *lsa, const FcLangSet *lsb);
 FcPublic FcChar32
 FcLangSetHash (const FcLangSet *ls);
 
+FcPublic FcStrSet *
+FcLangSetGetLangs (const FcLangSet *ls);
+
 /* fclist.c */
 FcPublic FcObjectSet *
 FcObjectSetCreate (void);

src/fclang.c

@@ -744,6 +744,38 @@ FcLangSetSerialize(FcSerialize *serialize, const FcLangSet *l)
     *l_serialize = *l;
     return l_serialize;
 }
+
+FcStrSet *
+FcLangSetGetLangs (const FcLangSet *ls)
+{
+    FcStrSet *langs;
+    int	      i;
+
+    langs = FcStrSetCreate();
+    if (!langs)
+	return 0;
+
+    for (i = 0; i < NUM_LANG_CHAR_SET; i++)
+	if (FcLangSetBitGet (ls, i))
+	    FcStrSetAdd (langs, fcLangCharSets[i].lang);
+
+    if (ls->extra)
+    {
+	FcStrList	*list = FcStrListCreate (ls->extra);
+	FcChar8		*extra;
+
+	if (list)
+	{
+	    while ((extra = FcStrListNext (list)))
+		FcStrSetAdd (langs, extra);
+
+	    FcStrListDone (list);
+	}
+    }
+
+    return langs;
+}
+
 #define __fclang__
 #include "fcaliastail.h"
 #include "fcftaliastail.h"