ICU4N.Text.TransliteratorIDParser::IDtoSTV(): Converted return array …

…to out parameters

src/ICU4N.Transliterator/Text/Transliterator.cs

@@ -1301,16 +1301,18 @@ public static string GetDisplayName(string id, UCultureInfo inLocale)
                 GetBundleInstance(ICUData.IcuTransliteratorBaseName, inLocale, ICUResourceBundle.IcuDataAssembly);
 
             // Normalize the ID
-            string[] stv = TransliteratorIDParser.IDtoSTV(id);
-            if (stv == null)
+            TransliteratorIDParser.IDtoSTV(id, out string source, out string target, out string variant, out bool _);
+            // ICU4N specific - since we are not returning an array, it cannot be null (and it was never null anyway)
+
+            // ICU4N specific - use Concat
+            string ID;
+            if (!string.IsNullOrEmpty(variant))
             {
-                // No target; malformed id
-                return "";
+                ID = string.Concat(source, "-", target, "/", variant);
             }
-            string ID = stv[0] + '-' + stv[1];
-            if (stv[2] != null && stv[2].Length > 0)
+            else
             {
-                ID = ID + '/' + stv[2];
+                ID = string.Concat(source, "-", target);
             }
 
             // Use the registered display name, if any
@@ -1335,7 +1337,7 @@ public static string GetDisplayName(string id, UCultureInfo inLocale)
                         bundle.GetString(RB_DISPLAY_NAME_PATTERN));
 
                 // Construct the argument array
-                object[] args = new object[] { 2, stv[0], stv[1] };
+                object[] args = new object[] { 2, source, target };
 
                 // Use display names for the scripts, if they exist
                 for (int j = 1; j <= 2; ++j)
@@ -1349,8 +1351,8 @@ public static string GetDisplayName(string id, UCultureInfo inLocale)
                 }
 
                 // Format it using the pattern in the resource
-                return (stv[2].Length > 0) ?
-                    (format.Format(args) + '/' + stv[2]) :
+                return (variant.Length > 0) ?
+                    (format.Format(args) + '/' + variant) :
                     format.Format(args);
             }
             catch (MissingManifestResourceException) { }

src/ICU4N.Transliterator/Text/TransliteratorIDParser.cs

@@ -522,24 +522,25 @@ internal static IList<Transliterator> InstantiateList(IList<SingleID> ids)
         /// ANY.
         /// </summary>
         /// <param name="id">The id string, in any of several forms.</param>
-        /// <returns>An array of 4 strings: source, target, variant, and
-        /// isSourcePresent.  If the source is not present, ANY will be
-        /// given as the source, and isSourcePresent will be null.  Otherwise
-        /// isSourcePresent will be non-null.  The target may be empty if the
-        /// id is not well-formed.  The variant may be empty.</returns>
-        public static string[] IDtoSTV(string id)
+        /// <param name="source">When this method returns, provides the source from the <paramref name="id"/>.</param>
+        /// <param name="target">When this method returns, provides the target from the <paramref name="id"/>.
+        /// The target may be empty if the id is not well-formed.</param>
+        /// <param name="variant">When this method returns, provides the variant from the <paramref name="id"/>.
+        /// The variant may be empty.</param>
+        /// <param name="isSourcePresent">When this method returns, provides a boolean value indicating whether source is present.</param>
+        public static void IDtoSTV(string id, out string source, out string target, out string variant, out bool isSourcePresent)
         {
-            string source = ANY;
-            string target = null;
-            string variant = "";
+            source = ANY;
+            target = null;
+            variant = "";
 
             int sep = id.IndexOf(TARGET_SEP);
             int var = id.IndexOf(VARIANT_SEP);
             if (var < 0)
             {
                 var = id.Length;
             }
-            bool isSourcePresent = false;
+            isSourcePresent = false;
 
             if (sep < 0)
             {
@@ -574,9 +575,6 @@ public static string[] IDtoSTV(string id)
             {
                 variant = variant.Substring(1);
             }
-
-            return new string[] { source, target, variant,
-                              isSourcePresent ? "" : null };
         }
 
         /// <summary>

src/ICU4N.Transliterator/Text/TransliteratorRegistry.cs

@@ -406,11 +406,11 @@ public virtual void Put(string id,
         /// </summary>
         public virtual void Remove(string id)
         {
-            string[] stv = TransliteratorIDParser.IDtoSTV(id);
+            TransliteratorIDParser.IDtoSTV(id, out string stv0, out string stv1, out string stv2, out bool _);
             // Only need to do this if ID.indexOf('-') < 0
-            string id2 = TransliteratorIDParser.STVtoID(stv[0], stv[1], stv[2]);
+            string id2 = TransliteratorIDParser.STVtoID(stv0, stv1, stv2);
             registry.Remove(new CaseInsensitiveString(id2));
-            RemoveSTV(stv[0], stv[1], stv[2]);
+            RemoveSTV(stv0, stv1, stv2);
             availableIDs.Remove(new CaseInsensitiveString(id2));
         }
 
@@ -540,10 +540,10 @@ private void RegisterEntry(string ID,
                                    object entry,
                                    bool visible)
         {
-            string[] stv = TransliteratorIDParser.IDtoSTV(ID);
+            TransliteratorIDParser.IDtoSTV(ID, out string stv0, out string stv1, out string stv2, out bool _);
             // Only need to do this if ID.indexOf('-') < 0
-            string id = TransliteratorIDParser.STVtoID(stv[0], stv[1], stv[2]);
-            RegisterEntry(id, stv[0], stv[1], stv[2], entry, visible);
+            string id = TransliteratorIDParser.STVtoID(stv0, stv1, stv2);
+            RegisterEntry(id, stv0, stv1, stv2, entry, visible);
         }
 
         /// <summary>
@@ -822,8 +822,8 @@ private object[] FindInBundle(Spec specToOpen,
         /// <returns></returns>
         private object[] Find(string ID)
         {
-            string[] stv = TransliteratorIDParser.IDtoSTV(ID);
-            return Find(stv[0], stv[1], stv[2]);
+            TransliteratorIDParser.IDtoSTV(ID, out string stv0, out string stv1, out string stv2, out bool _);
+            return Find(stv0, stv1, stv2);
         }
 
         /// <summary>