Langkit_Support.Text: add a function to decode strings to text

TN: RA02-064

Author: pmderodat

langkit/support/langkit_support-text.adb

@@ -164,4 +164,21 @@ package body Langkit_Support.Text is
          From_Code => Text_Charset);
    end Encode;
 
+   ------------
+   -- Decode --
+   ------------
+
+   function Decode (S : String; Charset : String) return Text_Type is
+      Result : constant String := GNATCOLL.Iconv.Iconv
+        (Input     => S,
+         To_Code   => Text_Charset,
+         From_Code => Charset);
+      pragma Assert (S'Length mod 4 = 0);
+
+      Text_Result : constant Text_Type (1 .. Result'Length / 4)
+         with Import, Address => Result'Address;
+   begin
+      return Text_Result;
+   end Decode;
+
 end Langkit_Support.Text;

langkit/support/langkit_support-text.ads

@@ -62,9 +62,12 @@ package Langkit_Support.Text is
    function Encode (Text : Text_Type; Charset : String) return String;
    --  Use GNATCOLL.Iconv to convert Text into a String encoded using the given
    --  Charset. Note that this is only a convenience wrapper around
-   --  GNATCOLL.Iconv: for instance, if performance needs dictatet to avoid
+   --  GNATCOLL.Iconv: for instance, if performance needs dictate to avoid
    --  secondary stack usage, please use directly GNATCOLL.Iconv.
 
+   function Decode (S : String; Charset : String) return Text_Type;
+   --  Likewise, but convert a string to text
+
    type Text_Access is access all Text_Type;
    type Text_Cst_Access is access constant Text_Type;