utf8 and utf16le streams

core/io/encodings/encodings.factor

@@ -36,14 +36,22 @@ SYMBOL: begin
 
 : full? ( resizable -- ? ) space zero? ;
 
-: decode-part-loop ( buf ch state stream quot -- string )
+: end-read-loop ( buf ch state stream quot -- string/f )
-    >r >r pick r> r> rot full?
+    2drop 2drop >string f like ;
-    [ 2drop 2drop >string ]
-    [ [ >r stream-read1 -rot r> call ] 2keep decode-part-loop ] if ; inline
 
-: decode-part ( length stream quot -- string )
+: under ( a b c -- c a b c )
+    tuck >r swapd r> ; inline
+
+: decode-read-loop ( buf ch state stream quot -- string/f )
+    >r >r pick r> r> rot full?  [ end-read-loop ] [
+        over stream-read1 [
+            -rot tuck >r >r >r -rot r> call r> r> decode-read-loop
+        ] [ end-read-loop ] if*
+    ] if ; inline
+
+: decode-read ( length stream quot -- string )
     >r swap start-decoding r>
-    decode-part-loop ; inline
+    decode-read-loop ; inline
 
 GENERIC: init-decoding ( stream encoding -- decoded-stream )
 

core/io/encodings/utf16/utf16.factor

@@ -114,3 +114,35 @@ SYMBOL: ignore
         { [ utf16be? ] [ decode-utf16be ] }
         { [ t ] [ decode-error ] }
     } cond ;
+
+! UTF16LE streams
+
+TUPLE: utf16le ;
+: <utf16le> utf16le construct-delegate ;
+! In the future, this should detect and ignore a BOM at the beginning
+
+M: utf16le init-decoding ( stream utf16le -- utf16le-stream )
+    tuck set-delegate ;
+
+M: utf16le init-encoding ( stream utf16le -- utf16le-stream )
+    tuck set-delegate ;
+
+M: utf16le stream-read1 1 swap stream-read ;
+
+M: utf16le stream-read
+    delegate [ decode-utf16le-step ] decode-read ;
+
+M: utf16le stream-read-partial stream-read ;
+
+M: utf16le stream-read-until
+    ! Copied from { c-reader stream-read-until }!!!
+    [ swap read-until-loop ] "" make
+    swap over empty? over not and [ 2drop f f ] when ;
+
+M: utf16le stream-write1
+    >r 1string r> stream-write ;
+
+M: utf16le stream-write
+    >r encode-utf16le r> delegate stream-write ;
+
+M: utf16le dispose delegate dispose ;

core/io/encodings/utf8/utf8.factor

@@ -90,7 +90,9 @@ M: utf8 init-encoding ( stream utf8 -- utf8-stream )
 M: utf8 stream-read1 1 swap stream-read ;
 
 M: utf8 stream-read
-    [ decode-utf8-step ] decode-part ;
+    delegate [ decode-utf8-step ] decode-read ;
+
+M: utf8 stream-read-partial stream-read ;
 
 M: utf8 stream-read-until
     ! Copied from { c-reader stream-read-until }!!!