ENHANCED: Read more characters at once, significantly speeding up library(pio).

src/lib/pio.pl

@@ -22,67 +22,21 @@ phrase_from_file(NT, File, Options) :-
         ;   Type = text
         ),
         setup_call_cleanup(open(File, read, Stream, [reposition(true)|Options]),
-                           (   stream_to_lazy_list(pio:Type, Stream, Xs),
+                           (   stream_to_lazy_list(Stream, Xs),
                                phrase(NT, Xs) ),
                            close(Stream))
    ).
 
 
-stream_to_lazy_list(Type_3, Stream, Xs) :-
+stream_to_lazy_list(Stream, Xs) :-
         stream_property(Stream, position(Pos)),
-        freeze(Xs, reader_step(Type_3, Stream, Pos, Xs)).
+        freeze(Xs, reader_step(Stream, Pos, Xs)).
 
-reader_step(Type_3, Stream, Pos, Xs0) :-
+reader_step(Stream, Pos, Xs0) :-
         set_stream_position(Stream, Pos),
         (   at_end_of_stream(Stream)
         ->  Xs0 = []
-        ;   % phrase(call(call(Type_3,Stream)), Xs0,Xs), % conforming call
-            call(Type_3, Stream, Cs,[]), % effective call
+        ;   '$get_n_chars'(Stream, 4096, Cs),
             partial_string(Cs, Xs0, Xs),
-            stream_to_lazy_list(Type_3, Stream, Xs)
+            stream_to_lazy_list(Stream, Xs)
         ).
-
-binary(Stream, Xs0, Xs) :- get_pending_bytes(Stream, Xs0, Xs).
-text(Stream, Xs0, Xs)   :- get_pending_chars(Stream, Xs0, Xs).
-
-
-get_pending_chars(Stream, Chs0,Chs) :-
-        n_get_chars(4096, Stream, Chs, Chs0,Chs).
-
-% EOF means: If EOF == [], then EOF has definitely been reached, otherwise
-% it is unknown and the argument remains uninstantiated.
-
-% To improve performance, the following predicates should be replaced
-% by a fast Rust implementation that reads a number of characters (or
-% bytes) at once.
-
-% Files that do not contain 0-bytes can even be mmapped to memory.
-
-n_get_chars(N0, Stream, EOF, Chs0,Chs) :-
-        N0 > 0,
-        N1 is N0-1,
-        get_char(Stream, Ch),
-        (   Ch == end_of_file
-        ->  Chs0 = Chs,
-            EOF = []
-        ;   Chs0 = [Ch|Chs1],
-            n_get_chars(N1, Stream, EOF, Chs1,Chs)
-        ).
-n_get_chars(0, _, _, Chs,Chs).
-
-
-get_pending_bytes(Stream, Chs0,Chs) :-
-        n_get_bytes(4096, Stream, Chs, Chs0,Chs).
-
-n_get_bytes(N0, Stream, EOF, Chs0,Chs) :-
-        N0 > 0,
-        N1 is N0-1,
-        get_byte(Stream, Byte),
-        (   Byte == -1
-        ->  Chs0 = Chs,
-            EOF = []
-        ;   char_code(Ch, Byte),
-            Chs0 = [Ch|Chs1],
-            n_get_bytes(N1, Stream, EOF, Chs1,Chs)
-        ).
-n_get_bytes(0, _, _, Chs,Chs).