ugly, but does read/write bytes

Author: [email protected]

src/lib/charsio.pl

@@ -423,7 +423,85 @@
 %    Stream = stream('$memory_stream'(2048)).
 % ```
 
-chars_to_stream(Chars, Stream, _) :-
-        must_be(chars, Chars),
+chars_to_stream(Chars, Stream, StreamOpts) :-
+        parse_stream_options(StreamOpts, [Alias, EOFAction, Reposition, Type]),
         '$memory_stream'(Stream),
-        maplist(put_char(Stream), Chars).
+        '$set_stream_options'(Stream, Alias ,EOFAction, Reposition, Type),
+        (   Type=binary
+        ->  maplist(put_byte(Stream), Chars)
+        ;   maplist(put_char(Stream), Chars)
+        ).
+
+%% ugly ripoff of parser from library(builtins).
+
+:- meta_predicate parse_options_list(?, 2, ?, ?, ?).
+
+parse_options_list(Options, Selector, DefaultPairs, OptionValues, Stub) :-
+    '$skip_max_list'(_, _, Options, Tail),
+    (  Tail == [] ->
+       true
+    ;  var(Tail) ->
+       throw(error(instantiation_error, Stub))       % 8.11.5.3c)
+    ;  Tail \== [] ->
+       throw(error(type_error(list, Options), Stub)) % 8.11.5.3e)
+    ),
+    (  lists:maplist('$call'(nonvar), Options), % need '$call' because
+                                                % maplist isn't
+                                                % declared as a
+                                                % meta-predicate yet
+       catch(lists:maplist(Selector, Options, OptionPairs0),
+             error(E, _),
+             builtins:throw(error(E, Stub))) ->
+       lists:append(DefaultPairs, OptionPairs0, OptionPairs1),
+       keysort(OptionPairs1, OptionPairs),
+       select_rightmost_options(OptionPairs, OptionValues)
+    ;
+       throw(error(instantiation_error, Stub))       % 8.11.5.3c)
+    ).
+
+parse_stream_options_(type(Type), type-Type) :-
+    (  var(Type) ->
+       throw(error(instantiation_error, open/4)) % 8.1.3 7)
+    ;
+       lists:member(Type, [text, binary]), !
+    ;
+       throw(error(domain_error(stream_option, type(Type)), _))
+    ).
+parse_stream_options_(reposition(Bool), reposition-Bool) :-
+    (  nonvar(Bool), lists:member(Bool, [true, false]), !
+    ;
+       throw(error(domain_error(stream_option, reposition(Bool)), _))
+    ).
+
+parse_stream_options_(alias(A), alias-A) :-
+
+    (  var(A) ->
+       throw(error(instantiation_error, open/4)) % 8.1.3 7)
+    ;
+       atom(A), A \== [] -> true
+    ;
+       throw(error(domain_error(stream_option, alias(A)), _))
+    ).
+parse_stream_options_(eof_action(Action), eof_action-Action) :-
+    (  nonvar(Action), lists:member(Action, [eof_code, error, reset]), !
+    ;
+       throw(error(domain_error(stream_option, eof_action(Action)), _))
+    ).
+parse_stream_options_(E, _) :-
+        throw(error(domain_error(stream_option, E), _)). % 8.11.5.3i) %
+
+parse_stream_options(Options, OptionValues) :-
+    DefaultOptions = [alias-[], eof_action-eof_code, reposition-false, type-text],
+    parse_options_list(Options, parse_stream_options_, DefaultOptions, OptionValues, chars_to_stream/3).
+
+
+select_rightmost_options([Option-Value | OptionPairs], OptionValues) :-
+    (  pairs:same_key(Option, OptionPairs, OtherValues, _),
+       OtherValues == []  ->
+       OptionValues = [Value | OptionValues0],
+       select_rightmost_options(OptionPairs, OptionValues0)
+    ;
+       select_rightmost_options(OptionPairs, OptionValues)
+    ).
+
+select_rightmost_options([], []).

src/tests/charsio.pl

@@ -1,4 +1,6 @@
 :- module(charsio_tests, []).
+:- use_module(library(os)).
+:- use_module(library(iso_ext)).
 :- use_module(library(debug)).
 :- use_module(library(lists)).
 :- use_module(library(charsio)).
@@ -56,3 +58,26 @@
       get_n_chars(Stream, N, Chars),
       Phrase=Chars
      )).
+
+
+test("can read/write bytes",
+     (
+      A=97,
+      B=98,
+      C=99,
+      chars_to_stream([A,B,C], Stream, [type(binary)]),
+      get_byte(Stream, A),
+      get_byte(Stream, B),
+      get_byte(Stream, C),
+      put_byte(Stream, A),
+      put_byte(Stream, B),
+      put_byte(Stream, C),
+      get_byte(Stream, A),
+      get_byte(Stream, B),
+      get_byte(Stream, C)
+      )).
+
+
+
+% ?- test_framework:main(charsio_tests). 
+