ref: d81447526cde6fa98dfa792a65f71acb78ef1398
parent: 8dd4f85c85aa9ab7a5f1219efd694e6707f2718c
author: Peter Mikkelsen <peter@pmikkelsen.com>
date: Fri Jul 2 18:01:59 EDT 2021
Start work on input/output streams
--- a/builtins.c
+++ b/builtins.c
@@ -35,6 +35,12 @@
BuiltinProto(builtinthrow);
BuiltinProto(builtinsetprologflag);
BuiltinProto(builtincurrentprologflag);
+BuiltinProto(builtinopen);
+BuiltinProto(builtinclose);
+BuiltinProto(builtincurrentinput);
+BuiltinProto(builtincurrentoutput);
+BuiltinProto(builtinsetinput);
+BuiltinProto(builtinsetoutput);
int compareterms(Term *, Term *);
@@ -98,6 +104,18 @@
return builtinsetprologflag;
if(Match(L"current_prolog_flag", 2))
return builtincurrentprologflag;
+ if(Match(L"open", 4))
+ return builtinopen;
+ if(Match(L"close", 2))
+ return builtinclose;
+ if(Match(L"current_input", 1))
+ return builtincurrentinput;
+ if(Match(L"current_output", 1))
+ return builtincurrentoutput;
+ if(Match(L"set_input", 1))
+ return builtinsetinput;
+ if(Match(L"set_output", 1))
+ return builtinsetoutput;
return nil;
}
@@ -582,3 +600,151 @@
return 1;
}
+int
+builtinopen(Term *database, Term *goal, Goal **goals, Choicepoint **choicestack, Binding **bindings)
+{+ USED(database);
+ USED(goals);
+ USED(choicestack);
+ USED(bindings);
+
+ Term *sourcesink = goal->children;
+ Term *mode = sourcesink->next;
+ Term *stream = mode->next;
+ Term *options = stream->next;
+
+ if(sourcesink->tag == VariableTerm || mode->tag == VariableTerm || options->tag == VariableTerm)
+ Throw(instantiationerror());
+
+ if(stream->tag != VariableTerm)
+ Throw(typeerror(L"variable", stream));
+
+ if(options->tag != AtomTerm || runestrcmp(options->text, L"[]") != 0)
+ Throw(typeerror(L"empty_list", options));
+
+ if(mode->tag != AtomTerm)
+ Throw(typeerror(L"atom", mode));
+
+ if(sourcesink->tag != AtomTerm)
+ Throw(domainerror(L"source_sink", sourcesink));
+
+ Term *newstream;
+ int error = openstream(sourcesink->text, mode->text, options, &newstream);
+ if(error)
+ Throw(newstream);
+ else
+ return unify(stream, newstream, bindings);
+
+ return 0;
+}
+
+int
+builtinclose(Term *database, Term *goal, Goal **goals, Choicepoint **choicestack, Binding **bindings)
+{+ USED(database);
+ USED(goals);
+ USED(choicestack);
+ USED(bindings);
+
+ Term *stream = goal->children;
+ Term *options = stream->next;
+
+ if(stream->tag == VariableTerm || options->tag == VariableTerm)
+ Throw(instantiationerror());
+
+ if(options->tag != AtomTerm || runestrcmp(options->text, L"[]") != 0)
+ Throw(typeerror(L"empty_list", options));
+
+ if((stream->tag != NumberTerm || stream->numbertype != NumberInt) && stream->tag != AtomTerm)
+ Throw(domainerror(L"stream_or_alias", stream));
+
+ if(!isopenstream(stream))
+ Throw(existenceerror(L"stream", stream));
+
+ closestream(stream);
+
+ return 1;
+}
+
+int
+builtincurrentinput(Term *database, Term *goal, Goal **goals, Choicepoint **choicestack, Binding **bindings)
+{+ USED(database);
+ USED(goals);
+ USED(choicestack);
+ USED(bindings);
+
+ Term *stream = goal->children;
+ if(stream->tag != VariableTerm && (stream->tag != NumberTerm || stream->numbertype != NumberInt))
+ Throw(domainerror(L"stream", stream));
+
+ Term *current = currentinputstream();
+ return unify(stream, current, bindings);
+}
+
+int
+builtincurrentoutput(Term *database, Term *goal, Goal **goals, Choicepoint **choicestack, Binding **bindings)
+{+ USED(database);
+ USED(goals);
+ USED(choicestack);
+ USED(bindings);
+
+ Term *stream = goal->children;
+ if(stream->tag != VariableTerm && (stream->tag != NumberTerm || stream->numbertype != NumberInt))
+ Throw(domainerror(L"stream", stream));
+
+ Term *current = currentoutputstream();
+ return unify(stream, current, bindings);
+}
+
+int
+builtinsetinput(Term *database, Term *goal, Goal **goals, Choicepoint **choicestack, Binding **bindings)
+{+ USED(database);
+ USED(goals);
+ USED(choicestack);
+ USED(bindings);
+
+ Term *stream = goal->children;
+ if(stream->tag == VariableTerm)
+ Throw(instantiationerror());
+
+ if((stream->tag != NumberTerm || stream->numbertype != NumberInt) && stream->tag != AtomTerm)
+ Throw(domainerror(L"stream_or_alias", stream));
+
+ if(!isopenstream(stream))
+ Throw(existenceerror(L"stream", stream));
+
+ if(!isinputstream(stream))
+ Throw(permissionerror(L"input", L"stream", stream));
+
+ setcurrentinputstream(stream);
+ return 1;
+}
+
+int
+builtinsetoutput(Term *database, Term *goal, Goal **goals, Choicepoint **choicestack, Binding **bindings)
+{+ USED(database);
+ USED(goal);
+ USED(goals);
+ USED(choicestack);
+ USED(bindings);
+
+ Term *stream = goal->children;
+ if(stream->tag == VariableTerm)
+ Throw(instantiationerror());
+
+ if((stream->tag != NumberTerm || stream->numbertype != NumberInt) && stream->tag != AtomTerm)
+ Throw(domainerror(L"stream_or_alias", stream));
+
+ if(!isopenstream(stream))
+ Throw(existenceerror(L"stream", stream));
+
+ if(!isoutputstream(stream))
+ Throw(permissionerror(L"output", L"stream", stream));
+
+ setcurrentoutputstream(stream);
+ return 1;
+}
\ No newline at end of file
--- a/fns.h
+++ b/fns.h
@@ -40,3 +40,15 @@
Term *evaluationerror(Rune *);
Term *resourceerror(Rune *);
Term *syntaxerror(Rune *);
+
+/* streams.c */
+void initstreams(void);
+int openstream(Rune *, Rune *, Term *, Term **);
+void closestream(Term *);
+Term *currentinputstream(void);
+Term *currentoutputstream(void);
+void setcurrentinputstream(Term *);
+void setcurrentoutputstream(Term *);
+int isopenstream(Term *);
+int isinputstream(Term *);
+int isoutputstream(Term *);
\ No newline at end of file
--- a/main.c
+++ b/main.c
@@ -26,6 +26,7 @@
usage();
initflags();
+ initstreams();
int fd = open("./stdlib.pl", OREAD); if(fd < 0){--- a/mkfile
+++ b/mkfile
@@ -11,7 +11,8 @@
misc.$O\
repl.$O\
flags.$O\
- error.$O
+ error.$O\
+ streams.$O
HFILES=dat.h fns.h
--- a/stdlib.pl
+++ b/stdlib.pl
@@ -69,6 +69,14 @@
member(X, [_|Tail]) :-
member(X, Tail).
+% Input output
+
+open(SourceSink, Mode, Stream) :-
+ open(SourceSink, Mode, Stream, []).
+
+close(StreamOrAlias) :-
+ close(StreamOrAlias, []).
+
% Standard exceptions
instantiation_error :-
--- /dev/null
+++ b/streams.c
@@ -1,0 +1,204 @@
+#include <u.h>
+#include <libc.h>
+
+#include "dat.h"
+#include "fns.h"
+
+typedef struct Stream Stream;
+
+struct Stream
+{+ ulong fd;
+ int type;
+ int mode;
+ int nalias;
+ Rune **aliases;
+ Stream *next;
+};
+
+enum {+ TextStream,
+ BinaryStream,
+};
+
+enum {+ ReadStream,
+ WriteStream,
+ AppendStream
+};
+
+static Stream *streams;
+static Stream *currentinput;
+static Stream *currentoutput;
+
+Stream *openstreamfd(int, int, int);
+Stream *getstreambyfd(int);
+Stream *getstreambyalias(Rune *);
+Stream *getstream(Term *);
+
+void
+initstreams(void)
+{+ currentinput = openstreamfd(0, TextStream, ReadStream);
+ currentoutput = openstreamfd(1, TextStream, WriteStream);
+}
+
+int
+openstream(Rune *sourcesink, Rune *mode, Term *options, Term **stream)
+{+ USED(options);
+ int omode;
+ int smode;
+ if(runestrcmp(mode, L"read") == 0){+ omode = OREAD;
+ smode = ReadStream;
+ }else if(runestrcmp(mode, L"write") == 0){+ omode = OWRITE;
+ smode = WriteStream;
+ }else if(runestrcmp(mode, L"append") == 0){+ omode = OWRITE; /* Is this correct? */
+ smode = AppendStream;
+ }else{+ *stream = existenceerror(L"source_sink", mkatom(sourcesink));
+ return 1;
+ }
+
+ char *filename = smprint("%S", sourcesink);+ int fd = open(filename, omode);
+ if(fd < 0){+ *stream = permissionerror(L"open", L"source_sink", mkatom(sourcesink));
+ return 1;
+ }
+ Stream *s = openstreamfd(fd, TextStream, smode);
+ *stream = mknumber(NumberInt, s->fd, 0);
+ return 0;
+}
+
+void
+closestream(Term *t)
+{+ Stream *s = getstream(t);
+ if(s == nil)
+ return;
+
+ Stream *tmp;
+ Stream *prev = nil;
+ for(tmp = streams; tmp != nil; tmp = tmp->next){+ if(tmp == s){+ if(prev == nil)
+ streams = tmp->next;
+ else
+ prev->next = tmp->next;
+ break;
+ }
+ if(prev == nil)
+ prev = tmp;
+ }
+}
+
+Term *
+currentinputstream(void)
+{+ return mknumber(NumberInt, currentinput->fd, 0);
+}
+
+Term *
+currentoutputstream(void)
+{+ return mknumber(NumberInt, currentoutput->fd, 0);
+}
+
+void
+setcurrentinputstream(Term *t)
+{+ Stream *s = getstream(t);
+ if(s)
+ currentinput = s;
+}
+
+void
+setcurrentoutputstream(Term *t)
+{+ Stream *s = getstream(t);
+ if(s)
+ currentoutput = s;
+}
+
+int
+isopenstream(Term *t)
+{+ Stream *s = getstream(t);
+ if(s)
+ return 1;
+ else
+ return 0;
+}
+
+int
+isinputstream(Term *t)
+{+ Stream *s = getstream(t);
+ if(s && s->mode == ReadStream)
+ return 1;
+ else
+ return 0;
+}
+
+int
+isoutputstream(Term *t)
+{+ Stream *s = getstream(t);
+ if(s && (s->mode == WriteStream || s->mode == AppendStream))
+ return 1;
+ else
+ return 0;
+}
+
+Stream *
+openstreamfd(int fd, int type, int mode)
+{+ Stream *s = malloc(sizeof(Stream));
+ s->fd = fd;
+ s->type = type;
+ s->mode = mode;
+ s->nalias = 0;
+ s->aliases = nil;
+ s->next = streams;
+ streams = s;
+ return s;
+}
+
+Stream *
+getstreambyfd(int fd)
+{+ Stream *s;
+ for(s = streams; s != nil; s = s->next)
+ if(s->fd == fd)
+ return s;
+ return nil;
+}
+
+Stream *
+getstreambyalias(Rune *alias)
+{+ Stream *s;
+ for(s = streams; s != nil; s = s->next){+ int i;
+ for(i = 0; i < s->nalias; i++){+ if(runestrcmp(alias, s->aliases[i]) == 0)
+ return s;
+ }
+ }
+ return nil;
+}
+
+Stream *
+getstream(Term *t)
+{+ Stream *s = nil;
+ if(t->tag == NumberTerm && t->numbertype == NumberInt)
+ s = getstreambyfd(t->ival);
+ else if(t->tag == AtomTerm)
+ s = getstreambyalias(t->text);
+ return s;
+}
\ No newline at end of file