ffi: new FFI type I/O functions.

* ffi.c (put_obj, get_obj, fill_obj): New functions.
(ffi_init): put-obj, get-obj, fill-obj intrinsics registered.

* ffi.h (put_obj, get_obj, fill_obj): Declared.

* txr.1: Documented.

3 files changed, 139 insertions, 0 deletions

diff --git a/ffi.c b/ffi.c
index b6eed992..82a28b5b 100644
--- a/ffi.c
+++ b/ffi.c
@@ -5486,6 +5486,48 @@ val zero_fill(val type, val obj)
   return ret;
 }
 
+val put_obj(val obj, val type, val stream)
+{
+  val self = lit("put-obj");
+  struct txr_ffi_type *tft = ffi_type_struct_checked(type);
+  cnum size = tft->size;
+  val len = num(size);
+  mem_t *data = coerce(mem_t *, zalloca(size));
+  obj_t buf_obj;
+  val buf = init_borrowed_buf(&buf_obj, len, data);
+  tft->put(tft, obj, data, self);
+  return eql(put_buf(buf, zero, stream), len);
+}
+
+
+val get_obj(val type, val stream)
+{
+  val self = lit("get-obj");
+  struct txr_ffi_type *tft = ffi_type_struct_checked(type);
+  cnum size = tft->size;
+  val len = num(size);
+  mem_t *data = coerce(mem_t *, zalloca(size));
+  obj_t buf_obj;
+  val buf = init_borrowed_buf(&buf_obj, len, data);
+  if (neql(fill_buf(buf, zero, stream), len))
+    return nil;
+  return tft->get(tft, data, self);
+}
+
+val fill_obj(val obj, val type, val stream)
+{
+  val self = lit("fill-obj");
+  struct txr_ffi_type *tft = ffi_type_struct_checked(type);
+  cnum size = tft->size;
+  val len = num(size);
+  mem_t *data = coerce(mem_t *, zalloca(size));
+  obj_t buf_obj;
+  val buf = init_borrowed_buf(&buf_obj, len, data);
+  if (neql(fill_buf(buf, zero, stream), len))
+    return nil;
+  return tft->in(tft, 1, data, obj, self);
+}
+
 void ffi_init(void)
 {
   prot1(&ffi_typedef_hash);
@@ -5615,6 +5657,9 @@ void ffi_init(void)
   reg_fun(intern(lit("union-out"), user_package), func_n3(union_out));
   reg_fun(intern(lit("make-zstruct"), user_package), func_n1v(make_zstruct));
   reg_fun(intern(lit("zero-fill"), user_package), func_n2(zero_fill));
+  reg_fun(intern(lit("put-obj"), user_package), func_n3o(put_obj, 2));
+  reg_fun(intern(lit("get-obj"), user_package), func_n2o(get_obj, 1));
+  reg_fun(intern(lit("fill-obj"), user_package), func_n3o(fill_obj, 2));
   ffi_typedef_hash = make_hash(nil, nil, nil);
   ffi_init_types();
   ffi_init_extra_types();
diff --git a/ffi.h b/ffi.h
index 93ac5639..3f59186b 100644
--- a/ffi.h
+++ b/ffi.h
@@ -134,4 +134,7 @@ val union_in(val uni, val memb, val memb_obj);
 val union_out(val uni, val memb, val memb_obj);
 val make_zstruct(val type, struct args *args);
 val zero_fill(val type, val obj);
+val put_obj(val obj, val type, val stream);
+val get_obj(val type, val stream);
+val fill_obj(val obj, val type, val stream);
 void ffi_init(void);
diff --git a/txr.1 b/txr.1
index ee6072f6..29195b97 100644
--- a/txr.1
+++ b/txr.1
@@ -58325,6 +58325,97 @@ an argument, in cases when the callback has updated the Lisp
 object corresponding to a union member, and that change needs
 to be propagated to the foreign caller.
 
+.SS* FFI-type-driven I/O Functions
+
+These functions provide a way to perform I/O on stream using the foreign
+representation of Lisp objects, performing conversion between the Lisp
+representations in memory and the foreign representations in a stream.
+
+The
+.meta stream
+argument used with these functions must be a stream object which,
+in the case of input functions, supports
+.code get-byte
+and, in the case of output, supports
+.codn put-byte .
+
+.coNP Function @ put-obj
+.synb
+.mets (put-obj < object < type <> [ stream ])
+.syne
+.desc
+The
+.code put-obj
+function encodes
+.meta object
+into a foreign representation, according to the FFI type
+.metn type .
+The bytes of the foreign representation are then written to
+.metn stream .
+
+If
+.meta stream
+is omitted, it defaults to
+.codn *stdout* .
+
+If the operation successfully writes all bytes of the representation to
+.metn stream ,
+the value
+.code t
+is returned. A partial write causes the return value to be
+.codn nil .
+
+All other stream error situations throw exceptions.
+
+.coNP Function @ get-obj
+.synb
+.mets (get-obj < type <> [ stream ])
+.syne
+.desc
+The
+.code get-obj
+function reads from
+.meta stream
+the bytes corresponding to a foreign representation according to the FFI type
+.metn type .
+
+If
+.meta stream
+is omitted, it defaults to
+.codn *stdin* .
+
+If the read is successful, these bytes are decoded, producing a Lisp
+object, which is returned.
+
+If the read is incomplete, the value returned is
+.metn nil .
+
+All other stream error situations throw exceptions.
+
+.coNP Function @ fill-obj
+.synb
+.mets (fill-obj < object < type <> [ stream ])
+.syne
+.desc
+The
+.code get-obj
+function reads from
+.meta stream
+the bytes corresponding to a foreign representation according to the FFI type
+.metn type .
+
+If the read is successful, then
+.meta object
+is updated, if possible, from that representation, using the by-value in
+semantics of the FFI type and returned. If a by-value update of
+.meta object
+isn't possible, then a new object is decoded from the data and returned.
+
+If the read is incomplete, the value returned is
+.metn nil .
+
+All other stream error situations throw exceptions.
+
 .SS* Buffer Functions
 
 Functions in this area provide a way to perform conversion between