ffi: support buf objects.

* buf.c (make_duplicate_buf, buf_get, buf_fill): New
functions.

* buf.h (make_duplicate_buf, buf_get, buf_fill): Declared.

* ffi.c (struct txr_ffi_type): New member, nelem.
Keeps track of number of elements, for types that are
FFI pointers. This lets us support the get method so that
a buf can be a C function return value, if its size is
declared in our FFI type system.
(ffi_buf_put, ffi_buf_get, ffi_buf_fill): New functions.
(ffi_type_compile): Handle two new cases of syntax for
buffers: (buf <size>) and buf.

1 files changed, 3 insertions, 0 deletions

diff --git a/buf.h b/buf.h
index 56a04c7e..8102fff8 100644
--- a/buf.h
+++ b/buf.h
@@ -27,9 +27,12 @@
 
 val make_buf(val len, val init_val, val alloc_size);
 val make_borrowed_buf(val len, mem_t *data);
+val make_duplicate_buf(val len, mem_t *data);
 val buf_trim(val buf);
 val buf_set_length(val obj, val len, val init_val);
 val length_buf(val buf);
+mem_t *buf_get(val buf, val self);
+void buf_fill(val buf, mem_t *src, val self);
 
 #if HAVE_I8
 val buf_put_i8(val buf, val pos, val num);