From 37f31f6c8b88dc19c5a6afc8f1405cdbab8aad10 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Wed, 17 May 2017 06:18:56 -0700
Subject: ffi: new carray_buf function.

Treat a buffer through a carray view.

* ffi.c (carray_buf): New function.
(ffi_init): Register carray-buf intrinsic.

* ffi.h (carray_buf): Declared.
---
 ffi.c | 11 +++++++++++
 ffi.h |  1 +
 2 files changed, 12 insertions(+)

diff --git a/ffi.c b/ffi.c
index b2631941..b2ce6441 100644
--- a/ffi.c
+++ b/ffi.c
@@ -2445,6 +2445,16 @@ val carray_blank(val nelem, val type)
   }
 }
 
+val carray_buf(val buf, val type)
+{
+  val self = lit("carray-buf");
+  cnum blen = c_num(length_buf(buf));
+  mem_t *data = buf_get(buf, self);
+  struct txr_ffi_type *tft = ffi_type_struct(type);
+  cnum nelem = if3(tft->size, blen / tft->size, 0);
+  return make_carray(type, data, nelem, buf);
+}
+
 val vec_carray(val carray, val null_term_p)
 {
   val nt_p = default_null_arg(null_term_p);
@@ -2573,6 +2583,7 @@ void ffi_init(void)
   reg_fun(intern(lit("length-carray"), user_package), func_n1(length_carray));
   reg_fun(intern(lit("carray-vec"), user_package), func_n3o(carray_vec, 2));
   reg_fun(intern(lit("carray-blank"), user_package), func_n2(carray_blank));
+  reg_fun(intern(lit("carray-buf"), user_package), func_n2(carray_buf));
   reg_fun(intern(lit("vec-carray"), user_package), func_n2o(vec_carray, 1));
   reg_fun(intern(lit("list-carray"), user_package), func_n2o(list_carray, 1));
   reg_fun(intern(lit("carray-ref"), user_package), func_n2(carray_ref));
diff --git a/ffi.h b/ffi.h
index e9b188f2..31031e3f 100644
--- a/ffi.h
+++ b/ffi.h
@@ -73,6 +73,7 @@ val length_carray(val carray);
 mem_t *carray_get(val carray, val type, val self);
 val carray_vec(val vec, val type, val null_term_p);
 val carray_blank(val nelem, val type);
+val carray_buf(val buf, val type);
 val vec_carray(val carray, val null_term_p);
 val list_carray(val carray, val null_term_p);
 val carray_ref(val carray, val idx);
-- 
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