From 96de8e6b3a7059173fb10dc3bf162e3df835cde5 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Tue, 8 Aug 2017 12:27:11 -0700
Subject: ffi: new buf-carray function.

* ffi.c (buf_carray): New function.
(ffi_init): Registered buf-carray intrinsic.

* ffi.c (buf_carray): Declared.

* txr.1: Documented.
---
 ffi.c |  9 +++++++++
 ffi.h |  2 ++
 txr.1 | 18 ++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/ffi.c b/ffi.c
index 625545bb..b6eed992 100644
--- a/ffi.c
+++ b/ffi.c
@@ -4838,6 +4838,14 @@ val carray_buf_sync(val carray)
   return buf;
 }
 
+val buf_carray(val carray)
+{
+  struct carray *scry = carray_struct_checked(carray);
+  struct txr_ffi_type *etft = scry->eltft;
+  cnum bytes = scry->nelem * etft->size;
+  return  make_duplicate_buf(num(bytes), scry->data);
+}
+
 val carray_cptr(val cptr, val type, val len)
 {
   mem_t *data = cptr_get(cptr);
@@ -5580,6 +5588,7 @@ void ffi_init(void)
   reg_fun(intern(lit("carray-blank"), user_package), func_n2(carray_blank));
   reg_fun(intern(lit("carray-buf"), user_package), func_n3o(carray_buf, 2));
   reg_fun(intern(lit("carray-buf-sync"), user_package), func_n1(carray_buf_sync));
+  reg_fun(intern(lit("buf-carray"), user_package), func_n1(buf_carray));
   reg_fun(intern(lit("carray-cptr"), user_package), func_n3o(carray_cptr, 2));
   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));
diff --git a/ffi.h b/ffi.h
index 9d244885..93ac5639 100644
--- a/ffi.h
+++ b/ffi.h
@@ -105,11 +105,13 @@ val carray_list(val list, val type, val null_term_p);
 val carray_blank(val nelem, val type);
 val carray_buf(val buf, val type, val offs);
 val carray_buf_sync(val carray);
+val buf_carray(val carray);
 val carray_cptr(val cptr, val type, val len);
 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);
 val carray_refset(val carray, val idx, val newval);
+val buf_carray(val carray);
 val carray_sub(val carray, val from, val to);
 val carray_replace(val carray, val values, val from, val to);
 val carray_get(val carray);
diff --git a/txr.1 b/txr.1
index e005a34b..d3ea01b9 100644
--- a/txr.1
+++ b/txr.1
@@ -58598,6 +58598,24 @@ length of
 .meta carray
 are altered to reflect the current state of the buffer.
 
+.coNP Function @ buf-carray
+.synb
+.mets (buf-carray << carray )
+.syne
+.desc
+The
+.code buf-carray
+function duplicates the underlying storage of
+.meta carray
+and returns that storage represented as an object of
+.code buf
+type.
+
+The storage size is calculated by multiplying the
+.code carray
+object's element size by the number of elements.
+Only that extent of the storage is duplicated.
+
 .coNP Function @ carray-cptr
 .synb
 .mets (carray-cptr < cptr < type <> [ length ])
-- 
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