From be410cc32ae0eefb53df1d92a3ff576628771075 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Sat, 10 Sep 2011 03:02:34 +0200
Subject: Add insert_element/3 and delete_element/2

* erlang:insert_element/3 - extend a tuple at an index
* erlang:delete_element/2 - remove an element at an index
---
 erts/emulator/beam/bif.c   | 72 ++++++++++++++++++++++++++++++++++++++++++++++
 erts/emulator/beam/bif.tab |  2 ++
 2 files changed, 74 insertions(+)

(limited to 'erts/emulator/beam')

diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index c4ff4fe982..97c8114437 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -2526,6 +2526,78 @@ BIF_RETTYPE append_element_2(BIF_ALIST_2)
     BIF_RET(res);
 }
 
+BIF_RETTYPE insert_element_3(BIF_ALIST_3)
+{
+    Eterm* ptr;
+    Eterm* hp;
+    Uint arity;
+    Eterm res;
+    Sint ix;
+
+    if (is_not_tuple(BIF_ARG_2) || is_not_small(BIF_ARG_1)) {
+	BIF_ERROR(BIF_P, BADARG);
+    }
+
+    ptr   = tuple_val(BIF_ARG_2);
+    arity = arityval(*ptr);
+    ix    = signed_val(BIF_ARG_1);
+
+    if ((ix < 1) || (ix > (arity + 1))) {
+	BIF_ERROR(BIF_P, BADARG);
+    }
+
+    hp  = HAlloc(BIF_P, arity + 1 + 1);
+    res = make_tuple(hp);
+    *hp = make_arityval(arity + 1);
+
+    ix--;
+    arity -= ix;
+
+    while (ix--) { *++hp = *++ptr; }
+
+    *++hp = BIF_ARG_3;
+
+    while(arity--) { *++hp = *++ptr; }
+
+    BIF_RET(res);
+}
+
+BIF_RETTYPE delete_element_2(BIF_ALIST_3)
+{
+    Eterm* ptr;
+    Eterm* hp;
+    Uint arity;
+    Eterm res;
+    Sint ix;
+
+    if (is_not_tuple(BIF_ARG_2) || is_not_small(BIF_ARG_1)) {
+	BIF_ERROR(BIF_P, BADARG);
+    }
+
+    ptr   = tuple_val(BIF_ARG_2);
+    arity = arityval(*ptr);
+    ix    = signed_val(BIF_ARG_1);
+
+    if ((ix < 1) || (ix > arity) || (arity == 0)) {
+	BIF_ERROR(BIF_P, BADARG);
+    }
+
+    hp  = HAlloc(BIF_P, arity + 1 - 1);
+    res = make_tuple(hp);
+    *hp = make_arityval(arity - 1);
+
+    ix--;
+    arity -= ix;
+
+    while (ix--) { *++hp = *++ptr; }
+
+    ++ptr;
+
+    while(arity--) { *++hp = *++ptr; }
+
+    BIF_RET(res);
+}
+
 /**********************************************************************/
 
 /* convert an atom to a list of ascii integer */
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 9a1a25031c..1799f15504 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -821,6 +821,8 @@ bif erlang:dt_append_vm_tag_data/1
 #
 bif erlang:prepare_loading/2
 bif erlang:finish_loading/1
+bif erlang:insert_element/3
+bif erlang:delete_element/2
 
 #
 # Obsolete
-- 
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