From 4dc6c3932f62d673766b1c9b35ddf11a70da000b Mon Sep 17 00:00:00 2001
From: Francois Perrad <francois.perrad@gadz.org>
Date: Fri, 6 Jan 2017 12:20:42 +0100
Subject: [PATCH] backport table.move from 5.3

---
 src/host/buildvm_libbc.h | 17 ++++++++++++++---
 src/lib_table.c          | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/src/host/buildvm_libbc.h b/src/host/buildvm_libbc.h
index 45f8f8cb..13546832 100644
--- a/src/host/buildvm_libbc.h
+++ b/src/host/buildvm_libbc.h
@@ -15,7 +15,12 @@ static const uint8_t libbc_code[] = {
 8,2,0,0,88,3,23,128,59,3,2,0,43,4,0,0,64,4,2,0,76,3,2,0,88,3,18,128,16,1,14,
 0,41,3,1,0,3,3,1,0,88,3,14,128,3,1,2,0,88,3,12,128,59,3,1,0,22,4,1,1,18,5,2,
 0,41,6,1,0,77,4,4,128,23,8,1,7,59,9,7,0,64,9,8,0,79,4,252,127,43,4,0,0,64,4,
-2,0,76,3,2,0,75,0,1,0,0,2,0
+2,0,76,3,2,0,75,0,1,0,0,2,0,5,10,0,0,1,38,16,0,12,0,16,1,14,0,16,2,14,0,16,
+3,14,0,10,4,0,0,88,5,2,128,14,0,4,0,88,5,1,128,18,4,0,0,16,4,12,0,3,1,2,0,88,
+5,25,128,0,2,3,0,88,5,4,128,2,3,1,0,88,5,2,128,4,4,0,0,88,5,9,128,18,5,1,0,
+18,6,2,0,41,7,1,0,77,5,4,128,59,9,8,0,64,9,3,4,22,3,0,3,79,5,252,127,88,5,10,
+128,32,5,2,3,33,3,1,5,18,5,2,0,18,6,1,0,41,7,255,255,77,5,4,128,59,9,8,0,64,
+9,3,4,23,3,0,3,79,5,252,127,76,4,2,0,2,0
 #else
 0,1,2,0,0,1,2,24,1,0,0,76,1,2,0,241,135,158,166,3,220,203,178,130,4,0,1,2,0,
 0,1,2,24,1,0,0,76,1,2,0,243,244,148,165,20,198,190,199,252,3,0,1,2,0,0,0,3,
@@ -28,7 +33,12 @@ static const uint8_t libbc_code[] = {
 8,2,0,0,88,3,23,128,59,3,2,0,43,4,0,0,64,4,2,0,76,3,2,0,88,3,18,128,16,1,14,
 0,41,3,1,0,3,3,1,0,88,3,14,128,3,1,2,0,88,3,12,128,59,3,1,0,22,4,1,1,18,5,2,
 0,41,6,1,0,77,4,4,128,23,8,1,7,59,9,7,0,64,9,8,0,79,4,252,127,43,4,0,0,64,4,
-2,0,76,3,2,0,75,0,1,0,0,2,0
+2,0,76,3,2,0,75,0,1,0,0,2,0,5,10,0,0,1,38,16,0,12,0,16,1,14,0,16,2,14,0,16,
+3,14,0,10,4,0,0,88,5,2,128,14,0,4,0,88,5,1,128,18,4,0,0,16,4,12,0,3,1,2,0,88,
+5,25,128,0,2,3,0,88,5,4,128,2,3,1,0,88,5,2,128,4,4,0,0,88,5,9,128,18,5,1,0,
+18,6,2,0,41,7,1,0,77,5,4,128,59,9,8,0,64,9,3,4,22,3,0,3,79,5,252,127,88,5,10,
+128,32,5,2,3,33,3,1,5,18,5,2,0,18,6,1,0,41,7,255,255,77,5,4,128,59,9,8,0,64,
+9,3,4,23,3,0,3,79,5,252,127,76,4,2,0,2,0
 #endif
 };
 
@@ -40,6 +50,7 @@ static const struct { const char *name; int ofs; } libbc_map[] = {
 {"table_foreach",136},
 {"table_getn",207},
 {"table_remove",226},
-{NULL,355}
+{"table_move",355},
+{NULL,515}
 };
 
diff --git a/src/lib_table.c b/src/lib_table.c
index f9a3693d..901b5d34 100644
--- a/src/lib_table.c
+++ b/src/lib_table.c
@@ -129,6 +129,38 @@ LJLIB_LUA(table_remove) /*
   end
 */
 
+/*
+** Copy elements (a1[f], ..., a1[e]) into (a2[t], a2[t+1], ...). Whenever
+** possible, copy in increasing order, which is better for rehashing.
+** "possible" means destination after original range, or smaller
+** than origin, or copying to another table.
+*/
+LJLIB_LUA(table_move) /*
+  function(a1, f, e, t, a2)
+    CHECK_tab(a1)
+    CHECK_int(f)
+    CHECK_int(e)
+    CHECK_int(t)
+    a2 = (a2 ~= nil) and a2 or a1
+    CHECK_tab(a2)
+    if e >= f then
+      if t > e or t <= f or a2 ~= a1 then
+        for i = f, e do
+          a2[t] = a1[i]
+          t = t + 1
+        end
+      else
+        t = t + e - f
+        for i = e, f, -1 do
+          a2[t] = a1[i]
+          t = t - 1
+        end
+      end
+    end
+    return a2
+  end
+*/
+
 LJLIB_CF(table_concat)		LJLIB_REC(.)
 {
   GCtab *t = lj_lib_checktab(L, 1);