From 1c0b1014eec84f42450cda8257545fd7d6d5d988 Mon Sep 17 00:00:00 2001
From: kyren <kerriganw@gmail.com>
Date: Mon, 5 Jun 2017 01:46:45 -0400
Subject: [PATCH] Improve performance of create_table / create_array_table

---
 Cargo.toml   |  2 +-
 src/lua.rs   | 24 +++++++++++++-----------
 src/tests.rs |  7 +++++++
 3 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 74abdbb..85da801 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "rlua"
-version = "0.4.5"
+version = "0.4.6"
 authors = ["kyren <catherine@chucklefish.org>"]
 description = "High level bindings to Lua 5.3"
 repository = "https://github.com/chucklefish/rlua"
diff --git a/src/lua.rs b/src/lua.rs
index 4d02af8..049dddb 100644
--- a/src/lua.rs
+++ b/src/lua.rs
@@ -822,24 +822,26 @@ impl Lua {
               V: ToLua<'lua>,
               I: IntoIterator<Item = (K, V)>
     {
-        let table = self.create_empty_table()?;
-        for (k, v) in cont {
-            table.set(k, v)?;
+        unsafe {
+            stack_guard(self.state, 0, || {
+                check_stack(self.state, 3)?;
+                ffi::lua_newtable(self.state);
+
+                for (k, v) in cont.into_iter() {
+                    self.push_value(self.state, k.to_lua(self)?)?;
+                    self.push_value(self.state, v.to_lua(self)?)?;
+                    ffi::lua_rawset(self.state, -3);
+                }
+                Ok(LuaTable(self.pop_ref(self.state)))
+            })
         }
-        Ok(table)
     }
 
     pub fn create_array_table<'lua, T, I>(&'lua self, cont: I) -> LuaResult<LuaTable>
         where T: ToLua<'lua>,
               I: IntoIterator<Item = T>
     {
-        let table = self.create_empty_table()?;
-        let mut index = 1;
-        for elem in cont {
-            table.set(index, elem)?;
-            index += 1;
-        }
-        Ok(table)
+        self.create_table(cont.into_iter().enumerate().map(|(k, v)| (k + 1, v)))
     }
 
     pub fn create_function<F>(&self, func: F) -> LuaResult<LuaFunction>
diff --git a/src/tests.rs b/src/tests.rs
index 5a499ef..2632d3e 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -77,6 +77,13 @@ fn test_table() {
     assert_eq!(table3.length().unwrap(), 5);
     assert_eq!(table3.array_values::<Option<i64>>().unwrap(),
                vec![Some(1), Some(2), None, Some(4), Some(5)]);
+
+    lua.set("table4",
+            lua.create_array_table(vec![1, 2, 3, 4, 5]).unwrap())
+        .unwrap();
+    let table4 = lua.get::<_, LuaTable>("table4").unwrap();
+    assert_eq!(table4.pairs::<i64, i64>().unwrap(),
+               vec![(1, 1), (2, 2), (3, 3), (4, 4), (5, 5)]);
 }
 
 #[test]