From 573a9c3b39bf1570a575ce3f077a33e752439165 Mon Sep 17 00:00:00 2001
From: Benoit Giannangeli <benoit.giannangeli@boursorama.fr>
Date: Thu, 16 Feb 2017 12:08:55 +0100
Subject: lua_pushvalue

---
 README.md               |  2 +-
 src/lapi.js             | 14 ++++++++------
 tests/C/Makefile        |  3 ++-
 tests/C/lua_pushvalue.c | 24 ++++++++++++++++++++++++
 tests/lapi.js           | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 82 insertions(+), 8 deletions(-)
 create mode 100644 tests/C/lua_pushvalue.c

diff --git a/README.md b/README.md
index 6fcea52..ad85079 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,7 @@
     - [x] lua_pushinteger
     - [x] lua_pushnumber
     - [x] lua_pushstring
+    - [x] lua_pushvalue
     - [ ] lua_absindex
     - [ ] lua_arith
     - [ ] lua_call
@@ -92,7 +93,6 @@
     - [ ] lua_pushliteral
     - [ ] lua_pushlstring
     - [ ] lua_pushthread
-    - [ ] lua_pushvalue
     - [ ] lua_pushvfstring
     - [ ] lua_rawequal
     - [ ] lua_rawget
diff --git a/src/lapi.js b/src/lapi.js
index 71cf3f6..dc60984 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -36,9 +36,11 @@ const index2addr = function(L, idx) {
         assert(idx <= ci.top - (ci.funcOff + 1), "unacceptable index");
         if (o >= L.top) return nil;
         else return L.stack[o];
-    } else if (idx < 0) // TODO: pseudo-indices
-        return nil; // TODO: G(L)->l_registry
-    else { /* upvalues */
+    } else if (idx < 0) { // TODO: pseudo-indices
+        assert(idx !== 0 && -idx <= L.top, "invalid index");
+        return L.stack[L.top + idx];
+    // TODO: if (idx == LUA_REGISTRYINDEX) return &G(L)->l_registry;
+    } else { /* upvalues */
         idx = -idx;
         assert(idx <= MAXUPVAL + 1, "upvalue index too large");
         if (ci.func.ttislcf()) /* light C function? */
@@ -59,7 +61,7 @@ const lua_gettop = function(L) {
 };
 
 const lua_pushvalue = function(L, idx) {
-    L.stack[L.top] = L.stack[index2addr(L, idx)];
+    L.stack[L.top] = index2addr(L, idx);
 
     L.top++;
     assert(L.top <= L.ci.top, "stack overflow");
@@ -166,7 +168,7 @@ const lua_pushlightuserdata = function(L, p) {
 */
 
 const lua_toboolean = function(L, idx) {
-    let o = L.stack[index2addr(L, idx)];
+    let o = index2addr(L, idx);
     return !l_isfalse(o);
 };
 
@@ -205,7 +207,7 @@ const lua_pcallk = function(L, nargs, nresults, errfunc, ctx, k) {
     if (errfunc === 0)
         func = 0;
     else {
-        let o = L.stack[index2addr(L, errfunc)];
+        let o = index2addr(L, errfunc);
         // TODO: api_checkstackindex(L, errfunc, o);
         func = errfunc;
     }
diff --git a/tests/C/Makefile b/tests/C/Makefile
index bc153a5..7d943b9 100644
--- a/tests/C/Makefile
+++ b/tests/C/Makefile
@@ -8,4 +8,5 @@ all:
 	$(CC) $(CFLAGS) $(LIBS) lua_pushnumber.c  -o lua_pushnumber.out
 	$(CC) $(CFLAGS) $(LIBS) lua_pushinteger.c -o lua_pushinteger.out
 	$(CC) $(CFLAGS) $(LIBS) lua_pushstring.c  -o lua_pushstring.out
-	$(CC) $(CFLAGS) $(LIBS) lua_pushboolean.c  -o lua_pushboolean.out
\ No newline at end of file
+	$(CC) $(CFLAGS) $(LIBS) lua_pushboolean.c  -o lua_pushboolean.out
+	$(CC) $(CFLAGS) $(LIBS) lua_pushvalue.c  -o lua_pushvalue.out
\ No newline at end of file
diff --git a/tests/C/lua_pushvalue.c b/tests/C/lua_pushvalue.c
new file mode 100644
index 0000000..055ee23
--- /dev/null
+++ b/tests/C/lua_pushvalue.c
@@ -0,0 +1,24 @@
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(void) {
+
+    lua_State *L = luaL_newstate();
+
+    luaL_openlibs(L);
+
+    lua_pushstring(L, "hello");
+
+    lua_pushvalue(L, -1);
+
+    printf("L->top(%d): %s\n", lua_gettop(L), luaL_typename(L, -1));
+    printf("L->top - 1(%d): %s\n", lua_gettop(L) - 1, luaL_typename(L, -2));
+
+    lua_close(L);
+
+    return 0;
+
+}
\ No newline at end of file
diff --git a/tests/lapi.js b/tests/lapi.js
index 6c5d7a4..8dd2680 100644
--- a/tests/lapi.js
+++ b/tests/lapi.js
@@ -168,4 +168,51 @@ test('lua_pushboolean', function (t) {
         true,
         "top is correct"
     );
+});
+
+
+test('lua_pushvalue', function (t) {
+    let L;
+    
+    t.plan(6);
+
+    t.doesNotThrow(function () {
+
+        L = lauxlib.luaL_newstate();
+
+        lapi.lua_pushstring(L, "hello");
+
+        lapi.lua_pushvalue(L, -1);
+
+    }, "JS Lua program ran without error");
+
+    t.strictEqual(
+        lapi.lua_gettop(L),
+        2,
+        "top is correct"
+    );
+
+    t.strictEqual(
+        lauxlib.luaL_typename(L, -1),
+        "string",
+        "Correct element(s) on the stack"
+    );
+
+    t.strictEqual(
+        lauxlib.luaL_typename(L, -2),
+        "string",
+        "Correct element(s) on the stack"
+    );
+
+    t.strictEqual(
+        L.stack[lapi.lua_gettop(L)].value,
+        "hello",
+        "top is correct"
+    );
+
+    t.strictEqual(
+        L.stack[lapi.lua_gettop(L) - 1].value,
+        "hello",
+        "top is correct"
+    );
 });
\ No newline at end of file
-- 
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