From 18631188532881934261e72321d9839ad42d1b06 Mon Sep 17 00:00:00 2001
From: Benoit Giannangeli <benoit.giannangeli@boursorama.fr>
Date: Fri, 17 Mar 2017 09:45:49 +0100
Subject: lua_todataview to use string as binary representation

---
 src/lapi.js      | 27 ++++++++++++++-------------
 src/lstrlib.js   |  5 +++--
 tests/lstrlib.js | 35 ++++++++++++++++-------------------
 3 files changed, 33 insertions(+), 34 deletions(-)

diff --git a/src/lapi.js b/src/lapi.js
index a51796b..a884a97 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -240,18 +240,6 @@ const lua_pushstring = function (L, s) {
     return s;
 };
 
-// Push string without 8-bit conversion
-const lua_pushrawstring = function(L, s) {
-    if (typeof s !== "string")
-        L.stack[L.top] = ldo.nil;
-    else {
-        L.stack[L.top] = new TValue(CT.LUA_TLNGSTR, s.split('').map(e => e.charCodeAt(0)));
-    }
-    L.top++;
-    assert(L.top <= L.ci.top, "stack overflow");
-    return s;
-};
-
 const lua_pushliteral = lua_pushstring;
 
 const lua_pushcclosure = function(L, fn, n) {
@@ -554,6 +542,19 @@ const lua_tolstring = function(L, idx) {
 
 const lua_tostring =  lua_tolstring;
 
+// Convert a string on the stack to a dataview, because lua_tostring will perform utf-8 to utf-16 conversion
+const lua_todataview = function(L, idx) {
+    let o = index2addr(L, idx);
+
+    if (!o.ttisstring() && !o.ttisnumber())
+        return null;
+
+    let dv = new DataView(new ArrayBuffer(o.value.length));
+    o.value.forEach((e, i) => dv.setUint8(i, e, true));
+
+    return dv;
+};
+
 const lua_rawlen = function(L, idx) {
     let o = index2addr(L, idx);
     switch (o.ttype()) {
@@ -893,7 +894,6 @@ module.exports.lua_pushliteral     = lua_pushliteral;
 module.exports.lua_pushlstring     = lua_pushlstring;
 module.exports.lua_pushnil         = lua_pushnil;
 module.exports.lua_pushnumber      = lua_pushnumber;
-module.exports.lua_pushrawstring   = lua_pushrawstring;
 module.exports.lua_pushstring      = lua_pushstring;
 module.exports.lua_pushthread      = lua_pushthread;
 module.exports.lua_pushtvalue      = lua_pushtvalue;
@@ -916,6 +916,7 @@ module.exports.lua_setupvalue      = lua_setupvalue;
 module.exports.lua_status          = lua_status;
 module.exports.lua_stringtonumber  = lua_stringtonumber;
 module.exports.lua_toboolean       = lua_toboolean;
+module.exports.lua_todataview      = lua_todataview;
 module.exports.lua_tointeger       = lua_tointeger;
 module.exports.lua_tointegerx      = lua_tointegerx;
 module.exports.lua_tolstring       = lua_tolstring;
diff --git a/src/lstrlib.js b/src/lstrlib.js
index 83e82b0..02feff6 100644
--- a/src/lstrlib.js
+++ b/src/lstrlib.js
@@ -3,9 +3,10 @@
 const assert  = require('assert');
 const sprintf = require('sprintf');
 
-const lua     = require('./lua.js');
 const lapi    = require('./lapi.js');
 const lauxlib = require('./lauxlib.js');
+const lobject = require('./lobject.js');
+const lua     = require('./lua.js');
 const luaconf = require('./luaconf.js');
 const CT      = lua.constant_types;
 
@@ -61,7 +62,7 @@ const str_dump = function(L) {
     lapi.lua_settop(L, 1);
     if (lapi.lua_dump(L, writer, b, strip) !== 0)
         return lauxlib.luaL_error(L, "unable to dump given function");
-    lapi.lua_pushrawstring(L, b.map(e => String.fromCharCode(e)).join(''));
+    L.stack[L.top++] = new lobject.TValue(CT.LUA_TLNGSTR, b); // We don't want lua > js > lua string conversion here
     return 1;
 };
 
diff --git a/tests/lstrlib.js b/tests/lstrlib.js
index aec8e2a..a7693a1 100644
--- a/tests/lstrlib.js
+++ b/tests/lstrlib.js
@@ -418,17 +418,15 @@ test('string.sub', function (t) {
 
 
 test('string.dump', function (t) {
-    let luaCodeToDump = `
-        local todump = function(p1, p2, p3)
-            local s = "hello"
-            local i = 12
-            local f = 12.5
-            local b = true
-
-            return p1 + p2 + p3
-        end`,
-        luaCode = `
-            ${luaCodeToDump}
+    let luaCode = `
+            local todump = function()
+                local s = "hello"
+                local i = 12
+                local f = 12.5
+                local b = true
+
+                return s .. i .. f
+            end
 
             return string.dump(todump)
         `, L, bytes = [];
@@ -436,11 +434,6 @@ test('string.dump', function (t) {
     t.plan(3);
 
     t.doesNotThrow(function () {
-
-        let bc = toByteCode(luaCodeToDump).dataView;
-        for (let i = 0; i < bc.byteLength; i++)
-            bytes.push(bc.getUint8(i, true));
-
         L = lauxlib.luaL_newstate();
 
         linit.luaL_openlibs(L);
@@ -453,11 +446,15 @@ test('string.dump', function (t) {
 
         lapi.lua_call(L, 0, -1);
 
+        let dv = lapi.lua_todataview(L, -1);
+
+        lapi.lua_load(L, null, dv, "test", "binary");
+
     }, "Lua program ran without error");
 
-    t.deepEqual(
-        L.stack[L.top -1].value,
-        bytes,
+    t.strictEqual(
+        lapi.lua_tostring(L, -1),
+        "hello1212.5",
         "Correct element(s) on the stack"
     );
 });
\ No newline at end of file
-- 
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