string.char bypass to_luastring conversion

2 files changed, 26 insertions, 3 deletions

diff --git a/src/lstrlib.js b/src/lstrlib.js
index 1b62db1..4bd8664 100644
--- a/src/lstrlib.js
+++ b/src/lstrlib.js
@@ -53,13 +53,14 @@ const str_len = function(L) {
 
 const str_char = function(L) {
     let n = lapi.lua_gettop(L);  /* number of arguments */
-    let p = "";
+    let p = [];
     for (let i = 1; i <= n; i++) {
         let c = lauxlib.luaL_checkinteger(L, i);
         lauxlib.luaL_argcheck(L, c >= 0 && c <= 255, "value out of range"); // Strings are 8-bit clean
-        p += String.fromCharCode(c);
+        p.push(c);
     }
-    lapi.lua_pushstring(L, p);
+    lapi.lua_pushstring(L, "");
+    L.stack[L.top - 1].value = p; // Since value are already capped, avoid conversion
     return 1;
 };
 
diff --git a/tests/single.lua b/tests/single.lua
index 616e2a4..c52a6fb 100644
--- a/tests/single.lua
+++ b/tests/single.lua
@@ -71,3 +71,25 @@ assert(string.len("1234567890") == 10)
 assert(#"" == 0)
 assert(#"\0\0\0" == 3)
 assert(#"1234567890" == 10)
+
+-- testing string.byte/string.char
+assert(string.byte("a") == 97)
+assert(string.byte("\xe4") > 127)
+assert(string.byte(string.char(255)) == 255)
+assert(string.byte(string.char(0)) == 0)
+assert(string.byte("\0") == 0)
+assert(string.byte("\0\0alo\0x", -1) == string.byte('x'))
+assert(string.byte("ba", 2) == 97)
+assert(string.byte("\n\n", 2, -1) == 10)
+assert(string.byte("\n\n", 2, 2) == 10)
+assert(string.byte("") == nil)
+assert(string.byte("hi", -3) == nil)
+assert(string.byte("hi", 3) == nil)
+assert(string.byte("hi", 9, 10) == nil)
+assert(string.byte("hi", 2, 1) == nil)
+assert(string.char() == "")
+assert(string.char(0, 255, 0) == "\0\255\0")
+assert(string.char(0, string.byte("\xe4"), 0) == "\0\xe4\0")
+assert(string.char(string.byte("\xe4l\0óu", 1, -1)) == "\xe4l\0óu")
+assert(string.char(string.byte("\xe4l\0óu", 1, 0)) == "")
+assert(string.char(string.byte("\xe4l\0óu", -10, 100)) == "\xe4l\0óu")