jscript: Optimize String.concat implementation.

dlls/jscript/string.c

@@ -377,26 +377,52 @@ static HRESULT String_charCodeAt(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags,
 static HRESULT String_concat(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, unsigned argc, jsval_t *argv,
         jsval_t *r)
 {
-    unsigned len = 0, i, str_cnt;
-    jsstr_t **strs, *ret = NULL;
-    WCHAR *ptr;
+    jsstr_t *ret, *str;
     HRESULT hres;
 
     TRACE("\n");
 
-    str_cnt = argc+1;
+    hres = get_string_val(ctx, jsthis, &str);
+    if(FAILED(hres))
+        return hres;
+
+    switch(argc) {
+    case 0:
+        ret = str;
+        break;
+    case 1: {
+        jsstr_t *arg_str;
+
+        hres = to_string(ctx, argv[0], &arg_str);
+        if(FAILED(hres)) {
+            jsstr_release(str);
+            return hres;
+        }
+
+        ret = jsstr_concat(str, arg_str);
+        jsstr_release(str);
+        if(!ret)
+            return E_OUTOFMEMORY;
+        break;
+    }
+    default: {
+        const unsigned str_cnt = argc+1;
+        unsigned len = 0, i;
+        jsstr_t **strs;
+        WCHAR *ptr;
+
         strs = heap_alloc_zero(str_cnt * sizeof(*strs));
-    if(!strs)
+        if(!strs) {
+            jsstr_release(str);
             return E_OUTOFMEMORY;
+        }
 
-    hres = to_string(ctx, jsval_disp(jsthis->u.disp), strs);
-    if(SUCCEEDED(hres)) {
+        strs[0] = str;
         for(i=0; i < argc; i++) {
             hres = to_string(ctx, argv[i], strs+i+1);
             if(FAILED(hres))
                 break;
         }
-    }
 
         if(SUCCEEDED(hres)) {
             for(i=0; i < str_cnt; i++) {
@@ -407,6 +433,7 @@ static HRESULT String_concat(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, uns
                 }
             }
 
+            if(SUCCEEDED(hres)) {
                 ptr = jsstr_alloc_buf(len, &ret);
                 if(ptr) {
                     for(i=0; i < str_cnt; i++)
@@ -415,13 +442,15 @@ static HRESULT String_concat(script_ctx_t *ctx, vdisp_t *jsthis, WORD flags, uns
                     hres = E_OUTOFMEMORY;
                 }
             }
+        }
 
-    for(i=0; i < str_cnt; i++)
+        while(i--)
             jsstr_release(strs[i]);
         heap_free(strs);
-
         if(FAILED(hres))
             return hres;
+    }
+    }
 
     if(r)
         *r = jsval_string(ret);