do not use RWOps in WIN_SetWindowIcon

include/SDL_assert.h

@@ -76,6 +76,7 @@ assert can have unique static variables associated with it.
 #endif
 #define SDL_FILE    __FILE__
 #define SDL_LINE    __LINE__
+#define SDL_STATIC_ASSERT(COND,MSG) typedef char static_assertion_##MSG[(COND)?1:-1];
 
 /*
 sizeof (x) makes the compiler still parse the expression even without

src/video/windows/SDL_windowswindow.c

@@ -442,39 +442,40 @@ WIN_SetWindowIcon(_THIS, SDL_Window * window, SDL_Surface * icon)
     HWND hwnd = ((SDL_WindowData *) window->driverdata)->hwnd;
     HICON hicon = NULL;
     BYTE *icon_bmp;
-    int icon_len, mask_len, y;
-    SDL_RWops *dst;
+    int icon_len, mask_len, row_len, y;
+    BITMAPINFOHEADER *bmi;
+    Uint8 *dst;
     SDL_bool isstack;
 
     /* Create temporary buffer for ICONIMAGE structure */
+    SDL_STATIC_ASSERT(sizeof(BITMAPINFOHEADER) == 40, WIN_SetWindowIcon_uses_BITMAPINFOHEADER_to_prepare_an_ICONIMAGE);
     mask_len = (icon->h * (icon->w + 7)/8);
-    icon_len = 40 + icon->h * icon->w * sizeof(Uint32) + mask_len;
+    icon_len = sizeof(BITMAPINFOHEADER) + icon->h * icon->w * sizeof(Uint32) + mask_len;
     icon_bmp = SDL_small_alloc(BYTE, icon_len, &isstack);
-    dst = SDL_RWFromMem(icon_bmp, icon_len);
-    if (!dst) {
-        SDL_small_free(icon_bmp, isstack);
-        return;
-    }
 
     /* Write the BITMAPINFO header */
-    SDL_WriteLE32(dst, 40);
-    SDL_WriteLE32(dst, icon->w);
-    SDL_WriteLE32(dst, icon->h * 2);
-    SDL_WriteLE16(dst, 1);
-    SDL_WriteLE16(dst, 32);
-    SDL_WriteLE32(dst, BI_RGB);
-    SDL_WriteLE32(dst, icon->h * icon->w * sizeof(Uint32));
-    SDL_WriteLE32(dst, 0);
-    SDL_WriteLE32(dst, 0);
-    SDL_WriteLE32(dst, 0);
-    SDL_WriteLE32(dst, 0);
+    bmi = (BITMAPINFOHEADER *)icon_bmp;
+    bmi->biSize = SDL_SwapLE32(sizeof(BITMAPINFOHEADER));
+    bmi->biWidth = SDL_SwapLE32(icon->w);
+    bmi->biHeight = SDL_SwapLE32(icon->h * 2);
+    bmi->biPlanes = SDL_SwapLE16(1);
+    bmi->biBitCount = SDL_SwapLE16(32);
+    bmi->biCompression = SDL_SwapLE32(BI_RGB);
+    bmi->biSizeImage = SDL_SwapLE32(icon->h * icon->w * sizeof(Uint32));
+    bmi->biXPelsPerMeter = SDL_SwapLE32(0);
+    bmi->biYPelsPerMeter = SDL_SwapLE32(0);
+    bmi->biClrUsed = SDL_SwapLE32(0);
+    bmi->biClrImportant = SDL_SwapLE32(0);
 
     /* Write the pixels upside down into the bitmap buffer */
     SDL_assert(icon->format->format == SDL_PIXELFORMAT_ARGB8888);
+    dst = &icon_bmp[sizeof(BITMAPINFOHEADER)];
+    row_len = icon->w * sizeof(Uint32);
     y = icon->h;
     while (y--) {
         Uint8 *src = (Uint8 *) icon->pixels + y * icon->pitch;
-        SDL_RWwrite(dst, src, icon->w * sizeof(Uint32), 1);
+        SDL_memcpy(dst, src, row_len);
+        dst += row_len;
     }
 
     /* Write the mask */
@@ -482,7 +483,6 @@ WIN_SetWindowIcon(_THIS, SDL_Window * window, SDL_Surface * icon)
 
     hicon = CreateIconFromResource(icon_bmp, icon_len, TRUE, 0x00030000);
 
-    SDL_RWclose(dst);
     SDL_small_free(icon_bmp, isstack);
 
     /* Set the icon for the window */