usp10: Check that there are sufficient script_items before setting the last pointer.

dlls/usp10/tests/usp10.c

@@ -673,6 +673,7 @@ static void test_ScriptItemIzeShapePlace(HDC hdc, unsigned short pwOutGlyphs[256
     WCHAR           TestItem3[] = {'T', 'e', 's', 't', 'c',' ','1','2','3',' ',' ','e','n','d',0};
     WCHAR           TestItem4[] = {'T', 'e', 's', 't', 'd',' ',0x0684,0x0694,0x06a4,' ',' ','\r','\n','e','n','d',0};
     WCHAR           TestItem5[] = {0x0684,'T','e','s','t','e',' ',0x0684,0x0694,0x06a4,' ',' ','e','n','d',0};
+    WCHAR           TestItem6[] = {'T', 'e', 's', 't', 'f',' ',' ',' ','\r','\n','e','n','d',0};
 
     SCRIPT_CACHE    psc;
     int             cChars;
@@ -848,6 +849,15 @@ static void test_ScriptItemIzeShapePlace(HDC hdc, unsigned short pwOutGlyphs[256
     ok (pcItems == 4, "There should have been 4 items, found %d\n", pcItems);
     ok (pItem[0].a.s.uBidiLevel == 1, "The first character should have been bidi=1 not %d\n",
                                        pItem[0].a.s.uBidiLevel);
+
+    /* This test checks to make sure that the test to see if there are sufficient buffers to store  *
+     * the pointer to the last char works.  Note that windows often needs a greater number of       *
+     * SCRIPT_ITEMS to process a string than is returned in pcItems.                                */
+    cInChars = (sizeof(TestItem6)/2)-1;
+    cMaxItems = 4;
+    hr = ScriptItemize(TestItem6, cInChars, cMaxItems, NULL, NULL, pItem, &pcItems);
+    ok (hr == E_OUTOFMEMORY, "ScriptItemize should return E_OUTOFMEMORY, returned %08x\n", hr);
+
 }
 
 static void test_ScriptGetCMap(HDC hdc, unsigned short pwOutGlyphs[256])

dlls/usp10/usp10.c

@@ -669,16 +669,17 @@ HRESULT WINAPI ScriptItemize(const WCHAR *pwcInChars, int cInChars, int cMaxItem
     /* While not strictly necessary according to the spec, make sure the n+1
      * item is set up to prevent random behaviour if the caller erroneously
      * checks the n+1 structure                                              */
-    memset(&pItems[index+1].a, 0, sizeof(SCRIPT_ANALYSIS));
+    index++;
+    memset(&pItems[index].a, 0, sizeof(SCRIPT_ANALYSIS));
 
-    TRACE("index=%d cnt=%d iCharPos=%d\n", index+1, cnt, pItems[index+1].iCharPos);
+    TRACE("index=%d cnt=%d iCharPos=%d\n", index, cnt, pItems[index].iCharPos);
 
     /*  Set one SCRIPT_STATE item being returned  */
-    if (pcItems) *pcItems = index + 1;
+    if  (index + 1 > cMaxItems) return E_OUTOFMEMORY;
+    if (pcItems) *pcItems = index;
 
     /*  Set SCRIPT_ITEM                                     */
-    pItems[index+1].iCharPos = cnt;       /* the last + 1 item
-                                             contains the ptr to the lastchar */
+    pItems[index].iCharPos = cnt;         /* the last item contains the ptr to the lastchar */
     heap_free(levels);
     return S_OK;
 }