combase: Implement WindowsSubstring.

dlls/api-ms-win-core-winrt-string-l1-1-0/api-ms-win-core-winrt-string-l1-1-0.spec

@@ -21,7 +21,7 @@
 @ stdcall WindowsPromoteStringBuffer(ptr ptr) combase.WindowsPromoteStringBuffer
 @ stub WindowsReplaceString
 @ stdcall WindowsStringHasEmbeddedNull(ptr ptr) combase.WindowsStringHasEmbeddedNull
-@ stub WindowsSubstring
+@ stdcall WindowsSubstring(ptr long ptr) combase.WindowsSubstring
 @ stub WindowsSubstringWithSpecifiedLength
 @ stub WindowsTrimStringEnd
 @ stub WindowsTrimStringStart

dlls/combase/combase.spec

@@ -302,7 +302,7 @@
 @ stdcall WindowsPromoteStringBuffer(ptr ptr)
 @ stub WindowsReplaceString
 @ stdcall WindowsStringHasEmbeddedNull(ptr ptr)
-@ stub WindowsSubstring
+@ stdcall WindowsSubstring(ptr long ptr)
 @ stub WindowsSubstringWithSpecifiedLength
 @ stub WindowsTrimStringEnd
 @ stub WindowsTrimStringStart

dlls/combase/string.c

@@ -255,6 +255,25 @@ HRESULT WINAPI WindowsStringHasEmbeddedNull(HSTRING str, BOOL *out)
 }
 
 /***********************************************************************
+ *      WindowsSubstring (combase.@)
+ */
+HRESULT WINAPI WindowsSubstring(HSTRING str, UINT32 start, HSTRING *out)
+{
+    struct hstring_private *priv = impl_from_HSTRING(str);
+    UINT32 len = WindowsGetStringLen(str);
+    if (out == NULL)
+        return E_INVALIDARG;
+    if (start > len)
+        return E_BOUNDS;
+    if (start == len)
+    {
+        *out = NULL;
+        return S_OK;
+    }
+    return WindowsCreateString(&priv->buffer[start], len - start, out);
+}
+
+/***********************************************************************
  *      WindowsIsStringEmpty (combase.@)
  */
 BOOL WINAPI WindowsIsStringEmpty(HSTRING str)

include/winerror.h

@@ -2092,6 +2092,7 @@ static inline HRESULT HRESULT_FROM_WIN32(unsigned int x)
 #define S_FALSE                                            _HRESULT_TYPEDEF_(1)
 
 #define E_PENDING                                          _HRESULT_TYPEDEF_(0x8000000A)
+#define E_BOUNDS                                           _HRESULT_TYPEDEF_(0x8000000B)
 
 
 #define E_NOTIMPL                                          _HRESULT_TYPEDEF_(0x80004001)