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Stephan Bergmann 73eed7cfe0 Properly fix use of uninitialized value

Following up on 66322c5f4a5465c74fa3ceefaa2f76e86a277c16 "Silence warning C4701:
potentially uninitialized local variable" (which had apparently wrongly assumed
that that MSVC warning was a false positive) and
b1a6bd87b803f760f5bf0e2b7bc519b3b2fbfa4e "ofz: Use-of-uninitialized-value in
ImplConvertUtf8ToUnicode", which had demonstrated that this was indeed a true
positive, as per the comment at
<https://gerrit.libreoffice.org/c/core/+/168079/2#message-8b941c986658cb41641c0a317937bd0d3574e0b9>
"ofz: Use-of-uninitialized-value in ImplConvertUtf8ToUnicode", and which could
also be observed with a local patch of

> diff --git a/sal/textenc/tcvtutf8.cxx b/sal/textenc/tcvtutf8.cxx
> index 05290cc204fd..319acd41c627 100644
> --- a/sal/textenc/tcvtutf8.cxx
> +++ b/sal/textenc/tcvtutf8.cxx
> @@ -56,7 +56,7 @@ void ImplResetUtf8ToUnicodeContext(void * pContext)
>  {
>      if (pContext != nullptr)
>      {
> -        static_cast< ImplUtf8ToUnicodeContext * >(pContext)->nBytes = int();
> +        static_cast< ImplUtf8ToUnicodeContext * >(pContext)->nBytes = 1234;
>          static_cast< ImplUtf8ToUnicodeContext * >(pContext)->nShift = -1;
>          static_cast< ImplUtf8ToUnicodeContext * >(pContext)->bCheckBom = true;
>      }
> @@ -74,7 +74,7 @@ sal_Size ImplConvertUtf8ToUnicode(
>  {
>      bool bJavaUtf8 = pData != nullptr;
>      sal_uInt32 nUtf32 = 0;
> -    int nBytes = int();
> +    int nBytes = 1234;
>      int nShift = -1;
>      bool bCheckBom = true;
>      sal_uInt32 nInfo = 0;
> @@ -208,6 +208,7 @@ sal_Size ImplConvertUtf8ToUnicode(
>          continue;
>
>      bad_input:
> +        assert(nBytes != 1234);
>          switch (sal::detail::textenc::handleBadInputTextToUnicodeConversion(
>                      false, nBytes != 1, 0, nFlags, &pDestBufPtr, pDestBufEnd,
>                      &nInfo))

and seeing CppunitTest_sal_rtl CPPUNIT_TEST_NAME=Test::testInvalidUtf8 fail by
hitting that assert.

So initialize nBytes to 1 to make that bad_input scenario call
handleBadInputTextToUnicodeConversion with a bMultiByte=false argument.

Change-Id: Ib8a326d497071f4249169e9d4f5871f06cfccbdf
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/168181
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <stephan.bergmann@allotropia.de>

2024-05-29 12:08:43 +02:00