/********************************************************************
StrAnsiAllocFormattedArgs - allocates or reuses dynamic ANSI string memory
and formats it with the passed in args
NOTE: caller is responsible for freeing ppsz even if function fails
********************************************************************/
extern "C" HRESULT DAPI StrAnsiAllocFormattedArgs(
__inout LPSTR* ppsz,
__in LPCSTR szFormat,
__in va_list args
)
{
Assert(ppsz && szFormat && *szFormat);
HRESULT hr = S_OK;
DWORD_PTR cch = *ppsz ? MemSize(*ppsz) / sizeof(CHAR) : 0;
LPSTR pszOriginal = NULL;
DWORD cchOriginal = 0;
if (*ppsz)
{
cch = MemSize(*ppsz); // get the count in bytes so we can check if it failed (returns -1)
if (-1 == cch)
ExitOnFailure(hr = E_INVALIDARG, "failed to get size of destination string");
cch /= sizeof(CHAR); //convert the count in bytes to count in characters
cchOriginal = lstrlenA(*ppsz);
}
if (0 == cch) // if there is no space in the string buffer
{
cch = 256;
hr = StrAnsiAlloc(ppsz, cch);
ExitOnFailure1(hr, "failed to allocate string to format: %s", szFormat);
}
// format the message (grow until it fits or there is a failure)
do
{
hr = StringCchVPrintfA(*ppsz, cch, szFormat, args);
if (STRSAFE_E_INSUFFICIENT_BUFFER == hr)
{
if (!pszOriginal)
{
// this allows you to pass the original string as a formatting argument and not crash
// save the original string and free it after the printf is complete
pszOriginal = *ppsz;
*ppsz = NULL;
// StringCchVPrintfW starts writing to the string...
// NOTE: this hack only works with sprintf(&pwz, "%s ...", pwz, ...);
pszOriginal[cchOriginal] = 0;
}
cch *= 2;
hr = StrAnsiAlloc(ppsz, cch);
ExitOnFailure1(hr, "failed to allocate string to format: %S", szFormat);
hr = S_FALSE;
}
} while (S_FALSE == hr);
ExitOnFailure(hr, "failed to format string");
LExit:
ReleaseStr((void*) pszOriginal);
return hr;
}
/********************************************************************
ResReadStringAnsi
NOTE: ppszString should be freed with StrFree()
********************************************************************/
extern "C" HRESULT DAPI ResReadStringAnsi(
__in HINSTANCE hinst,
__in UINT uID,
__deref_out_z LPSTR* ppszString
)
{
Assert(hinst && ppszString);
HRESULT hr = S_OK;
DWORD cch = 64; // first guess
DWORD cchReturned = 0;
do
{
hr = StrAnsiAlloc(ppszString, cch);
ExitOnFailureDebugTrace1(hr, "Failed to allocate string for resource id: %d", uID);
#pragma prefast(push)
#pragma prefast(disable:25068)
cchReturned = ::LoadStringA(hinst, uID, *ppszString, cch);
#pragma prefast(pop)
if (0 == cchReturned)
{
ExitWithLastError1(hr, "Failed to load string resource id: %d", uID);
}
// if the returned string count is one character too small, it's likely we have
// more data to read
if (cchReturned + 1 == cch)
{
cch *= 2;
hr = S_FALSE;
}
} while (S_FALSE == hr);
ExitOnFailure1(hr, "failed to load string resource id: %d", uID);
LExit:
return hr;
}
