/********************************************************************
StrAllocString - allocates or reuses dynamic string memory and copies in an existing string
NOTE: caller is responsible for freeing ppwz even if function fails
NOTE: cchSource does not have to equal the length of wzSource
NOTE: if cchSource == 0, length of wzSource is used instead
********************************************************************/
extern "C" HRESULT DAPI StrAllocString(
__inout LPWSTR* ppwz,
__in LPCWSTR wzSource,
__in DWORD_PTR cchSource
)
{
Assert(ppwz && wzSource); // && *wzSource);
HRESULT hr = S_OK;
DWORD_PTR cch = 0;
if (*ppwz)
{
cch = MemSize(*ppwz); // 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(WCHAR); //convert the count in bytes to count in characters
}
if (0 == cchSource)
cchSource = lstrlenW(wzSource);
if (cch < cchSource + 1)
{
cch = cchSource + 1; // add one for the null terminator
hr = StrAlloc(ppwz, cch);
ExitOnFailure1(hr, "failed to allocate string from string: %S", wzSource);
}
// copy everything (the NULL terminator will be included)
hr = StringCchCopyNExW(*ppwz, cch, wzSource, cchSource, NULL, NULL, STRSAFE_FILL_BEHIND_NULL);
LExit:
return hr;
}
HRESULT StringCchCopyExW(
LPWSTR pszDest,
size_t cchDest,
LPCWSTR pszSrc,
LPWSTR *ppszDestEnd,
size_t * pcchRemaining,
DWORD dwFlags){
return StringCchCopyNExW(pszDest, cchDest, pszSrc, cchDest,
ppszDestEnd, pcchRemaining, dwFlags);
}
