odbccp32: Implement SQLGetPrivateProfileString (try 6 - resend)

[Hugh McMaster]

>+    LONG ret = 0;
>+    HKEY hkey;
>+    DWORD size = 0;
>+    BOOL usedefault = TRUE;
>+
/* snip */
>+    clear_errors();
>+
>+    if(!cbRetBuffer)
>+       return 0;
>+
>+    if(RetBuffer)
>+        RetBuffer[0] = 0;
>+
>+    if(!lpszSection || !lpszEntry || !lpszDefault || !RetBuffer || !cbRetBuffer)
>+        return ret;

You are checking "if (!cbRetBuffer)" twice. Same in the next function.

You don't need to clear RetBuffer. RegGetValue adds a null terminating character if it doesn't already exist.

You also "return 0" and "return ret". They are the same at the moment, so be consistent.

>+size = cbRetBuffer;
>+if(RegGetValueW(hkeysect, NULL, lpszEntry, RRF_RT_REG_SZ, &type, RetBuffer, &size) == ERROR_SUCCESS)

cbRetBuffer is the size in characters of the buffer pointed to by RetBuffer.[1]
size needs to be in bytes, so unless RetBuffer uses char, this is wrong.

>+    ret = SQLGetPrivateProfileStringW(sect, entry, string, retval, cbRetBuffer, file);
>+    if(ret)
>+    {
>+        WideCharToMultiByte(CP_ACP, 0, retval, -1, RetBuffer, ret+1, NULL, NULL);
>+    }

This doesn't look right to me. "ret+1" should be the size, in bytes, of RetBuffer. [2]

[1] https://msdn.microsoft.com/en-us/library/windows/desktop/ms724868%28v=vs.85%29.aspx
[2] https://msdn.microsoft.com/en-us/library/windows/desktop/dd374130%28v=vs.85%29.aspx