125 lines
2.8 KiB
C
125 lines
2.8 KiB
C
|
/*
|
||
|
|
* BSTRING.H
|
||
|
|
*
|
||
|
|
* Defines a BSTRING C++ class that allows us to wrap the OLE BSTR (Basic
|
||
|
|
* String) type, primarily to simplify the creation and freeing of these
|
||
|
|
* objects. This is intended to be a lightweight wrapper with minimal
|
||
|
|
* overhead.
|
||
|
|
*
|
||
|
|
* If no input string is specified to the constructor or if the allocation
|
||
|
|
* of the BSTR fails, then the <m_bstr> member is set to NULL.
|
||
|
|
*
|
||
|
|
* Note: The BSTRING class is not intended to allow managing multiple BSTR
|
||
|
|
* strings with a single object.
|
||
|
|
*
|
||
|
|
* Usage scenarios:
|
||
|
|
*
|
||
|
|
* 1) Create a BSTR from an existing string, have it automatically freed
|
||
|
|
* when done.
|
||
|
|
*
|
||
|
|
* // Allocate BSTR using SysAllocString()
|
||
|
|
* BSTRING bstrComputerName(lpstrComputerName);
|
||
|
|
*
|
||
|
|
* ...
|
||
|
|
*
|
||
|
|
* // Automatic, lightweight cast to BSTR
|
||
|
|
* SomeFunctionThatTakesABSTR(bstrComputerName);
|
||
|
|
*
|
||
|
|
* ...
|
||
|
|
*
|
||
|
|
* // SysFreeString() gets called automatically when the scope of
|
||
|
|
* // bstrComputerName ends.
|
||
|
|
*
|
||
|
|
* 2) Create a null BSTRING object, pass it to a function that returns an
|
||
|
|
* allocated BSTR, then have it automatically freed when done.
|
||
|
|
*
|
||
|
|
* // Create null BSTRING
|
||
|
|
* BSTRING bstrReturnedComputerName;
|
||
|
|
*
|
||
|
|
* ...
|
||
|
|
*
|
||
|
|
* // Call a function that returns an allocated BSTR.
|
||
|
|
* SomeFunctionThatReturnsABSTR(bstrReturnedComputerName.GetLPBSTR());
|
||
|
|
*
|
||
|
|
* ...
|
||
|
|
*
|
||
|
|
* // SysFreeString() gets called automatically when the scope of
|
||
|
|
* // bstrReturnedComputerName ends.
|
||
|
|
*
|
||
|
|
* Author:
|
||
|
|
* dannygl, 29 Oct 96
|
||
|
|
*/
|
||
|
|
|
||
|
|
#if !defined(_BSTRING_H_)
|
||
|
|
#define _BSTRING_H_
|
||
|
|
|
||
|
|
#include <oleauto.h>
|
||
|
|
#include <confdbg.h>
|
||
|
|
|
||
|
|
class BSTRING
|
||
|
|
{
|
||
|
|
private:
|
||
|
|
BSTR m_bstr;
|
||
|
|
|
||
|
|
public:
|
||
|
|
// Constructors
|
||
|
|
BSTRING() {m_bstr = NULL;}
|
||
|
|
|
||
|
|
inline BSTRING(LPCWSTR lpcwString);
|
||
|
|
|
||
|
|
#if !defined(UNICODE)
|
||
|
|
// We don't support construction from an ANSI string in the Unicode build.
|
||
|
|
BSTRING(LPCSTR lpcString);
|
||
|
|
#endif // !defined(UNICODE)
|
||
|
|
|
||
|
|
// Destructor
|
||
|
|
inline ~BSTRING();
|
||
|
|
|
||
|
|
// Cast to BSTR
|
||
|
|
operator BSTR() {return m_bstr;}
|
||
|
|
|
||
|
|
// Get a BSTR pointer.
|
||
|
|
//
|
||
|
|
// This member function is intended for passing this object to
|
||
|
|
// functions that allocate a BSTR, return a pointer to this BSTR,
|
||
|
|
// and expect the caller to free the BSTR when done. The BSTR is
|
||
|
|
// freed when the BSTRING destructor gets called.
|
||
|
|
inline LPBSTR GetLPBSTR(void);
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
BSTRING::BSTRING(LPCWSTR lpcwString)
|
||
|
|
{
|
||
|
|
if (NULL != lpcwString)
|
||
|
|
{
|
||
|
|
// SysAllocString returns NULL on failure
|
||
|
|
m_bstr = SysAllocString(lpcwString);
|
||
|
|
|
||
|
|
ASSERT(NULL != m_bstr);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
m_bstr = NULL;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
BSTRING::~BSTRING()
|
||
|
|
{
|
||
|
|
if (NULL != m_bstr)
|
||
|
|
{
|
||
|
|
SysFreeString(m_bstr);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
inline LPBSTR BSTRING::GetLPBSTR(void)
|
||
|
|
{
|
||
|
|
// This function is intended to be used to set the BSTR value for
|
||
|
|
// objects that are initialized to NULL. It should not be called
|
||
|
|
// on objects which already have a non-NULL BSTR.
|
||
|
|
ASSERT(NULL == m_bstr);
|
||
|
|
|
||
|
|
return &m_bstr;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif // !defined(_BSTRING_H_)
|