/***
*mbsncpy_s.inl - general implementation of _mbsncpy_s and _mbsnbcpy_s
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
* This file contains the general algorithm for _mbsncpy_s and _mbsnbcpy_s.
*
* _COUNT_IN_BYTES defined to 1 implements _mbsnbcpy_s
* _COUNT_IN_BYTES defined to 0 implements _mbsncpy_s
*
****/
_FUNC_PROLOGUE
#if _USE_LOCALE_ARG
errno_t __cdecl _FUNC_NAME(unsigned char *_DEST, size_t _SizeInBytes, const unsigned char *_SRC, size_t _COUNT, _LOCALE_ARG_DECL)
#else /* _USE_LOCALE_ARG */
errno_t __cdecl _FUNC_NAME(unsigned char *_DEST, size_t _SizeInBytes, const unsigned char *_SRC, size_t _COUNT)
#endif /* _USE_LOCALE_ARG */
{
unsigned char *p;
size_t available;
BOOL fFoundInvalidMBC;
BOOL fIsLeadPrefix;
fFoundInvalidMBC = FALSE;
if (_COUNT == 0 && _DEST == NULL && _SizeInBytes == 0)
{
/* this case is allowed; nothing to do */
_RETURN_NO_ERROR;
}
/* validation section */
_VALIDATE_STRING(_DEST, _SizeInBytes);
if (_COUNT == 0)
{
/* notice that the source string pointer can be NULL in this case */
_RESET_STRING(_DEST, _SizeInBytes);
_RETURN_NO_ERROR;
}
_VALIDATE_POINTER_RESET_STRING(_SRC, _DEST, _SizeInBytes);
#if _USE_LOCALE_ARG
_LOCALE_UPDATE;
if (_LOCALE_SHORTCUT_TEST)
{
return _SB_FUNC_NAME((char *)_DEST, _SizeInBytes, (const char *)_SRC, _COUNT);
}
#endif /* _USE_LOCALE_ARG */
p = _DEST;
available = _SizeInBytes;
if (_COUNT == _TRUNCATE)
{
while ((*p++ = *_SRC++) != 0 && --available > 0)
{
}
/*
* loop terminates with either:
* - src, p pointing 1 byte past null, avail includes the null
* - available == 0, p points 1 past end of dst buffer
*/
}
else
{
_ASSERT_EXPR((!_CrtGetCheckCount() || _COUNT < _SizeInBytes), L"Buffer is too small");
#if _COUNT_IN_BYTES
while ((*p++ = *_SRC++) != 0 && --available > 0 && --_COUNT > 0)
{
}
/*
* loop terminates with either:
* - p points 1 byte past null, avail includes null, count includes null
* - available == 0, p points 1 past end of dst buffer (inaccessible)
* - count == 0, p points 1 past last written byte, space available in dst buffer
*
* always p[-1] is written.
* sometimes p[-1] is null.
*/
#else /* _COUNT_IN_BYTES */
/* at this point, avail count be 1. */
/* Need to track lead-byte context in order to track character count. */
do
{
if (_ISMBBLEAD(*_SRC))
{
if (_SRC[1] == 0)
{
/*
* Invalid MBC, write null to dst string, we are finished
* copying. We know that available is >= 1, so there is
* room for the null termination. If we decrement available
* then we will incorrectly report BUFFER_TOO_SMALL.
*/
*p++ = 0;
fFoundInvalidMBC = TRUE;
break;
}
if (available {
/* not enough space for a dbc and null */
available = 0;
break;
}
*p++ = *_SRC++;
*p++ = *_SRC++;
available -= 2;
}
else
{
if ((*p++ = *_SRC++) == 0 || --available == 0)
{
break;
}
}
}
while (--_COUNT > 0);
#endif /* _COUNT_IN_BYTES */
/* If count == 0 then at least one byte was copied and available is still > 0 */
if (_COUNT == 0)
{
*p++ = 0;
/* Note that available is not decremented here. */
}
}
if (available == 0)
{
#if _COUNT_IN_BYTES
/*
* For COUNT_IN_BYTES, the above loop copied at least one byte so src,p point
* past a written byte.
*/
if (*_SRC == 0 || _COUNT == 1)
{
fIsLeadPrefix = FALSE;
_ISMBBLEADPREFIX(fIsLeadPrefix, _DEST, &p[-1]);
if (fIsLeadPrefix)
{
/* the source string ended with a lead byte: we remove it */
p[-1] = 0;
_RETURN_MBCS_ERROR;
}
}
#endif /* _COUNT_IN_BYTES */
if (_COUNT == _TRUNCATE)
{
if (fFoundInvalidMBC)
{
_SET_MBCS_ERROR;
}
if (_SizeInBytes > 1)
{
fIsLeadPrefix = FALSE;
/* Check if 2nd to last copied byte acted as a lead.
* Do not set mbcs error because we are truncating.
*/
_ISMBBLEADPREFIX(fIsLeadPrefix,_DEST,&_DEST[_SizeInBytes - 2]);
if (fIsLeadPrefix)
{
_DEST[_SizeInBytes - 2] = 0;
_FILL_BYTE(_DEST[_SizeInBytes - 1]);
_RETURN_TRUNCATE;
}
}
_DEST[_SizeInBytes - 1] = 0;
_RETURN_TRUNCATE;
}
_RESET_STRING(_DEST, _SizeInBytes);
_RETURN_BUFFER_TOO_SMALL(_DEST, _SizeInBytes);
}
#if _COUNT_IN_BYTES
/*
* COUNT_IN_BYTES copy loop doesn't track lead-byte context, so can't detect
* invalid mbc. Detect them here.
* available < _SizeInBytes means that at least one byte was copied so p is >= &dstBuffer[1]
*/
if ((p - _DEST) >= 2)
{
_ISMBBLEADPREFIX(fIsLeadPrefix, _DEST,&p[-2]);
if (fIsLeadPrefix)
{
/* the source string ended with a lead byte: we remove it */
p[-2] = 0;
available++;
fFoundInvalidMBC = TRUE;
}
}
#endif /* _COUNT_IN_BYTES */
_FILL_STRING(_DEST, _SizeInBytes, _SizeInBytes - available + 1);
if (fFoundInvalidMBC)
{
_RETURN_MBCS_ERROR;
}
_RETURN_NO_ERROR;
}
