int strstreambuf::overflow(int meta)
{ // try to extend write area
if (meta == EOF)
return (0); // nothing to write
else if (pptr() != 0 && pptr() < epptr())
return ((unsigned char)(*_Pninc() = meta)); // room in buffer
else if (!(_Strmode & _Dynamic)
|| _Strmode & (_Constant | _Frozen))
return (EOF); // can't extend
else
{ // okay to extend
int oldsize = gptr() == 0 ? 0 : epptr() - eback();
int newsize = oldsize;
int inc = newsize / 2 < _Minsize
? _Minsize : newsize / 2; // grow by 50 per cent if possible
_Minsize = _MINSIZE; // back to default for future growth
char *ptr = 0;
while (0 < inc && INT_MAX - inc < newsize)
inc /= 2; // reduce growth increment if too big
if (0 < inc)
{ // room to grow, increase size
newsize += inc;
ptr = _Palloc != 0 ? (char *)(*_Palloc)(newsize)
: _NEW_CRT char[newsize];
}
if (ptr == 0)
return (EOF); // couldn't grow, return failure
if (0 < oldsize)
memcpy(ptr, eback(), oldsize); // copy existing buffer
if (!(_Strmode & _Allocated))
; // no buffer to free
else if (_Pfree != 0)
(*_Pfree)(eback()); // free with function call
else
_DELETE_CRT_VEC(eback()); // free by deleting array
_Strmode |= _Allocated;
if (oldsize == 0)
{ // set up new buffer
_Seekhigh = ptr;
setp(ptr, ptr + newsize);
setg(ptr, ptr, ptr);
}
else
{ // revise old pointers
_Seekhigh = _Seekhigh - eback() + ptr;
setp(pbase() - eback() + ptr, pptr() - eback() + ptr,
ptr + newsize);
setg(ptr, gptr() - eback() + ptr, pptr() + 1);
}
return ((unsigned char)(*_Pninc() = meta));
}
_CRTIMP2 int strstreambuf::overflow(int ch)
{ // try to extend write area
if (ch == EOF)
return (0);
else if (pptr() != 0 && pptr() < epptr())
return ((unsigned char)(*_Pninc() = (char)ch));
else if (!(_Strmode & _Dynamic)
|| _Strmode & (_Constant | _Frozen))
return (EOF);
else
{ // okay to extend
int osize = gptr() == 0 ? 0 : epptr() - eback();
int nsize = osize + _Alsize;
char *p = _Palloc != 0 ? (char *)(*_Palloc)(nsize)
: new char[nsize];
if (p == 0)
return (EOF);
if (0 < osize)
memcpy(p, eback(), osize);
else if (_ALSIZE < _Alsize)
_Alsize = _ALSIZE;
if (!(_Strmode & _Allocated))
;
else if (_Pfree != 0)
(*_Pfree)(eback());
else
delete[] eback();
_Strmode |= _Allocated;
if (osize == 0)
{ // setup new buffer
_Seekhigh = p;
setp(p, p + nsize);
setg(p, p, p);
}
else
{ // revise old pointers
_Seekhigh = _Seekhigh - eback() + p;
setp(pbase() - eback() + p, pptr() - eback() + p,
p + nsize);
setg(p, gptr() - eback() + p, pptr() + 1);
}
return ((unsigned char)(*_Pninc() = (char)ch));
}
}
