Issue reading / writing a dynamic BYTE array to the registry [duplicate] - arrays

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How to get size of dynamic array in C++ [duplicate]
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Closed 6 years ago.
I have this method that initializes a buffer:
void CCreateReportDlg::InitAutoAssignStates()
{
int iNumColumns = m_Grid.GetColumnCount();
ASSERT(m_pbyAutoAssignStates == NULL);
if (m_pbyAutoAssignStates == NULL)
{
m_pbyAutoAssignStates = new BYTE[iNumColumns];
if (m_pbyAutoAssignStates != NULL)
{
// This sets them all to AUTO_ASSIGN_INCLUDE
ZeroMemory(m_pbyAutoAssignStates, iNumColumns * sizeof(BYTE));
// DATE is never used for auto assign
m_pbyAutoAssignStates[COLUMN_DATE] = AUTO_ASSIGN_NOT_USED;
}
}
}
So far, so good. This buffer gets passed into a dialog class.
// Receives pointer to a BYTE* array.
// This is owned by the parent.
void CAutoAssignSettingsDlg::SetAutoAssignStates(BYTE *pbyAutoAssignStates)
{
m_pbyAutoAssignStates = pbyAutoAssignStates;
}
No problems there. I then have a checked list on the dialog that is mapped to each of the states in the above buffer.
When the popup dialog is about to close it revises the buffer:
void CAutoAssignSettingsDlg::UpdateAutoAssignStates()
{
LVITEM sItem;
int iAssign, iNumAssign;
if (m_pbyAutoAssignStates != NULL)
{
sItem.mask = LVIF_IMAGE|LVIF_PARAM;
sItem.iSubItem = 0;
iNumAssign = m_listAssign.GetItemCount();
for (iAssign = 0; iAssign < iNumAssign; iAssign++)
{
sItem.iItem = iAssign;
m_listAssign.GetItem(&sItem);
if (sItem.iImage == IMG_CHECKED)
m_pbyAutoAssignStates[sItem.lParam] = AUTO_ASSIGN_EXCLUDE;
else
m_pbyAutoAssignStates[sItem.lParam] = AUTO_ASSIGN_INCLUDE;
}
}
}
This all works. But then I want to save it to the registry. At the moment I do it like this:
theApp.WriteProfileBinary(strSection, _T("AssignStates"), m_pbyAutoAssignStates, sizeof(m_pbyAutoAssignStates));
Finally, in the parent dialog, I adjusted the code that reads the settings in from the registry. So now, before the InitAutoAssignStates call I do this:
theApp.GetProfileBinary(strSection,_T("AssignStates"), &ppData, &uSize);
if (uSize > 0)
{
m_pbyAutoAssignStates = new BYTE[uSize];
memcpy(m_pbyAutoAssignStates, ppData, uSize);
}
// Tidy memory
if (uSize != 0)
{
delete[] ppData;
ppData = NULL;
}
The subsequent InitAutoAssignStates method is only called now if the buffer is NULL. So in theory I shoudlread back in the buffer that I saved. But it is not working. The set of items ticked in my check boxes do not match.
What am I doing wrong?

Answer 1

I found a related question that said you could not do what I was trying to achieve without knowing the number of elements. This did surprise me but I am not going to argue.
I adjusted my code to pass in the number of elements to the popup dialog and then I was able to save like this:
theApp.WriteProfileBinary(strSection, _T("AssignStates"),
m_pbyAutoAssignStates,
sizeof(m_pbyAutoAssignStates[0]) * m_iNumAutoAssignStateValues);
This works correctly. When I read this buffer back I get matching check boxes in my list.