Pool allocator implementation - c++

Question

I have two questions about pool allocator implementation:
In given pool allocator implementation how can I check that void*
pointer that I pass to deallocate function is exactly one of those
that I allocated previously?
What should I do to allocate size
of memory bigger than size of block? Just calculate amount of blocks
that would be enough to fit given size and move my next free element pointer x blocks forward, where x is amount of blocks I need ?
class Pool_c { // Basic type define
typedef unsigned int uint;
typedef unsigned char uchar;
uint m_numOfBlocks; // Num of blocks
uint m_sizeOfEachBlock; // Size of each block
uint m_numFreeBlocks; // Num of remaining blocks
uint m_numInitialized; // Num of initialized blocks
uchar* m_memStart; // Beginning of memory pool
uchar* m_next; // Num of next free block
public:
Pool_c()
{
m_numOfBlocks = 0;
m_sizeOfEachBlock = 0;
m_numFreeBlocks = 0;
m_numInitialized = 0;
m_memStart = NULL;
m_next = 0;
}
~Pool_c() { DestroyPool(); }
void CreatePool(size_t sizeOfEachBlock,
uint numOfBlocks)
{
m_numOfBlocks = numOfBlocks;
m_sizeOfEachBlock = sizeOfEachBlock;
m_memStart = new uchar[m_sizeOfEachBlock * m_numOfBlocks];
m_numFreeBlocks = numOfBlocks;
m_next = m_memStart;
}
void DestroyPool()
{
delete[] m_memStart;
m_memStart = NULL;
}
uchar* AddrFromIndex(uint i) const
{
return m_memStart + (i * m_sizeOfEachBlock);
}
uint IndexFromAddr(const uchar* p) const
{
return (((uint)(p - m_memStart)) / m_sizeOfEachBlock);
}
void* Allocate()
{
if (m_numInitialized < m_numOfBlocks) {
uint* p = (uint*)AddrFromIndex(m_numInitialized);
*p = m_numInitialized + 1;
m_numInitialized++;
}
void* ret = NULL;
if (m_numFreeBlocks > 0) {
ret = (void*)m_next;
--m_numFreeBlocks;
if (m_numFreeBlocks != 0) {
m_next = AddrFromIndex(*((uint*)m_next));
}
else {
m_next = NULL;
}
}
return ret;
}
void DeAllocate(void* p)
{
if (m_next != NULL) {
(*(uint*)p) = IndexFromAddr(m_next);
m_next = (uchar*)p;
}
else {
*((uint*)p) = m_numOfBlocks;
m_next = (uchar*)p;
}
++m_numFreeBlocks;
}