C++ array of unsigned char arrays - c++

Question

I'm trying to understand how to create & handle an array of unsigned char arrays in C++. Such as:
Array[0] = { new array of unsigned chars }
Array[1] = { new array of unsigned chars }
Array[2] = { new array of unsigned chars }
....and so on
I've written the next code but I have the feeling that I'm doing something wrong. The code works correctly, but I don't know if the way I declare the "buffer" and how I delete the cache is the correct way, or if it can produce a memory leak.
#define MAX_BUFFER 10
unsigned char* cache[MAX_BUFFER];
bool cache_full = false;
void AddToCache(unsigned char *buffer, const size_t buffer_size)
{
if (cache_full == true)
{
return;
}
for (int index = 0; index < MAX_BUFFER; index++)
{
if (cache[index] == NULL)
{
cache[index] = new unsigned char[buffer_size];
memcpy(cache[index], buffer, buffer_size);
}
if (index < MAX_BUFFER - 1)
{
cache_full = true;
}
}
}
void ClearCache()
{
for (int index = 0; index < MAX_BUFFER; index++)
{
if (cache[index] != NULL)
{
delete[] cache[index];
cache[index] = NULL;
}
}
cache_full = false;
}
bool IsCacheFull()
{
return cache_full;
}

Answer 1

This works?
memcpy(cache, buffer, buffer_size);
It shouldn't. That's overwriting all the pointers in cache with the contents of buffer. In context, this should probably be:
memcpy(cache[index], buffer, buffer_size);
Also, you'll be setting cache_full to true, repeatedly, every time you add to the cache. Try:
AddToCache(unsigned char *buffer, const size_t buffer_size)
{
for (int index = 0; index < MAX_BUFFER; index++)
{
if (cache[index] == NULL)
{
cache[index] = new unsigned char[buffer_size];
memcpy(cache[index], buffer, buffer_size);
return(index); // in case you want to find it again
}
}
// if we get here, we didn't find an empty space
cache_full = true;
return -1;
}