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// ClassPool implementation
#include "classpool.h"
#include <stdlib.h> // for malloc, free
#include <iostream>
using std::cout;
using std::cerr;
using std::endl;
#include <exception> // for std::bad_alloc
using std::bad_alloc;
// Globals
bool ClassPool::empty = true;
int ClassPool::next = 0;
void* ClassPool::pool[MAX_MEMORY];
ClassPool::ClassPool() {
cout << "Constructing an object" << endl;
}
ClassPool::~ClassPool() {
cout << "Destroying an object" << endl;
}
// ClassPool's default constructor implicitly called here
void* ClassPool::operator new (size_t size) {
cout << "Allocate memory size to pool: " << size << endl;
void *p = allocate_from_pool(size);
return p;
}
// ClassPool's destructor implicitly called at this point
void ClassPool::operator delete (void *p) {
// return memory to pool
cout << "return memory to pool: " << p << endl;
release(p);
}
void* ClassPool::allocate_from_pool(size_t size) {
if ( empty ) {
empty = false;
cout << "Allocating memory for " << MAX_MEMORY << " items." << endl;
for (int i=0; i < MAX_MEMORY; i++) pool[i] = malloc(size);
for (int i=0; i < MAX_MEMORY; i++) cout << i << ": " << pool[i] << endl;
}
if ( next >= MAX_MEMORY ) {
cerr << "Out of memory!" << endl;
throw std::bad_alloc(); // ANSI/ISO compliant behavior
// exit(12); // Can not allocate memory on Red Had linux
}
next++;
return pool[next-1];
}
void ClassPool::release (void *p) {
int index = 0;
void* ptr;
cout << "releasing this memory: " << p << endl;
// shuffle memory references till the free memory is at the end
while ( index < MAX_MEMORY && p != pool[index] ) {
cout << index << " : " << pool[index] << endl;
++index;
}
if ( index == MAX_MEMORY ) { // found nothing?
cout << "No memory match in pool" << endl;
return;
} else if ( next == 0 ) { // allocated nothing?
cout << "No memory in pool" << endl;
return;
}
cout << "Memory pointer found in index: " << index<< endl;
cout << "Current pointer: " << next << endl;
ptr = pool[index];
next--;
pool[index] = pool[next];
pool[next] = ptr;
cout << "New pointer: " << next << endl;
cout << "Memory restored to pool: " << ptr << endl;
}
void ClassPool::release_all() {
empty = true;
cout << "Releasing " << MAX_MEMORY << " items in class memory pool" << endl;
for (int i=0; i < MAX_MEMORY; i++) cout << i << ": " << pool[i] << endl;
for (int i = 0; i < MAX_MEMORY; ++i) free(pool[i]), pool[i] = NULL;
next = 0;
}
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