Example 1
Author: Ambreen Ilyas

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//// This example is from the ACE Programmers Guide.
//// Chapter: "Memory Management"
//// For details please see the guide at
//// http://www.cs.wustl.edu/~schmidt/ACE.html
//// AUTHOR: Umar Syyid (usyyid@hns.com)
//// and Ambreen Ilyas (ambreen@bitsmart.com)
/////////////////////////////////////////////////////////////////////////////////////////////////////////////

//Example 1
#include "ace/Malloc.h"
//A chunk of size 1K is created
typedef char MEMORY_BLOCK[1024];

//Create an ACE_Cached_Allocator which is passed in the type of the
//chunk that it must pre-allocate and assign on the free
//list
typedef ACE_Cached_Allocator<MEMORY_BLOCK,ACE_SYNCH_MUTEX> Allocator;
class MessageManager{
public:
//The constructor is passed the number of chunks that the allocator should pre-allocate //and maintain on its free list.
MessageManager(int n_blocks):
allocator_(n_blocks),message_count_(0){}

//Allocate memory for a message using the Allocator
void allocate_msg(const char *msg){
mesg_array_[message_count_]=
(char*)allocator_.malloc(ACE_OS::strlen(msg));
ACE_OS::strcpy(mesg_array_[message_count_],msg);
message_count_++;
}

//Free all memory allocated. This will cause the chunks to be returned
//to the allocators internal free list and NOT to the OS.
void free_all_msg(){
for(int i=0;i<message_count_;i++)
allocator_.free(mesg_array_[i]);
message_count_=0;
}
void display_all_msg(){
for(int i=0;i<message_count_;i++)
ACE_OS::printf("%s\n",mesg_array_[i]);
}
private:
char *mesg_array_[20];
Allocator allocator_;
int message_count_;
};

int main(int argc, char* argv[]){

if(argc<2){
ACE_OS::printf("Usage: egXX <Number of blocks>\n");
exit(1);
}
//Instatiate the Memory Manager class
int n_blocks=ACE_OS::atoi(argv[1]);
MessageManager mm(n_blocks);

//Use the Memory Manager class to assign messages and free them. Run this in your
//debug environment and you will notice that //the amount of memory your program uses
//after Memory Manager has been instantiated remains the same. That means the
//Cached Allocator controls or manages all the memory for the application.

//Do forever.
while(1){
//allocate the messages somewhere
for(int i=0; i<n_blocks;i++)
mm.allocate_msg("Hi there");
//show the messages
mm.display_all_msg();
for( i=0;i<n_blocks;i++)
mm.free_all_msg();
}
}

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