testmain.c

写程序是经常遇到内存不足,这个程序可以自动释放不用的内存

/*
______________________________________________________________________________________

					Designed by: 
					Niraj Kedar,
					Systems Engineer,
					L&T Infotech Ltd,
					Bangalore, India.

					e-mail: [e-mail]

					Date:	July, 2001.

______________________________________________________________________________________
*/

#include "recycle.h"

//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
// enumerated return type
typedef enum RETURN_TYPE
{
	// equating the 'success' enum with the value of MALLOC_SUCCESS
	SUCCESS = SET_SUCCESS_VAL,
	FAIL, // failure condition
	INVALID, // some other conditions

}RETURN_TYPE;

//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
// a sample link-list data structure.
typedef struct node
{
	int data;
	struct node* pNext;
}node;

typedef struct handle
{
	node* pHead;
}handle;
//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

// test functions.
RETURN_TYPE Trial1();
RETURN_TYPE Trial2();
RETURN_TYPE Trial3();
RETURN_TYPE Trial4();

// prints the final values of all the variables.
void PrintAll();
//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

// global pointers
char*	pCh = 0;
int*	pInt = 0;


// global hadle object of the sample link-list.
handle hdl;

// macro for declaring the global Recycle stack handle object.
// protect this with some mutual exclusion mechanism in multithreaded environments.
DECL_STACK_HANDLE;

main()
{
	// return type variable
	RETURN_TYPE ret;
	
	// use the macro for initializing Recycle stack handle
	MEMSET_STACK_HANDLE;	

	// call the function Trial1()
	ret = Trial1();

	PrintAll();
}

RETURN_TYPE Trial1()
{
	// return type variable
	RETURN_TYPE ret;
	
	// set the function scope by using this macro.
	SET_FN_SCOPE(Trial1);
	
	// allocate memory for a character array. Type of memory - persistant
	if((ret = Allocate(6, &pCh, GET_FN_SCOPE, MALLOC_SUCCESS)) != MALLOC_SUCCESS)
	{
		printf("memory allocation failed...\n");
		RETURN(ret);
	}

	// copy some string
	strcpy(pCh, "Niraj");
	// trial print
	printf("\nThe value of pCh in Trial1() is %s\n", pCh);

	// call Trial2()
	ret = Trial2();
	
	// use this macro in place of normal return statements
	RETURN(ret);
//	RETURN(MALLOC_FAIL); // for test
}

RETURN_TYPE Trial2()
{
	RETURN_TYPE ret;
	SET_FN_SCOPE(Trial2);

	int iTemp = 1024;
	
	// allocate memory for a character array. Type of memory - out of scope
	if((ret = Allocate(sizeof(int), &pInt, GET_FN_SCOPE, OUT_OF_SCOPE)) != MALLOC_SUCCESS)
	{
		printf("memory allocation failed...\n");
		RETURN(ret);
	}

	// copy value
	memcpy(pInt, &iTemp, sizeof(int));

	printf("\nThe value in pInt in Trial2() is %d\n", *pInt);

	//call Trial3()
	ret = Trial3();

	RETURN(ret);
//	RETURN(MALLOC_SUCCESS); // for trial
}

RETURN_TYPE Trial3()
{
	RETURN_TYPE ret;
	SET_FN_SCOPE(Trial3);

	node* pTemp = 0;
	node* pNew = 0;
	node* pHead = 0;

	short iCnt = 0;
	
	
	// allocate memory for a linklist. Type of  memory - persistant
	while(iCnt++ < 10)
	{
		if((ret = Allocate(sizeof(node), &pNew, GET_FN_SCOPE, MALLOC_SUCCESS)) != MALLOC_SUCCESS)
		{
			printf("memory allocation failed...\n");
			RETURN(ret);
		}

		pNew->data = iCnt;
		pNew->pNext = 0;

		if(pHead == 0)
			pTemp = pHead = pNew;
		else
		{
			pTemp->pNext = pNew;
			pTemp = pTemp->pNext;
		}
	}

	hdl.pHead = pHead;

	ret = Trial4();

	RETURN(ret);
//	RETURN(MALLOC_FAIL); for trial
}

RETURN_TYPE Trial4()
{
	RETURN_TYPE ret;
	SET_FN_SCOPE(Trial4);
	
	RETURN(MALLOC_SUCCESS);
}

void PrintAll()
{
	node* pIter = 0;

	// print all final values
	printf("Final value of char array is %s\n\n", pCh);
	
	printf("Final Value of pInt is %d\n\n", *pInt);

	printf("printing Final linklist...\n\n");

	for(pIter = hdl.pHead; pIter != 0; pIter = pIter->pNext)
	{
		printf("%d\n", pIter->data);
	}
	printf("\n\n");
}