#include <stdio.h>
#include <stdlib.h>
#include "MailManager.h"

MailManager::MailManager(void)
    :mailQueuePool(NULL), freeMailQueue(NULL) {}

MailManager::~MailManager(void) { destroy(); }

int
MailManager::init(int num)
{
    if (!mailQueuePool) {
	return extend_pool(num);
    }
    return 0;
}

int
MailManager::extend_pool(int num)
{
    MailQueuePtr q;
	
    q = (MailQueuePtr)malloc(sizeof(MailQueue)*(num+1));
	
    if (q == NULL) {
	return -1;
    }
    q->next = mailQueuePool;
    mailQueuePool = q;
	
    /* Connect all free queue in the pool */
    for (q = mailQueuePool + 1; --num > 0; q++) {
	q->next = q + 1;
    }
    q->next = freeMailQueue;
    freeMailQueue = mailQueuePool + 1;
	
    return 0;
}

MailQueuePtr
MailManager::create(memaddr data)
{
    MailQueuePtr q;
	
    if (!freeMailQueue) {
	extend_pool(30);
    }
    q = freeMailQueue;
    freeMailQueue = freeMailQueue->next;
	
    q->data = data;
    q->next = NULL;
	
    return q;
}

void
MailManager::free(MailQueuePtr q)
{
    q->next = freeMailQueue;
    freeMailQueue = q;
}


void
MailManager::destroy(void)
{
    MailQueuePtr q;

#if 0
    for (q = mailQueuePool; q; q = q->next) {
	free(q);
    }
#else
    q = mailQueuePool;
    while (q) {
	MailQueuePtr tmp = q->next;
	free(q);
	q = tmp;
    }
#endif
    freeMailQueue = mailQueuePool = NULL;
}


MailQueuePtr
MailManager::append_mailQueue(MailQueuePtr list, MailQueuePtr q)
{
    MailQueuePtr p = list;
	
    if (p == NULL) {
	return q;
    } else {
	while(p->next) p = p->next;
	p->next = q;
	return list;
    }
}

int
MailManager::length(MailQueuePtr list)
{
    MailQueuePtr p = list;
    MailQueuePtr q = p;
    int i = 0;

    while(p) {
	i++;
	p=p->next;
	if (i%2==0) {
	    q = q->next;
	}
	if (p==q)
	    return -1; // means loop
    }
    return i;
}

/* end */