#include "cache.h"



cache_page_t* cache_page_new(cache_t* parent, db_data_t* data)
{
	cache_page_t* cp = NULL;
	cp = (cache_page_t*) malloc(sizeof(cache_page_t));
	if(!cp)
	{
		fprintf(stderr, "Unable to allocate %ld bytes for cache page (cache_page_new())",
												sizeof(cache_page_t));
		perror(" ");
		return NULL;
	}
	
	memset(cp, 0, sizeof(cache_page_t));
	cp->ptr=data;
	cp->page_size=parent->page_size;
	return cp;
}

void cache_page_set_value(cache_page_t* cp, db_interval_t inter, db_data_t* data)
{
	memcpy(cp->ptr, data, sizeof(db_data_t)*cp->page_size);
	cp->inter=inter;
}

void cache_page_insert(cache_page_t* parent, cache_page_t* new)
{
	cache_page_t *tmp = parent->next;
	parent->next=new;
	new->next=tmp;
	new->prev=parent;
	if(tmp) tmp->prev=new;
}

cache_page_t* cache_page_remove(cache_page_t* tr)
{
	if(tr->next)
		tr->next->prev=tr->prev;
	if(tr->prev)
		tr->prev->next=tr->next;
	
	
	tr->next=NULL;
	tr->prev=NULL;
	return tr;
}

void cache_page_free(cache_page_t* tr)
{
	free(tr);
}


int cache_init(cache_t *cache, int page_size_byte, int page_count)
{
	cache_page_t *curr=NULL;
	int i;
	if(!cache) return -1;
	cache->page_count=page_count;
	cache->page_size=(1+page_size_byte)/sizeof(db_data_t*);
	cache->cache=(db_data_t*) malloc((page_count)*page_size_byte);
	if(!cache->cache)
	{
		fprintf(stderr, "Unable to allocate %d bytes for cache (cache_init())",
												(page_count)*page_size_byte);
		perror(" ");
		return -1;
	}
	
	cache->head=cache_page_new(cache, NULL);
	for(i=0, curr=cache->head; i<page_count; i++, curr=curr->next)
	{
		cache_page_t *cp = cache_page_new(cache, &cache->cache[i]);
		cache_page_insert(curr, cp);
	}
	
	return 0;
}


void cache_free(cache_t *cache)
{
	cache_page_t* curr = cache->head;
	free(cache->cache);
	while(curr)
	{
		cache_page_t * c = curr;
		curr=curr->next;
		cache_page_free(c);
	}
}



void cache_get(cache_t* cache, db_time_t start, db_time_t end)
{
	
}

void printcache(cache_page_t* cache)
{
	cache_page_t *cp = cache->next;
	while(cp)
	{
		printf("%d ", cp->data);
		cp=cp->next;
	}
	printf("\n");
}