/* $Id: q_malloc.c 5990 2009-08-20 06:58:17Z bogdan_iancu $
 *
 * Copyright (C) 2001-2003 FhG Fokus
 *
 * This file is part of opensips, a free SIP server.
 *
 * opensips is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * opensips is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 * History:
 * --------
 *  ????-??-??  created by andrei
 *  2003-04-14  more debugging added in DBG_QM_MALLOC mode (andrei)
 *  2003-06-29  added qm_realloc (andrei)
 *  2004-07-19  fragments book keeping code and support for 64 bits
 *              memory blocks (64 bits machine & size>=2^32) (andrei)
 *              GET_HASH s/</<=/ (avoids waste of 1 hash cell) (andrei)
 *  2004-11-10  support for > 4Gb mem., switched to long (andrei)
 *  2005-03-02  added qm_info() (andrei)
 *  2005-12-12  fixed realloc shrink real_used & used accounting;
 *              fixed initial size (andrei)
 */
#include "precompile.h"

#include "q_malloc.h"

/*useful macros*/
#define FRAG_END(f)  \
	((struct qm_frag_end*)((char*)(f)+sizeof(struct qm_frag)+ \
	   (f)->size))

#define FRAG_NEXT(f) \
	((struct qm_frag*)((char*)(f)+sizeof(struct qm_frag)+(f)->size+ \
	   sizeof(struct qm_frag_end)))
			
#define FRAG_PREV(f) \
	( (struct qm_frag*) ( ((char*)(f)-sizeof(struct qm_frag_end))- \
	((struct qm_frag_end*)((char*)(f)-sizeof(struct qm_frag_end)))->size- \
	   sizeof(struct qm_frag) ) )

#define PREV_FRAG_END(f) \
	((struct qm_frag_end*)((char*)(f)-sizeof(struct qm_frag_end)))


#define FRAG_OVERHEAD	(sizeof(struct qm_frag)+sizeof(struct qm_frag_end))


#define ROUNDTO_MASK	(~((unsigned long)ROUNDTO-1))
#define ROUNDUP(s)		(((s)+(ROUNDTO-1))&ROUNDTO_MASK)
#define ROUNDDOWN(s)	((s)&ROUNDTO_MASK)

/*
#define ROUNDUP(s)		(((s)%ROUNDTO)?((s)+ROUNDTO)/ROUNDTO*ROUNDTO:(s))
#define ROUNDDOWN(s)	(((s)%ROUNDTO)?((s)-ROUNDTO)/ROUNDTO*ROUNDTO:(s))
*/



	/* finds the hash value for s, s=ROUNDTO multiple*/
#define GET_HASH(s)   ( ((unsigned long)(s)<=QM_MALLOC_OPTIMIZE)?\
							(unsigned long)(s)/ROUNDTO: \
							QM_MALLOC_OPTIMIZE/ROUNDTO+big_hash_idx((s))- \
								QM_MALLOC_OPTIMIZE_FACTOR+1 )

#define UN_HASH(h)	( ((unsigned long)(h)<=(QM_MALLOC_OPTIMIZE/ROUNDTO))?\
							(unsigned long)(h)*ROUNDTO: \
							1UL<<((h)-QM_MALLOC_OPTIMIZE/ROUNDTO+\
								QM_MALLOC_OPTIMIZE_FACTOR-1)\
					)


/* mark/test used/unused frags */
#define FRAG_MARK_USED(f)
#define FRAG_CLEAR_USED(f)
#define FRAG_WAS_USED(f)   (1)

/* other frag related defines:
 * MEM_COALESCE_FRAGS 
 * MEM_FRAG_AVOIDANCE
 */

#define MEM_FRAG_AVOIDANCE



/* computes hash number for big buckets*/
__inline static unsigned long big_hash_idx(unsigned long s)
{
	int idx;
	/* s is rounded => s = k*2^n (ROUNDTO=2^n) 
	 * index= i such that 2^i > s >= 2^(i-1)
	 *
	 * => index = number of the first non null bit in s*/
	idx=sizeof(long)*8-1;
	for (; !(s&(1UL<<(sizeof(long)*8-1))) ; s<<=1, idx--);
	return idx;
}

static __inline void qm_insert_free(struct qm_block* qm, struct qm_frag* frag)
{
	struct qm_frag* f;
	struct qm_frag* prev;
	int hash;
	
	hash=GET_HASH(frag->size);
	for(f=qm->free_hash[hash].head.u.nxt_free; f!=&(qm->free_hash[hash].head);
			f=f->u.nxt_free){
		if (frag->size <= f->size) break;
	}
	/*insert it here*/
	prev=FRAG_END(f)->prev_free;
	prev->u.nxt_free=frag;
	FRAG_END(frag)->prev_free=prev;
	frag->u.nxt_free=f;
	FRAG_END(f)->prev_free=frag;
	qm->free_hash[hash].no++;
}



/* init malloc and return a qm_block*/
struct qm_block* qm_malloc_init(char* address, unsigned long size)
{
	char* start;
	char* end;
	struct qm_block* qm;
	unsigned long init_overhead;
	int h;
	
	/* make address and size multiple of 8*/
	start=(char*)ROUNDUP((unsigned long) address);
	if (size<(unsigned long)(start-address)) return 0;
	size-=(start-address);
	if (size <(MIN_FRAG_SIZE+FRAG_OVERHEAD)) return 0;
	size=ROUNDDOWN(size);
	
	init_overhead=ROUNDUP(sizeof(struct qm_block))+sizeof(struct qm_frag)+
		sizeof(struct qm_frag_end);
	
	if (size < init_overhead)
	{
		/* not enough mem to create our control structures !!!*/
		return 0;
	}
	end=start+size;
	qm=(struct qm_block*)start;
	memset(qm, 0, sizeof(struct qm_block));
	qm->size=size;
	qm->real_used=init_overhead;
	qm->max_real_used=qm->real_used;
	size-=init_overhead;
	
	qm->first_frag=(struct qm_frag*)(start+ROUNDUP(sizeof(struct qm_block)));
	qm->last_frag_end=(struct qm_frag_end*)(end-sizeof(struct qm_frag_end));
	/* init initial fragment*/
	qm->first_frag->size=size;
	qm->last_frag_end->size=size;
	
	/* init free_hash* */
	for (h=0; h<QM_HASH_SIZE;h++){
		qm->free_hash[h].head.u.nxt_free=&(qm->free_hash[h].head);
		qm->free_hash[h].tail.prev_free=&(qm->free_hash[h].head);
		qm->free_hash[h].head.size=0;
		qm->free_hash[h].tail.size=0;
	}
	
	/* link initial fragment into the free list*/
	
	qm_insert_free(qm, qm->first_frag);
	
	/*qm->first_frag->u.nxt_free=&(qm->free_lst);
	  qm->last_frag_end->prev_free=&(qm->free_lst);
	*/
	
	
	return qm;
}



static __inline void qm_detach_free(struct qm_block* qm, struct qm_frag* frag)
{
	struct qm_frag *prev;
	struct qm_frag *next;
	
	prev=FRAG_END(frag)->prev_free;
	next=frag->u.nxt_free;
	prev->u.nxt_free=next;
	FRAG_END(next)->prev_free=prev;
	
}



static __inline struct qm_frag* qm_find_free(struct qm_block* qm, 
											unsigned long size,
											int* h)
{
	int hash;
	struct qm_frag* f;

	for (hash=GET_HASH(size); hash<QM_HASH_SIZE; hash++){
		for (f=qm->free_hash[hash].head.u.nxt_free; 
					f!=&(qm->free_hash[hash].head); f=f->u.nxt_free){
			if (f->size>=size){ *h=hash; return f; }
		}
	/*try in a bigger bucket*/
	}
	/* not found */
	return 0;
}


/* returns 0 on success, -1 on error;
 * new_size < size & rounded-up already!*/
static __inline
int split_frag(struct qm_block* qm, struct qm_frag* f, unsigned long new_size)
{
	unsigned long rest;
	struct qm_frag* n;
	struct qm_frag_end* end;
	
	rest=f->size-new_size;
#ifdef MEM_FRAG_AVOIDANCE
	if ((rest> (FRAG_OVERHEAD+QM_MALLOC_OPTIMIZE))||
		(rest>=(FRAG_OVERHEAD+new_size))){/* the residue fragm. is big enough*/
#else
	if (rest>(FRAG_OVERHEAD+MIN_FRAG_SIZE)){
#endif
		f->size=new_size;
		/*split the fragment*/
		end=FRAG_END(f);
		end->size=new_size;
		n=(struct qm_frag*)((char*)end+sizeof(struct qm_frag_end));
		n->size=rest-FRAG_OVERHEAD;
		FRAG_END(n)->size=n->size;
		FRAG_CLEAR_USED(n); /* never used */
		qm->real_used+=FRAG_OVERHEAD;
		/* reinsert n in free list*/
		qm_insert_free(qm, n);
		return 0;
	}else{
			/* we cannot split this fragment any more */
		return -1;
	}
}

void* qm_malloc(struct qm_block* qm, unsigned long size)
{
	struct qm_frag* f;
	int hash;
	
	/*size must be a multiple of 8*/
	size=ROUNDUP(size);
	if (size>(qm->size-qm->real_used)) return 0;

	/*search for a suitable free frag*/
	if ((f=qm_find_free(qm, size, &hash))!=0){
		/* we found it!*/
		/*detach it from the free list*/
		qm_detach_free(qm, f);
		/*mark it as "busy"*/
		f->u.is_free=0;
		qm->free_hash[hash].no--;
		/* we ignore split return */
		split_frag(qm, f, size);
		qm->real_used+=f->size;
		qm->used+=f->size;
		if (qm->max_real_used<qm->real_used)
			qm->max_real_used=qm->real_used;
		return (char*)f+sizeof(struct qm_frag);
	}
	return 0;
}



void qm_free(struct qm_block* qm, void* p)
{
	struct qm_frag* f;
	struct qm_frag* prev;
	struct qm_frag* next;
	unsigned long size;

	if (p==0) {
		return;
	}
	prev=next=0;
	f=(struct qm_frag*) ((char*)p-sizeof(struct qm_frag));
	size=f->size;
	qm->used-=size;
	qm->real_used-=size;

	/* join packets if possible*/
	next=FRAG_NEXT(f);
	if (((char*)next < (char*)qm->last_frag_end) &&( next->u.is_free)){
		/* join */
		qm_detach_free(qm, next);
		size+=next->size+FRAG_OVERHEAD;
		qm->real_used-=FRAG_OVERHEAD;
		qm->free_hash[GET_HASH(next->size)].no--; /* FIXME slow */
	}
	
	if (f > qm->first_frag){
		prev=FRAG_PREV(f);
		/*	(struct qm_frag*)((char*)f - (struct qm_frag_end*)((char*)f-
								sizeof(struct qm_frag_end))->size);*/
		if (prev->u.is_free){
			/*join*/
			qm_detach_free(qm, prev);
			size+=prev->size+FRAG_OVERHEAD;
			qm->real_used-=FRAG_OVERHEAD;
			qm->free_hash[GET_HASH(prev->size)].no--; /* FIXME slow */
			f=prev;
		}
	}
	f->size=size;
	FRAG_END(f)->size=f->size;

	qm_insert_free(qm, f);
}







void qm_lock(struct qm_block* qm)
{
	DWORD i = 0;
	DWORD spin = 256;
	while (InterlockedCompareExchange((LONG*)&qm->lock, 1, 0) == 1) {
		for (; i < spin; ++i)
			if (qm->lock == 0)
				break;
		if (i >= spin)
			Sleep(1); /* yield cpu */
	}
}

void qm_unlock(struct qm_block* qm)
{
	InterlockedExchange((LONG*)&qm->lock, 0);
}