path: root/libs/pbd/tlsf.cc

/*
 * Two Levels Segregate Fit memory allocator (TLSF)
 * Version 2.4.6
 *
 * Written by Miguel Masmano Tello <mimastel@doctor.upv.es>
 *
 * Thanks to Ismael Ripoll for his suggestions and reviews
 *
 * Copyright (C) 2008, 2007, 2006, 2005, 2004
 *
 * This code is released using a dual license strategy: GPL/LGPL
 * You can choose the licence that better fits your requirements.
 *
 * Released under the terms of the GNU General Public License Version 2.0
 * Released under the terms of the GNU Lesser General Public License Version 2.1
 *
 */

/*
 * Code contributions:
 *
 * (Jul 28 2007)  Herman ten Brugge <hermantenbrugge@home.nl>:
 *
 * - Add 64 bit support. It now runs on x86_64 and solaris64.
 * - I also tested this on vxworks/32and solaris/32 and i386/32 processors.
 * - Remove assembly code. I could not measure any performance difference
 *   on my core2 processor. This also makes the code more portable.
 * - Moved defines/typedefs from tlsf.h to tlsf.c
 * - Changed MIN_BLOCK_SIZE to sizeof (free_ptr_t) and BHDR_OVERHEAD to
 *   (sizeof (bhdr_t) - MIN_BLOCK_SIZE). This does not change the fact
 *    that the minumum size is still sizeof
 *   (bhdr_t).
 * - Changed all C++ comment style to C style. (// -> /.* ... *./)
 * - Used ls_bit instead of ffs and ms_bit instead of fls. I did this to
 *   avoid confusion with the standard ffs function which returns
 *   different values.
 * - Created set_bit/clear_bit fuctions because they are not present
 *   on x86_64.
 * - Added locking support + extra file target.h to show how to use it.
 * - Added get_used_size function (REMOVED in 2.4)
 * - Added rtl_realloc and rtl_calloc function
 * - Implemented realloc clever support.
 * - Added some test code in the example directory.
 * - Bug fixed (discovered by the rockbox project: www.rockbox.org).
 *
 * (Oct 23 2006) Adam Scislowicz:
 *
 * - Support for ARMv5 implemented
 *
 */

//#define TLSF_STATISTIC 1

#ifndef USE_PRINTF
#define USE_PRINTF      (1)
#endif

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#ifndef TLSF_STATISTIC
#define    TLSF_STATISTIC     (0)
#endif

#if TLSF_STATISTIC
#define TLSF_ADD_SIZE(tlsf, b) do {                                  \
        tlsf->used_size += (b->size & BLOCK_SIZE) + BHDR_OVERHEAD;   \
        if (tlsf->used_size > tlsf->max_size)                        \
            tlsf->max_size = tlsf->used_size;                        \
        } while(0)

#define TLSF_REMOVE_SIZE(tlsf, b) do {                                \
        tlsf->used_size -= (b->size & BLOCK_SIZE) + BHDR_OVERHEAD;    \
    } while(0)
#else
#define    TLSF_ADD_SIZE(tlsf, b)         do{}while(0)
#define    TLSF_REMOVE_SIZE(tlsf, b)    do{}while(0)
#endif

#include "pbd/tlsf.h"

#if !defined(__GNUC__)
#ifndef __inline__
#define __inline__
#endif
#endif

/* The  debug functions  only can  be used  when _DEBUG_TLSF_  is set. */
#ifndef _DEBUG_TLSF_
#define _DEBUG_TLSF_  (0)
#endif

/*************************************************************************/
/* Definition of the structures used by TLSF */


/* Some IMPORTANT TLSF parameters */
/* Unlike the preview TLSF versions, now they are statics */
#define BLOCK_ALIGN (sizeof(void *) * 2)

#define MAX_FLI        (30)
#define MAX_LOG2_SLI   (5)
#define MAX_SLI        (1 << MAX_LOG2_SLI) /* MAX_SLI = 2^MAX_LOG2_SLI */

#define FLI_OFFSET     (6) /* tlsf structure just will manage blocks bigger */
/* than 128 bytes */
#define SMALL_BLOCK    (128)
#define REAL_FLI       (MAX_FLI - FLI_OFFSET)
#define MIN_BLOCK_SIZE (sizeof (free_ptr_t))
#define BHDR_OVERHEAD  (sizeof (bhdr_t) - MIN_BLOCK_SIZE)
#define TLSF_SIGNATURE (0x2A59FA59)

#define PTR_MASK       (sizeof(void *) - 1)
#define BLOCK_SIZE     (0xFFFFFFFF - PTR_MASK)

#define GET_NEXT_BLOCK(_addr, _r) ((bhdr_t *) ((char *) (_addr) + (_r)))
#define MEM_ALIGN          ((BLOCK_ALIGN) - 1)
#define ROUNDUP_SIZE(_r)   (((_r) + MEM_ALIGN) & ~MEM_ALIGN)
#define ROUNDDOWN_SIZE(_r) ((_r) & ~MEM_ALIGN)
#define ROUNDUP(_x, _v)    ((((~(_x)) + 1) & ((_v)-1)) + (_x))

#define BLOCK_STATE  (0x1)
#define PREV_STATE   (0x2)

/* bit 0 of the block size */
#define FREE_BLOCK   (0x1)
#define USED_BLOCK   (0x0)

/* bit 1 of the block size */
#define PREV_FREE    (0x2)
#define PREV_USED    (0x0)


#ifdef USE_PRINTF
#include <stdio.h>
# define PRINT_MSG(fmt, args...) printf(fmt, ## args)
# define ERROR_MSG(fmt, args...) printf(fmt, ## args)
#else
# if !defined(PRINT_MSG)
#  define PRINT_MSG(fmt, args...)
# endif
# if !defined(ERROR_MSG)
#  define ERROR_MSG(fmt, args...)
# endif
#endif

typedef unsigned int u32_t; /* NOTE: Make sure that this type is 4 bytes long on your computer */
typedef unsigned char u8_t; /* NOTE: Make sure that this type is 1 byte on your computer */

typedef struct free_ptr_struct {
	struct bhdr_struct *prev;
	struct bhdr_struct *next;
} free_ptr_t;

typedef struct bhdr_struct {
	/* This pointer is just valid if the first bit of size is set */
	struct bhdr_struct *prev_hdr;
	/* The size is stored in bytes */
	size_t size;      /* bit 0 indicates whether the block is used and */
	/* bit 1 allows to know whether the previous block is free */
	union {
		struct free_ptr_struct free_ptr;
		u8_t buffer[1]; /*sizeof(struct free_ptr_struct)]; */
	} ptr;
} bhdr_t;

/* This structure is embedded at the beginning of each area, giving us
 * enough information to cope with a set of areas */

typedef struct area_info_struct {
	bhdr_t *end;
	struct area_info_struct *next;
} area_info_t;

typedef struct TLSF_struct {
	/* the TLSF's structure signature */
	u32_t tlsf_signature;

#if TLSF_STATISTIC
	/* These can not be calculated outside tlsf because we
	 * do not know the sizes when freeing/reallocing memory. */
	size_t used_size;
	size_t max_size;
#endif

	/* A linked list holding all the existing areas */
	area_info_t *area_head;

	/* the first-level bitmap */
	/* This array should have a size of REAL_FLI bits */
	u32_t fl_bitmap;

	/* the second-level bitmap */
	u32_t sl_bitmap[REAL_FLI];

	bhdr_t *matrix[REAL_FLI][MAX_SLI];
} tlsf_t;


/******************************************************************/
/**************     Helping functions    **************************/
/******************************************************************/
static __inline__ void set_bit(int nr, u32_t * addr);
static __inline__ void clear_bit(int nr, u32_t * addr);
static __inline__ int ls_bit(int x);
static __inline__ int ms_bit(int x);
static __inline__ void MAPPING_SEARCH(size_t * _r, int *_fl, int *_sl);
static __inline__ void MAPPING_INSERT(size_t _r, int *_fl, int *_sl);
static __inline__ bhdr_t *FIND_SUITABLE_BLOCK(tlsf_t * _tlsf, int *_fl, int *_sl);
static __inline__ bhdr_t *process_area(void *area, size_t size);

static const int table[] = {
	-1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4,
	4, 4,
	4, 4, 4, 4, 4, 4, 4,
	5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
	5,
	5, 5, 5, 5, 5, 5, 5,
	6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
	6,
	6, 6, 6, 6, 6, 6, 6,
	6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
	6,
	6, 6, 6, 6, 6, 6, 6,
	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
	7,
	7, 7, 7, 7, 7, 7, 7,
	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
	7,
	7, 7, 7, 7, 7, 7, 7,
	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
	7,
	7, 7, 7, 7, 7, 7, 7,
	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
	7,
	7, 7, 7, 7, 7, 7, 7
};

static __inline__ int ls_bit(int i)
{
	unsigned int a;
	unsigned int x = i & -i;

	a = x <= 0xffff ? (x <= 0xff ? 0 : 8) : (x <= 0xffffff ? 16 : 24);
	return table[x >> a] + a;
}

static __inline__ int ms_bit(int i)
{
	unsigned int a;
	unsigned int x = (unsigned int) i;

	a = x <= 0xffff ? (x <= 0xff ? 0 : 8) : (x <= 0xffffff ? 16 : 24);
	return table[x >> a] + a;
}

static __inline__ void set_bit(int nr, u32_t * addr)
{
	addr[nr >> 5] |= 1 << (nr & 0x1f);
}

static __inline__ void clear_bit(int nr, u32_t * addr)
{
	addr[nr >> 5] &= ~(1 << (nr & 0x1f));
}

static __inline__ void MAPPING_SEARCH(size_t * _r, int *_fl, int *_sl)
{
	int _t;

	if (*_r < SMALL_BLOCK) {
		*_fl = 0;
		*_sl = *_r / (SMALL_BLOCK / MAX_SLI);
	} else {
		_t = (1 << (ms_bit(*_r) - MAX_LOG2_SLI)) - 1;
		*_r = *_r + _t;
		*_fl = ms_bit(*_r);
		*_sl = (*_r >> (*_fl - MAX_LOG2_SLI)) - MAX_SLI;
		*_fl -= FLI_OFFSET;
		/*if ((*_fl -= FLI_OFFSET) < 0) // FL wil be always >0!
		 *_fl = *_sl = 0;
		 */
		*_r &= ~_t;
	}
}

static __inline__ void MAPPING_INSERT(size_t _r, int *_fl, int *_sl)
{
	if (_r < SMALL_BLOCK) {
		*_fl = 0;
		*_sl = _r / (SMALL_BLOCK / MAX_SLI);
	} else {
		*_fl = ms_bit(_r);
		*_sl = (_r >> (*_fl - MAX_LOG2_SLI)) - MAX_SLI;
		*_fl -= FLI_OFFSET;
	}
}


static __inline__ bhdr_t *FIND_SUITABLE_BLOCK(tlsf_t * _tlsf, int *_fl, int *_sl)
{
	u32_t _tmp = _tlsf->sl_bitmap[*_fl] & (~0 << *_sl);
	bhdr_t *_b = NULL;

	if (_tmp) {
		*_sl = ls_bit(_tmp);
		_b = _tlsf->matrix[*_fl][*_sl];
	} else {
		*_fl = ls_bit(_tlsf->fl_bitmap & (~0 << (*_fl + 1)));
		if (*_fl > 0) {         /* likely */
			*_sl = ls_bit(_tlsf->sl_bitmap[*_fl]);
			_b = _tlsf->matrix[*_fl][*_sl];
		}
	}
	return _b;
}


#define EXTRACT_BLOCK_HDR(_b, _tlsf, _fl, _sl) do {                  \
        _tlsf -> matrix [_fl] [_sl] = _b -> ptr.free_ptr.next;       \
        if (_tlsf -> matrix[_fl][_sl])                               \
            _tlsf -> matrix[_fl][_sl] -> ptr.free_ptr.prev = NULL;   \
        else {                                                       \
            clear_bit (_sl, &_tlsf -> sl_bitmap [_fl]);              \
            if (!_tlsf -> sl_bitmap [_fl])                           \
                clear_bit (_fl, &_tlsf -> fl_bitmap);                \
        }                                                            \
        _b -> ptr.free_ptr.prev =  NULL;                             \
        _b -> ptr.free_ptr.next =  NULL;                             \
    }while(0)


#define EXTRACT_BLOCK(_b, _tlsf, _fl, _sl) do {                                     \
        if (_b -> ptr.free_ptr.next)                                                \
            _b -> ptr.free_ptr.next -> ptr.free_ptr.prev = _b -> ptr.free_ptr.prev; \
        if (_b -> ptr.free_ptr.prev)                                                \
            _b -> ptr.free_ptr.prev -> ptr.free_ptr.next = _b -> ptr.free_ptr.next; \
        if (_tlsf -> matrix [_fl][_sl] == _b) {                                     \
            _tlsf -> matrix [_fl][_sl] = _b -> ptr.free_ptr.next;                   \
            if (!_tlsf -> matrix [_fl][_sl]) {                                      \
                clear_bit (_sl, &_tlsf -> sl_bitmap[_fl]);                          \
                if (!_tlsf -> sl_bitmap [_fl])                                      \
                    clear_bit (_fl, &_tlsf -> fl_bitmap);                           \
            }                                                                       \
        }                                                                           \
        _b -> ptr.free_ptr.prev = NULL;                                             \
        _b -> ptr.free_ptr.next = NULL;                                             \
    } while(0)

#define INSERT_BLOCK(_b, _tlsf, _fl, _sl) do {                       \
        _b -> ptr.free_ptr.prev = NULL;                              \
        _b -> ptr.free_ptr.next = _tlsf -> matrix [_fl][_sl];        \
        if (_tlsf -> matrix [_fl][_sl])                              \
            _tlsf -> matrix [_fl][_sl] -> ptr.free_ptr.prev = _b;    \
        _tlsf -> matrix [_fl][_sl] = _b;                             \
        set_bit (_sl, &_tlsf -> sl_bitmap [_fl]);                    \
        set_bit (_fl, &_tlsf -> fl_bitmap);                          \
    } while(0)

static __inline__ bhdr_t *process_area(void *area, size_t size)
{
	bhdr_t *b, *lb, *ib;
	area_info_t *ai;

	ib = (bhdr_t *) area;
	ib->size =
		(sizeof(area_info_t) <
		 MIN_BLOCK_SIZE) ? MIN_BLOCK_SIZE : ROUNDUP_SIZE(sizeof(area_info_t)) | USED_BLOCK | PREV_USED;
	b = (bhdr_t *) GET_NEXT_BLOCK(ib->ptr.buffer, ib->size & BLOCK_SIZE);
	b->size = ROUNDDOWN_SIZE(size - 3 * BHDR_OVERHEAD - (ib->size & BLOCK_SIZE)) | USED_BLOCK | PREV_USED;
	b->ptr.free_ptr.prev = b->ptr.free_ptr.next = 0;
	lb = GET_NEXT_BLOCK(b->ptr.buffer, b->size & BLOCK_SIZE);
	lb->prev_hdr = b;
	lb->size = 0 | USED_BLOCK | PREV_FREE;
	ai = (area_info_t *) ib->ptr.buffer;
	ai->next = 0;
	ai->end = lb;
	return ib;
}

/* ****************************************************************************/

#ifndef PLATFORM_WINDOWS
#include <sys/mman.h>
#endif

PBD::TLSF::TLSF (std::string name, size_t mem_pool_size)
    : _name (name)
{
	mem_pool_size = ROUNDUP_SIZE (mem_pool_size);
	char * mem_pool = (char*) ::malloc (mem_pool_size);

	assert (mem_pool);
	assert (mem_pool_size >= sizeof(tlsf_t) + BHDR_OVERHEAD * 8);

#ifndef __MINGW64__ // cast fails
	assert (0 == (((unsigned long)mem_pool) & PTR_MASK));
#endif

#ifndef PLATFORM_WINDOWS
	memset (mem_pool, 0, mem_pool_size); // make resident
	mlock (mem_pool, mem_pool_size);
#endif

	bhdr_t *b, *ib;

	tlsf_t *tlsf = (tlsf_t *) mem_pool;
	_mp = mem_pool;

	/* Zeroing the memory pool */
	memset(_mp, 0, sizeof(tlsf_t));

	tlsf->tlsf_signature = TLSF_SIGNATURE;

	ib = process_area(GET_NEXT_BLOCK
			(_mp, ROUNDUP_SIZE(sizeof(tlsf_t))), ROUNDDOWN_SIZE(mem_pool_size - sizeof(tlsf_t)));
	b = GET_NEXT_BLOCK(ib->ptr.buffer, ib->size & BLOCK_SIZE);
	_free(b->ptr.buffer);
	tlsf->area_head = (area_info_t *) ib->ptr.buffer;

#if TLSF_STATISTIC
	tlsf->used_size = mem_pool_size - (b->size & BLOCK_SIZE);
	tlsf->max_size = tlsf->used_size;
	PRINT_MSG ("TLSF '%s': free %ld, reserved: %ld [bytes]\n",
			_name.c_str(),
			b->size & BLOCK_SIZE,
			get_used_size());
#endif
}

PBD::TLSF::~TLSF ()
{
#if TLSF_STATISTIC
	PRINT_MSG ("TLSF '%s': used: %ld, max: %ld [bytes]\n",
			_name.c_str(),
			get_used_size(),
			get_max_size());
#endif
	tlsf_t *tlsf = (tlsf_t *) _mp;
	tlsf->tlsf_signature = 0;
	::free (_mp);
	_mp = NULL;
}

size_t
PBD::TLSF::get_used_size () const
{
#if TLSF_STATISTIC
	return ((tlsf_t *) _mp)->used_size;
#else
	return 0;
#endif
}

size_t
PBD::TLSF::get_max_size () const
{
#if TLSF_STATISTIC
	return ((tlsf_t *) _mp)->max_size;
#else
	return 0;
#endif
}

void *
PBD::TLSF::_malloc (size_t size)
{
	tlsf_t *tlsf = (tlsf_t *) _mp;
	bhdr_t *b, *b2, *next_b;
	int fl, sl;
	size_t tmp_size;

	size = (size < MIN_BLOCK_SIZE) ? MIN_BLOCK_SIZE : ROUNDUP_SIZE(size);

	/* Rounding up the requested size and calculating fl and sl */
	MAPPING_SEARCH(&size, &fl, &sl);

	/* Searching a free block, recall that this function changes the values of fl and sl,
		 so they are not longer valid when the function fails */
	b = FIND_SUITABLE_BLOCK(tlsf, &fl, &sl);
	if (!b)
		return NULL; /* Not found */

	EXTRACT_BLOCK_HDR(b, tlsf, fl, sl);

	/*-- found: */
	next_b = GET_NEXT_BLOCK(b->ptr.buffer, b->size & BLOCK_SIZE);
	/* Should the block be split? */
	tmp_size = (b->size & BLOCK_SIZE) - size;
	if (tmp_size >= sizeof(bhdr_t)) {
		tmp_size -= BHDR_OVERHEAD;
		b2 = GET_NEXT_BLOCK(b->ptr.buffer, size);
		b2->size = tmp_size | FREE_BLOCK | PREV_USED;
		next_b->prev_hdr = b2;
		MAPPING_INSERT(tmp_size, &fl, &sl);
		INSERT_BLOCK(b2, tlsf, fl, sl);

		b->size = size | (b->size & PREV_STATE);
	} else {
		next_b->size &= (~PREV_FREE);
		b->size &= (~FREE_BLOCK); /* Now it's used */
	}

	TLSF_ADD_SIZE(tlsf, b);

	return (void *) b->ptr.buffer;
}

void
PBD::TLSF::_free (void *ptr)
{
	tlsf_t *tlsf = (tlsf_t *) _mp;
	bhdr_t *b, *tmp_b;
	int fl = 0, sl = 0;

	if (!ptr) {
		return;
	}
	b = (bhdr_t *) ((char *) ptr - BHDR_OVERHEAD);
	b->size |= FREE_BLOCK;

	TLSF_REMOVE_SIZE(tlsf, b);

	b->ptr.free_ptr.prev = NULL;
	b->ptr.free_ptr.next = NULL;
	tmp_b = GET_NEXT_BLOCK(b->ptr.buffer, b->size & BLOCK_SIZE);
	if (tmp_b->size & FREE_BLOCK) {
		MAPPING_INSERT(tmp_b->size & BLOCK_SIZE, &fl, &sl);
		EXTRACT_BLOCK(tmp_b, tlsf, fl, sl);
		b->size += (tmp_b->size & BLOCK_SIZE) + BHDR_OVERHEAD;
	}
	if (b->size & PREV_FREE) {
		tmp_b = b->prev_hdr;
		MAPPING_INSERT(tmp_b->size & BLOCK_SIZE, &fl, &sl);
		EXTRACT_BLOCK(tmp_b, tlsf, fl, sl);
		tmp_b->size += (b->size & BLOCK_SIZE) + BHDR_OVERHEAD;
		b = tmp_b;
	}
	MAPPING_INSERT(b->size & BLOCK_SIZE, &fl, &sl);
	INSERT_BLOCK(b, tlsf, fl, sl);

	tmp_b = GET_NEXT_BLOCK(b->ptr.buffer, b->size & BLOCK_SIZE);
	tmp_b->size |= PREV_FREE;
	tmp_b->prev_hdr = b;
}

void*
PBD::TLSF::_realloc(void *ptr, size_t new_size)
{
	tlsf_t *tlsf = (tlsf_t *) _mp;
	void *ptr_aux;
	unsigned int cpsize;
	bhdr_t *b, *tmp_b, *next_b;
	int fl, sl;
	size_t tmp_size;

	if (!ptr) {
		if (new_size)
			return (void *) _malloc (new_size);
		if (!new_size)
			return NULL;
	} else if (!new_size) {
		_free(ptr);
		return NULL;
	}

	b = (bhdr_t *) ((char *) ptr - BHDR_OVERHEAD);
	next_b = GET_NEXT_BLOCK(b->ptr.buffer, b->size & BLOCK_SIZE);
	new_size = (new_size < MIN_BLOCK_SIZE) ? MIN_BLOCK_SIZE : ROUNDUP_SIZE(new_size);
	tmp_size = (b->size & BLOCK_SIZE);
	if (new_size <= tmp_size) {
		TLSF_REMOVE_SIZE(tlsf, b);
		if (next_b->size & FREE_BLOCK) {
			MAPPING_INSERT(next_b->size & BLOCK_SIZE, &fl, &sl);
			EXTRACT_BLOCK(next_b, tlsf, fl, sl);
			tmp_size += (next_b->size & BLOCK_SIZE) + BHDR_OVERHEAD;
			next_b = GET_NEXT_BLOCK(next_b->ptr.buffer, next_b->size & BLOCK_SIZE);
			/* We allways reenter this free block because tmp_size will
				 be greater then sizeof (bhdr_t) */
		}
		tmp_size -= new_size;
		if (tmp_size >= sizeof(bhdr_t)) {
			tmp_size -= BHDR_OVERHEAD;
			tmp_b = GET_NEXT_BLOCK(b->ptr.buffer, new_size);
			tmp_b->size = tmp_size | FREE_BLOCK | PREV_USED;
			next_b->prev_hdr = tmp_b;
			next_b->size |= PREV_FREE;
			MAPPING_INSERT(tmp_size, &fl, &sl);
			INSERT_BLOCK(tmp_b, tlsf, fl, sl);
			b->size = new_size | (b->size & PREV_STATE);
		}
		TLSF_ADD_SIZE(tlsf, b);
		return (void *) b->ptr.buffer;
	}
	if ((next_b->size & FREE_BLOCK)) {
		if (new_size <= (tmp_size + (next_b->size & BLOCK_SIZE))) {
			TLSF_REMOVE_SIZE(tlsf, b);
			MAPPING_INSERT(next_b->size & BLOCK_SIZE, &fl, &sl);
			EXTRACT_BLOCK(next_b, tlsf, fl, sl);
			b->size += (next_b->size & BLOCK_SIZE) + BHDR_OVERHEAD;
			next_b = GET_NEXT_BLOCK(b->ptr.buffer, b->size & BLOCK_SIZE);
			next_b->prev_hdr = b;
			next_b->size &= ~PREV_FREE;
			tmp_size = (b->size & BLOCK_SIZE) - new_size;
			if (tmp_size >= sizeof(bhdr_t)) {
				tmp_size -= BHDR_OVERHEAD;
				tmp_b = GET_NEXT_BLOCK(b->ptr.buffer, new_size);
				tmp_b->size = tmp_size | FREE_BLOCK | PREV_USED;
				next_b->prev_hdr = tmp_b;
				next_b->size |= PREV_FREE;
				MAPPING_INSERT(tmp_size, &fl, &sl);
				INSERT_BLOCK(tmp_b, tlsf, fl, sl);
				b->size = new_size | (b->size & PREV_STATE);
			}
			TLSF_ADD_SIZE(tlsf, b);
			return (void *) b->ptr.buffer;
		}
	}

	if (!(ptr_aux = _malloc (new_size))){
		return NULL;
	}

	cpsize = ((b->size & BLOCK_SIZE) > new_size) ? new_size : (b->size & BLOCK_SIZE);

	memcpy(ptr_aux, ptr, cpsize);

	_free(ptr);
	return ptr_aux;
}