[perl5.git] / malloc.c

/* $Header: malloc.c,v 3.0.1.2 89/11/11 04:36:37 lwall Locked $
 *
 * $Log:	malloc.c,v $
 * Revision 3.0.1.2  89/11/11  04:36:37  lwall
 * patch2: malloc pointer corruption check made more portable
 * 
 * Revision 3.0.1.1  89/10/26  23:15:05  lwall
 * patch1: some declarations were missing from malloc.c
 * patch1: sparc machines had alignment problems in malloc.c
 * 
 * Revision 3.0  89/10/18  15:20:39  lwall
 * 3.0 baseline
 * 
 */

#ifndef lint
static char sccsid[] = "@(#)malloc.c	4.3 (Berkeley) 9/16/83";

#ifdef DEBUGGING
#define RCHECK
#endif
/*
 * malloc.c (Caltech) 2/21/82
 * Chris Kingsley, kingsley@cit-20.
 *
 * This is a very fast storage allocator.  It allocates blocks of a small 
 * number of different sizes, and keeps free lists of each size.  Blocks that
 * don't exactly fit are passed up to the next larger size.  In this 
 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
 * This is designed for use in a program that uses vast quantities of memory,
 * but bombs when it runs out. 
 */

#include "EXTERN.h"
#include "perl.h"

static findbucket(), morecore();

/* I don't much care whether these are defined in sys/types.h--LAW */

#define u_char unsigned char
#define u_int unsigned int
#define u_short unsigned short

/*
 * The overhead on a block is at least 4 bytes.  When free, this space
 * contains a pointer to the next free block, and the bottom two bits must
 * be zero.  When in use, the first byte is set to MAGIC, and the second
 * byte is the size index.  The remaining bytes are for alignment.
 * If range checking is enabled and the size of the block fits
 * in two bytes, then the top two bytes hold the size of the requested block
 * plus the range checking words, and the header word MINUS ONE.
 */
union	overhead {
	union	overhead *ov_next;	/* when free */
#if defined (mips) || defined (sparc)
	double  strut;			/* alignment problems */
#endif
	struct {
		u_char	ovu_magic;	/* magic number */
		u_char	ovu_index;	/* bucket # */
#ifdef RCHECK
		u_short	ovu_size;	/* actual block size */
		u_int	ovu_rmagic;	/* range magic number */
#endif
	} ovu;
#define	ov_magic	ovu.ovu_magic
#define	ov_index	ovu.ovu_index
#define	ov_size		ovu.ovu_size
#define	ov_rmagic	ovu.ovu_rmagic
};

#define	MAGIC		0xff		/* magic # on accounting info */
#define OLDMAGIC	0x7f		/* same after a free() */
#define RMAGIC		0x55555555	/* magic # on range info */
#ifdef RCHECK
#define	RSLOP		sizeof (u_int)
#else
#define	RSLOP		0
#endif

/*
 * nextf[i] is the pointer to the next free block of size 2^(i+3).  The
 * smallest allocatable block is 8 bytes.  The overhead information
 * precedes the data area returned to the user.
 */
#define	NBUCKETS 30
static	union overhead *nextf[NBUCKETS];
extern	char *sbrk();

#ifdef MSTATS
/*
 * nmalloc[i] is the difference between the number of mallocs and frees
 * for a given block size.
 */
static	u_int nmalloc[NBUCKETS];
#include <stdio.h>
#endif

#ifdef debug
#define	ASSERT(p)   if (!(p)) botch("p"); else
static
botch(s)
	char *s;
{

	printf("assertion botched: %s\n", s);
	abort();
}
#else
#define	ASSERT(p)
#endif

char *
malloc(nbytes)
	register unsigned nbytes;
{
  	register union overhead *p;
  	register int bucket = 0;
  	register unsigned shiftr;

	/*
	 * Convert amount of memory requested into
	 * closest block size stored in hash buckets
	 * which satisfies request.  Account for
	 * space used per block for accounting.
	 */
  	nbytes += sizeof (union overhead) + RSLOP;
  	nbytes = (nbytes + 3) &~ 3; 
  	shiftr = (nbytes - 1) >> 2;
	/* apart from this loop, this is O(1) */
  	while (shiftr >>= 1)
  		bucket++;
	/*
	 * If nothing in hash bucket right now,
	 * request more memory from the system.
	 */
  	if (nextf[bucket] == NULL)    
  		morecore(bucket);
  	if ((p = (union overhead *)nextf[bucket]) == NULL)
  		return (NULL);
	/* remove from linked list */
#ifdef RCHECK
	if (*((int*)p) & (sizeof(union overhead) - 1))
#ifndef I286
	    fprintf(stderr,"Corrupt malloc ptr 0x%x at 0x%x\n",*((int*)p),p);
#else
	    fprintf(stderr,"Corrupt malloc ptr 0x%lx at 0x%lx\n",*((int*)p),p);
#endif
#endif
  	nextf[bucket] = p->ov_next;
	p->ov_magic = MAGIC;
	p->ov_index= bucket;
#ifdef MSTATS
  	nmalloc[bucket]++;
#endif
#ifdef RCHECK
	/*
	 * Record allocated size of block and
	 * bound space with magic numbers.
	 */
  	if (nbytes <= 0x10000)
		p->ov_size = nbytes - 1;
	p->ov_rmagic = RMAGIC;
  	*((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
#endif
  	return ((char *)(p + 1));
}

/*
 * Allocate more memory to the indicated bucket.
 */
static
morecore(bucket)
	register int bucket;
{
  	register union overhead *op;
  	register int rnu;       /* 2^rnu bytes will be requested */
  	register int nblks;     /* become nblks blocks of the desired size */
	register int siz;

  	if (nextf[bucket])
  		return;
	/*
	 * Insure memory is allocated
	 * on a page boundary.  Should
	 * make getpageize call?
	 */
  	op = (union overhead *)sbrk(0);
#ifndef I286
  	if ((int)op & 0x3ff)
  		(void)sbrk(1024 - ((int)op & 0x3ff));
#else
	/* The sbrk(0) call on the I286 always returns the next segment */
#endif

#ifndef I286
	/* take 2k unless the block is bigger than that */
  	rnu = (bucket <= 8) ? 11 : bucket + 3;
#else
	/* take 16k unless the block is bigger than that 
	   (80286s like large segments!)		*/
  	rnu = (bucket <= 11) ? 14 : bucket + 3;
#endif
  	nblks = 1 << (rnu - (bucket + 3));  /* how many blocks to get */
  	if (rnu < bucket)
		rnu = bucket;
	op = (union overhead *)sbrk(1 << rnu);
	/* no more room! */
  	if ((int)op == -1)
  		return;
	/*
	 * Round up to minimum allocation size boundary
	 * and deduct from block count to reflect.
	 */
#ifndef I286
  	if ((int)op & 7) {
  		op = (union overhead *)(((int)op + 8) &~ 7);
  		nblks--;
  	}
#else
	/* Again, this should always be ok on an 80286 */
#endif
	/*
	 * Add new memory allocated to that on
	 * free list for this hash bucket.
	 */
  	nextf[bucket] = op;
  	siz = 1 << (bucket + 3);
  	while (--nblks > 0) {
		op->ov_next = (union overhead *)((caddr_t)op + siz);
		op = (union overhead *)((caddr_t)op + siz);
  	}
}

free(cp)
	char *cp;
{   
  	register int size;
	register union overhead *op;

  	if (cp == NULL)
  		return;
	op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
#ifdef debug
  	ASSERT(op->ov_magic == MAGIC);		/* make sure it was in use */
#else
	if (op->ov_magic != MAGIC) {
		warn("%s free() ignored",
		    op->ov_magic == OLDMAGIC ? "Duplicate" : "Bad");
		return;				/* sanity */
	}
	op->ov_magic = OLDMAGIC;
#endif
#ifdef RCHECK
  	ASSERT(op->ov_rmagic == RMAGIC);
	if (op->ov_index <= 13)
		ASSERT(*(u_int *)((caddr_t)op + op->ov_size + 1 - RSLOP) == RMAGIC);
#endif
  	ASSERT(op->ov_index < NBUCKETS);
  	size = op->ov_index;
	op->ov_next = nextf[size];
  	nextf[size] = op;
#ifdef MSTATS
  	nmalloc[size]--;
#endif
}

/*
 * When a program attempts "storage compaction" as mentioned in the
 * old malloc man page, it realloc's an already freed block.  Usually
 * this is the last block it freed; occasionally it might be farther
 * back.  We have to search all the free lists for the block in order
 * to determine its bucket: 1st we make one pass thru the lists
 * checking only the first block in each; if that fails we search
 * ``reall_srchlen'' blocks in each list for a match (the variable
 * is extern so the caller can modify it).  If that fails we just copy
 * however many bytes was given to realloc() and hope it's not huge.
 */
int reall_srchlen = 4;	/* 4 should be plenty, -1 =>'s whole list */

char *
realloc(cp, nbytes)
	char *cp; 
	unsigned nbytes;
{   
  	register u_int onb;
	union overhead *op;
  	char *res;
	register int i;
	int was_alloced = 0;

  	if (cp == NULL)
  		return (malloc(nbytes));
	op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
	if (op->ov_magic == MAGIC) {
		was_alloced++;
		i = op->ov_index;
	} else {
		/*
		 * Already free, doing "compaction".
		 *
		 * Search for the old block of memory on the
		 * free list.  First, check the most common
		 * case (last element free'd), then (this failing)
		 * the last ``reall_srchlen'' items free'd.
		 * If all lookups fail, then assume the size of
		 * the memory block being realloc'd is the
		 * smallest possible.
		 */
		if ((i = findbucket(op, 1)) < 0 &&
		    (i = findbucket(op, reall_srchlen)) < 0)
			i = 0;
	}
	onb = (1 << (i + 3)) - sizeof (*op) - RSLOP;
	/* avoid the copy if same size block */
	if (was_alloced &&
	    nbytes <= onb && nbytes > (onb >> 1) - sizeof(*op) - RSLOP) {
#ifdef RCHECK
		/*
		 * Record new allocated size of block and
		 * bound space with magic numbers.
		 */
		if (op->ov_index <= 13) {
			/*
			 * Convert amount of memory requested into
			 * closest block size stored in hash buckets
			 * which satisfies request.  Account for
			 * space used per block for accounting.
			 */
			nbytes += sizeof (union overhead) + RSLOP;
			nbytes = (nbytes + 3) &~ 3; 
			op->ov_size = nbytes - 1;
			*((u_int *)((caddr_t)op + nbytes - RSLOP)) = RMAGIC;
		}
#endif
		return(cp);
	}
  	if ((res = malloc(nbytes)) == NULL)
  		return (NULL);
  	if (cp != res)			/* common optimization */
		(void)bcopy(cp, res, (int)((nbytes < onb) ? nbytes : onb));
  	if (was_alloced)
		free(cp);
  	return (res);
}

/*
 * Search ``srchlen'' elements of each free list for a block whose
 * header starts at ``freep''.  If srchlen is -1 search the whole list.
 * Return bucket number, or -1 if not found.
 */
static
findbucket(freep, srchlen)
	union overhead *freep;
	int srchlen;
{
	register union overhead *p;
	register int i, j;

	for (i = 0; i < NBUCKETS; i++) {
		j = 0;
		for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
			if (p == freep)
				return (i);
			j++;
		}
	}
	return (-1);
}

#ifdef MSTATS
/*
 * mstats - print out statistics about malloc
 * 
 * Prints two lines of numbers, one showing the length of the free list
 * for each size category, the second showing the number of mallocs -
 * frees for each size category.
 */
mstats(s)
	char *s;
{
  	register int i, j;
  	register union overhead *p;
  	int totfree = 0,
  	totused = 0;

  	fprintf(stderr, "Memory allocation statistics %s\nfree:\t", s);
  	for (i = 0; i < NBUCKETS; i++) {
  		for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
  			;
  		fprintf(stderr, " %d", j);
  		totfree += j * (1 << (i + 3));
  	}
  	fprintf(stderr, "\nused:\t");
  	for (i = 0; i < NBUCKETS; i++) {
  		fprintf(stderr, " %d", nmalloc[i]);
  		totused += nmalloc[i] * (1 << (i + 3));
  	}
  	fprintf(stderr, "\n\tTotal in use: %d, total free: %d\n",
	    totused, totfree);
}
#endif
#endif /* lint */
Commit	Line	Data
bf38876a	1	/* $Header: malloc.c,v 3.0.1.2 89/11/11 04:36:37 lwall Locked $
8d063cd8 LW	2	*
8d063cd8 LW	3	* $Log: malloc.c,v $
bf38876a LW	4	* Revision 3.0.1.2 89/11/11 04:36:37 lwall
	5	* patch2: malloc pointer corruption check made more portable
	6	*
03a14243 LW	7	* Revision 3.0.1.1 89/10/26 23:15:05 lwall
	8	* patch1: some declarations were missing from malloc.c
	9	* patch1: sparc machines had alignment problems in malloc.c
	10	*
a687059c LW	11	* Revision 3.0 89/10/18 15:20:39 lwall
a687059c LW	12	* 3.0 baseline
8d063cd8 LW	13	*
	14	*/
	15
	16	#ifndef lint
	17	static char sccsid[] = "@(#)malloc.c 4.3 (Berkeley) 9/16/83";
8d063cd8	18
a687059c	19	#ifdef DEBUGGING
8d063cd8	20	#define RCHECK
a687059c	21	#endif
8d063cd8 LW	22	/*
	23	* malloc.c (Caltech) 2/21/82
	24	* Chris Kingsley, kingsley@cit-20.
	25	*
	26	* This is a very fast storage allocator. It allocates blocks of a small
	27	* number of different sizes, and keeps free lists of each size. Blocks that
	28	* don't exactly fit are passed up to the next larger size. In this
	29	* implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
	30	* This is designed for use in a program that uses vast quantities of memory,
	31	* but bombs when it runs out.
	32	*/
	33
135863df	34	#include "EXTERN.h"
135863df AB	35	#include "perl.h"
135863df AB	36
03a14243 LW	37	static findbucket(), morecore();
03a14243 LW	38
135863df AB	39	/* I don't much care whether these are defined in sys/types.h--LAW */
	40
	41	#define u_char unsigned char
	42	#define u_int unsigned int
	43	#define u_short unsigned short
8d063cd8	44
8d063cd8 LW	45	/*
	46	* The overhead on a block is at least 4 bytes. When free, this space
	47	* contains a pointer to the next free block, and the bottom two bits must
	48	* be zero. When in use, the first byte is set to MAGIC, and the second
	49	* byte is the size index. The remaining bytes are for alignment.
	50	* If range checking is enabled and the size of the block fits
	51	* in two bytes, then the top two bytes hold the size of the requested block
	52	* plus the range checking words, and the header word MINUS ONE.
	53	*/
	54	union overhead {
	55	union overhead ov_next; / when free */
03a14243	56	#if defined (mips) \|\| defined (sparc)
a687059c LW	57	double strut; /* alignment problems */
a687059c LW	58	#endif
8d063cd8 LW	59	struct {
	60	u_char ovu_magic; /* magic number */
	61	u_char ovu_index; /* bucket # */
	62	#ifdef RCHECK
	63	u_short ovu_size; /* actual block size */
	64	u_int ovu_rmagic; /* range magic number */
	65	#endif
	66	} ovu;
	67	#define ov_magic ovu.ovu_magic
	68	#define ov_index ovu.ovu_index
	69	#define ov_size ovu.ovu_size
	70	#define ov_rmagic ovu.ovu_rmagic
	71	};
	72
	73	#define MAGIC 0xff /* magic # on accounting info */
378cc40b	74	#define OLDMAGIC 0x7f /* same after a free() */
8d063cd8 LW	75	#define RMAGIC 0x55555555 /* magic # on range info */
	76	#ifdef RCHECK
	77	#define RSLOP sizeof (u_int)
	78	#else
	79	#define RSLOP 0
	80	#endif
	81
	82	/*
	83	* nextf[i] is the pointer to the next free block of size 2^(i+3). The
	84	* smallest allocatable block is 8 bytes. The overhead information
	85	* precedes the data area returned to the user.
	86	*/
	87	#define NBUCKETS 30
	88	static union overhead *nextf[NBUCKETS];
	89	extern char *sbrk();
	90
	91	#ifdef MSTATS
	92	/*
	93	* nmalloc[i] is the difference between the number of mallocs and frees
	94	* for a given block size.
	95	*/
	96	static u_int nmalloc[NBUCKETS];
	97	#include <stdio.h>
	98	#endif
	99
	100	#ifdef debug
	101	#define ASSERT(p) if (!(p)) botch("p"); else
	102	static
	103	botch(s)
	104	char *s;
	105	{
	106
	107	printf("assertion botched: %s\n", s);
	108	abort();
	109	}
	110	#else
	111	#define ASSERT(p)
	112	#endif
	113
	114	char *
	115	malloc(nbytes)
	116	register unsigned nbytes;
	117	{
	118	register union overhead *p;
	119	register int bucket = 0;
	120	register unsigned shiftr;
	121
	122	/*
	123	* Convert amount of memory requested into
	124	* closest block size stored in hash buckets
	125	* which satisfies request. Account for
	126	* space used per block for accounting.
	127	*/
	128	nbytes += sizeof (union overhead) + RSLOP;
	129	nbytes = (nbytes + 3) &~ 3;
	130	shiftr = (nbytes - 1) >> 2;
	131	/* apart from this loop, this is O(1) */
	132	while (shiftr >>= 1)
	133	bucket++;
	134	/*
	135	* If nothing in hash bucket right now,
	136	* request more memory from the system.
	137	*/
	138	if (nextf[bucket] == NULL)
139	morecore(bucket);
140	if ((p = (union overhead *)nextf[bucket]) == NULL)
141	return (NULL);
142	/* remove from linked list */
bf38876a LW	143	#ifdef RCHECK
bf38876a LW	144	if (((int)p) & (sizeof(union overhead) - 1))
a687059c	145	#ifndef I286
8d063cd8	146	fprintf(stderr,"Corrupt malloc ptr 0x%x at 0x%x\n",((int)p),p);
a687059c LW	147	#else
	148	fprintf(stderr,"Corrupt malloc ptr 0x%lx at 0x%lx\n",((int)p),p);
	149	#endif
bf38876a LW	150	#endif
bf38876a LW	151	nextf[bucket] = p->ov_next;
8d063cd8 LW	152	p->ov_magic = MAGIC;
	153	p->ov_index= bucket;
	154	#ifdef MSTATS
	155	nmalloc[bucket]++;
	156	#endif
	157	#ifdef RCHECK
	158	/*
	159	* Record allocated size of block and
	160	* bound space with magic numbers.
	161	*/
	162	if (nbytes <= 0x10000)
	163	p->ov_size = nbytes - 1;
	164	p->ov_rmagic = RMAGIC;
	165	((u_int )((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
	166	#endif
	167	return ((char *)(p + 1));
	168	}
	169
	170	/*
	171	* Allocate more memory to the indicated bucket.
	172	*/
	173	static
	174	morecore(bucket)
a687059c	175	register int bucket;
8d063cd8 LW	176	{
	177	register union overhead *op;
	178	register int rnu; /* 2^rnu bytes will be requested */
	179	register int nblks; /* become nblks blocks of the desired size */
	180	register int siz;
	181
	182	if (nextf[bucket])
	183	return;
	184	/*
	185	* Insure memory is allocated
	186	* on a page boundary. Should
	187	* make getpageize call?
	188	*/
	189	op = (union overhead *)sbrk(0);
a687059c	190	#ifndef I286
8d063cd8	191	if ((int)op & 0x3ff)
a687059c LW	192	(void)sbrk(1024 - ((int)op & 0x3ff));
	193	#else
	194	/* The sbrk(0) call on the I286 always returns the next segment */
	195	#endif
	196
	197	#ifndef I286
8d063cd8 LW	198	/* take 2k unless the block is bigger than that */
8d063cd8 LW	199	rnu = (bucket <= 8) ? 11 : bucket + 3;
a687059c LW	200	#else
	201	/* take 16k unless the block is bigger than that
	202	(80286s like large segments!) */
	203	rnu = (bucket <= 11) ? 14 : bucket + 3;
	204	#endif
8d063cd8 LW	205	nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */
	206	if (rnu < bucket)
	207	rnu = bucket;
	208	op = (union overhead *)sbrk(1 << rnu);
	209	/* no more room! */
	210	if ((int)op == -1)
	211	return;
	212	/*
	213	* Round up to minimum allocation size boundary
	214	* and deduct from block count to reflect.
	215	*/
a687059c	216	#ifndef I286
8d063cd8 LW	217	if ((int)op & 7) {
	218	op = (union overhead *)(((int)op + 8) &~ 7);
	219	nblks--;
	220	}
a687059c LW	221	#else
	222	/* Again, this should always be ok on an 80286 */
	223	#endif
8d063cd8 LW	224	/*
	225	* Add new memory allocated to that on
	226	* free list for this hash bucket.
	227	*/
	228	nextf[bucket] = op;
	229	siz = 1 << (bucket + 3);
	230	while (--nblks > 0) {
	231	op->ov_next = (union overhead *)((caddr_t)op + siz);
	232	op = (union overhead *)((caddr_t)op + siz);
	233	}
	234	}
	235
	236	free(cp)
	237	char *cp;
	238	{
	239	register int size;
	240	register union overhead *op;
	241
	242	if (cp == NULL)
	243	return;
	244	op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
	245	#ifdef debug
	246	ASSERT(op->ov_magic == MAGIC); /* make sure it was in use */
	247	#else
378cc40b	248	if (op->ov_magic != MAGIC) {
a687059c	249	warn("%s free() ignored",
378cc40b	250	op->ov_magic == OLDMAGIC ? "Duplicate" : "Bad");
8d063cd8	251	return; /* sanity */
378cc40b LW	252	}
378cc40b LW	253	op->ov_magic = OLDMAGIC;
8d063cd8 LW	254	#endif
	255	#ifdef RCHECK
	256	ASSERT(op->ov_rmagic == RMAGIC);
	257	if (op->ov_index <= 13)
	258	ASSERT((u_int )((caddr_t)op + op->ov_size + 1 - RSLOP) == RMAGIC);
	259	#endif
	260	ASSERT(op->ov_index < NBUCKETS);
	261	size = op->ov_index;
	262	op->ov_next = nextf[size];
	263	nextf[size] = op;
	264	#ifdef MSTATS
	265	nmalloc[size]--;
	266	#endif
	267	}
	268
	269	/*
	270	* When a program attempts "storage compaction" as mentioned in the
	271	* old malloc man page, it realloc's an already freed block. Usually
	272	* this is the last block it freed; occasionally it might be farther
	273	* back. We have to search all the free lists for the block in order
	274	* to determine its bucket: 1st we make one pass thru the lists
	275	* checking only the first block in each; if that fails we search
378cc40b	276	* ``reall_srchlen'' blocks in each list for a match (the variable
8d063cd8 LW	277	* is extern so the caller can modify it). If that fails we just copy
	278	* however many bytes was given to realloc() and hope it's not huge.
	279	*/
378cc40b	280	int reall_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */
8d063cd8 LW	281
	282	char *
	283	realloc(cp, nbytes)
	284	char *cp;
	285	unsigned nbytes;
	286	{
	287	register u_int onb;
	288	union overhead *op;
	289	char *res;
	290	register int i;
	291	int was_alloced = 0;
	292
	293	if (cp == NULL)
	294	return (malloc(nbytes));
	295	op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
	296	if (op->ov_magic == MAGIC) {
	297	was_alloced++;
	298	i = op->ov_index;
	299	} else {
	300	/*
	301	* Already free, doing "compaction".
	302	*
	303	* Search for the old block of memory on the
	304	* free list. First, check the most common
	305	* case (last element free'd), then (this failing)
378cc40b	306	* the last ``reall_srchlen'' items free'd.
8d063cd8 LW	307	* If all lookups fail, then assume the size of
	308	* the memory block being realloc'd is the
	309	* smallest possible.
	310	*/
	311	if ((i = findbucket(op, 1)) < 0 &&
378cc40b	312	(i = findbucket(op, reall_srchlen)) < 0)
8d063cd8 LW	313	i = 0;
	314	}
	315	onb = (1 << (i + 3)) - sizeof (*op) - RSLOP;
	316	/* avoid the copy if same size block */
	317	if (was_alloced &&
a687059c LW	318	nbytes <= onb && nbytes > (onb >> 1) - sizeof(*op) - RSLOP) {
	319	#ifdef RCHECK
	320	/*
	321	* Record new allocated size of block and
	322	* bound space with magic numbers.
	323	*/
	324	if (op->ov_index <= 13) {
	325	/*
	326	* Convert amount of memory requested into
	327	* closest block size stored in hash buckets
	328	* which satisfies request. Account for
	329	* space used per block for accounting.
	330	*/
	331	nbytes += sizeof (union overhead) + RSLOP;
	332	nbytes = (nbytes + 3) &~ 3;
	333	op->ov_size = nbytes - 1;
	334	((u_int )((caddr_t)op + nbytes - RSLOP)) = RMAGIC;
	335	}
	336	#endif
8d063cd8	337	return(cp);
a687059c	338	}
8d063cd8 LW	339	if ((res = malloc(nbytes)) == NULL)
	340	return (NULL);
	341	if (cp != res) /* common optimization */
a687059c	342	(void)bcopy(cp, res, (int)((nbytes < onb) ? nbytes : onb));
8d063cd8 LW	343	if (was_alloced)
	344	free(cp);
	345	return (res);
	346	}
	347
	348	/*
	349	* Search ``srchlen'' elements of each free list for a block whose
	350	* header starts at ``freep''. If srchlen is -1 search the whole list.
	351	* Return bucket number, or -1 if not found.
	352	*/
	353	static
	354	findbucket(freep, srchlen)
	355	union overhead *freep;
	356	int srchlen;
	357	{
	358	register union overhead *p;
	359	register int i, j;
	360
	361	for (i = 0; i < NBUCKETS; i++) {
	362	j = 0;
	363	for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
	364	if (p == freep)
	365	return (i);
	366	j++;
	367	}
	368	}
	369	return (-1);
	370	}
	371
	372	#ifdef MSTATS
	373	/*
	374	* mstats - print out statistics about malloc
	375	*
	376	* Prints two lines of numbers, one showing the length of the free list
	377	* for each size category, the second showing the number of mallocs -
	378	* frees for each size category.
	379	*/
	380	mstats(s)
	381	char *s;
	382	{
	383	register int i, j;
	384	register union overhead *p;
	385	int totfree = 0,
	386	totused = 0;
	387
	388	fprintf(stderr, "Memory allocation statistics %s\nfree:\t", s);
	389	for (i = 0; i < NBUCKETS; i++) {
	390	for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
	391	;
	392	fprintf(stderr, " %d", j);
	393	totfree += j * (1 << (i + 3));
	394	}
	395	fprintf(stderr, "\nused:\t");
	396	for (i = 0; i < NBUCKETS; i++) {
	397	fprintf(stderr, " %d", nmalloc[i]);
	398	totused += nmalloc[i] * (1 << (i + 3));
	399	}
	400	fprintf(stderr, "\n\tTotal in use: %d, total free: %d\n",
	401	totused, totfree);
	402	}
	403	#endif
a687059c	404	#endif /* lint */