[perl5.git] / malloc.c

/* $RCSfile: malloc.c,v $$Revision: 4.0.1.4 $$Date: 92/06/08 14:28:38 $
 *
 * $Log:	malloc.c,v $
 * Revision 4.0.1.4  92/06/08  14:28:38  lwall
 * patch20: removed implicit int declarations on functions
 * patch20: hash tables now split only if the memory is available to do so
 * patch20: realloc(0, size) now does malloc in case library routines call it
 * 
 * Revision 4.0.1.3  91/11/05  17:57:40  lwall
 * patch11: safe malloc code now integrated into Perl's malloc when possible
 * 
 * Revision 4.0.1.2  91/06/07  11:20:45  lwall
 * patch4: many, many itty-bitty portability fixes
 * 
 * Revision 4.0.1.1  91/04/11  17:48:31  lwall
 * patch1: Configure now figures out malloc ptr type
 * 
 * Revision 4.0  91/03/20  01:28:52  lwall
 * 4.0 baseline.
 * 
 */

#ifndef lint
/*SUPPRESS 592*/
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 ALIGNBYTES > 4
	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 void
botch(s)
	char *s;
{

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

#ifdef safemalloc
static int an = 0;
#endif

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

#ifdef safemalloc
#ifdef DEBUGGING
	MEM_SIZE size = nbytes;
#endif

#ifdef MSDOS
	if (nbytes > 0xffff) {
		fprintf(stderr, "Allocation too large: %lx\n", (long)nbytes);
		exit(1);
	}
#endif /* MSDOS */
#ifdef DEBUGGING
	if ((long)nbytes < 0)
	    fatal("panic: malloc");
#endif
#endif /* safemalloc */

	/*
	 * 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) {
#ifdef safemalloc
		if (!nomemok) {
		    fputs("Out of memory!\n", stderr);
		    exit(1);
		}
#else
  		return (NULL);
#endif
	}

#ifdef safemalloc
#ifdef DEBUGGING
#  if !(defined(I286) || defined(atarist))
    if (debug & 128)
        fprintf(stderr,"0x%x: (%05d) malloc %ld bytes\n",p+1,an++,(long)size);
#  else
    if (debug & 128)
        fprintf(stderr,"0x%lx: (%05d) malloc %ld bytes\n",p+1,an++,(long)size);
#  endif
#endif
#endif /* safemalloc */

	/* remove from linked list */
#ifdef RCHECK
	if (*((int*)p) & (sizeof(union overhead) - 1))
#if !(defined(I286) || defined(atarist))
	    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 ((MALLOCPTRTYPE *)(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 MEM_SIZE siz;

  	if (nextf[bucket])
  		return;
	/*
	 * Insure memory is allocated
	 * on a page boundary.  Should
	 * make getpageize call?
	 */
#ifndef atarist /* on the atari we dont have to worry about this */
  	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
#endif /* atarist */

#if !(defined(I286) || defined(atarist))
	/* 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!), probably good on the atari too */
  	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(1L << 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 *)(((MEM_SIZE)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);
  	}
}

void
free(mp)
	MALLOCPTRTYPE *mp;
{   
  	register MEM_SIZE size;
	register union overhead *op;
	char *cp = (char*)mp;

#ifdef safemalloc
#ifdef DEBUGGING
#  if !(defined(I286) || defined(atarist))
	if (debug & 128)
		fprintf(stderr,"0x%x: (%05d) free\n",cp,an++);
#  else
	if (debug & 128)
		fprintf(stderr,"0x%lx: (%05d) free\n",cp,an++);
#  endif
#endif
#endif /* safemalloc */

  	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 */

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

#ifdef safemalloc
#ifdef DEBUGGING
	MEM_SIZE size = nbytes;
#endif

#ifdef MSDOS
	if (nbytes > 0xffff) {
		fprintf(stderr, "Reallocation too large: %lx\n", size);
		exit(1);
	}
#endif /* MSDOS */
	if (!cp)
		return malloc(nbytes);
#ifdef DEBUGGING
	if ((long)nbytes < 0)
		fatal("panic: realloc");
#endif
#endif /* safemalloc */

	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 = (1L << (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
		res = cp;
	}
	else {
		if ((res = (char*)malloc(nbytes)) == NULL)
			return (NULL);
		if (cp != res)			/* common optimization */
			Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
		if (was_alloced)
			free(cp);
	}

#ifdef safemalloc
#ifdef DEBUGGING
#  if !(defined(I286) || defined(atarist))
	if (debug & 128) {
	    fprintf(stderr,"0x%x: (%05d) rfree\n",res,an++);
	    fprintf(stderr,"0x%x: (%05d) realloc %ld bytes\n",res,an++,(long)size);
	}
#  else
	if (debug & 128) {
	    fprintf(stderr,"0x%lx: (%05d) rfree\n",res,an++);
	    fprintf(stderr,"0x%lx: (%05d) realloc %ld bytes\n",res,an++,(long)size);
	}
#  endif
#endif
#endif /* safemalloc */
  	return ((MALLOCPTRTYPE*)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 int
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.
 */
void
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
ee0007ab	1	/* $RCSfile: malloc.c,v $$Revision: 4.0.1.4 $$Date: 92/06/08 14:28:38 $
8d063cd8 LW	2	*
8d063cd8 LW	3	* $Log: malloc.c,v $
ee0007ab LW	4	* Revision 4.0.1.4 92/06/08 14:28:38 lwall
	5	* patch20: removed implicit int declarations on functions
	6	* patch20: hash tables now split only if the memory is available to do so
	7	* patch20: realloc(0, size) now does malloc in case library routines call it
	8	*
45d8adaa LW	9	* Revision 4.0.1.3 91/11/05 17:57:40 lwall
	10	* patch11: safe malloc code now integrated into Perl's malloc when possible
	11	*
352d5a3a LW	12	* Revision 4.0.1.2 91/06/07 11:20:45 lwall
	13	* patch4: many, many itty-bitty portability fixes
	14	*
35c8bce7 LW	15	* Revision 4.0.1.1 91/04/11 17:48:31 lwall
	16	* patch1: Configure now figures out malloc ptr type
	17	*
fe14fcc3 LW	18	* Revision 4.0 91/03/20 01:28:52 lwall
fe14fcc3 LW	19	* 4.0 baseline.
8d063cd8 LW	20	*
	21	*/
	22
	23	#ifndef lint
45d8adaa	24	/SUPPRESS 592/
8d063cd8	25	static char sccsid[] = "@(#)malloc.c 4.3 (Berkeley) 9/16/83";
8d063cd8	26
a687059c	27	#ifdef DEBUGGING
8d063cd8	28	#define RCHECK
a687059c	29	#endif
8d063cd8 LW	30	/*
	31	* malloc.c (Caltech) 2/21/82
	32	* Chris Kingsley, kingsley@cit-20.
	33	*
	34	* This is a very fast storage allocator. It allocates blocks of a small
	35	* number of different sizes, and keeps free lists of each size. Blocks that
	36	* don't exactly fit are passed up to the next larger size. In this
	37	* implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
	38	* This is designed for use in a program that uses vast quantities of memory,
	39	* but bombs when it runs out.
	40	*/
	41
135863df	42	#include "EXTERN.h"
135863df AB	43	#include "perl.h"
135863df AB	44
03a14243 LW	45	static findbucket(), morecore();
03a14243 LW	46
135863df AB	47	/* I don't much care whether these are defined in sys/types.h--LAW */
	48
	49	#define u_char unsigned char
	50	#define u_int unsigned int
	51	#define u_short unsigned short
8d063cd8	52
8d063cd8 LW	53	/*
	54	* The overhead on a block is at least 4 bytes. When free, this space
	55	* contains a pointer to the next free block, and the bottom two bits must
	56	* be zero. When in use, the first byte is set to MAGIC, and the second
	57	* byte is the size index. The remaining bytes are for alignment.
	58	* If range checking is enabled and the size of the block fits
	59	* in two bytes, then the top two bytes hold the size of the requested block
	60	* plus the range checking words, and the header word MINUS ONE.
	61	*/
	62	union overhead {
	63	union overhead ov_next; / when free */
c623bd54 LW	64	#if ALIGNBYTES > 4
c623bd54 LW	65	double strut; /* alignment problems */
a687059c	66	#endif
8d063cd8 LW	67	struct {
	68	u_char ovu_magic; /* magic number */
	69	u_char ovu_index; /* bucket # */
	70	#ifdef RCHECK
	71	u_short ovu_size; /* actual block size */
	72	u_int ovu_rmagic; /* range magic number */
	73	#endif
	74	} ovu;
	75	#define ov_magic ovu.ovu_magic
	76	#define ov_index ovu.ovu_index
	77	#define ov_size ovu.ovu_size
	78	#define ov_rmagic ovu.ovu_rmagic
	79	};
	80
	81	#define MAGIC 0xff /* magic # on accounting info */
378cc40b	82	#define OLDMAGIC 0x7f /* same after a free() */
8d063cd8 LW	83	#define RMAGIC 0x55555555 /* magic # on range info */
	84	#ifdef RCHECK
	85	#define RSLOP sizeof (u_int)
	86	#else
	87	#define RSLOP 0
	88	#endif
	89
	90	/*
	91	* nextf[i] is the pointer to the next free block of size 2^(i+3). The
	92	* smallest allocatable block is 8 bytes. The overhead information
	93	* precedes the data area returned to the user.
	94	*/
	95	#define NBUCKETS 30
	96	static union overhead *nextf[NBUCKETS];
	97	extern char *sbrk();
	98
	99	#ifdef MSTATS
	100	/*
	101	* nmalloc[i] is the difference between the number of mallocs and frees
	102	* for a given block size.
	103	*/
	104	static u_int nmalloc[NBUCKETS];
	105	#include <stdio.h>
	106	#endif
	107
	108	#ifdef debug
	109	#define ASSERT(p) if (!(p)) botch("p"); else
ee0007ab	110	static void
8d063cd8 LW	111	botch(s)
	112	char *s;
	113	{
	114
	115	printf("assertion botched: %s\n", s);
	116	abort();
	117	}
	118	#else
	119	#define ASSERT(p)
	120	#endif
	121
45d8adaa LW	122	#ifdef safemalloc
	123	static int an = 0;
	124	#endif
	125
35c8bce7	126	MALLOCPTRTYPE *
8d063cd8	127	malloc(nbytes)
ee0007ab	128	register MEM_SIZE nbytes;
8d063cd8 LW	129	{
	130	register union overhead *p;
	131	register int bucket = 0;
ee0007ab	132	register MEM_SIZE shiftr;
8d063cd8	133
45d8adaa LW	134	#ifdef safemalloc
45d8adaa LW	135	#ifdef DEBUGGING
ee0007ab	136	MEM_SIZE size = nbytes;
45d8adaa LW	137	#endif
	138
	139	#ifdef MSDOS
	140	if (nbytes > 0xffff) {
ee0007ab	141	fprintf(stderr, "Allocation too large: %lx\n", (long)nbytes);
45d8adaa LW	142	exit(1);
	143	}
	144	#endif /* MSDOS */
	145	#ifdef DEBUGGING
	146	if ((long)nbytes < 0)
	147	fatal("panic: malloc");
	148	#endif
	149	#endif /* safemalloc */
	150
8d063cd8 LW	151	/*
	152	* Convert amount of memory requested into
	153	* closest block size stored in hash buckets
	154	* which satisfies request. Account for
	155	* space used per block for accounting.
	156	*/
	157	nbytes += sizeof (union overhead) + RSLOP;
	158	nbytes = (nbytes + 3) &~ 3;
	159	shiftr = (nbytes - 1) >> 2;
	160	/* apart from this loop, this is O(1) */
	161	while (shiftr >>= 1)
	162	bucket++;
	163	/*
	164	* If nothing in hash bucket right now,
	165	* request more memory from the system.
	166	*/
	167	if (nextf[bucket] == NULL)
	168	morecore(bucket);
45d8adaa LW	169	if ((p = (union overhead *)nextf[bucket]) == NULL) {
45d8adaa LW	170	#ifdef safemalloc
ee0007ab LW	171	if (!nomemok) {
	172	fputs("Out of memory!\n", stderr);
	173	exit(1);
	174	}
45d8adaa	175	#else
8d063cd8	176	return (NULL);
45d8adaa LW	177	#endif
	178	}
	179
	180	#ifdef safemalloc
	181	#ifdef DEBUGGING
ee0007ab	182	# if !(defined(I286) \|\| defined(atarist))
45d8adaa	183	if (debug & 128)
ee0007ab	184	fprintf(stderr,"0x%x: (%05d) malloc %ld bytes\n",p+1,an++,(long)size);
45d8adaa LW	185	# else
45d8adaa LW	186	if (debug & 128)
ee0007ab	187	fprintf(stderr,"0x%lx: (%05d) malloc %ld bytes\n",p+1,an++,(long)size);
45d8adaa LW	188	# endif
	189	#endif
	190	#endif /* safemalloc */
	191
8d063cd8	192	/* remove from linked list */
bf38876a LW	193	#ifdef RCHECK
bf38876a LW	194	if (((int)p) & (sizeof(union overhead) - 1))
ee0007ab	195	#if !(defined(I286) \|\| defined(atarist))
8d063cd8	196	fprintf(stderr,"Corrupt malloc ptr 0x%x at 0x%x\n",((int)p),p);
a687059c LW	197	#else
	198	fprintf(stderr,"Corrupt malloc ptr 0x%lx at 0x%lx\n",((int)p),p);
	199	#endif
bf38876a LW	200	#endif
bf38876a LW	201	nextf[bucket] = p->ov_next;
8d063cd8 LW	202	p->ov_magic = MAGIC;
	203	p->ov_index= bucket;
	204	#ifdef MSTATS
	205	nmalloc[bucket]++;
	206	#endif
	207	#ifdef RCHECK
	208	/*
	209	* Record allocated size of block and
	210	* bound space with magic numbers.
	211	*/
	212	if (nbytes <= 0x10000)
	213	p->ov_size = nbytes - 1;
	214	p->ov_rmagic = RMAGIC;
	215	((u_int )((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
	216	#endif
352d5a3a	217	return ((MALLOCPTRTYPE *)(p + 1));
8d063cd8 LW	218	}
	219
	220	/*
	221	* Allocate more memory to the indicated bucket.
	222	*/
	223	static
	224	morecore(bucket)
a687059c	225	register int bucket;
8d063cd8 LW	226	{
	227	register union overhead *op;
	228	register int rnu; /* 2^rnu bytes will be requested */
	229	register int nblks; /* become nblks blocks of the desired size */
ee0007ab	230	register MEM_SIZE siz;
8d063cd8 LW	231
	232	if (nextf[bucket])
	233	return;
	234	/*
	235	* Insure memory is allocated
	236	* on a page boundary. Should
	237	* make getpageize call?
	238	*/
ee0007ab	239	#ifndef atarist /* on the atari we dont have to worry about this */
8d063cd8	240	op = (union overhead *)sbrk(0);
a687059c	241	#ifndef I286
8d063cd8	242	if ((int)op & 0x3ff)
a687059c LW	243	(void)sbrk(1024 - ((int)op & 0x3ff));
	244	#else
	245	/* The sbrk(0) call on the I286 always returns the next segment */
	246	#endif
ee0007ab	247	#endif /* atarist */
a687059c	248
ee0007ab	249	#if !(defined(I286) \|\| defined(atarist))
8d063cd8 LW	250	/* take 2k unless the block is bigger than that */
8d063cd8 LW	251	rnu = (bucket <= 8) ? 11 : bucket + 3;
a687059c LW	252	#else
a687059c LW	253	/* take 16k unless the block is bigger than that
ee0007ab	254	(80286s like large segments!), probably good on the atari too */
a687059c LW	255	rnu = (bucket <= 11) ? 14 : bucket + 3;
a687059c LW	256	#endif
8d063cd8 LW	257	nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */
	258	if (rnu < bucket)
	259	rnu = bucket;
ee0007ab	260	op = (union overhead *)sbrk(1L << rnu);
8d063cd8 LW	261	/* no more room! */
	262	if ((int)op == -1)
	263	return;
	264	/*
	265	* Round up to minimum allocation size boundary
	266	* and deduct from block count to reflect.
	267	*/
a687059c	268	#ifndef I286
8d063cd8	269	if ((int)op & 7) {
ee0007ab	270	op = (union overhead *)(((MEM_SIZE)op + 8) &~ 7);
8d063cd8 LW	271	nblks--;
8d063cd8 LW	272	}
a687059c LW	273	#else
	274	/* Again, this should always be ok on an 80286 */
	275	#endif
8d063cd8 LW	276	/*
	277	* Add new memory allocated to that on
	278	* free list for this hash bucket.
	279	*/
	280	nextf[bucket] = op;
	281	siz = 1 << (bucket + 3);
	282	while (--nblks > 0) {
	283	op->ov_next = (union overhead *)((caddr_t)op + siz);
	284	op = (union overhead *)((caddr_t)op + siz);
	285	}
	286	}
	287
fe14fcc3	288	void
352d5a3a LW	289	free(mp)
352d5a3a LW	290	MALLOCPTRTYPE *mp;
8d063cd8	291	{
ee0007ab	292	register MEM_SIZE size;
8d063cd8	293	register union overhead *op;
352d5a3a	294	char cp = (char)mp;
8d063cd8	295
45d8adaa LW	296	#ifdef safemalloc
45d8adaa LW	297	#ifdef DEBUGGING
ee0007ab	298	# if !(defined(I286) \|\| defined(atarist))
45d8adaa LW	299	if (debug & 128)
	300	fprintf(stderr,"0x%x: (%05d) free\n",cp,an++);
	301	# else
	302	if (debug & 128)
	303	fprintf(stderr,"0x%lx: (%05d) free\n",cp,an++);
	304	# endif
	305	#endif
	306	#endif /* safemalloc */
	307
8d063cd8 LW	308	if (cp == NULL)
	309	return;
	310	op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
	311	#ifdef debug
	312	ASSERT(op->ov_magic == MAGIC); /* make sure it was in use */
	313	#else
378cc40b	314	if (op->ov_magic != MAGIC) {
a687059c	315	warn("%s free() ignored",
378cc40b	316	op->ov_magic == OLDMAGIC ? "Duplicate" : "Bad");
8d063cd8	317	return; /* sanity */
378cc40b LW	318	}
378cc40b LW	319	op->ov_magic = OLDMAGIC;
8d063cd8 LW	320	#endif
	321	#ifdef RCHECK
	322	ASSERT(op->ov_rmagic == RMAGIC);
	323	if (op->ov_index <= 13)
	324	ASSERT((u_int )((caddr_t)op + op->ov_size + 1 - RSLOP) == RMAGIC);
	325	#endif
	326	ASSERT(op->ov_index < NBUCKETS);
	327	size = op->ov_index;
	328	op->ov_next = nextf[size];
	329	nextf[size] = op;
	330	#ifdef MSTATS
	331	nmalloc[size]--;
	332	#endif
	333	}
	334
	335	/*
	336	* When a program attempts "storage compaction" as mentioned in the
	337	* old malloc man page, it realloc's an already freed block. Usually
	338	* this is the last block it freed; occasionally it might be farther
	339	* back. We have to search all the free lists for the block in order
	340	* to determine its bucket: 1st we make one pass thru the lists
	341	* checking only the first block in each; if that fails we search
378cc40b	342	* ``reall_srchlen'' blocks in each list for a match (the variable
8d063cd8 LW	343	* is extern so the caller can modify it). If that fails we just copy
	344	* however many bytes was given to realloc() and hope it's not huge.
	345	*/
378cc40b	346	int reall_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */
8d063cd8	347
35c8bce7	348	MALLOCPTRTYPE *
352d5a3a LW	349	realloc(mp, nbytes)
352d5a3a LW	350	MALLOCPTRTYPE *mp;
ee0007ab	351	MEM_SIZE nbytes;
8d063cd8	352	{
ee0007ab	353	register MEM_SIZE onb;
8d063cd8 LW	354	union overhead *op;
	355	char *res;
	356	register int i;
	357	int was_alloced = 0;
352d5a3a	358	char cp = (char)mp;
8d063cd8	359
45d8adaa LW	360	#ifdef safemalloc
45d8adaa LW	361	#ifdef DEBUGGING
ee0007ab	362	MEM_SIZE size = nbytes;
45d8adaa LW	363	#endif
	364
	365	#ifdef MSDOS
	366	if (nbytes > 0xffff) {
	367	fprintf(stderr, "Reallocation too large: %lx\n", size);
	368	exit(1);
	369	}
	370	#endif /* MSDOS */
	371	if (!cp)
ee0007ab	372	return malloc(nbytes);
45d8adaa LW	373	#ifdef DEBUGGING
	374	if ((long)nbytes < 0)
	375	fatal("panic: realloc");
	376	#endif
	377	#endif /* safemalloc */
	378
8d063cd8 LW	379	op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
	380	if (op->ov_magic == MAGIC) {
	381	was_alloced++;
	382	i = op->ov_index;
	383	} else {
	384	/*
	385	* Already free, doing "compaction".
	386	*
	387	* Search for the old block of memory on the
	388	* free list. First, check the most common
	389	* case (last element free'd), then (this failing)
378cc40b	390	* the last ``reall_srchlen'' items free'd.
8d063cd8 LW	391	* If all lookups fail, then assume the size of
	392	* the memory block being realloc'd is the
	393	* smallest possible.
	394	*/
	395	if ((i = findbucket(op, 1)) < 0 &&
378cc40b	396	(i = findbucket(op, reall_srchlen)) < 0)
8d063cd8 LW	397	i = 0;
8d063cd8 LW	398	}
ee0007ab	399	onb = (1L << (i + 3)) - sizeof (*op) - RSLOP;
8d063cd8 LW	400	/* avoid the copy if same size block */
8d063cd8 LW	401	if (was_alloced &&
a687059c LW	402	nbytes <= onb && nbytes > (onb >> 1) - sizeof(*op) - RSLOP) {
	403	#ifdef RCHECK
	404	/*
	405	* Record new allocated size of block and
	406	* bound space with magic numbers.
	407	*/
	408	if (op->ov_index <= 13) {
	409	/*
	410	* Convert amount of memory requested into
	411	* closest block size stored in hash buckets
	412	* which satisfies request. Account for
	413	* space used per block for accounting.
	414	*/
	415	nbytes += sizeof (union overhead) + RSLOP;
	416	nbytes = (nbytes + 3) &~ 3;
	417	op->ov_size = nbytes - 1;
	418	((u_int )((caddr_t)op + nbytes - RSLOP)) = RMAGIC;
	419	}
	420	#endif
45d8adaa	421	res = cp;
a687059c	422	}
45d8adaa LW	423	else {
	424	if ((res = (char*)malloc(nbytes)) == NULL)
	425	return (NULL);
	426	if (cp != res) /* common optimization */
ee0007ab	427	Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
45d8adaa LW	428	if (was_alloced)
	429	free(cp);
	430	}
	431
	432	#ifdef safemalloc
	433	#ifdef DEBUGGING
ee0007ab	434	# if !(defined(I286) \|\| defined(atarist))
45d8adaa LW	435	if (debug & 128) {
45d8adaa LW	436	fprintf(stderr,"0x%x: (%05d) rfree\n",res,an++);
ee0007ab	437	fprintf(stderr,"0x%x: (%05d) realloc %ld bytes\n",res,an++,(long)size);
45d8adaa LW	438	}
	439	# else
	440	if (debug & 128) {
	441	fprintf(stderr,"0x%lx: (%05d) rfree\n",res,an++);
ee0007ab	442	fprintf(stderr,"0x%lx: (%05d) realloc %ld bytes\n",res,an++,(long)size);
45d8adaa LW	443	}
	444	# endif
	445	#endif
	446	#endif /* safemalloc */
352d5a3a	447	return ((MALLOCPTRTYPE*)res);
8d063cd8 LW	448	}
	449
	450	/*
	451	* Search ``srchlen'' elements of each free list for a block whose
	452	* header starts at ``freep''. If srchlen is -1 search the whole list.
	453	* Return bucket number, or -1 if not found.
	454	*/
ee0007ab	455	static int
8d063cd8 LW	456	findbucket(freep, srchlen)
	457	union overhead *freep;
	458	int srchlen;
	459	{
	460	register union overhead *p;
	461	register int i, j;
	462
	463	for (i = 0; i < NBUCKETS; i++) {
	464	j = 0;
	465	for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
	466	if (p == freep)
	467	return (i);
	468	j++;
	469	}
	470	}
	471	return (-1);
	472	}
	473
	474	#ifdef MSTATS
	475	/*
	476	* mstats - print out statistics about malloc
	477	*
	478	* Prints two lines of numbers, one showing the length of the free list
	479	* for each size category, the second showing the number of mallocs -
	480	* frees for each size category.
	481	*/
ee0007ab	482	void
8d063cd8 LW	483	mstats(s)
	484	char *s;
	485	{
	486	register int i, j;
	487	register union overhead *p;
	488	int totfree = 0,
	489	totused = 0;
	490
	491	fprintf(stderr, "Memory allocation statistics %s\nfree:\t", s);
	492	for (i = 0; i < NBUCKETS; i++) {
	493	for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
	494	;
	495	fprintf(stderr, " %d", j);
	496	totfree += j * (1 << (i + 3));
	497	}
	498	fprintf(stderr, "\nused:\t");
	499	for (i = 0; i < NBUCKETS; i++) {
	500	fprintf(stderr, " %d", nmalloc[i]);
	501	totused += nmalloc[i] * (1 << (i + 3));
	502	}
	503	fprintf(stderr, "\n\tTotal in use: %d, total free: %d\n",
	504	totused, totfree);
	505	}
	506	#endif
a687059c	507	#endif /* lint */