src/common/malloc.c

/* Copyright (c) 1992 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 * Fast malloc for memory hogs and VM environments.
 * Performs a minimum of searching through free lists.
 * malloc(), realloc() and free() use buckets
 *      containing blocks in powers of two, similar to CIT routines.
 * bfree() puts memory from any source into malloc free lists.
 * bmalloc() doesn't keep track of free lists -- it's usually
 *      just a buffered call to sbrk(2).  However, bmalloc will
 *      call mscrounge() if sbrk fails.
 * mscrounge() returns whatever free memory it can find to satisfy the
 *      request along with the number of bytes (modified).
 * mcompact() takes the same arguments as mscrounge() (and is in fact
 *      called by mscrounge() under dire circumstances), but it uses
 *      memory compaction to return a larger block.  (MCOMP)
 *
 *      Greg Ward       Lawrence Berkeley Laboratory
 */

#include  <errno.h>

extern int      errno;

#ifndef  BSD
#define  bcopy(s,d,n)           (void)memcpy(d,s,n)
#define  bzero(d,n)             (void)memset(d,0,n)
extern char  *memcpy(), *memset();
#endif

#ifdef MSTATS
#include  <stdio.h>
static unsigned b_nsbrked = 0;
static unsigned b_nalloced = 0;
static unsigned b_nfreed = 0;
static unsigned b_nscrounged = 0;
static unsigned b_ncompacted = 0;
static unsigned m_nalloced = 0;
static unsigned m_nfreed = 0;
static unsigned m_nwasted = 0;
#else
#define  NULL           0
#endif

#ifndef ALIGN
#define  ALIGN          int                     /* align type */
#endif
#define  BYTES_WORD     sizeof(ALIGN)

#ifndef  MAXINCR
#define  MAXINCR        (1<<16)                 /* largest sbrk(2) increment */
#endif
                                        /* malloc free lists */
typedef union m_head {
        union m_head    *next;
        struct {
                short           magic;
                short           bucket;
        }       a;
        ALIGN           dummy;
} M_HEAD;

#define MAGIC           0x1a2           /* magic number for allocated memory */

#define FIRSTBUCKET     3
#define NBUCKETS        30

static M_HEAD   *free_list[NBUCKETS];

static ALIGN    dummy_mem;

static char     *memlim[2];

#define DUMMYLOC        ((char *)&dummy_mem)

#define BADPTR(p)       ((p) < memlim[0] | (p) >= memlim[1])

#ifdef  MCOMP                   /* memory compaction routines */
static char     seedtab[1024];          /* seed for compaction table */

static struct mblk {
        char            *ptr;   /* pointer to memory block */
        unsigned        siz;    /* size of memory block */
}       cptab = {seedtab, sizeof(seedtab)};

#define mtab(mb)        ((struct mblk *)(mb)->ptr)
#define mtablen(mb)     ((mb)->siz/sizeof(struct mblk))


static int
mbcmp(m1, m2)           /* compare memory block locations */
register struct mblk    *m1, *m2;
{
                                /* put empty blocks at end */
        if (m1->siz == 0)
                return(m2->siz == 0 ? 0 : 1);
        if (m2->siz == 0)
                return(-1);
                                /* otherwise, ascending order */
        return(m1->ptr - m2->ptr);
}


int
compactfree()           /* compact free lists (moving to table) */
{
        register struct mblk    *tp;
        register int    bucket;
        unsigned        n, bsiz, ncomp;
                                /* fill table from free lists */
        tp = mtab(&cptab); n = mtablen(&cptab);
        bucket = NBUCKETS-1; bsiz = 1<<(NBUCKETS-1);
        ncomp = 0;
        for ( ; ; ) {
                while (tp->siz) {       /* find empty slot */
                        if (--n == 0)
                                goto loopexit;
                        tp++;
                }
                while (free_list[bucket] == NULL) {     /* find block */
                        if (--bucket < FIRSTBUCKET)
                                goto loopexit;
                        bsiz >>= 1;
                }
                tp->ptr = (char *)free_list[bucket];
                ncomp += (tp->siz = bsiz + sizeof(M_HEAD));
                free_list[bucket] = free_list[bucket]->next;
        }
loopexit:
        if (ncomp == 0)
                return(0);              /* nothing new to compact */
#ifdef MSTATS
        b_ncompacted += ncomp;
#endif
        tp = mtab(&cptab); n = mtablen(&cptab);         /* sort table */
        qsort((char *)tp, n, sizeof(struct mblk), mbcmp);
        ncomp = 0;                                      /* collect blocks */
        while (--n && tp[1].siz) {
                if (tp[0].ptr + tp[0].siz == tp[1].ptr) {
                        tp[1].ptr = tp[0].ptr;
                        tp[1].siz += tp[0].siz;
                        ncomp += tp[0].siz;
                        tp[0].siz = 0;
                }
                tp++;
        }
        return(ncomp);
}


char *
mcompact(np)            /* compact free lists to satisfy request */
unsigned        *np;
{
        struct mblk     *tab;
        unsigned        tablen;
        register struct mblk    *bp, *big;

        for ( ; ; ) {
                                        /* compact free lists */
                compactfree();
                                        /* find largest block */
                tab = mtab(&cptab); tablen = mtablen(&cptab);
                big = tab;
                bp = tab + tablen;
                while (--bp > tab)
                        if (bp->siz > big->siz)
                                big = bp;
                if (big->siz >= *np) {          /* big enough? */
                        *np = big->siz;
                        big->siz = 0;           /* remove from table */
                        return(big->ptr);       /* return it */
                }
                if (mtablen(big) <= tablen) {
                        *np = 0;                /* cannot grow table */
                        return(NULL);           /* report failure */
                }
                                /* enlarge table, free old one */
                mtab(big)[0].ptr = cptab.ptr;
                mtab(big)[0].siz = cptab.siz;
                cptab.ptr = big->ptr;
                cptab.siz = big->siz;
                big->siz = 0;                   /* clear and copy */
                bcopy((char *)tab, (char *)(mtab(&cptab)+1),
                                tablen*sizeof(struct mblk));
                bzero((char *)(mtab(&cptab)+tablen+1),
                        (mtablen(&cptab)-tablen-1)*sizeof(struct mblk));
        }                       /* next round */
}
#endif          /* MCOMP */


char *
mscrounge(np)           /* search free lists to satisfy request */
register unsigned       *np;
{
        char    *p;
        register int    bucket;
        register unsigned       bsiz;

        for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET;
                        bucket < NBUCKETS; bucket++, bsiz <<= 1)
                if (free_list[bucket] != NULL && bsiz+sizeof(M_HEAD) >= *np) {
                        *np = bsiz+sizeof(M_HEAD);
                        p = (char *)free_list[bucket];
                        free_list[bucket] = free_list[bucket]->next;
#ifdef MSTATS
                        b_nscrounged += *np;
#endif
                        return(p);
                }
#ifdef MCOMP
        return(mcompact(np));           /* try compaction */
#else
        *np = 0;
        return(NULL);
#endif
}


char *
bmalloc(n)              /* allocate a block of n bytes, sans header */
register unsigned  n;
{
        extern char  *sbrk();
        static unsigned  pagesz = 0;
        static unsigned  amnt;
        static char  *bpos;
        static unsigned  nrem;
        unsigned  thisamnt;
        register char   *p;

        if (pagesz == 0) {                              /* initialize */
                pagesz = amnt = getpagesize();
                nrem = (int)sbrk(0);                    /* page align break */
                nrem = pagesz - (nrem&(pagesz-1));
                bpos = sbrk(nrem);
                if ((int)bpos == -1)
                        return(NULL);
#ifdef MSTATS
                b_nsbrked += nrem;
#endif
                bpos += nrem & (BYTES_WORD-1);          /* align pointer */
                nrem &= ~(BYTES_WORD-1);
                memlim[0] = bpos;
                memlim[1] = bpos + nrem;
        }

        n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1);         /* word align rqst. */

        if (n > nrem) {                                 /* need more core */
                if (n > amnt) {                         /* big chunk */
                        thisamnt = (n+(pagesz-1))&~(pagesz-1);
                        if (thisamnt <= MAXINCR)        /* increase amnt */
                                amnt = thisamnt;
                } else
                        thisamnt = amnt;
                p = sbrk(thisamnt);
                if ((int)p == -1) {                     /* uh-oh, ENOMEM */
                        thisamnt = n;                   /* search free lists */
                        p = mscrounge(&thisamnt);
                        if (p == NULL)                  /* we're really out */
                                return(NULL);
                }
#ifdef MSTATS
                else b_nsbrked += thisamnt;
#endif
                if (p != bpos+nrem) {                   /* not an increment */
                        bfree(bpos, nrem);              /* free what we have */
                        bpos = p;
                        nrem = thisamnt;
                } else                                  /* otherwise tack on */
                        nrem += thisamnt;
                if (bpos < memlim[0])
                        memlim[0] = bpos;
                if (bpos + nrem > memlim[1])
                        memlim[1] = bpos + nrem;
        }
        p = bpos;
        bpos += n;                                      /* advance */
        nrem -= n;
#ifdef MSTATS
        b_nalloced += n;
#endif
        return(p);
}


bfree(p, n)                     /* free n bytes of random memory */
register char  *p;
register unsigned  n;
{
        register int    bucket;
        register unsigned       bsiz;

        if (n < 1<<FIRSTBUCKET)
                return;
#ifdef MSTATS
        b_nfreed += n;
#endif
                                        /* align pointer */
        bsiz = BYTES_WORD - ((unsigned)p&(BYTES_WORD-1));
        if (bsiz < BYTES_WORD) {
                p += bsiz;
                n -= bsiz;
        }
        if (p < memlim[0])
                memlim[0] = p;
        if (p + n > memlim[1])
                memlim[1] = p + n;
                                        /* fill big buckets first */
        for (bucket = NBUCKETS-1, bsiz = 1<<(NBUCKETS-1);
                        bucket >= FIRSTBUCKET; bucket--, bsiz >>= 1)
                if (n >= bsiz+sizeof(M_HEAD)) {
                        ((M_HEAD *)p)->next = free_list[bucket];
                        free_list[bucket] = (M_HEAD *)p;
                        p += bsiz+sizeof(M_HEAD);
                        n -= bsiz+sizeof(M_HEAD);
                }
}


char *
malloc(n)                       /* allocate n bytes of memory */
unsigned        n;
{
        register M_HEAD *mp;
        register int    bucket;
        register unsigned       bsiz;
                                        /* don't return NULL on 0 request */
        if (n == 0)
                return(DUMMYLOC);
                                        /* find first bucket that fits */
        for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET;
                        bucket < NBUCKETS; bucket++, bsiz <<= 1)
                if (bsiz >= n)
                        break;
        if (bucket >= NBUCKETS) {
                errno = EINVAL;
                return(NULL);
        }
        if (free_list[bucket] == NULL) {        /* need more core */
                mp = (M_HEAD *)bmalloc(bsiz+sizeof(M_HEAD));
                if (mp == NULL)
                        return(NULL);
        } else {                                /* got it */
                mp = free_list[bucket];
                free_list[bucket] = mp->next;
        }
#ifdef MSTATS
        m_nalloced += bsiz + sizeof(M_HEAD);
        m_nwasted += bsiz + sizeof(M_HEAD) - n;
#endif
        mp->a.magic = MAGIC;                    /* tag block */
        mp->a.bucket = bucket;
        return((char *)(mp+1));
}


char *
realloc(op, n)                  /* reallocate memory using malloc() */
register char   *op;
unsigned        n;
{
        char    *p;
        register unsigned       on;
                                        /* get old size */
        if (op != DUMMYLOC && !BADPTR(op) &&
                        ((M_HEAD *)op-1)->a.magic == MAGIC)
                on = 1 << ((M_HEAD *)op-1)->a.bucket;
        else
                on = 0;
        if (n <= on && (n > on>>1 || on == 1<<FIRSTBUCKET))
                return(op);             /* same bucket */
        if ((p = malloc(n)) == NULL)
                return(n<=on ? op : NULL);
        if (on) {
                bcopy(op, p, n>on ? on : n);
                free(op);
        }
        return(p);
}


free(p)                 /* free memory allocated by malloc */
char    *p;
{
        register M_HEAD *mp;
        register int    bucket;

        if (p == DUMMYLOC)
                return(1);
        if (BADPTR(p))
                goto invalid;
        mp = (M_HEAD *)p - 1;
        if (mp->a.magic != MAGIC)               /* sanity check */
                goto invalid;
        bucket = mp->a.bucket;
        if (bucket < FIRSTBUCKET | bucket >= NBUCKETS)
                goto invalid;
        mp->next = free_list[bucket];
        free_list[bucket] = mp;
#ifdef MSTATS
        m_nfreed += (1 << bucket) + sizeof(M_HEAD);
#endif
        return(1);
invalid:
        errno = EINVAL;
        return(0);
}


#ifdef MSTATS
printmemstats(fp)               /* print memory statistics to stream */
FILE    *fp;
{
        register int    i;
        int     n;
        register M_HEAD *mp;
        unsigned int    total = 0;

        fprintf(fp, "Memory statistics:\n");
        fprintf(fp, "\tbmalloc: %d bytes from sbrk\n", b_nsbrked);
        fprintf(fp, "\tbmalloc: %d bytes allocated\n", b_nalloced);
        fprintf(fp, "\tbmalloc: %d bytes freed\n", b_nfreed);
        fprintf(fp, "\tbmalloc: %d bytes scrounged\n", b_nscrounged);
        fprintf(fp, "\tbmalloc: %d bytes compacted\n", b_ncompacted);
        fprintf(fp, "\tmalloc: %d bytes allocated\n", m_nalloced);
        fprintf(fp, "\tmalloc: %d bytes wasted (%.1f%%)\n", m_nwasted,
                        100.0*m_nwasted/m_nalloced);
        fprintf(fp, "\tmalloc: %d bytes freed\n", m_nfreed);
        for (i = NBUCKETS-1; i >= FIRSTBUCKET; i--) {
                n = 0;
                for (mp = free_list[i]; mp != NULL; mp = mp->next)
                        n++;
                if (n) {
                        fprintf(fp, "\t%d * %u\n", n, 1<<i);
                        total += n * ((1<<i) + sizeof(M_HEAD));
                }
        }
        fprintf(fp, "\t %u total bytes in free list\n", total);
}
#endif
Revision:	2.7
Committed:	Fri Sep 4 18:36:05 1992 UTC (31 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.6:	+7 -12 lines
Log Message:	minor aesthetic changes
#	User	Rev	Content
1	greg	2.3	/* Copyright (c) 1992 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* Fast malloc for memory hogs and VM environments.
9			* Performs a minimum of searching through free lists.
10	greg	1.4	* malloc(), realloc() and free() use buckets
11			* containing blocks in powers of two, similar to CIT routines.
12			* bfree() puts memory from any source into malloc free lists.
13			* bmalloc() doesn't keep track of free lists -- it's usually
14	greg	1.3	* just a buffered call to sbrk(2). However, bmalloc will
15			* call mscrounge() if sbrk fails.
16	greg	1.8	* mscrounge() returns whatever free memory it can find to satisfy the
17	greg	1.3	* request along with the number of bytes (modified).
18	greg	1.14	* mcompact() takes the same arguments as mscrounge() (and is in fact
19			* called by mscrounge() under dire circumstances), but it uses
20			* memory compaction to return a larger block. (MCOMP)
21	greg	1.1	*
22			* Greg Ward Lawrence Berkeley Laboratory
23			*/
24
25	greg	1.6	#include <errno.h>
26
27	greg	2.6	extern int errno;
28
29	greg	2.7	#ifndef BSD
30			#define bcopy(s,d,n) (void)memcpy(d,s,n)
31			#define bzero(d,n) (void)memset(d,0,n)
32			extern char memcpy(), memset();
33			#endif
34
35	greg	1.9	#ifdef MSTATS
36			#include <stdio.h>
37	greg	2.6	static unsigned b_nsbrked = 0;
38	greg	1.9	static unsigned b_nalloced = 0;
39			static unsigned b_nfreed = 0;
40			static unsigned b_nscrounged = 0;
41	greg	1.14	static unsigned b_ncompacted = 0;
42	greg	1.9	static unsigned m_nalloced = 0;
43			static unsigned m_nfreed = 0;
44			static unsigned m_nwasted = 0;
45			#else
46	greg	1.1	#define NULL 0
47	greg	1.9	#endif
48	greg	1.1
49			#ifndef ALIGN
50			#define ALIGN int /* align type */
51			#endif
52			#define BYTES_WORD sizeof(ALIGN)
53
54	greg	1.16	#ifndef MAXINCR
55	greg	1.9	#define MAXINCR (1<<16) /* largest sbrk(2) increment */
56	greg	1.1	#endif
57			/* malloc free lists */
58			typedef union m_head {
59			union m_head *next;
60	greg	1.12	struct {
61			short magic;
62			short bucket;
63			} a;
64	greg	1.1	ALIGN dummy;
65			} M_HEAD;
66
67	greg	1.12	#define MAGIC 0x1a2 /* magic number for allocated memory */
68
69	greg	1.1	#define FIRSTBUCKET 3
70			#define NBUCKETS 30
71
72			static M_HEAD *free_list[NBUCKETS];
73
74	greg	1.12	static ALIGN dummy_mem;
75	greg	1.1
76	greg	2.6	static char *memlim[2];
77
78	greg	1.12	#define DUMMYLOC ((char *)&dummy_mem)
79	greg	1.10
80	greg	2.6	#define BADPTR(p) ((p) < memlim[0] \| (p) >= memlim[1])
81
82	greg	1.14	#ifdef MCOMP /* memory compaction routines */
83			static char seedtab[1024]; /* seed for compaction table */
84	greg	1.12
85	greg	1.14	static struct mblk {
86			char ptr; / pointer to memory block */
87			unsigned siz; /* size of memory block */
88			} cptab = {seedtab, sizeof(seedtab)};
89
90			#define mtab(mb) ((struct mblk *)(mb)->ptr)
91			#define mtablen(mb) ((mb)->siz/sizeof(struct mblk))
92
93
94			static int
95			mbcmp(m1, m2) /* compare memory block locations */
96			register struct mblk m1, m2;
97			{
98			/* put empty blocks at end */
99			if (m1->siz == 0)
100			return(m2->siz == 0 ? 0 : 1);
101			if (m2->siz == 0)
102			return(-1);
103			/* otherwise, ascending order */
104			return(m1->ptr - m2->ptr);
105			}
106
107
108			int
109			compactfree() /* compact free lists (moving to table) */
110			{
111			register struct mblk *tp;
112			register int bucket;
113			unsigned n, bsiz, ncomp;
114			/* fill table from free lists */
115			tp = mtab(&cptab); n = mtablen(&cptab);
116			bucket = NBUCKETS-1; bsiz = 1<<(NBUCKETS-1);
117			ncomp = 0;
118			for ( ; ; ) {
119			while (tp->siz) { /* find empty slot */
120			if (--n == 0)
121			goto loopexit;
122			tp++;
123			}
124			while (free_list[bucket] == NULL) { /* find block */
125			if (--bucket < FIRSTBUCKET)
126			goto loopexit;
127			bsiz >>= 1;
128			}
129			tp->ptr = (char *)free_list[bucket];
130			ncomp += (tp->siz = bsiz + sizeof(M_HEAD));
131			free_list[bucket] = free_list[bucket]->next;
132			}
133			loopexit:
134			if (ncomp == 0)
135			return(0); /* nothing new to compact */
136			#ifdef MSTATS
137			b_ncompacted += ncomp;
138			#endif
139			tp = mtab(&cptab); n = mtablen(&cptab); /* sort table */
140			qsort((char *)tp, n, sizeof(struct mblk), mbcmp);
141			ncomp = 0; /* collect blocks */
142			while (--n && tp[1].siz) {
143			if (tp[0].ptr + tp[0].siz == tp[1].ptr) {
144			tp[1].ptr = tp[0].ptr;
145			tp[1].siz += tp[0].siz;
146			ncomp += tp[0].siz;
147			tp[0].siz = 0;
148			}
149			tp++;
150			}
151			return(ncomp);
152			}
153
154
155	greg	1.1	char *
156	greg	1.14	mcompact(np) /* compact free lists to satisfy request */
157			unsigned *np;
158			{
159			struct mblk *tab;
160			unsigned tablen;
161			register struct mblk bp, big;
162
163			for ( ; ; ) {
164			/* compact free lists */
165			compactfree();
166			/* find largest block */
167			tab = mtab(&cptab); tablen = mtablen(&cptab);
168			big = tab;
169			bp = tab + tablen;
170			while (--bp > tab)
171			if (bp->siz > big->siz)
172			big = bp;
173			if (big->siz >= np) { / big enough? */
174			*np = big->siz;
175			big->siz = 0; /* remove from table */
176			return(big->ptr); /* return it */
177			}
178	greg	2.7	if (mtablen(big) <= tablen) {
179	greg	1.14	np = 0; / cannot grow table */
180			return(NULL); /* report failure */
181			}
182			/* enlarge table, free old one */
183			mtab(big)[0].ptr = cptab.ptr;
184			mtab(big)[0].siz = cptab.siz;
185			cptab.ptr = big->ptr;
186			cptab.siz = big->siz;
187			big->siz = 0; /* clear and copy */
188			bcopy((char )tab, (char )(mtab(&cptab)+1),
189			tablen*sizeof(struct mblk));
190			bzero((char *)(mtab(&cptab)+tablen+1),
191			(mtablen(&cptab)-tablen-1)*sizeof(struct mblk));
192			} /* next round */
193			}
194			#endif /* MCOMP */
195
196
197			char *
198	greg	1.4	mscrounge(np) /* search free lists to satisfy request */
199	greg	1.3	register unsigned *np;
200			{
201			char *p;
202			register int bucket;
203			register unsigned bsiz;
204
205			for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET;
206			bucket < NBUCKETS; bucket++, bsiz <<= 1)
207			if (free_list[bucket] != NULL && bsiz+sizeof(M_HEAD) >= *np) {
208			*np = bsiz+sizeof(M_HEAD);
209			p = (char *)free_list[bucket];
210			free_list[bucket] = free_list[bucket]->next;
211	greg	1.9	#ifdef MSTATS
212			b_nscrounged += *np;
213			#endif
214	greg	1.3	return(p);
215			}
216	greg	1.14	#ifdef MCOMP
217			return(mcompact(np)); /* try compaction */
218			#else
219	greg	1.3	*np = 0;
220			return(NULL);
221	greg	1.14	#endif
222	greg	1.3	}
223
224
225			char *
226	greg	1.1	bmalloc(n) /* allocate a block of n bytes, sans header */
227			register unsigned n;
228			{
229			extern char *sbrk();
230	greg	1.3	static unsigned pagesz = 0;
231			static unsigned amnt;
232	greg	1.1	static char *bpos;
233	greg	1.3	static unsigned nrem;
234			unsigned thisamnt;
235	greg	1.1	register char *p;
236
237			if (pagesz == 0) { /* initialize */
238	greg	1.2	pagesz = amnt = getpagesize();
239	greg	1.1	nrem = (int)sbrk(0); /* page align break */
240			nrem = pagesz - (nrem&(pagesz-1));
241	greg	2.3	bpos = sbrk(nrem);
242	greg	1.1	if ((int)bpos == -1)
243			return(NULL);
244	greg	1.14	#ifdef MSTATS
245			b_nsbrked += nrem;
246			#endif
247	greg	2.4	bpos += nrem & (BYTES_WORD-1); /* align pointer */
248			nrem &= ~(BYTES_WORD-1);
249	greg	2.6	memlim[0] = bpos;
250			memlim[1] = bpos + nrem;
251	greg	1.1	}
252
253			n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align rqst. */
254
255			if (n > nrem) { /* need more core */
256	greg	1.3	if (n > amnt) { /* big chunk */
257			thisamnt = (n+(pagesz-1))&~(pagesz-1);
258			if (thisamnt <= MAXINCR) /* increase amnt */
259			amnt = thisamnt;
260			} else
261			thisamnt = amnt;
262			p = sbrk(thisamnt);
263	greg	1.4	if ((int)p == -1) { /* uh-oh, ENOMEM */
264	greg	1.3	thisamnt = n; /* search free lists */
265			p = mscrounge(&thisamnt);
266			if (p == NULL) /* we're really out */
267			return(NULL);
268			}
269	greg	1.14	#ifdef MSTATS
270			else b_nsbrked += thisamnt;
271			#endif
272	greg	1.3	if (p != bpos+nrem) { /* not an increment */
273	greg	1.4	bfree(bpos, nrem); /* free what we have */
274	greg	1.1	bpos = p;
275	greg	1.3	nrem = thisamnt;
276	greg	1.4	} else /* otherwise tack on */
277	greg	1.3	nrem += thisamnt;
278	greg	2.6	if (bpos < memlim[0])
279			memlim[0] = bpos;
280			if (bpos + nrem > memlim[1])
281			memlim[1] = bpos + nrem;
282	greg	1.1	}
283			p = bpos;
284			bpos += n; /* advance */
285			nrem -= n;
286	greg	1.13	#ifdef MSTATS
287			b_nalloced += n;
288			#endif
289	greg	1.1	return(p);
290			}
291
292
293			bfree(p, n) /* free n bytes of random memory */
294	greg	1.2	register char *p;
295			register unsigned n;
296	greg	1.1	{
297			register int bucket;
298			register unsigned bsiz;
299	greg	1.9
300	greg	1.15	if (n < 1<<FIRSTBUCKET)
301			return;
302	greg	1.9	#ifdef MSTATS
303			b_nfreed += n;
304			#endif
305	greg	1.4	/* align pointer */
306	greg	1.6	bsiz = BYTES_WORD - ((unsigned)p&(BYTES_WORD-1));
307	greg	1.4	if (bsiz < BYTES_WORD) {
308			p += bsiz;
309			n -= bsiz;
310	greg	1.1	}
311	greg	2.6	if (p < memlim[0])
312			memlim[0] = p;
313			if (p + n > memlim[1])
314			memlim[1] = p + n;
315	greg	1.4	/* fill big buckets first */
316			for (bucket = NBUCKETS-1, bsiz = 1<<(NBUCKETS-1);
317			bucket >= FIRSTBUCKET; bucket--, bsiz >>= 1)
318			if (n >= bsiz+sizeof(M_HEAD)) {
319			((M_HEAD *)p)->next = free_list[bucket];
320			free_list[bucket] = (M_HEAD *)p;
321			p += bsiz+sizeof(M_HEAD);
322			n -= bsiz+sizeof(M_HEAD);
323			}
324	greg	1.1	}
325
326
327			char *
328			malloc(n) /* allocate n bytes of memory */
329			unsigned n;
330			{
331			register M_HEAD *mp;
332			register int bucket;
333			register unsigned bsiz;
334	greg	1.10	/* don't return NULL on 0 request */
335			if (n == 0)
336			return(DUMMYLOC);
337	greg	1.2	/* find first bucket that fits */
338	greg	1.6	for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET;
339			bucket < NBUCKETS; bucket++, bsiz <<= 1)
340			if (bsiz >= n)
341			break;
342			if (bucket >= NBUCKETS) {
343			errno = EINVAL;
344			return(NULL);
345			}
346	greg	1.4	if (free_list[bucket] == NULL) { /* need more core */
347	greg	1.1	mp = (M_HEAD *)bmalloc(bsiz+sizeof(M_HEAD));
348			if (mp == NULL)
349			return(NULL);
350	greg	1.4	} else { /* got it */
351	greg	1.1	mp = free_list[bucket];
352			free_list[bucket] = mp->next;
353			}
354	greg	1.13	#ifdef MSTATS
355			m_nalloced += bsiz + sizeof(M_HEAD);
356			m_nwasted += bsiz + sizeof(M_HEAD) - n;
357			#endif
358	greg	1.12	mp->a.magic = MAGIC; /* tag block */
359			mp->a.bucket = bucket;
360	greg	1.1	return((char *)(mp+1));
361			}
362
363
364			char *
365			realloc(op, n) /* reallocate memory using malloc() */
366	greg	1.6	register char *op;
367	greg	1.1	unsigned n;
368			{
369	greg	1.6	char *p;
370	greg	1.1	register unsigned on;
371	greg	1.6	/* get old size */
372	greg	2.6	if (op != DUMMYLOC && !BADPTR(op) &&
373			((M_HEAD *)op-1)->a.magic == MAGIC)
374	greg	1.12	on = 1 << ((M_HEAD *)op-1)->a.bucket;
375	greg	1.5	else
376			on = 0;
377	greg	1.6	if (n <= on && (n > on>>1 \|\| on == 1<<FIRSTBUCKET))
378	greg	1.5	return(op); /* same bucket */
379	greg	1.13	if ((p = malloc(n)) == NULL)
380	greg	2.5	return(n<=on ? op : NULL);
381	greg	1.13	if (on) {
382	greg	1.2	bcopy(op, p, n>on ? on : n);
383	greg	1.13	free(op);
384			}
385	greg	1.1	return(p);
386			}
387
388
389			free(p) /* free memory allocated by malloc */
390			char *p;
391			{
392			register M_HEAD *mp;
393			register int bucket;
394
395	greg	2.6	if (p == DUMMYLOC)
396	greg	1.13	return(1);
397	greg	2.6	if (BADPTR(p))
398			goto invalid;
399	greg	1.1	mp = (M_HEAD *)p - 1;
400	greg	1.12	if (mp->a.magic != MAGIC) /* sanity check */
401	greg	2.6	goto invalid;
402	greg	1.12	bucket = mp->a.bucket;
403	greg	2.2	if (bucket < FIRSTBUCKET \| bucket >= NBUCKETS)
404	greg	2.6	goto invalid;
405	greg	1.1	mp->next = free_list[bucket];
406			free_list[bucket] = mp;
407	greg	1.9	#ifdef MSTATS
408			m_nfreed += (1 << bucket) + sizeof(M_HEAD);
409			#endif
410	greg	1.13	return(1);
411	greg	2.6	invalid:
412			errno = EINVAL;
413			return(0);
414	greg	1.1	}
415	greg	1.9
416
417			#ifdef MSTATS
418			printmemstats(fp) /* print memory statistics to stream */
419			FILE *fp;
420			{
421			register int i;
422			int n;
423			register M_HEAD *mp;
424			unsigned int total = 0;
425
426			fprintf(fp, "Memory statistics:\n");
427	greg	1.14	fprintf(fp, "\tbmalloc: %d bytes from sbrk\n", b_nsbrked);
428	greg	1.9	fprintf(fp, "\tbmalloc: %d bytes allocated\n", b_nalloced);
429			fprintf(fp, "\tbmalloc: %d bytes freed\n", b_nfreed);
430			fprintf(fp, "\tbmalloc: %d bytes scrounged\n", b_nscrounged);
431	greg	1.14	fprintf(fp, "\tbmalloc: %d bytes compacted\n", b_ncompacted);
432	greg	1.9	fprintf(fp, "\tmalloc: %d bytes allocated\n", m_nalloced);
433			fprintf(fp, "\tmalloc: %d bytes wasted (%.1f%%)\n", m_nwasted,
434			100.0*m_nwasted/m_nalloced);
435			fprintf(fp, "\tmalloc: %d bytes freed\n", m_nfreed);
436			for (i = NBUCKETS-1; i >= FIRSTBUCKET; i--) {
437			n = 0;
438			for (mp = free_list[i]; mp != NULL; mp = mp->next)
439			n++;
440			if (n) {
441			fprintf(fp, "\t%d * %u\n", n, 1<<i);
442			total += n * ((1<<i) + sizeof(M_HEAD));
443			}
444			}
445			fprintf(fp, "\t %u total bytes in free list\n", total);
446			}
447	greg	1.1	#endif