src/common/malloc.c

#ifndef lint
static const char       RCSid[] = "$Id: malloc.c,v 2.15 2003/05/13 17:58:32 greg Exp $";
#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 "copyright.h"

#include  <errno.h>
#include  <string.h>


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

#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;
        ALIGNT          dummy;
} M_HEAD;

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

#define FIRSTBUCKET     3
#define NBUCKETS        30

static M_HEAD   *free_list[NBUCKETS];

static ALIGNT   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 */
                while (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 */
                memcpy((char *)(mtab(&cptab)+1), (char *)tab,
                                tablen*sizeof(struct mblk));
                memset((char *)(mtab(&cptab)+tablen+1), '\0',
                        (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 */
        tryagain:
                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 */
                        errno = 0;                      /* call cavalry */
                        if (thisamnt >= n+pagesz) {
                                amnt = pagesz;          /* minimize request */
                                goto tryagain;
                        }
                        thisamnt = n;
                        p = mscrounge(&thisamnt);       /* search free lists */
                        if (p == NULL) {                /* we're really out */
                                errno = ENOMEM;
                                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 || p == NULL)
                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) {
                memcpy(p, op, 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:	2.16
Committed:	Mon Jun 30 14:59:11 2003 UTC (20 years, 10 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R6P1, rad3R6
Changes since 2.15:	+5 -8 lines
Log Message:	Replaced most outdated BSD function calls with their posix equivalents, and cleaned up a few other platform dependencies.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	schorsch	2.16	static const char RCSid[] = "$Id: malloc.c,v 2.15 2003/05/13 17:58:32 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* Fast malloc for memory hogs and VM environments.
6			* Performs a minimum of searching through free lists.
7	greg	1.4	* malloc(), realloc() and free() use buckets
8			* containing blocks in powers of two, similar to CIT routines.
9			* bfree() puts memory from any source into malloc free lists.
10			* bmalloc() doesn't keep track of free lists -- it's usually
11	greg	1.3	* just a buffered call to sbrk(2). However, bmalloc will
12			* call mscrounge() if sbrk fails.
13	greg	1.8	* mscrounge() returns whatever free memory it can find to satisfy the
14	greg	1.3	* request along with the number of bytes (modified).
15	greg	1.14	* mcompact() takes the same arguments as mscrounge() (and is in fact
16			* called by mscrounge() under dire circumstances), but it uses
17			* memory compaction to return a larger block. (MCOMP)
18	greg	1.1	*
19			* Greg Ward Lawrence Berkeley Laboratory
20			*/
21
22	greg	2.13	#include "copyright.h"
23	greg	2.12
24	greg	1.6	#include <errno.h>
25	schorsch	2.16	#include <string.h>
26	greg	1.6
27	greg	2.7
28	greg	1.9	#ifdef MSTATS
29			#include <stdio.h>
30	greg	2.6	static unsigned b_nsbrked = 0;
31	greg	1.9	static unsigned b_nalloced = 0;
32			static unsigned b_nfreed = 0;
33			static unsigned b_nscrounged = 0;
34	greg	1.14	static unsigned b_ncompacted = 0;
35	greg	1.9	static unsigned m_nalloced = 0;
36			static unsigned m_nfreed = 0;
37			static unsigned m_nwasted = 0;
38			#else
39	greg	1.1	#define NULL 0
40	greg	1.9	#endif
41	greg	1.1
42	greg	2.12	#ifndef ALIGNT
43			#define ALIGNT int /* align type */
44	greg	1.1	#endif
45	greg	2.12	#define BYTES_WORD sizeof(ALIGNT)
46	greg	1.1
47	greg	1.16	#ifndef MAXINCR
48	greg	1.9	#define MAXINCR (1<<16) /* largest sbrk(2) increment */
49	greg	1.1	#endif
50			/* malloc free lists */
51			typedef union m_head {
52			union m_head *next;
53	greg	1.12	struct {
54			short magic;
55			short bucket;
56			} a;
57	greg	2.12	ALIGNT dummy;
58	greg	1.1	} M_HEAD;
59
60	greg	1.12	#define MAGIC 0x1a2 /* magic number for allocated memory */
61
62	greg	1.1	#define FIRSTBUCKET 3
63			#define NBUCKETS 30
64
65			static M_HEAD *free_list[NBUCKETS];
66
67	greg	2.12	static ALIGNT dummy_mem;
68	greg	1.1
69	greg	2.6	static char *memlim[2];
70
71	greg	1.12	#define DUMMYLOC ((char *)&dummy_mem)
72	greg	1.10
73	greg	2.6	#define BADPTR(p) ((p) < memlim[0] \| (p) >= memlim[1])
74
75	greg	1.14	#ifdef MCOMP /* memory compaction routines */
76			static char seedtab[1024]; /* seed for compaction table */
77	greg	1.12
78	greg	1.14	static struct mblk {
79			char ptr; / pointer to memory block */
80			unsigned siz; /* size of memory block */
81			} cptab = {seedtab, sizeof(seedtab)};
82
83			#define mtab(mb) ((struct mblk *)(mb)->ptr)
84			#define mtablen(mb) ((mb)->siz/sizeof(struct mblk))
85
86
87			static int
88			mbcmp(m1, m2) /* compare memory block locations */
89			register struct mblk m1, m2;
90			{
91			/* put empty blocks at end */
92			if (m1->siz == 0)
93			return(m2->siz == 0 ? 0 : 1);
94			if (m2->siz == 0)
95			return(-1);
96			/* otherwise, ascending order */
97			return(m1->ptr - m2->ptr);
98			}
99
100
101			int
102			compactfree() /* compact free lists (moving to table) */
103			{
104			register struct mblk *tp;
105			register int bucket;
106			unsigned n, bsiz, ncomp;
107			/* fill table from free lists */
108			tp = mtab(&cptab); n = mtablen(&cptab);
109			bucket = NBUCKETS-1; bsiz = 1<<(NBUCKETS-1);
110			ncomp = 0;
111			for ( ; ; ) {
112			while (tp->siz) { /* find empty slot */
113			if (--n == 0)
114			goto loopexit;
115			tp++;
116			}
117			while (free_list[bucket] == NULL) { /* find block */
118			if (--bucket < FIRSTBUCKET)
119			goto loopexit;
120			bsiz >>= 1;
121			}
122			tp->ptr = (char *)free_list[bucket];
123			ncomp += (tp->siz = bsiz + sizeof(M_HEAD));
124			free_list[bucket] = free_list[bucket]->next;
125			}
126			loopexit:
127			if (ncomp == 0)
128			return(0); /* nothing new to compact */
129			#ifdef MSTATS
130			b_ncompacted += ncomp;
131			#endif
132			tp = mtab(&cptab); n = mtablen(&cptab); /* sort table */
133			qsort((char *)tp, n, sizeof(struct mblk), mbcmp);
134			ncomp = 0; /* collect blocks */
135			while (--n && tp[1].siz) {
136			if (tp[0].ptr + tp[0].siz == tp[1].ptr) {
137			tp[1].ptr = tp[0].ptr;
138			tp[1].siz += tp[0].siz;
139			ncomp += tp[0].siz;
140			tp[0].siz = 0;
141			}
142			tp++;
143			}
144			return(ncomp);
145			}
146
147
148	greg	1.1	char *
149	greg	1.14	mcompact(np) /* compact free lists to satisfy request */
150			unsigned *np;
151			{
152			struct mblk *tab;
153			unsigned tablen;
154			register struct mblk bp, big;
155
156			for ( ; ; ) {
157			/* compact free lists */
158	greg	2.9	while (compactfree())
159			;
160	greg	1.14	/* find largest block */
161			tab = mtab(&cptab); tablen = mtablen(&cptab);
162			big = tab;
163			bp = tab + tablen;
164			while (--bp > tab)
165			if (bp->siz > big->siz)
166			big = bp;
167			if (big->siz >= np) { / big enough? */
168			*np = big->siz;
169			big->siz = 0; /* remove from table */
170			return(big->ptr); /* return it */
171			}
172	greg	2.7	if (mtablen(big) <= tablen) {
173	greg	1.14	np = 0; / cannot grow table */
174			return(NULL); /* report failure */
175			}
176			/* enlarge table, free old one */
177			mtab(big)[0].ptr = cptab.ptr;
178			mtab(big)[0].siz = cptab.siz;
179			cptab.ptr = big->ptr;
180			cptab.siz = big->siz;
181			big->siz = 0; /* clear and copy */
182	schorsch	2.16	memcpy((char )(mtab(&cptab)+1), (char )tab,
183	greg	1.14	tablen*sizeof(struct mblk));
184	schorsch	2.16	memset((char *)(mtab(&cptab)+tablen+1), '\0',
185	greg	1.14	(mtablen(&cptab)-tablen-1)*sizeof(struct mblk));
186			} /* next round */
187			}
188			#endif /* MCOMP */
189
190
191			char *
192	greg	1.4	mscrounge(np) /* search free lists to satisfy request */
193	greg	1.3	register unsigned *np;
194			{
195			char *p;
196			register int bucket;
197			register unsigned bsiz;
198
199			for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET;
200			bucket < NBUCKETS; bucket++, bsiz <<= 1)
201			if (free_list[bucket] != NULL && bsiz+sizeof(M_HEAD) >= *np) {
202			*np = bsiz+sizeof(M_HEAD);
203			p = (char *)free_list[bucket];
204			free_list[bucket] = free_list[bucket]->next;
205	greg	1.9	#ifdef MSTATS
206			b_nscrounged += *np;
207			#endif
208	greg	1.3	return(p);
209			}
210	greg	1.14	#ifdef MCOMP
211			return(mcompact(np)); /* try compaction */
212			#else
213	greg	1.3	*np = 0;
214			return(NULL);
215	greg	1.14	#endif
216	greg	1.3	}
217
218
219			char *
220	greg	1.1	bmalloc(n) /* allocate a block of n bytes, sans header */
221			register unsigned n;
222			{
223			extern char *sbrk();
224	greg	1.3	static unsigned pagesz = 0;
225			static unsigned amnt;
226	greg	1.1	static char *bpos;
227	greg	1.3	static unsigned nrem;
228			unsigned thisamnt;
229	greg	1.1	register char *p;
230
231			if (pagesz == 0) { /* initialize */
232	greg	1.2	pagesz = amnt = getpagesize();
233	greg	1.1	nrem = (int)sbrk(0); /* page align break */
234			nrem = pagesz - (nrem&(pagesz-1));
235	greg	2.3	bpos = sbrk(nrem);
236	greg	1.1	if ((int)bpos == -1)
237			return(NULL);
238	greg	1.14	#ifdef MSTATS
239			b_nsbrked += nrem;
240			#endif
241	greg	2.4	bpos += nrem & (BYTES_WORD-1); /* align pointer */
242			nrem &= ~(BYTES_WORD-1);
243	greg	2.6	memlim[0] = bpos;
244			memlim[1] = bpos + nrem;
245	greg	1.1	}
246
247			n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align rqst. */
248
249			if (n > nrem) { /* need more core */
250	greg	2.8	tryagain:
251	greg	1.3	if (n > amnt) { /* big chunk */
252			thisamnt = (n+(pagesz-1))&~(pagesz-1);
253			if (thisamnt <= MAXINCR) /* increase amnt */
254			amnt = thisamnt;
255			} else
256			thisamnt = amnt;
257			p = sbrk(thisamnt);
258	greg	1.4	if ((int)p == -1) { /* uh-oh, ENOMEM */
259	greg	2.8	errno = 0; /* call cavalry */
260			if (thisamnt >= n+pagesz) {
261			amnt = pagesz; /* minimize request */
262			goto tryagain;
263			}
264			thisamnt = n;
265			p = mscrounge(&thisamnt); /* search free lists */
266			if (p == NULL) { /* we're really out */
267			errno = ENOMEM;
268	greg	1.3	return(NULL);
269	greg	2.8	}
270	greg	1.3	}
271	greg	1.14	#ifdef MSTATS
272			else b_nsbrked += thisamnt;
273			#endif
274	greg	1.3	if (p != bpos+nrem) { /* not an increment */
275	greg	1.4	bfree(bpos, nrem); /* free what we have */
276	greg	1.1	bpos = p;
277	greg	1.3	nrem = thisamnt;
278	greg	1.4	} else /* otherwise tack on */
279	greg	1.3	nrem += thisamnt;
280	greg	2.6	if (bpos < memlim[0])
281			memlim[0] = bpos;
282			if (bpos + nrem > memlim[1])
283			memlim[1] = bpos + nrem;
284	greg	1.1	}
285			p = bpos;
286			bpos += n; /* advance */
287			nrem -= n;
288	greg	1.13	#ifdef MSTATS
289			b_nalloced += n;
290			#endif
291	greg	1.1	return(p);
292			}
293
294
295			bfree(p, n) /* free n bytes of random memory */
296	greg	1.2	register char *p;
297			register unsigned n;
298	greg	1.1	{
299			register int bucket;
300			register unsigned bsiz;
301	greg	1.9
302	gwlarson	2.11	if (n < 1<<FIRSTBUCKET \|\| p == NULL)
303	greg	1.15	return;
304	greg	1.9	#ifdef MSTATS
305			b_nfreed += n;
306			#endif
307	greg	1.4	/* align pointer */
308	greg	1.6	bsiz = BYTES_WORD - ((unsigned)p&(BYTES_WORD-1));
309	greg	1.4	if (bsiz < BYTES_WORD) {
310			p += bsiz;
311			n -= bsiz;
312	greg	1.1	}
313	greg	2.6	if (p < memlim[0])
314			memlim[0] = p;
315			if (p + n > memlim[1])
316			memlim[1] = p + n;
317	greg	1.4	/* fill big buckets first */
318			for (bucket = NBUCKETS-1, bsiz = 1<<(NBUCKETS-1);
319			bucket >= FIRSTBUCKET; bucket--, bsiz >>= 1)
320			if (n >= bsiz+sizeof(M_HEAD)) {
321			((M_HEAD *)p)->next = free_list[bucket];
322			free_list[bucket] = (M_HEAD *)p;
323			p += bsiz+sizeof(M_HEAD);
324			n -= bsiz+sizeof(M_HEAD);
325			}
326	greg	1.1	}
327
328
329			char *
330			malloc(n) /* allocate n bytes of memory */
331			unsigned n;
332			{
333			register M_HEAD *mp;
334			register int bucket;
335			register unsigned bsiz;
336	greg	1.10	/* don't return NULL on 0 request */
337			if (n == 0)
338			return(DUMMYLOC);
339	greg	1.2	/* find first bucket that fits */
340	greg	1.6	for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET;
341			bucket < NBUCKETS; bucket++, bsiz <<= 1)
342			if (bsiz >= n)
343			break;
344			if (bucket >= NBUCKETS) {
345			errno = EINVAL;
346			return(NULL);
347			}
348	greg	1.4	if (free_list[bucket] == NULL) { /* need more core */
349	greg	1.1	mp = (M_HEAD *)bmalloc(bsiz+sizeof(M_HEAD));
350			if (mp == NULL)
351			return(NULL);
352	greg	1.4	} else { /* got it */
353	greg	1.1	mp = free_list[bucket];
354			free_list[bucket] = mp->next;
355			}
356	greg	1.13	#ifdef MSTATS
357			m_nalloced += bsiz + sizeof(M_HEAD);
358			m_nwasted += bsiz + sizeof(M_HEAD) - n;
359			#endif
360	greg	1.12	mp->a.magic = MAGIC; /* tag block */
361			mp->a.bucket = bucket;
362	greg	1.1	return((char *)(mp+1));
363			}
364
365
366			char *
367			realloc(op, n) /* reallocate memory using malloc() */
368	greg	1.6	register char *op;
369	greg	1.1	unsigned n;
370			{
371	greg	1.6	char *p;
372	greg	1.1	register unsigned on;
373	greg	1.6	/* get old size */
374	greg	2.6	if (op != DUMMYLOC && !BADPTR(op) &&
375			((M_HEAD *)op-1)->a.magic == MAGIC)
376	greg	1.12	on = 1 << ((M_HEAD *)op-1)->a.bucket;
377	greg	1.5	else
378			on = 0;
379	greg	1.6	if (n <= on && (n > on>>1 \|\| on == 1<<FIRSTBUCKET))
380	greg	1.5	return(op); /* same bucket */
381	greg	1.13	if ((p = malloc(n)) == NULL)
382	greg	2.5	return(n<=on ? op : NULL);
383	greg	1.13	if (on) {
384	schorsch	2.16	memcpy(p, op, n>on ? on : n);
385	greg	1.13	free(op);
386			}
387	greg	1.1	return(p);
388			}
389
390
391			free(p) /* free memory allocated by malloc */
392			char *p;
393			{
394			register M_HEAD *mp;
395			register int bucket;
396
397	greg	2.6	if (p == DUMMYLOC)
398	greg	1.13	return(1);
399	greg	2.6	if (BADPTR(p))
400			goto invalid;
401	greg	1.1	mp = (M_HEAD *)p - 1;
402	greg	1.12	if (mp->a.magic != MAGIC) /* sanity check */
403	greg	2.6	goto invalid;
404	greg	1.12	bucket = mp->a.bucket;
405	greg	2.2	if (bucket < FIRSTBUCKET \| bucket >= NBUCKETS)
406	greg	2.6	goto invalid;
407	greg	1.1	mp->next = free_list[bucket];
408			free_list[bucket] = mp;
409	greg	1.9	#ifdef MSTATS
410			m_nfreed += (1 << bucket) + sizeof(M_HEAD);
411			#endif
412	greg	1.13	return(1);
413	greg	2.6	invalid:
414			errno = EINVAL;
415			return(0);
416	greg	1.1	}
417	greg	1.9
418
419			#ifdef MSTATS
420			printmemstats(fp) /* print memory statistics to stream */
421			FILE *fp;
422			{
423			register int i;
424			int n;
425			register M_HEAD *mp;
426			unsigned int total = 0;
427
428			fprintf(fp, "Memory statistics:\n");
429	greg	1.14	fprintf(fp, "\tbmalloc: %d bytes from sbrk\n", b_nsbrked);
430	greg	1.9	fprintf(fp, "\tbmalloc: %d bytes allocated\n", b_nalloced);
431			fprintf(fp, "\tbmalloc: %d bytes freed\n", b_nfreed);
432			fprintf(fp, "\tbmalloc: %d bytes scrounged\n", b_nscrounged);
433	greg	1.14	fprintf(fp, "\tbmalloc: %d bytes compacted\n", b_ncompacted);
434	greg	1.9	fprintf(fp, "\tmalloc: %d bytes allocated\n", m_nalloced);
435			fprintf(fp, "\tmalloc: %d bytes wasted (%.1f%%)\n", m_nwasted,
436			100.0*m_nwasted/m_nalloced);
437			fprintf(fp, "\tmalloc: %d bytes freed\n", m_nfreed);
438			for (i = NBUCKETS-1; i >= FIRSTBUCKET; i--) {
439			n = 0;
440			for (mp = free_list[i]; mp != NULL; mp = mp->next)
441			n++;
442			if (n) {
443			fprintf(fp, "\t%d * %u\n", n, 1<<i);
444			total += n * ((1<<i) + sizeof(M_HEAD));
445			}
446			}
447			fprintf(fp, "\t %u total bytes in free list\n", total);
448			}
449	greg	1.1	#endif