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/* Copyright (c) 1991 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* Fast malloc for memory hogs and VM environments. |
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* Performs a minimum of searching through free lists. |
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* malloc(), realloc() and free() use buckets |
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* containing blocks in powers of two, similar to CIT routines. |
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* bfree() puts memory from any source into malloc free lists. |
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* bmalloc() doesn't keep track of free lists -- it's usually |
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* just a buffered call to sbrk(2). However, bmalloc will |
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* call mscrounge() if sbrk fails. |
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* mscrounge() returns whatever free memory it can find to satisfy the |
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* request along with the number of bytes (modified). |
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* mcompact() takes the same arguments as mscrounge() (and is in fact |
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* called by mscrounge() under dire circumstances), but it uses |
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* memory compaction to return a larger block. (MCOMP) |
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* |
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* Greg Ward Lawrence Berkeley Laboratory |
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*/ |
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|
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#include <errno.h> |
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|
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#ifdef MSTATS |
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#include <stdio.h> |
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static unsigned b_nsbrked = 0; |
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static unsigned b_nalloced = 0; |
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static unsigned b_nfreed = 0; |
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static unsigned b_nscrounged = 0; |
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static unsigned b_ncompacted = 0; |
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static unsigned m_nalloced = 0; |
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static unsigned m_nfreed = 0; |
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static unsigned m_nwasted = 0; |
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#else |
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#define NULL 0 |
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#endif |
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|
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#ifndef ALIGN |
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#define ALIGN int /* align type */ |
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#endif |
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#define BYTES_WORD sizeof(ALIGN) |
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|
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#ifndef MAXINCR |
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#define MAXINCR (1<<16) /* largest sbrk(2) increment */ |
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#endif |
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/* malloc free lists */ |
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typedef union m_head { |
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union m_head *next; |
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struct { |
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short magic; |
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short bucket; |
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} a; |
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ALIGN dummy; |
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} M_HEAD; |
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|
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#define MAGIC 0x1a2 /* magic number for allocated memory */ |
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|
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#define FIRSTBUCKET 3 |
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#define NBUCKETS 30 |
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|
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static M_HEAD *free_list[NBUCKETS]; |
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|
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static ALIGN dummy_mem; |
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|
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#define DUMMYLOC ((char *)&dummy_mem) |
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|
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#ifdef MCOMP /* memory compaction routines */ |
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static char seedtab[1024]; /* seed for compaction table */ |
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|
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static struct mblk { |
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char *ptr; /* pointer to memory block */ |
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unsigned siz; /* size of memory block */ |
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} cptab = {seedtab, sizeof(seedtab)}; |
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|
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#define mtab(mb) ((struct mblk *)(mb)->ptr) |
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#define mtablen(mb) ((mb)->siz/sizeof(struct mblk)) |
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|
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|
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static int |
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mbcmp(m1, m2) /* compare memory block locations */ |
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register struct mblk *m1, *m2; |
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{ |
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/* put empty blocks at end */ |
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if (m1->siz == 0) |
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return(m2->siz == 0 ? 0 : 1); |
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if (m2->siz == 0) |
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return(-1); |
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/* otherwise, ascending order */ |
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return(m1->ptr - m2->ptr); |
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} |
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|
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|
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int |
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compactfree() /* compact free lists (moving to table) */ |
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{ |
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register struct mblk *tp; |
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register int bucket; |
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unsigned n, bsiz, ncomp; |
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/* fill table from free lists */ |
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tp = mtab(&cptab); n = mtablen(&cptab); |
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bucket = NBUCKETS-1; bsiz = 1<<(NBUCKETS-1); |
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ncomp = 0; |
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for ( ; ; ) { |
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while (tp->siz) { /* find empty slot */ |
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if (--n == 0) |
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goto loopexit; |
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tp++; |
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} |
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while (free_list[bucket] == NULL) { /* find block */ |
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if (--bucket < FIRSTBUCKET) |
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goto loopexit; |
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bsiz >>= 1; |
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} |
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tp->ptr = (char *)free_list[bucket]; |
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ncomp += (tp->siz = bsiz + sizeof(M_HEAD)); |
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free_list[bucket] = free_list[bucket]->next; |
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} |
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loopexit: |
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if (ncomp == 0) |
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return(0); /* nothing new to compact */ |
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#ifdef MSTATS |
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b_ncompacted += ncomp; |
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#endif |
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tp = mtab(&cptab); n = mtablen(&cptab); /* sort table */ |
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qsort((char *)tp, n, sizeof(struct mblk), mbcmp); |
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ncomp = 0; /* collect blocks */ |
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while (--n && tp[1].siz) { |
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if (tp[0].ptr + tp[0].siz == tp[1].ptr) { |
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tp[1].ptr = tp[0].ptr; |
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tp[1].siz += tp[0].siz; |
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ncomp += tp[0].siz; |
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tp[0].siz = 0; |
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} |
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tp++; |
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} |
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return(ncomp); |
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} |
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|
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|
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char * |
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mcompact(np) /* compact free lists to satisfy request */ |
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unsigned *np; |
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{ |
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struct mblk *tab; |
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unsigned tablen; |
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register struct mblk *bp, *big; |
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|
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for ( ; ; ) { |
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/* compact free lists */ |
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compactfree(); |
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/* find largest block */ |
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tab = mtab(&cptab); tablen = mtablen(&cptab); |
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big = tab; |
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bp = tab + tablen; |
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while (--bp > tab) |
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if (bp->siz > big->siz) |
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big = bp; |
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if (big->siz >= *np) { /* big enough? */ |
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*np = big->siz; |
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big->siz = 0; /* remove from table */ |
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return(big->ptr); /* return it */ |
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} |
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if (mtablen(big) < tablen+1) { |
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*np = 0; /* cannot grow table */ |
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return(NULL); /* report failure */ |
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} |
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/* enlarge table, free old one */ |
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mtab(big)[0].ptr = cptab.ptr; |
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mtab(big)[0].siz = cptab.siz; |
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cptab.ptr = big->ptr; |
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cptab.siz = big->siz; |
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big->siz = 0; /* clear and copy */ |
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#ifdef BSD |
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bcopy((char *)tab, (char *)(mtab(&cptab)+1), |
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tablen*sizeof(struct mblk)); |
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bzero((char *)(mtab(&cptab)+tablen+1), |
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(mtablen(&cptab)-tablen-1)*sizeof(struct mblk)); |
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#else |
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(void)memcpy((char *)(mtab(&cptab)+1), (char *)tab, |
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tablen*sizeof(struct mblk)); |
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memset((char *)(mtab(&cptab)+tablen+1), 0, |
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(mtablen(&cptab)-tablen-1)*sizeof(struct mblk)); |
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#endif |
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} /* next round */ |
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} |
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#endif /* MCOMP */ |
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|
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|
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char * |
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mscrounge(np) /* search free lists to satisfy request */ |
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register unsigned *np; |
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{ |
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char *p; |
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register int bucket; |
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register unsigned bsiz; |
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|
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for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET; |
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bucket < NBUCKETS; bucket++, bsiz <<= 1) |
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if (free_list[bucket] != NULL && bsiz+sizeof(M_HEAD) >= *np) { |
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*np = bsiz+sizeof(M_HEAD); |
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p = (char *)free_list[bucket]; |
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free_list[bucket] = free_list[bucket]->next; |
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#ifdef MSTATS |
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b_nscrounged += *np; |
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#endif |
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return(p); |
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} |
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#ifdef MCOMP |
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return(mcompact(np)); /* try compaction */ |
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#else |
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*np = 0; |
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return(NULL); |
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#endif |
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} |
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|
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|
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char * |
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bmalloc(n) /* allocate a block of n bytes, sans header */ |
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register unsigned n; |
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{ |
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extern char *sbrk(); |
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static unsigned pagesz = 0; |
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static unsigned amnt; |
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static char *bpos; |
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static unsigned nrem; |
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unsigned thisamnt; |
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register char *p; |
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|
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if (pagesz == 0) { /* initialize */ |
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pagesz = amnt = getpagesize(); |
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nrem = (int)sbrk(0); /* page align break */ |
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nrem = pagesz - (nrem&(pagesz-1)); |
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bpos = sbrk(nrem); /* word aligned! */ |
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if ((int)bpos == -1) |
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return(NULL); |
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#ifdef MSTATS |
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b_nsbrked += nrem; |
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#endif |
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} |
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|
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n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align rqst. */ |
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|
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if (n > nrem) { /* need more core */ |
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if (n > amnt) { /* big chunk */ |
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thisamnt = (n+(pagesz-1))&~(pagesz-1); |
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if (thisamnt <= MAXINCR) /* increase amnt */ |
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amnt = thisamnt; |
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} else |
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thisamnt = amnt; |
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p = sbrk(thisamnt); |
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if ((int)p == -1) { /* uh-oh, ENOMEM */ |
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thisamnt = n; /* search free lists */ |
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p = mscrounge(&thisamnt); |
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if (p == NULL) /* we're really out */ |
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return(NULL); |
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} |
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#ifdef MSTATS |
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else b_nsbrked += thisamnt; |
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#endif |
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if (p != bpos+nrem) { /* not an increment */ |
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bfree(bpos, nrem); /* free what we have */ |
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bpos = p; |
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nrem = thisamnt; |
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} else /* otherwise tack on */ |
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nrem += thisamnt; |
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} |
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p = bpos; |
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bpos += n; /* advance */ |
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nrem -= n; |
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#ifdef MSTATS |
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b_nalloced += n; |
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#endif |
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return(p); |
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} |
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|
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|
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bfree(p, n) /* free n bytes of random memory */ |
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register char *p; |
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register unsigned n; |
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{ |
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register int bucket; |
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register unsigned bsiz; |
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|
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if (n < 1<<FIRSTBUCKET) |
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return; |
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#ifdef MSTATS |
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b_nfreed += n; |
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#endif |
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/* align pointer */ |
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bsiz = BYTES_WORD - ((unsigned)p&(BYTES_WORD-1)); |
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if (bsiz < BYTES_WORD) { |
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p += bsiz; |
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n -= bsiz; |
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} |
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/* fill big buckets first */ |
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for (bucket = NBUCKETS-1, bsiz = 1<<(NBUCKETS-1); |
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bucket >= FIRSTBUCKET; bucket--, bsiz >>= 1) |
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if (n >= bsiz+sizeof(M_HEAD)) { |
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((M_HEAD *)p)->next = free_list[bucket]; |
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free_list[bucket] = (M_HEAD *)p; |
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p += bsiz+sizeof(M_HEAD); |
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n -= bsiz+sizeof(M_HEAD); |
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} |
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} |
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|
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|
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char * |
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malloc(n) /* allocate n bytes of memory */ |
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unsigned n; |
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{ |
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extern int errno; |
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register M_HEAD *mp; |
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register int bucket; |
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register unsigned bsiz; |
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/* don't return NULL on 0 request */ |
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if (n == 0) |
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return(DUMMYLOC); |
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/* find first bucket that fits */ |
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for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET; |
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bucket < NBUCKETS; bucket++, bsiz <<= 1) |
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if (bsiz >= n) |
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break; |
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if (bucket >= NBUCKETS) { |
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errno = EINVAL; |
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return(NULL); |
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} |
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if (free_list[bucket] == NULL) { /* need more core */ |
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mp = (M_HEAD *)bmalloc(bsiz+sizeof(M_HEAD)); |
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if (mp == NULL) |
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return(NULL); |
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} else { /* got it */ |
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mp = free_list[bucket]; |
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free_list[bucket] = mp->next; |
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} |
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#ifdef MSTATS |
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m_nalloced += bsiz + sizeof(M_HEAD); |
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m_nwasted += bsiz + sizeof(M_HEAD) - n; |
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#endif |
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mp->a.magic = MAGIC; /* tag block */ |
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mp->a.bucket = bucket; |
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return((char *)(mp+1)); |
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} |
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|
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|
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char * |
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realloc(op, n) /* reallocate memory using malloc() */ |
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register char *op; |
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unsigned n; |
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{ |
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char *p; |
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register unsigned on; |
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/* get old size */ |
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if (op != NULL && op != DUMMYLOC && ((M_HEAD *)op-1)->a.magic == MAGIC) |
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on = 1 << ((M_HEAD *)op-1)->a.bucket; |
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else |
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on = 0; |
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if (n <= on && (n > on>>1 || on == 1<<FIRSTBUCKET)) |
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return(op); /* same bucket */ |
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if ((p = malloc(n)) == NULL) |
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return(NULL); |
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if (on) { |
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#ifdef BSD |
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bcopy(op, p, n>on ? on : n); |
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#else |
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(void)memcpy(p, op, n>on ? on : n); |
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#endif |
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free(op); |
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} |
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return(p); |
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} |
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|
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|
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free(p) /* free memory allocated by malloc */ |
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char *p; |
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{ |
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register M_HEAD *mp; |
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register int bucket; |
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|
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if (p == NULL || p == DUMMYLOC) |
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return(1); |
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mp = (M_HEAD *)p - 1; |
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if (mp->a.magic != MAGIC) /* sanity check */ |
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return(0); |
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bucket = mp->a.bucket; |
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mp->next = free_list[bucket]; |
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free_list[bucket] = mp; |
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#ifdef MSTATS |
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m_nfreed += (1 << bucket) + sizeof(M_HEAD); |
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#endif |
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return(1); |
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} |
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|
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|
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#ifdef MSTATS |
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printmemstats(fp) /* print memory statistics to stream */ |
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FILE *fp; |
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{ |
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register int i; |
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int n; |
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register M_HEAD *mp; |
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unsigned int total = 0; |
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|
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fprintf(fp, "Memory statistics:\n"); |
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fprintf(fp, "\tbmalloc: %d bytes from sbrk\n", b_nsbrked); |
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fprintf(fp, "\tbmalloc: %d bytes allocated\n", b_nalloced); |
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fprintf(fp, "\tbmalloc: %d bytes freed\n", b_nfreed); |
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fprintf(fp, "\tbmalloc: %d bytes scrounged\n", b_nscrounged); |
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fprintf(fp, "\tbmalloc: %d bytes compacted\n", b_ncompacted); |
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fprintf(fp, "\tmalloc: %d bytes allocated\n", m_nalloced); |
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fprintf(fp, "\tmalloc: %d bytes wasted (%.1f%%)\n", m_nwasted, |
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100.0*m_nwasted/m_nalloced); |
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fprintf(fp, "\tmalloc: %d bytes freed\n", m_nfreed); |
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for (i = NBUCKETS-1; i >= FIRSTBUCKET; i--) { |
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n = 0; |
| 418 |
for (mp = free_list[i]; mp != NULL; mp = mp->next) |
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n++; |
| 420 |
if (n) { |
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fprintf(fp, "\t%d * %u\n", n, 1<<i); |
| 422 |
total += n * ((1<<i) + sizeof(M_HEAD)); |
| 423 |
} |
| 424 |
} |
| 425 |
fprintf(fp, "\t %u total bytes in free list\n", total); |
| 426 |
} |
| 427 |
#endif |
